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Essential
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IGCSE
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Gareth
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Richard
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the
Contents
Introduction
Unit
1
1
Characteristics
of
living
Characteristics
1.2
Classication
Features
of
of
Vertebrates
1.5
Invertebrates
1.6
Ferns
1.7
Dichotomous
Starvation
7.5
Digestion
78
7.6
Teeth
80
living
organisms
7.7
Mouth,
7.8
Small
intestine
and
absorption
84
7.9
Large
intestine
and
intestinal
86
Unit
2
2.1
oesophagus
Structure
Different
2.4
Levels
owering
plants
keys
8
Plant
transport
Transport
Water
8.3
Transpiration
94
of
cells
8.4
Translocation
96
Practice
98
types
of
of
cell
organisation
Movement
Osmosis
Active
in
in
and
plant
out
of
cells
and
animal
cells
transport
Transport
24
9.1
Circulation
100
26
9.2
The
102
Chemical
9.3
Heart
9.4
Blood
9.5
Coronary
9.6
Blood
9.7
Blood
9.8
Lymph
heart
and
molecules
106
heart
disease
(CHD)
108
110
32
in
defence
112
and
for
tissue
uid
114
questions
116
10
Diseases
and
immunity
118
38
biological
molecules
questions
10.1
Disease
10.2
Defence
118
10.3
Aspects
10.4
Controlling
40
against
disease
120
Structure
5.2
Factors
and
action
of
enzymes
enzyme
Practice
Plant
and
pH
6.1
Photosynthesis
6.2
What
6.3
Products
of
Unit
11
Gas
spread
122
of
disease
questions
exchange
124
126
in
humans
128
11.1
The
gas
11.2
Gas
exchange
exchange
11.3
Breathing
11.4
Rate
system
128
needed
132
52
photosynthesis?
photosynthesis
photosynthesis
and
Practice
54
54
for
130
50
nutrition
of
46
the
48
questions
is
immunity
action:
temperature
Enzymes
Practice
46
affecting
of
44
Enzymes
Rate
104
42
5.1
6.4
exercise
vessels
38
DNA
Practice
6
100
36
molecules
tests
humans
28
Unit
Biological
in
34
questions
Biological
questions
9
Practice
Unit
92
22
questions
Practice
5.3
90
20
30
5
systems
uptake
18
Osmosis
Unit
90
8.2
3.2
4.3
88
8.1
28
4.2
questions
16
Diffusion
4.1
disease
14
3.1
4
82
12
organelles
Practice
Unit
stomach
10
Unit
3.4
and
18
2.3
3.3
76
8
Cells
Cell
3
74
deciency
6
questions
2.2
Unit
needs
nutrient
2
Unit
Practice
and
4
Practice
and
energy
2
organisms
1.4
Balancing
7.4
classication
organisms
1.1
1.3
and
7.3
Unit
12
of
breathing
134
136
Respiration
138
56
12.1
Aerobic
12.2
Anaerobic
respiration
138
58
respiration
140
60
Practice
production
depth
questions
questions
142
6.5
Glasshouse
62
6.6
Leaves
6.7
Mineral
requirements
66
13.1
Excretion
144
Practice
questions
68
13.2
Kidney
structure
146
13.3
Kidney
function
148
13.4
Kidney
Unit
Unit
7
7.1
Animal
A
13
Excretion
nutrition
balanced
diet
70
dialysis
Sources
of
nutrients
and
kidney
transplants
150
70
Practice
7.2
144
64
questions
152
72
iii
Contents
Unit
14
Coordination
and
control
14.1
Nervous
14.2
Neurones
14.3
Synapses
14.4
Sense
14.5
The
14.6
Hormones
14.7
Controlling
conditions
14.8
Controlling
body
14.9
Tropic
and
and
in
response
humans
reex
arcs
drugs
organs
eye
154
Unit
the
body
Unit
15
18.1
Variation
232
18.2
Mutations
234
158
18.3
Adaptive
236
160
18.4
Natural
162
18.5
Selective
15.2
Heroin
15.3
Alcohol
questions
and
Practice
Smoking
the
and
misuse
of
health
Asexual
16.2
Flower
16.3
Pollination
16.4
Fertilisation
16.5
The
male
16.6
The
female
16.7
Fertilisation
16.8
Pregnancy
and
sexual
reproduction
and
seed
formation
system
Pyramids
19.3
Shortening
19.4
Nutrient
174
19.5
The
176
19.6
Populations,
178
19.7
Human
Methods
reproductive
and
environment
244
ow
244
of
numbers
and
biomass
246
the
food
chain
248
Control
care
of
of
Sexually
system
implantation
nitrogen
250
cycle
252
communities
and
254
populations
Practice
256
questions
258
20
Biotechnology
and
genetic
engineering
260
184
20.1
Microorganisms
186
20.2
Enzymes
188
20.3
Fermenters
264
190
20.4
Genetic
engineering
266
Practice
questions
268
Human
inuences
and
and
biotechnology
biotechnology
260
262
194
21
on
ecosystems
270
196
and
birth
21.1
Food
21.2
Habitat
supply
270
21.3
Pollution
274
21.4
Water
276
21.5
The
21.6
Acid
21.7
Sustainable
21.8
Sewage
21.9
Endangered
destruction
272
200
202
cycle
birth
greenhouse
effect
278
206
fertility
transmitted
pollution
204
control
rain
280
208
infections
(STIs)
questions
resources
282
210
treatment
and
recycling
284
212
Inheritance
species
286
214
21.10
genes
and
Conservation
288
Practice
290
Chromosomes,
17.2
Protein
17.3
Mitosis
17.4
Meiosis
17.5
Inheritance
17.6
Monohybrid
17.7
Codominance
226
17.8
Sex
228
synthesis
and
genes
inheritance
linkage
questions
DNA
214
17.1
Practice
cycles
198
menstrual
Practice
iv
their
ecosystems
192
hormones
The
17
and
Energy
184
reproductive
Ante-natal
16.12
Unit
242
182
structure
16.11
16.14
Organisms
19.2
Unit
16.13
questions
19.1
180
Reproduction
Sex
19
drugs
questions
16.1
16.9
240
166
Unit
16.10
238
breeding
172
sport
Practice
16
features
selection
174
Drugs
Unit
232
170
Drugs
in
selection
168
responses
15.1
15.4
temperature
and
154
164
in
Variation
156
Unit
Practice
18
questions
216
Alternative
218
Glossary
298
220
Index
307
222
224
230
to
practical
paper
292
Introduction
This
book
is
designed
specically
for
Cambridge
®
IGCSE
Biology
involved
in
planning
match
all
to
0610.
Experienced
aspects
ensure
possible
to
of
that
the
the
the
teachers
book,
have
including
content
gives
been
STUD
Y
the
Expe
rienc
ed
best
you
syllabus.
to
Using
this
book
will
ensure
that
you
are
for
studies
beyond
the
IGCSE
level
in
avoid
pure
to
sciences,
in
vocational
below
and
are
applied
courses.
sciences
The
designed
effective
as
to
make
the
learning
book
as
you
the
at
and
end
of
the
will
should
tnemelppuS
Some
be
are
able
the
only
if
supplement
clearly
start
tell
on
or
how
ques
tions
.
interesting
KEY
of
you
to
each
do
will
you
the
at
the
the
as
spread
is
are
not
questions
you
to
test
included
your
in
every
understanding
topic
of
and
the
syllabus.
At
needed
but
the
interest
are
goes
in
the
covered
end
of
in
in
are
the
each
topic.
unit
there
questions
is
a
double
written
by
page
the
of
authors.
the
At
throughout
from
any
that
KNOW?
examination
most
learn
QUESTIONS
examination-style
These
the
to
spread.
SUMMARY
these
work
YOU
things
taking
and
allow
beyond
summarise
important
be
are
paper
labelled,
in
POINTS
These
what
These
content
your
errors
advi
ce
spread.
outcomes
needed
DID
give
how
outlined
OUTCOMES
are
spread
a
of
comm
on
useful
tack
le
science-dependent
on
possible:
These
•
in
features
LEARNING
•
or
teach
ers
sugg
estio
ns
well
give
prepared
TIP…
detailed
the
end
of
the
book
Alternative
to
practical
you
will
also
nd:
found
book
to
stimulate
paper
biology.
A
glossary
of
many
Assessment
important
terms
used
in
the
book.
structure
PRACTICAL
These
show
work.
The
you
do
End
of
at
Unit
opportunities
results
not
studying
the
are
actually
included
tackle
the
for
to
Paper
1:
Multiple
Choice
(Core)
Paper
2:
Multiple
Choice
(Supplement)
Paper
3:
Theory
(Core)
Paper
4:
Theory
(Supplement)
Paper
5:
Practical
Paper
6:
Alternative
practical
help
you
experiment
if
or
are
home.
answers
are
provided
at
Test
to
Practical
www.oxfordsecondary.com/
essential-biology-answers
1
1
Characteristics
of
living
1.1
and
classication
organisms
Characteristics
of
living
organisms
Biology
LEARNING
is
classied
•
List
the
living
study
characteristics
of
animals,
into
ve
Describe
plants,
the
characteristics
living
things
fungi,
groups
or
living
called
organisms,
which
are
protoctists
kingdoms:
and
prokaryotes
(bacteria)
are
seven
characteristics
of
living
organisms.
These
of
characteristics
living
of
major
organisms
There
•
the
OUTCOMES
are
often
described
as
life
processes:
organisms
nutrition,
and
respiration,
movement,
growth,
excretion,
sensitivity
reproduction.
Nutrition
Nutrition
needed
is
the
for
growth,
compounds
proteins
energy
nutrition
for
from
complex
plants
or
taking
in
All
Respi
ratio
n
energy
cells
no t
in
is
the
from
in
the
all
relea
se
food
the
body
.
breath
ing,
the
other
food
as
gills
in
which
that
livin
g
It
is
living
involves
make
to
their
is
called
and
not
to
as
make
own
gain
used
then
substances
are
carbohydrates,
ions).
to
turn
convert
cellulose
and
in
which
carbon
these
the
dioxide
simple
proteins.
They
sugars
need
proteins.
food
like
energy
ingestion.
then
plants,
and
and
The
assimilated
digested
organisms
chemical
nutrients,
needed
such
for
respiration
so
they
by
nutrients.
have
food
cells
absorbed
is
is
The
to
eat
digested,
for
growth
egested
in
process
of
absorbed
and
repair.
faeces.
respire
reactions
as
glucose,
respiration
involving
to
because
that
to
they
occur
release
happen.
all
in
need
cells
energy.
This
is
the
to
energy.
break
Oxygen
word
Respiration
down
is
usually
equation
for
oxygen:
whic
h
orga
ns,
+
oxygen
→
carbon
dioxide
+
water
+
energy
released
such
Living
or
soil
animals
is
blood
glucose
happ
ens
the
mineral
and
Plants
and
Nutrients
(like
photosynthesis,
absorbed
such
energy
repair.
complex
(like
involves
sugars.
provide
and
and
simple
compounds,
cannot
to
Respiration
TIP
happ
ens
large
or
is
simple
from
food
bears.
Food
of
into
ions
be
plants
sunlight
into
into
STUD
Y
green
water
Animals
provide
in
of
development
may
vitamins)
and
mineral
Salmon
that
and
Nutrition
obtaining
things
use
this
energy
for
movement,
growth,
repair
and
lung
s.
reproduction.
Movement
Organisms
move
areas
change
or
Plants
soil
2
move
and
move
to
to
themselves
slowly
their
face
when
leaves
the
or
move
parts
of
themselves
into
new
position.
and
Sun
so
they
stems
they
grow.
move
can
Their
up
roots
move
towards
absorb
as
the
much
down
light.
light
as
into
Leaves
the
can
possible.
Most
animals
obtain
their
animals
able
to
are
able
food
remain
move
or
to
xed
parts,
to
move
avoid
to
one
such
their
being
place
as
the
whole
bodies.
caught
by
on
move
predators.
throughout
tentacles
They
their
a
sea
to
Some
lives,
but
they
are
anemone.
Growth
Growth
is
increase
a
in
complex
permanent
cell
increase
number
,
chemicals,
cell
such
as
size
in
or
size
of
both.
proteins,
an
It
organism.
always
which
is
This
involves
why
the
involves
making
dry
mass
an
more
increases.
Sea
Plants
carry
when
they
on
growing
reach
a
throughout
certain
their
lives.
Animals
stop
anemone.
growing
size.
Excretion
All
living
result
of
occur
in
organisms
produce
metabolism.
an
toxic
(poisonous)
Metabolism
organism.
Respiration
is
is
a
all
the
major
waste
substances
chemical
part
of
reactions
as
a
STUD
Y
TIP
that
Excreti
on is
metabolism.
meta
bolic
Excretion
is
the
removal
of
these
waste
materials
and
substances
of
requirements
from
the
body.
Plants
store
waste
food
which
their
leaves,
so
the
waste
chemicals
are
removed
when
the
off.
Animals
breathe
out
carbon
dioxide;
other
waste
substances
the
body
in
the
gut
digest
ed.
confu
se
leave
the
leaves
being
fall
has
substances
throug
h
in
remov
al
of
wast
e. Eges
tion
in
is
excess
the
the
urine.
passe
d
withou
t
Do
two
not
term
s.
Sensitivity
Living
organisms
external
Sensitivity
Plants
light.
is
the
respond
The
Animals
touch,
are
able
environments.
ability
to
owers
have
to
to
detect
change
detect
movement
of
some
sensory
pressure
A
and
of
and
chemicals
sense
this
these
the
plants
cells
or
like
in
Sun
the
changes
a
stimuli
open
sense
is
by
in
and
for
air
in
internal
(plural:
their
morning
organs
and
their
respond
moving
the
in
stimulus
to
leaves
and
detecting
and
stimuli).
them.
to
close
light,
face
at
the
KEY
POINTS
night.
sound,
food.
The
mnemonic,
can
help
seven
you
‘Mrs
Gren’
remember
characteristics
of
the
living
organisms:
Reproduction
Movement
Organisms
reproduce
to
make
new
individuals.
Asexual
to
involves
each
one
other
organisms
next
parent
and
to
the
producing
generation.
each
giving
other
or
to
The
rise
parent.
to
Sexual
gametes
offspring
their
offspring
(sex
are
often
reproduction
cells)
show
that
which
variation.
fuse
They
identical
involves
to
give
are
not
parent
to
the
identical
to
parents.
Respiration
reactions
in
A
visitor
outer
lands
on
Earth.
The
rst
thing
that
is
is
a
in
to
is
a
motor
car
passing
Give
two
reasons
why
the
b
Give
two
reasons
why
you
visitor
thinks
that
the
car
is
think
that
the
visitor
is
wrong.
waste
cells
out
and
ways
a
in
animals
then
describe
which
feed,
b
are
two
how
groups
plants
of
living
differ
organisms.
from
animals
the
to
detect
permanent
and
grow,
d
use
their
of
dry
results
new
is
the
mass.
in
the
individuals.
removal
chemicals
during
Nutrition
food
c
able
made
of
in
the
metabolism.
Find
in
they:
move,
energy
alive.
Excretion
and
chemical
by.
a
Plants
place.
it
formation
2
or
stimuli.
size
Reproduction
sees
organism
release
being
respond
Growth
space
involves
that
Sensitivity
QUESTIONS
from
an
position
cells.
increase
1
its
to
two
rise
change
and
SUMMARY
causes
reproduction
for
involves
energy
the
and
use
of
growth.
senses.
3
1.2
Classication
We
LEARNING
classify
(see
•
Dene
the
term
T
opic
kingdom
binomial
1.1)
tnemelppuS
kingdom
Describe
the
importance
to
rst
groups.
all
is
some
plants
smallest
similar
are
subdivided
The
the
largest
grouping
species.
features.
green
into
is
and
For
carry
groups
The
is
the
kingdom
organisms
example,
out
known
within
the
photosynthesis.
as
phyla
in
a
plant
Each
(singular:
we
must
explain
how
organisms
are
phylum).
named.
evolution
The
binomial
Meerkat,
suricate
that
in
lives
confusion,
system
A
and
can
within
A
is
also
the
genus
one
other
The
Sun
group
a
species
binomial
in
is
The
as
that
to
a
names
look
give
the
system
name
type
To
of
mongoose
avoid
using
alike.
the
They
offspring
is
are
used
by
rst
name
name
that
should
that
Some
case
genus
the
trivial
species
other.
is
that
names:
the
trivial
of
each
species,
scientic
for
Africa.
binomial
names’).
together
two
name
group
with
names
southern
live
which
in
are
the
fertile
together.
given
genus.
is
given
‘two
are
in
individuals
breed
breed
is
are
of
angel
Desert
means
and
second
interbreed
only
a
species
the
and
Kalahari
organisms
habitat
Each
and
the
system
(binomial
species
same
A
into
the
of
But
classication
and
share
kingdom,
system
•
organisms
OUTCOMES
are
with
never
closely
genera
is
for
the
applies
be
to
used
related,
(plural
meerkats.
of
genus
one
on
but
do
genus)
This
may
species
its
own.
not
consist
be
of
because
extinct.
biologists
all
over
the
world
as
it
is
meerkat.
an
international
language
for
naming
organisms.
The
table
has
some
examples.
Suricata
human
Homo
cholera
tree
oyster
white
pelican,
Pelecanus
The
sorting
as
They
have
whereas
philippensis
4
along
follow
the
a
of
of
and
sapiens
digitata
cholerae
Plasmodium
Pleurotus
falciparum
ostreatus
classication
the
vast
at
the
between
same
similar
its
is
the
have
into
groups
looked
at
is
the
and
anatomy
appearance
of
of
living
an
organism,
structure.
may
instance,
known
organisms
traditionally
organisms.
outward
internal
For
pattern
living
between
organisms
lines.
of
morphology
Morphology
is
array
Scientists
similarities
anatomy
Similarities
Pelecanus
out
looked
organisms.
pelican,
parasite
classication.
differences
(grey)
Vibrio
mushroom
importance
known
spot-billed
suricatta
onocrotalus
The
The
name
Adansonia
bacterium
malarial
great
scientic
meerkat
baobab
The
name
as
occur
the
the
because
limb
bones
they
of
pentadactyl
have
evolved
mammals
limb
tnemelppuS
common
tnemelppuS
Front
Each
and
on
limb
has
ve
this
bones
one
digits
fossil
record,
bases
in
of
limb
species
bone
classication.
also
of
study
the
mammal
(blue),
numbered
scientists
but
their
three
(green,
method
relationships,
of
upper
two
1–5).
T
o
not
structure
the
of
shown
limb
However
,
obtain
only
are
lower
we
evidence
of
proteins
Figure
cannot
from
anatomy
their
in
bones
always
STUD
Y
the
Rem
embe
r
and
nam
e
the
sequence
are
DNA.
methods
(see
now
been
involve
T
opic
4.1)
Haemoglobin
example,
is
coded
for
the
the
more
studying
and
is
a
human
by
same
the
the
bases,
These
that
protein
in
so
sequences
to
of
of
bases
transports
has
classify
574
in
oxygen
amino
are
at
compared
any
two
The
animals
in
1722
in
bases
amino
that
more
closely
the
a
once
bo th
has
then
shor
tened
H.
is
nam
e
it
like
sapien
s.
For
acid
code
sequences
similarities
If
that
species
4.3).
animals.
Each
this:
a
used
be
These
proteins
T
opic
many
with
more
the
(see
acids.
are
for
least
acids
DNA
there
animals.
organisms.
amino
sequences
different
are
to
sequences
sequences
protein
between
likely
methods
haemoglobin
three
protein.
accurate
of
nam
es.
of
can
There
TIP
rely
evolutionary
organisms
and
1.2.1.
(yellow)
for
there
related
are
SUMMARY
QUESTIONS
1
complete
they
be.
Copy
and
sentences
using
fertile
the
these
genus
words:
shared
humerus
trivial
1
classication
humerus
radius
binomial
breed
2
ulna
The
system
organisms
of
putting
into
groups
is
called
5
.
The
system
is
4
used
for
naming
Each
organism
organisms.
3
radius
has
two
names.
bat
The
(flying)
rst
is
called
the
ulna
name
and
the
name.
second
A
is
species
the
is
a
humerus
very
similar
that
can
group
of
individuals
ulna
together
produce
radius
and
offspring.
We
1
classify
living
things
on
the
5
basis
4
2
of
their
features.
3
2
human
a
Explain
the
term
binomial
1
(manipulating)
system
2
3
4
5
b
Find
the
scientic
names
seal
of
(swimming)
Figure
1.2.1
The
variations
on
a
pentadactyl
two
two
limb.
plant
animal
mentioned
and
KEY
write
The
binomial
system
uses
two
names
for
each
species:
A
this
topic
alongside
name
species
that
is
breed
and
a
the
group
together
trivial
of
to
Classication
4
The
is
individuals,
produce
important
In
the
living
fertile
in
the
same
habitat
means
of
of
bases
in
18th
century,
Linnaeus
worked
binomial
system
living
offspring.
in
the
study
of
DNA
is
used
as
things.
life
Carl
and
out
of
Find
work
the
naming
out
and
about
then
evolution.
write
sequence
names.
name.
his
3
common
the
3
genus
2
in
them
and
not
POINTS
their
1
species
species
a
more
accurate
your
a
brief
own
biography
in
words.
classication.
5
1.3
Features
The
LEARNING
cells
of
all
State
living
•
List
the
features
of
cells
structures
in
enzymes
organisms
the
organisms
organisms
are
made
up
of
a
cell
membrane,
OUTCOMES
cytoplasm
•
living
of
features
organisms
into
used
one
to
of
place
the
ve
kingdoms.
There
that
you
can
and
Biologists
are
large
cell
see
are
in
the
of
carry
cell.
that
as
out
processes
Cells
of
There
same
are
The
synthesis
simple
do
as
to
of
small
and
structure
have
all
a
other
eukaryotic.
classify
all
because
kingdoms,
cell
not
cells
example,
kingdom
ve
a
share
For
cytoplasm
respiration.
known
organisms
the
the
bacteria
are
kingdoms.
as
have
cells.
cells
in
protein
such
Bacteria
these
into
structure.
that
present
prokaryotic
features
known
have
1.3.1.
as
and
together
cell
also
in
Figure
nuclei
groups
same
types
known
have
classied
the
stored
involved
main
use
They
ribosomes
are
two
organisms
ve
DNA.
called
that
are
nucleus
and
them
into
bacteria
they
including
have
the
plant
wall
food
kingdom
and
the
animal
kingdom.
cell
reser ve
membrane
Plant
kingdom
plants
are
Plants
are
multicellular
organisms.
The
bodies
of
roots
spread
out
ribosomes
through
flagellum
not
the
compact
soil
to
like
gain
those
water
of
and
animals.
salts
and
Their
their
stems
grow
many
plasmid
leaves
DNA
of
Figure
1.3.1
A
typical
to
roots
absorb
and
light.
stems.
Growth
This
occurs
kingdom
in
special
includes
places
mosses
such
and
as
ferns,
the
tips
which
bacterium.
do
not
reproduce
conifers
out
and
the
using
photosynthesis,
chloroplasts
full
seeds,
owering
of
using
and
plants.
light
to
chlorophyll,
the
All
seed-bearing
plants
make
have
their
cellulose
cell
plants,
such
chlorophyll
own
walls
food.
and
a
as
and
Plant
large
carry
cells
have
sap-lled
vacuole.
Animal
animals
kingdom
have
throughout
their
not
food
have
nervous
Animals
much
the
by
more
body.
eating
cell
walls,
systems
are
also
compact
Animals
plants
do
which
bodies
not
and/or
chloroplasts
multicellular
or
coordinate
than
organisms.
plants.
photosynthesise
other
animals.
large
their
Growth
and
Animal
vacuoles.
All
responses
to
Most
occurs
obtain
cells
animals
stimuli
do
have
and
their
Prokaryote
you
Staphylococcus,
on
the
human
a
type
skin
of
bacterium
can
see
kingdom
in
Figure
are
rod-shaped.
are
a
Bacteria
1.3.1.
Many
exist
have
Some
in
a
simple
bacteria
short
chains
cell
are
of
structure
spherical
cells.
that
and
Most
some
bacteria
found
few
micrometres
in
length
and
can
only
be
seen
with
light
(×4000).
and
electron
microscopes.
(One
micrometre
is
one-thousandth
of
a
millimetre.)
Bacterial
species
There
is
Bacteria
called
from
cells
are
no
are
also
nucleus,
often
animal
mould,
Rhizopus
nigricans,
is
a
and
6
black
structures
contain
spores.
just
a
by
by
loop
additional
(see
page
plant
Some
cell
of
cells
as
of
The
they
have
The
cells
of
some
bacterial
capsules.
DNA
loops
267).
bacteria
walls.
slime
within
DNA
the
structure
do
not
cytoplasm.
inside
of
have
extensions
their
cytoplasm
bacteria
differs
chloroplasts
called
or
agella
fungus.
(singular:
The
have
plasmids
mitochondria.
Bread
surrounded
surrounded
agellum)
for
moving
through
water
or
other
uids.
tnemelppuS
movement.
tnemelppuS
Protoctists
This
are
in
classied
four
and
some
parasitic
and
are
this
kingdoms.
are
commonly
All
they
vary
in
kingdom
as
is
as
size
from
plenty
do
light
not
cells
they
any
are
of
many
include
‘forests’
to
in
the
are
which
other
unicellular
organisms
which
classied
organisms
can
in
organisms
Plasmodium,
Algae
unicellular
of
nuclei;
protoctists
underwater
so
group
belong
with
including
malaria.
tiny
form
of
diverse
Unicellular
causes
that
a
they
have
protozoans
that
seaweeds
there
contains
protoctists
multicellular
.
known
organism
giant
where
kingdom
as
the
is
kelps
parts
of
the
protoctists
which
the
sea
photosynthesise.
Paramecium,
a
single-celled
protoctist
(×206).
genetic
Fungi
kingdom
Fungi
are
visible
under
a
light
microscope.
Many
are
material
also
visible
to
the
naked
eye.
Most
fungi
are
multicellular
although
sur face
yeasts
are
single-celled.
Each
cell
has
a
nucleus
and
a
cell
wall
which
coat
is
made
out
chlorophyll
The
main
its
chitin,
and
body
network
food
not
cannot
fungus
branching
of
of
source,
of
cellulose
carry
is
out
called
threads
releasing
in
plants.
Fungi
do
not
proteins
have
photosynthesis.
the
or
as
mycelium.
hyphae
enzymes
It
which
which
consists
grow
digest
of
over
the
a
the
food
surface
outside
Figure
the
fungus.
The
digested
food
is
then
absorbed
by
the
Viruses
Fungi
reproduce
Most
fungi
are
by
making
spores
saprotrophs,
that
which
can
be
means
carried
they
feed
by
the
on
wind.
dead
matter,
but
some
are
are
causes
in
or
of
decaying
1.3.2
Structure
of
a
human
virus.
hyphae.
inuenza
size.
a
extremely
(One
is
small.
about
nanometre
micrometre.)
120
is
Viruses
This
virus
that
nanometres
one-thousandth
are
visible
only
parasites
under
an
electron
microscope.
Viruses
are
or
RNA)
of
a
not
cells.
surrounded
few
genes
that
They
by
a
are
particles
protein
code
for
the
made
coat.
The
proteins
up
of
genetic
that
genetic
material
material
form
the
is
coat
(DNA
composed
and
maybe
KEY
other
cells
proteins
of
that
another
help
it
organism
reproduce.
(the
host)
Viruses
in
order
are
to
parasites
multiply
.
that
Viruses
enter
take
over
1
the
host
cell
and
direct
it
to
make
new
viruses.
Viruses
are
not
POINTS
the
The
cells
have
in
any
in
the
of
the
kingdoms
described
here.
All
the
organisms
do
not
have
of
kingdoms
have
cells.
Viruses
cells
in
a
different
way.
Their
classication
is
based
and
so
material
and
protein
coat
that
they
on
the
type
There
are
Prokaryotes
under
The
plant
species
with
features
kingdom
that
are
animals.
tnemelppuS
Compare
a
Make
a
present
in
all
cells.
and
familiar
Y
ou
the
to
should
animal
us.
kingdom
Make
include
a
table
similarities
contain
to
Why
the
table
6
How
are
Plant,
Protoctist
cells
be
without
seen
only
microscope.
organisms
with
as
well
eukaryoltic
structure
of
bacterial
cells
with
the
to
compare
the
features
of
the
as
cells
ve
viruses
not
classied
in
one
of
the
ve
plants
5
Fungi
called
differences.
of
a
nanometres
are
there
in
a
group
many
of
features
cells.
are
made
hyphae.
the
food
up
of
These
supply,
threads
grow
digest
it
plant.
and
then
absorb
it.
kingdoms.
kingdoms?
Viruses
an
can
electron
are
many
a
many
compare
6
5
can
light
externally
4
have
are
over
3
They
Protoctists
of
2
kingdoms:
QUESTIONS
4
the
ve
Prokaryote,
Fungi.
nuclei.
State
DNA.
have.
3
1
and
of
and
SUMMARY
organisms
cell
are
Animal,
genetic
a
classied
2
classied
living
cytoplasm,
membrane
ve
all
classied
tnemelppuS
Viruses
not
be
seen
only
microscope.
cells
but
a
few
under
They
genes
metre?
inside
a
protein
coat.
7
1.4
Vertebrates
Animals
LEARNING
that
have
vertebrates.
•
Dene
•
Describe
the
term
vertebrate
bone
or
some
of
the
ve
vertebrates
external
main
using
visible,
characteristic
Describe
how
vertebrates
All
vertebral
vertebrates
column
cartilage.
They
invertebrates
all
that
have
an
or
backbone
belong
share
to
internal
are
the
common
skeleton
called
phylum
features
made
chordata
with
the
of
either
which
includes
vertebrates.
groups
There
are
ve
main
groups
of
vertebrates:
features
sh,
•
a
OUTCOMES
amphibians,
reptiles,
birds
and
mammals.
these
are
adapted
to
Fish
their
environment
Most
sh
as
the
of
time.
Typically,
This
dace
has
ns,
tail
and
a
their
–
adaptations
for
have
gills.
herring,
sh,
sound
and
eyes
They
Their
shark,
the
can
and
skin
and
a
is
there
out
of
have
lateral
line
and
of
for
for
with
some
for
species,
varying
swimming
detecting
oxygen
from
scales.
such
lengths
and
for
pressure
the
water
Examples
include
cod.
vertebrates
although
are
water
ns
dissolved
covered
classes
limbs,
but
survive
breathe
catsh
other
four
permanently,
that
streamlined
water.
Unlike
some
have
have
ears
evolved
for
into
detecting
legless
forms
streamlined
like
shape
in
water
are
They
changes
tuna,
in
skipper,
sh
balance.
using
live
mud
snakes
and
some
lizards.
swimming.
Amphibians
These
vertebrates
amphibians
is
external
inside
a
hatch
into
On
are
have
on
the
body).
adult
water,
amphibians
they
sperm
swimming
in
smooth,
land,
because
female
land,
they
live
and
eggs
can
frogs,
is
which
amphibians
skin.
to
are
Development
tadpoles
they
include
moist
return
toads
external:
gills
using
through
and
to
released
have
breathe
breathe
Although
water
most
breed.
into
the
for
water
fertilised
(not
eggs
breathing.
lungs,
their
Fertilisation
the
but
skin.
when
Examples
of
salamanders.
Reptiles
The
bright
thought
for
the
to
red
eyes
startle
frog
to
of
this
tree
predators,
frog
giving
are
time
Reptiles
have
dry,
scaly
skin
to
cut
down
water
loss.
They
can
live
in
escape.
dry
regions
Fertilisation
as
takes
development
shells
air
.
they
which
is
not
place
them
lizards,
have
inside
external
stop
Crocodiles,
do
as
the
they
from
to
return
female’s
lay
eggs
drying
snakes,
to
out.
turtles
water
body.
with
breed.
However
,
leathery,
Reptiles
and
to
have
tortoises
waterproof
lungs
are
all
to
breathe
reptiles.
Birds
Birds
of
Birds
with
American
8
crocodile,
Crocodylus
acutus
have
them
feathers
are
have
able
no
different
and
to
teeth
types
y
but
of
their
but
front
some,
different
food.
limbs
like
are
modied
penguins
species
have
and
beaks
as
wings.
ostriches,
adapted
Most
cannot.
to
deal
Fertilisation
is
eggs
which
are
Birds
are
able
to
even
internal
protected
homeothermic
regulate
though
include
and
their
the
hawks,
development
by
eagles,
external
temperature.
temperature
sparrows,
as
the
females
lay
shells.
(warm-blooded).
body
outside
hard
is
This
They
can
changes.
parrots
and
means
keep
that
it
they
are
constant
Examples
of
birds
starlings.
Mammals
Mammals
internal
they
are
young
ones
Like
are
and
born
on
like
is
vertebrates
milk
that
development.
already
from
whales
birds,
internal
the
so
well
mammals
dolphins,
are
temperature.
also
or
All
lungs
bats,
Fertilisation
in
a
mammals
mammals,
for
is
womb
and
suckle
their
even
Grey
Heron,
long
beak
Ardea
for
are
all
maintaining
dolphins,
bears,
a
STUD
Y
constant
lemurs
learn
ve
this
DID
has
hands
and
feet
adapted
to
living
in
a
and
complete
the
sentences
using
these
ve
classes
wings
breed
scaly
y
sh
moist
fur
land
water
are
different
group
in
groups
called
and
have
skin
have
front
skin
limbs
have
and
or
feathers
of
vertebrate.
Sharks
2
a
the
learn
rare
spend
all
their
hair
that
are
most
and
and
lay
return
their
modied
are
give
and
able
birth
to
to
time
in
species
are
.
of
their
golden
were
an
lmed
Blood.
frogs
were
for
BBC
After
Sir
TV
the
moved
David
series
Life
lming
them
from
to
a
zoo
disease,
to
habitat
and
pollution.
Birds
They
Mammals
in
Panamanian
.
.
.
young
extinction.
.
to
on
form
to
to
water
eggs
with
belong
also
have
advanced
KEY
state
you
KNOW?
amphibian
Cold
loss
Amphibians
have
these
to pic.
protect
Reptiles
you
of
Mak
ing
help
Attenborough’s
the
the
help
words:
frogs
to
a
QUESTIONS
development
There
to
featur
es
will
YOU
Some
Copy
table
the
threatened
1
with
trees.
Many
SUMMARY
bird
TIP
grou
ps.
table
chimpanzee
a
and
mammals.
A
–
sh.
aquatic
Mak
e
wolves
cinerea
catching
breathing.
homeothermic,
Leopards,
fur.
develop
Female
glands.
use
hair
young
developed.
mammary
and
have
The
POINTS
.
State
the
features
that
are
exhibited
by
all
vertebrates.
1
Vertebrates
have
b
Name
c
Give
the
ve
groups
of
a
are
animals
vertebral
column
that
or
vertebrates.
backbone.
an
example
of
each
group.
2
3
T
o
which
group
of
vertebrates
does
each
of
the
following
The
into
a
turtle
b
bat
f
hawk
g
shark
c
whale
d
salamander
e
vertebrates
are
divided
belong?
ve
groups:
snake
sh,
amphibians,
birds
and
reptiles,
mammals.
9
1.5
Invertebrates
Invertebrates
LEARNING
are
animals
that
do
not
have
a
vertebral
column
or
OUTCOMES
backbone.
•
Describe
the
external
features
Arthropods
of
contains
•
Describe
of
is
the
largest
of
the
groups
in
the
animal
kingdom
as
it
arthropods
the
insects,
features
segmented
and
myriapods
used
body,
number
an
of
external
species.
skeleton
Each
arthropod
(exoskeleton)
species
and
has
jointed
a
legs.
hard
to
classify
them
exoskeleton
allows
arthropods
to
live
on
dry
land.
When
that
they
are
largest
crustaceans,
The
arachnids
the
grow
too
big
for
their
exoskeleton,
they
moult
and
grow
a
new
into
one.
Some
moult
all
through
their
lives,
others
moult
only
during
the
groups
early
•
Describe
these
their
how
groups
the
are
animals
adapted
stages
of
their
life.
in
Four
to
of
the
different
types
of
arthropod
are:
environment
crustaceans,
myriapods,
insects
and
arachnids
Crustaceans
Crustaceans
and
abdomen.
hard
two
ve
and
crabs
of
Woodlouse
detecting
or
slater.
Notice
its
antennae
of
all
are
and
so
the
made
bodies
the
are.
and
crab,
Grapsus
feeding
grapsus.
and
exoskeleton
against
in
They
they
(also
do
crabs,
eyes.
breathe
water.
Some
use
shrimps,
as
They
water
have
a
very
have
between
gills
live
on
slaters)
for
craysh
provides
Crustaceans
using
crabs
known
not
that
predators.
(head-thorax)
land
and
breeding.
and
but
some
return
land
Examples
lobsters.
Notice
centipedes
up
of
many
not
divided
Centipedes
total
number
Centipedes
paralyse
have
slow-moving
two
and
into
have
of
are
millipedes.
separate
one
legs
pair
They
pairs
regions
of
depends
fast-moving
their
herbivores.
the
have
long
segments.
legs
upon
such
on
how
carnivores.
as
each
the
many
They
thorax
segment
segments
have
powerful
prey.
of
legs
You
can
on
each
often
body
nd
segment.
them
They
feeding
in
are
leaf
litter.
defence.
Millipede
moving
10
as
cephalothorax
compound
legs.
live
include
are
can
Millipedes
for
and
of
Woodlice
exceptions
are
that
jaws
claws
pairs
breed.
abdomen.
there
lightfoot
chalky
a
Myriapods
Their
large
a
into
for
stimuli.
bodies
its
have
crustaceans
to
divided
protection
antennae
crustaceans
These
Sally
body
Many
twenty
water
a
effective
pairs
and
Nearly
to
have
–
with
its
efciently.
many
legs
for
Centipede
–
a
fast-moving
carnivore.
Insects
Insects
and
On
have
bodies
that
are
divided
into
three
parts:
head,
thorax
abdomen.
the
two
thorax
pairs
of
compound
They
eyes
breathe
called
there
wings.
are
three
They
that
are
through
pairs
have
one
made
holes
in
of
of
legs
pair
of
many
the
and
tiny
sides
many
antennae
of
species
on
individual
the
thorax
the
have
head
and
components.
and
abdomen
spiracles
Monarch
Insects
have
colonised
most
habitats
in
the
world,
although
Notice
are
very
few
species
that
live
in
the
sea.
T
wo
reasons
why
they
are
on
that
them
stops
This
is
the
beetles,
bees
is
that
losing
largest
ies,
and
land
group
locusts,
they
too
are
much
within
covered
water,
the
cockroaches,
by
and
a
waterproof
they
arthropods.
dragonies,
can
its
wings
Danaus
for
its
plexippus.
migration
over
so
long
successful
buttery,
there
distances.
cuticle
y!
Examples
include
butteries,
moths,
wasps.
Arachnids
These
and
arthropods
have
bodies
divided
into
two
parts,
the
cephalothorax
abdomen.
Arachnids
antennae
They
have
but
paralyse
silken
webs
four
do
their
with
pairs
have
prey
their
of
legs
several
with
and
pairs
poison
spinnerets.
no
of
wings.
simple,
fangs.
They
not
Spiders
Scorpions,
have
no
compound,
are
ticks
able
and
eyes.
to
mites
weave
are
also
T
arantula
classied
as
arachnids.
paralyse
SUMMARY
QUESTIONS
1
four
a
Name
b
List
c
State
the
groups
key
of
features
ways
in
a
large
spider
with
venom
to
prey.
arthropod.
of
insects.
DID
three
–
its
which
arachnids
look
different
YOU
KNOW?
from
There
are
over
a
million
known
insects.
2
3
Distinguish
between
a
centipedes
b
crustaceans
Describe
the
successfully
4
Copy
and
and
the
and
basis
of
visible
features:
altogether
,
of
insects
that
adapt
them
for
of
the
knows.
crustaceans
insects
arachnids
KEY
POINTS
of
Arthropods
are
segmented
legs
an
regions
number
of
one
table:
animals
body
no
living
1
pairs
but
arachnids
myriapods
number
the
land.
complete
feature
on
millipedes
features
on
following
pairs
2
of
with
jointed
legs
and
exoskeleton.
Arthropods
different
are
classied
groups
into
including:
antennae
crustaceans,
type
of
myriapods,
eyes
insects
and
arachnids
wings
11
1.6
Ferns
and
owering
plants
tnemelppuS
Like
LEARNING
•
State
that
owering
making
•
State
and
plants
the
owering
•
ferns
non-
reproduce
by
the
between
plants,
ferns
green
in
These
chloroplasts
absorbs
made
spores
Describe
all
and
owering
plants
are
multicellular.
They
are
OUTCOMES
main
features
of
plants
Both
of
differences
dicotyledons
light
of
and
mineral
adapted
monocotyledons
for
tubes.
substances
and
because
many
contain
of
the
their
green
photosynthesis.
cells
contain
pigment
Each
cell
is
chloroplasts.
chlorophyll,
surrounded
by
which
a
cell
wall
cellulose.
ferns
tiny
and
colour
owering
These
salts,
such
to
live
are
and
as
on
plants
called
have
phloem
sugars.
transport
xylem
vessels,
tubes,
Both
ferns
which
and
systems
which
consisting
carry
transport
owering
water
dissolved
plants
are
well
land.
Ferns
Ferns
on
a
are
land.
waxy
them
to
left.
quite
supports
grow
If
fern
Dryopteris
lix-mas
you
will
Ferns
a
look
under
Features
Flowering
by
means
inside
the
Shoots
apical
of
and
are
helps
the
at
leaves
that
carried
by
have
true
which
within
the
tree
stem
ferns
and
the
the
of
several
ferns
at
a
in
do
have
a
life
have
Most
of
photograph
some
thick
metres.
not
that
stem
Many
produce
times
of
microscopic
form
loss.
the
for
leaves
that
ferns
rhizome.
certain
to
Their
including
that
called
adapted
water
species
habitats
release
wind
well
leaves.
reduce
ferns
heights
of
make
of
plants,
and
to
different
owering
the
become
roots
those
many
leaves
have
underground
owers
ovary
in
owering
plants
of
of
and
are
which
largest
thick
structures
spores
that
stems,
resembling
live
crown
a
plants
strong
cuticle)
The
conifers
see
These
(the
dry.
of
have
leaves
from
Unlike
The
group
layer
have
the
are
a
Ferns
new
the
seeds.
year
you
spores.
plants.
plants
stems,
make
roots
and
seeds.
The
leaves.
seeds
They
are
reproduce
produced
ower.
roots
bud
The
up
shoot
of
a
is
stem
the
part
bearing
of
the
plant
leaves,
buds
above
and
ground.
owers.
The
The
shoot
apical
is
made
bud
is
leaf
stem
side
buds
side
main
root
Figure
1.6.1
root
root
cap
Structure
of
a
typical
dicotyledonous
plant.
Magnolia
12
is
a
dicotyledon.
Maize,
Zea
mays,
is
a
monocotyledon.
part
where
the
stem
grows
new
leaves.
The
stem
supports
the
clusters
structures
receive
The
which
stem
food
the
roots
are
anchor
blown
from
shoot,
are
the
by
soil
to
of
in
wind.
Topic
Dicotyledons
of
(see
out
to
of
owering
the
6.6)
also
the
the
not
It
soil
the
up
to
such
found
contain
they
of
flowers
can
owers
the
as
in
leaves
the
a
below
water
it
ground.
from
and
and
roots.
chlorophyll.
prevent
absorb
that
holds
plant,
and
so
place.
plants
do
ground
Roots
leaves
take
from
parts
they
the
Topic
water
since
rmly
(see
air
other
parts
the
spaces
pollination
white
plant
over
and
transport
leaves
usually
the
the
light
and
enables
allows
from
Roots
the
adequate
position
The
of
tnemelppuS
the
Roots
being
mineral
ions
8.2).
and
monocotyledons
leaf
Flowering
plants
dicotyledons
can
and
be
divided
into
two
main
groups:
monocotyledons
Figure
1.6.2
Structure
of
a
typical
monocotyledon
Dicotyledons
look
like
Their
leaves
are
parts
of
ower,
often
the
plant
broad
at
with
the
a
bottom
network
of
of
the
opposite
branching
veins.
The
STUD
Y
are
in
the
multiples
cotyledons
Grasses
are
of
example
four
(seed
and
for
or
leaves)
cereals,
like
ve
in
the
the
in
a
male
each
parts
ower.
known
as
Dicotyledons
have
two
Be
plant
at
the
bottom
of
page
and
12
of
have
most
long,
monocotyledons
narrow
leaves.
have
Other
parallel
veins.
Grasses
monocotyledons
have
a
variety
ower
inside
are
in
each
of
shapes,
multiples
such
of
as
three.
those
of
palm
trees.
Monocotyledons
The
have
parts
one
of
1
complete
and
the
parallel
sentences
two
using
these
words:
Flowering
plants
multicellular
narrow
network
are
with
plants
veins.
They
often
have
Dicotyledons
wall;
have
that
often
have
have
with
some
inside
a
the
names
of
ve
inside
dicotyledonous
that
grow
key
for
the
ten
plants
Make
a
table
of
differences
between
is
leaves
each
plants
where
you
in
ferns
and
and
have
their
one
seeds
and
seed.
you
have
contain
Monocotyledons
with
parallel
veins.
ve
live.
Dicotyledons
have
two
Construct
and
broad
leaves
identied.
with
3
in
stems
cotyledons
dichotomous
cell
cellulose
the
3
plants
a
of
leaves
monocotyledonous
by
chloroplasts.
cotyledon
leaves
cotyledons
are
each
those
cotyledon
They
–
one
2
a
2.1)
(from
owering
and
Monocotyledons
Find
in
POINTS
cell
broad
2
(T
opic
16).
surrounded
veins.
and
differ
ences
cotyledon
1
seed.
plan
ts
Note
repro
duct
ion
the
KEY
QUESTIONS
leaves
differ
ences
seed.
SUMMARY
Copy
the
and
leaves
Unit
with
the
struct
ure
and
cereals
of
owe
ring
anim
als.
learn
monocotyledons.
leaves
awar
e
be tw
een
cell
The
TIP
stamens,
seed.
maize
plant.
page.
owering
plants.
a
network
of
branching
veins.
4
Ferns
to
life
xylem
are
on
plants
land.
and
means
of
well
They
adapted
have
reproduce
by
spores.
13
1.7
Dichotomous
Sorting
LEARNING
Construct
and
use
identify
dichotomous
keys
to
•
Identify
in
a
name
book
of
a
until
plant
you
or
animal
found
the
you
right
a
lot
of
time
and
and
for
through
that
the
would
effort.
features
of
start
useful
look
However,
animals
external
animals
could
one.
identify
take
and
the
simple
pictures
plants
out
OUTCOMES
To
•
things
keys
plants
making
a
that
here
are
key
has
it
got
yes
no
legs?
has
a
it
got
shell?
snail
has
it
no
6
has
it
earthworm
got
yes
legs?
got
yes
no
2
pairs
of
wings?
Figure
1.7.1
Scientists
A
use
key
and
key
has
the
you
answer
to
Use
out
1
2
3
4
Figure
14
1.7.2
Five
invertebrates.
numbered
‘yes’
to
the
means
number
nd
another
above
at
a
a
of
key
‘no’
question
identify
numbered
or
steps
on
–
this
or
and
an
rst
to
to
2
Has
no
Go
to
4
Has
6
legs
Go
to
3
Has
8
legs
Spider
Has
1
pair
Has
2
pairs
Has
a
Has
no
shell
shell
wings
see
At
things.
or
it
Snail
Earthworm
step
at
the
the
in
Use
branching
the
the
key
branching
beginning
statement.
the
same
works
questions
Wasp
in
This
and
takes
branching
you
key
left.
but
Housey
them
each
Start
identify
the
Go
of
the
key,
legs
wings
can
question
to
living
two.
page.
Has
of
identify
identication.
answer
legs
to
you
rst
below
the
key.
statement.
the
to
into
animals
key
from
beginning
to
the
keys
dividing
question
or
differently
the
dichotomous
dichotomous
Dichotomous
A
branching
at
in
animals.
the
each
same
stage.
It
is
way.
set
Start
PRACTICAL
STUD
Y
Making
Now
try
a
leaf
making
a
key
of
your
Whe
n
own.
‘size
’
1
T
ake
six
different
leaves
and
label
them
A
to
Put
the
six
leaves
3
Think
of
a
4
Write
down
5
Now
6
Write
7
Carry
question
think
the
up
these
on
out
in
front
that
will
of
you.
divide
into
two
Write
out
questions
you
your
to
divide
each
group
into
come
to
the
last
pair
of
as
a
branching
key
or
as
a
numbered
the
are
key.
making
a
livin
g
muc
h
featu
re
thing
s
in
size.
TIP
exam
ination
,
usua
lly
rather
key
of
these
pond
animals
below.
it
than
How
ever
,
aske
d
is
to
easies
t
bran
chin
g
damsel
fly
keys
num
bered
if
key
are
try
key ,
leaves.
keys
.
Now
a
good
two.
STUD
Y
key
animals
as
so
keys
Pond
a
question.
In
8
not
groups.
down.
until
use
vary
them
mak
ing
is
F
.
to
2
TIP
key
bran
ched
you
mak
e
to
a
mak
e
key.
Y
ou
key
a
may
lar va
also
be
freshwater
aske
d
featur
es
shrimp
for
that
mak
ing
to
iden
tify
are
suita
ble
keys
.
water
beetle
KEY
1
POINTS
Dichotomous
keys
are
used
water
to
scorpion
identify
plants
pond
snail
2
A
and
organisms,
such
as
animals.
dichotomous
key
includes
ramshorn
a
snail
series
or
of
paired
questions
identication.
Figure
1.7.3
Pond
1
When
She
a
made
some
laboratory.
Give
b
Make
2
Write
an
Her
each
either
a
could
down
use
an
drawings
drawings
a
a
branching
the
features
a
pages
to
reptile,
8
and
identify
island
and
are
9
each
discovered
brought
on
an
dividing
into
two.
key
to
identify
or
as
to
of
a
would
bird
them
the
some
back
to
insects.
the
right.
name.
key
that
a
she
shown
suitable
dichotomous
as
on
visited
insect
amphibian,
photos
to
QUESTIONS
scientist
a
lead
Dichotomous
animals.
means
SUMMARY
statements
which
and
help
a
enable
Present
you
mammal.
you.)
these
them.
numbered
Now
to
classify
(Y
ou
make
vertebrate
your
key
key.
a
a
sh,
can
use
key
that
the
you
groups.
15
PRACTICE
1
Which
QUESTIONS
process
organisms
is
that
carried
live
in
a
out
by
all
the
6
forest?
Which
is
not
associated
with
excretion
from
a
mammal?
A
moulting
A
exhaling
B
photosynthesis
B
release
C
pollination
C
removal
D
respiration
carbon
of
heat
of
dioxide
from
toxic
from
the
waste
the
lungs
skin
products
of
metabolism
D
(Paper
1)
removal
of
water
that
the
body
does
not
[1]
need
2
What
are
characteristics
of
all
organisms?
(Paper
A
excretion
and
respiration
B
ingestion
and
growth
C
photosynthesis
D
respiration
7
The
2)
evolutionary
species
3
(Paper
1)
Which
group
and
and
[1]
are
relationships
shown
in
the
between
ve
diagram.
egestion
V
photosynthesis
[1]
of
animals
includes
those
with
W
a
X
segmented
body,
an
exoskeleton
and
jointed
Y
limbs?
A
amphibians
B
arthropods
C
reptiles
D
vertebrates
Z
(Paper
1)
Which
group
time
[1]
An
4
of
vertebrate
includes
those
analysis
DNA
dry
scaly
skin
and
A
amphibians
four
of
base
sequences
from
the
with
of
these
ve
species
was
carried
out.
legs?
Which
two
species
will
have
the
most
similar
sequences?
B
sh
C
mammals
D
reptiles
(Paper
5
Each
and
1)
cell
[1]
is
surrounded
contains
by
a
cell
membrane
table
Which
from
A
B
C
D
ve
shows
organisms
other
the
in
all
features
features
ve
of
shown
cells.
by
B
W
W
C
X
and
Z
D
Y
and
Z
and
(Paper
2)
Which
is
feature
X
[1]
an
example
used
in
of
a
classifying
morphological
vertebrates?
A
egg
laying
B
type
of
body
C
type
of
diet
D
pattern
kingdoms?
enzymes
nucleus
✗
✓
✓
✓
✗
✗
✓
✗
✓
✓
✓
✗
✓
✗
✓
✓
✓
✗
✓
✗
2)
and
cells
chloroplasts
(Paper
16
shows
row
V
cytoplasm.
8
The
A
DNA
ribosomes
[1]
(Paper
2)
of
covering
bones
in
the
front
limb
[1]
9
The
to
drawings
the
same
show
ve
arthropods
(not
drawn
11
(a)
scale).
Five
of
their
the
features
denitions
Match
each
denition
of
by
of
are
the
A
movement
B
respiration
D
a
things
and
below.
features
pairing
C
living
listed
with
letter
its
and
a
number.
sensitivity
nutrition
E
growth
Denitions
A
B
1
A
permanent
2
The
to
increase
chemical
break
release
reactions
down
of
in
size
that
nutrient
occur
in
molecules
cells
with
the
energy
C
3
An
action
change
4
The
by
of
an
ability
to
environment
5
The
taking
Make
a
table
to
compare
the
features
or
detect
and
in
environment
(a)
organism
position
of
cause
changes
respond
materials
for
to
a
place
energy,
to
in
the
them
from
the
growth
and
of
development
the
ve
arthropods
that
you
see
in
[3]
the
(b)
drawings.
Explain
what
is
meant
by
the
term
species
[6]
[2]
(b)
Use
in
the
your
features
table
arthropods.
to
that
you
make
(The
key
a
have
key
may
to
be
used
the
(Paper
ve
either
a
12
branching
key
or
a
numbered
3)
key.)
The
drawings
owering
(Paper
10
Copy
plant.
leaves
They
are
from
not
three
drawn
species
to
of
scale.
3)
and
crosses
show
show
[6]
to
the
complete
indicate
features
feature
sh
the
table
whether
or
using
the
ticks
four
and
groups
not.
amphibian
bird
mammal
backbone
ns
A
C
B
wings
(a)
(i)
Identify
the
group
of
owering
plants
fur
to
which
each
species
belongs.
homeothermic
(ii)
State
the
make
(Paper
3)
features
your
that
you
used
to
identications.
[5]
[5]
(b)
List
ve
would
key
to
features
be
shown
useful
identify
in
by
the
devising
species
of
a
leaves
that
dichotomous
owering
plants.
[5]
(c)
(i)
State
ferns
three
have
structural
in
features
common
with
that
owering
plants.
(ii)
Explain
walls,
[3]
why
are
kingdom
(Paper
fungi,
not
with
which
classied
plants.
in
have
the
cell
same
[3]
4)
17
2
Cells
2.1
Structure
of
cells
Cells
LEARNING
OUTCOMES
Cells
•
Describe
the
structures
Very
plant
and
under
•
a
animal
light
Describe
the
cells
are
the
small
building
blocks
that
as
microscope
differences
small
living
things
such
as
bacteria
An
insect
for
certain
such
as
how
a
y
many
may
contain
cells
there
millions
are
in
animal
plant
State
between
the
functions
of
organisms.
only
one
cell.
a
of
cells.
human
No
being
one
–
knows
estimates
10
×
12
10
and
50
×
10
seen
under
cells
Plant
cells
the
cell
membrane
the
cell
cell
living
of
cells
structures
light
all
and
Animal
•
up
made
in
12
between
are
seen
vary
structure
make
of
microscope
and
in
the
in
the
animal
wall
plant
cell
nucleus
cytoplasm
cell
membrane
nucleolus
Figure
2.1.1
A
cheek
cell
(stained
nucleolus
with
a
blue
dye).
nucleus
Figure
2.1.2
A
palisade
cell
Differences
Liver
cells
magnied
by
The
differences
this
table.
between
between
plant
plant
and
and
from
animal
animal
cells
are
mesophyll
a
leaf.
cells
summarised
in
×300.
feature
cellulose
cell
plant
wall
cell
animal
present
cell
absent
present;
cell
STUD
Y
membrane
present
surrounded
TIP
permanent
Whe
n
you
have
differ
ence
s
plan
t
mak
e
state
wall
shape
determined
by
the
cell
shapes
be tw
een
shape
wall;
and
sure
of
anim
al
you
cells
,
write
shapes
can
abou
t
bo th
chloroplasts
nearly
spherical,
like
cylindrical
or
present
in
some
vary
as
there
be
cell
wall
box-
cells
absent
cell.
large
vacuole
permanent
vacuole
in
containing
present
nucleus
side
the
cytoplasm
18
cell
no
some
thin
g
type
s
to
by
of
cell
present
cytoplasm
cell
(often
the
small
cell
wall)
sap
at
the
close
to
vacuoles
cytoplasm;
do
in
not
contain
cell
present
(found
anywhere
cell)
present
sap
within
the
is
Functions
of
cell
structures
STUD
Y
cell
structure
•
forms
a
barrier
between
the
cell
and
Mak
e
its
liver
surroundings
•
•
cell
TIP
functions
membrane
keeps
allows
cell,
•
simple
e.g.
controls
out
•
contents
of
often
of
cell
oxygen,
carbon
movement
the
cell,
e.g.
described
as
of
to
enter
dioxide
other
and
and
leave
the
the
water
substances
into
and
can
page
the
use
of
palis
cells
.
struct
ures
write
and
each
label
func
tions
.
your
ade
Labe
l
Y
ou
draw
ings
permeable
to
(see
and
unde
rnea
th
glucose
partially
cells
meso
phyl
l
inside
substances
draw
ings
help
your
revisi
on.
28)
•
controls
all
•
controls
how
activities
•
place
in
the
cell
nucleus
where
cells
many
develop
chemical
reactions
take
place,
cytoplasm
e.g.
respiration
and
making
proteins
for
the
cell
chloroplast
(plant
•
photosynthesis
•
stores
•
stops
•
gives
•
allows
cells
starch
only)
cell
wall
cells
cells
from
shape
to
bursting
when
they
ll
with
water
cells
(plant
water
and
dissolved
substances
to
pass
only)
through
freely
(often
described
as
freely
or
fully
permeable)
sap
vacuole
(plant
•
cells
full
of
water
only)
•
stores
salts
SUMMARY
QUESTIONS
1
complete
Copy
and
indicate
to
maintain
shape
and
‘rmness’
of
cell
if
the
this
structures
and
table
are
cell
cheek
structures
(animal)
by
using
present
cell
Cells
sugars
ticks
or
onion
and
crosses
of
onion
magnied
by
×250.
to
not.
cell
leaf
cell
KEY
(plant)
POINTS
(plant)
nucleus
1
A
cell
and
cell
epidermis
a
membrane,
nucleus
cytoplasm
are
found
in
wall
both
plant
and
animal
cells.
chloroplasts
2
large
All
plant
cells
have
a
vacuole
cellulose
cell
wall;
some
have
cytoplasm
chloroplasts
containing
2
State
the
functions
a
chloroplast
e
cytoplasm
b
cell
of
the
following
membrane
c
parts:
cell
wall
d
cells
vacuoles
cell
not
a
vacuole
sap.
have
Animal
these
parts.
nucleus
3
f
do
and
Refer
for
to
the
the
table
functions
above
of
the
cell
structures.
19
Cell
LEARNING
OUTCOMES
As
you
know,
structures
•
State
that
the
organelles
all
cells
contains
ribosomes
endoplasmic
on
Identify
rough
ER
in
•
State
that
occurs
in
Calculate
and
the
a
cell.
number
These
of
are
small
called
include
mitochondria,
vesicles
and
cell
ribosomes
on
reticulum
diagrams
of
and
The
cells
aerobic
endoplasmic
reticulum
and
endoplasmic
membranes.
respiration
which
reticulum
They
allow
contain
materials
to
(ER)
is
a
complex
uid-lled
be
spaces
transported
system
of
between
throughout
double
the
membranes
the
cell.
the
membranes
mitochondria
the
actual
specimens
as
contain
of
reticulum
Where
•
cells
cytoplasm
rough
mitochondria
photographs
and
endoplasmic
Rough
•
animal
the
vesicles
rough
and
and
in
cytoplasm
organelles
of
plant
present
magnication
size
of
using
are
biological
of
micrometres
ribosomes
called
rough
rough
ER
is
are
present
on
endoplasmic
to
package
their
outer
reticulum
and
surface,
(ER).
transport
The
proteins
main
function
made
by
the
ribosomes.
units
Cells
that
digestive
rough
Small
small
a
lot
in
of
the
protein,
for
alimentary
instance
canal,
those
have
large
making
amounts
of
ER.
pieces
of
vesicles.
rough
Ribosomes
produce
enzymes
ER
rough
In
and
this
ER
may
way
be
pinched
proteins
transported
around
can
the
be
off
at
the
made
cell
in
ends
and
the
to
stored
small
form
in
the
vesicles.
Ribosomes
Ribosomes
cells.
cells
Cisterna
They
but
are
are
smaller
cytoplasm,
The
Lamellae
small
not
function
organelles
about
in
20
prokaryotic
attached
of
that
are
nanometres
to
ribosomes
cells
rough
is
to
found
(nm)
where
in
in
huge
diameter
they
are
numbers
in
in
all
eukaryotic
found
free
in
the
ER.
synthesise
proteins,
such
as
those
of
enzymes
involved
in
respiration.
reticulum
made
of
up
double
Mitochondria
membrane
Mitochondria
Figure
2.2.1
Structure
of
are
relatively
large
organelles
found
in
all
eukaryotic
rough
cells.
endoplasmic
reticulum
They
are
often
visible
under
the
electron
microscope
as
sausage-
(ER).
shaped
Each
structures
about
mitochondrion
controls
many
the
folds
entry
on
has
and
which
1 µm
a
exit
wide
double
of
some
and
the
long.
membrane,
materials.
of
5 µm
The
chemical
the
inner
outer
one
membrane
reactions
of
of
which
forms
aerobic
Folds
respiration
take
Mitochondria
they
Inner
Outer
membrane
Cells
are
the
with
vast
2.2.2
Structure
of
a
mitochondrion.
20
are
sites
high
often
of
described
aerobic
rates
of
as
the
‘power
plants’
of
the
cell
since
respiration.
respiration
have
many
mitochondria
to
provide
membrane
sufcient
Figure
place.
energy
.
numbers
of
For
example,
insect
mitochondria.
ight
muscle
and
liver
cells
contain
tnemelppuS
2.2
Look
of
at
1000
cells
the
To
work
Now
larger
1000
out
magnied
we
specimens
photograph
times
magnied
and
can
than
of
in
actual
in
size
use
size
human
life.
of
millimetres.
this
a
This
cell,
Let’s
formula
image
actual
some
real
cheek
means
cells.
that
The
they
cells
have
are
been
times.
the
cell
tnemelppuS
Size
to
measure
say
that
work
out
it
the
length
measures
actual
of
one
13 mm.
size:
size
=
Human
cheek
cells
(×1000).
magnication
13
So
the
actual
size
of
our
cell
=
=
0.013 mm
1000
There
are
answer
We
as
can
in
1000
to
use
this
T
o
a
similar
of
size
actual
using
calculate
the
1
2
Which
a
in
a
in
the
millimetre.
by
when
goldsh.
1000
the
This
of
you
an
image
size
actual
size
We
can
to
give
image
size
time
photograph.
formula
magnication
If
will
there
you
nd
image
we
it
convert
has
has
been
been
calculate
is
the
13 µm.
the
90 mm
reorganise
reduced,
a
sh’s
long.
the
formula:
=
The
image
(×0.33)
of
this
actual
goldsh
is
one
third
size.
QUESTIONS
organelles
manufacture
b
convert
c
control
d
carry
e
package
the
carry
out
the
following
functions?
proteins
light
out
and
( µm)
multiplying
same
a
Copy
of
size
the
magnication
SUMMARY
by
technique
photograph
reduction
actual
micrometres
micrometres
energy
into
substances
reactions
and
in
the
that
pass
aerobic
transport
complete
chemical
by
into
and
out
of
a
cell
respiration
proteins
table
energy
around
using
ticks
the
and
cell
crosses.
Figure
2.2.3
An
of
feature
bacterial
cell
liver
cell
palisade
electron
a
micrograph
mitochondrion
cell
(×80 000).
cell
wall
rough
ER
KEY
POINTS
chloroplast
1
mitochondrion
Ribosomes
the
on
cytoplasm
rough
make
ER
and
in
proteins.
vesicle
2
Rough
ER
packages
transports
3
a
Measure
the
length
of
the
mitochondrion
in
the
electron
3
micrograph.
It
has
been
magnied
80 000
times
and
proteins.
(x
Aerobic
respiration
occurs
in
80 000).
mitochondria.
Calculate
the
micrometres
actual
length
of
the
mitochondrion
in
4
( µm).
Cells
with
high
respiration
b
Calculate
the
actual
size
of
the
liver
cells
and
the
rates
have
of
many
onion
mitochondria.
cells
on
pages
18
and
19.
21
2.3
Different
T
o
LEARNING
function
Identify
cell
different
from
types
diagrams
of
of
cells
In
Relate
cells
the
to
features
their
the
of
to
body
organism
and
photographs
•
are
Calculate
and
organisms
have
cell
and
topic
certain
divided
we
between
from
change
look
a
to
at
functions.
different
fertilised
become
some
This
cells
egg,
groups
new
of
of
cells
specialised
examples
means
that
for
that
are
the
cells.
are
functions
an
produced.
certain
specialised
As
These
functions.
cells.
these
functions
cells
magnication
actual
size
of
biological
Ciliated
specimens
using
cells
are
found
in
the
air
passages
in
the
lungs
(trachea
and
millimetres
bronchi)
as
out
develops
grow
this
carry
Specialised
•
many-celled
of
OUTCOMES
specialised
•
efciently,
types
and
in
the
oviducts
in
the
female
reproductive
system.
These
units
cells
have
current
cilia
in
the
on
their
uid
surfaces.
next
to
the
Cilia
cell
beat
back
and
forth
to
create
a
surfaces.
cilia move
ciliated
these cells
cells
make mucus
In
the
up
to
the
area
root
2.3.1
Ciliated
cells
line
to
hair
to
move
and
throat.
the
the
mucus
In
the
that
traps
oviducts,
cilia
dust
and
move
pathogens
the
egg
from
uterus.
cells
absorb
hair
cilia
nose
ovary
Root
Figure
airways,
the
have
water
long
and
extensions
ions
from
that
the
give
them
a
large
surface
soil.
cells
xylem
vessels
the
airways.
STUD
Y
Whe
n
a
cell
TIP
explai
ning
Figure
2.3.2
Root
and
is
adap
ted
hair
to
thin
you
tions
give
featur
es
each
one
carry
,
mak
the
say
helps
its
the
are
long
Figure
how
Xylem
vessels
columns
of
like
cellulose
water
and
tubes
the
help
from
are
pipes.
and
ions
Ner ve
cells
to
the
up
soil.
a
cylindrical
The
cell
and
walls
waterproof
to
move
support
cells
are
cytoplasm
form
Red
empty.
are
from
They
thickened
material
the
called
roots
of
nerve
blood
the
highly
like
and
specialised
wires.
impulses
cells
stem
are
carry
small
water
the
stem.
are
arranged
with
bands
lignin.
These
into
or
spirals
to
the
rest
of
the
cells
plant.
allow
They
They
are
around
leaves.
cells.
able
the
protein
that
carries
shaped
This
surface
their
Nerve
cells
carry
like
shape
the
oxygen.
They
thin
extensions
information
in
of
the
body.
blood
cells
attened
provides
volume
a
discs.
large
compared
which
are
with
makes
for
Figure
impulses
body.
have
transmit
haemoglobin
area
efcient
around
They
to
contain
red
the
absorption
of
2.3.5
Red
blood
cells
have
a
substance
oxygen.
called
haemoglobin
oxygen.
22
vessels
that
func
tion.
Nerve
2.3.4
Xylem
cell
also
Figure
2.3.3
absorb
sure
struct
ural
and
out
e
to
its
water
func
cells
how
that
carries
Palisade
These
The
cell.
by
plant
cells
have
chloroplasts
have
cell
mesophyll
trap
cell
wall
In
the
cytoplasm
sap.
numerous
light
a
made
Starch
up
of
are
and
chloroplasts
energy
there
grains
photosynthesis
cells
tough
is
a
a
in
in
the
cytoplasm.
photosynthesis.
cellulose
large
found
are
for
which
vacuole
the
which
cytoplasm.
temporary
store
of
Palisade
strengthens
is
lled
These
cells
the
with
are
formed
energy.
Figure
Sperm
the
sperm
female
Egg
of
cells
have
carries
parent.
cells
are
energy
.
a
tail
genetic
Genes
much
Genes
and
of
adapted
information
from
bigger
the
are
the
from
father
than
mother
are
sperm
are
for
the
male
present
cells.
found
swimming.
They
inside
in
parent
the
head
to
yolk
nucleus
Leaf
lots
palisade
of
cells
contain
chloroplasts
photosynthesis
for
(×500).
nucleus.
as
of
2.3.6
of
the
sperm
contain
the
The
a
the
store
egg.
middle
head
Look
real
To
of
carefully
life.
work
the
This
out
cells
at
Figure
means
the
in
2.3.6.
that
actual
the
size
millimetres.
The
cells
of
cells
have
these
Let’s
are
say
been
cells,
it
500
times
larger
magnied
measure
measures
the
500
than
times.
length
20 mm.
Now
of
we
one
can
a
use
a
formula
to
work
out
the
image
actual
size
actual
size
of
the
tail
piece
in
sperm
cell:
size
=
Figure
2.3.7
Sperm
cells
have
a
tail
for
magnication
swimming
So
T
o
the
actual
calculate
size
the
of
actual
cell
is
magnication
magnication
The
our
20
of
divided
an
image
size
actual
size
by
object
500
we
=
(×2000).
0.04 mm
reorganise
the
formula:
membrane
=
diameter
of
an
egg
cell
cytoplasm
is
0.1 mm.
To
calculate
its
jelly
magnication
by
0.1 mm
to
in
Figure
give
SUMMARY
2.3.8
we
divided
the
diameter
of
the
×180.
nucleus
QUESTIONS
Figure
2.3.8
Egg
cells
store
1
Draw
its
a
table
correct
T
ype
of
matching
shape
cell
and
the
type
of
cell
in
the
blood
Shape
cells
rst
hollow
like
with
the
air
from
passages
dust
water
and
wires
ions
KEY
transmit
root
hair
cells
at
energy
tube
transport
cells
an
Function
free
ciliated
column
contain
(×180).
function:
keep
red
coat
drawing
POINTS
electrical
discs
1
During
development,
cells
impulses
change
nerve
cells
long
and
thin
transport
often
absorb
xylem
vessels
have
cilia
that
their
water
from
their
the
2
Specialised
structure
Here
the
out
are
some
functions
their
other
of
specialised
these
cells
and
cells.
how
Use
they
this
are
book
to
adapted
functions.
nd
to
out
carry
to
carry
muscle
d
pollen
cell
b
goblet
cell
c
white
blood
cells
that
out
a
function,
e.g.
have
to
cilia
along
a
and
shape.
move
soil
2
structure
oxygen
the
have
a
enables
them
particular
ciliated
move
cells
mucus
windpipe.
cell
cell
23
2.4
Levels
Tissues
LEARNING
Dene
the
terms
tissue,
group
organ
Describe
of
same
examples
of
and
that
occur
in
is
work
called
a
tissue.
together
to
All
carry
the
out
a
cells
tissue
and
is
made
so
the
tissue:
blocks
similar
up
of
muscle
identical
tissue
muscle
cells.
in
working
the
groups
look
These
cells
work
system:
same
way
of
tissues
a
working
group
cells
contract
muscle
tissue
is
made
your
heart
is
made
of
cardiac
muscle
cells
that
contract
muscle
and
other
pumps
blood
tissues;
it
2.4.1
Levels
of
organisation
relax
in
the
together
human
An
circulatory
organ
together
The
STUD
Y
heart
Lear
n
these
book
.
deni
tions
orga
n
and
Mak
e
exam
ples
plan
t
as
work
system
.
orga
n
working
your
group
of
body
your
and
your
carries
blood
vessels
circulator y
blood
system
around
body
made
up
perform
an
of
a
specic
example
of
different
tissues
that
work
functions.
an
organ.
It
is
made
up
of
different
tissues
TIP
such
tissu
e,
is
organs
system.
is
to
around
up
which
relax
and
heart
make
and
of
of
together
together
your
cardiac
of
a
list
of
and
orga
ns
system
s
together
muscle,
to
nervous
pump
blood
tissue,
around
brous
the
tissue
and
blood
that
body.
of
The
anim
al
tissu
es,
cardiac
stomach,
lungs,
brain
and
kidneys
are
all
organs.
orga
n
from
and
this
Different
systems
blood
are
to
other
and
a
work
digestive
liver
work
of
perform
vessels
some
The
organs
consist
together
•
body
of
as
part
organs
as
part
of
an
with
functions.
together
For
of
organ
related
example,
the
system.
functions,
the
circulatory
heart
Organ
working
and
system.
Here
systems:
system
is
made
up
of
the
gullet,
stomach,
pancreas,
intestines.
The
excretory
•
The
nervous
•
The
reproductive
and
vagina;
and
penis.
the
together
group
organ
•
All
24
tissue
contracts.
organ:
cells
together
Figure
a
function.
animals
building
muscle
in
shared
plants
cells:
the
cells
they
the
together
above
similar
and
system
Muscle
•
organs
organ
the
and
organisation
OUTCOMES
A
•
and
of
system
system
in
different
is
is
made
made
system
males
organ
it
is
in
up
up
of
of
the
the
females
the
systems
is
testes,
make
kidneys,
brain,
the
a
spinal
ovaries,
sperm
up
ureters
ducts,
living
and
cord
bladder
.
and
oviducts,
prostate
organism
nerves.
uterus
gland
Plant
The
tissues
diagrams
and
show
photosynthesis
in
organs
the
tissues
leaves
is
in
called
a
leaf.
The
tissue
mesophyll.
The
that
cells
carries
out
making
up
DID
layer
of
the
mesophyll
are
called
palisade
cells.
These
cells
word
packed
and
full
of
chloroplasts
so
that
they
are
well
the
absorb
lots
of
light.
The
palisade
cells
make
up
the
tissue.
All
the
cells
making
up
this
tissue
is
are
used
close
like
the
wooden
stakes
palisade
used
mesophyll
cells
adapted
together
to
‘palisade’
are
because
closely
KNOW?
the
The
upper
YOU
look
alike
to
make
walls
known
as
and
palisades.
do
A
the
leaf
Other
same
is
an
function
organ.
structures,
cells:
the
building
–
they
Other
such
absorb
plant
as
light
organs
owers
and
for
are
photosynthesis.
roots
fruits,
are
and
stems.
modied
leaves.
blocks
organ:
groups
working
tissue:
leaf
similar
cells
of
tissues
together
working
palisade
together
in
the
same
way
the
leaf
food
for
palisade
mesophyll
makes
and
gas
allows
exchange
cells
upper
epidermis
photosynthesis
takes
place
cells
in
the
mesophyll
tissue
organism:
milkweed
spongy
mesophyll
is
cells
made
the
plant
up
of
organs
lower
Figure
2.4.2
Levels
of
organisation
SUMMARY
QUESTIONS
1
complete
in
a
owering
epidermis
cells
plant.
STUD
Y
Mak
Copy
and
the
sentences
using
these
e
words:
TIP
sure
explai
n
organ
system
cells
tissues
tissue
An
is
organ
made
is
An
formed
is
several
up
a
body
of
that
from
group
of
a
group
organs
carry
out
of
the
same
working
working
together
to
.
adap
ted
together.
to
Copy
out
correct
the
organs
system
listin
g
the
from
listed
those
on
the
listed
left.
on
Match
the
each
with
trachea
digestive
and
blood
vessels
nervous
brain
and
spinal
cord
gas
KEY
one
Cells
that
oviducts
and
uterus
stomach
and
intestines
the
bladder
following
with
the
are
to
grouped
form
tissues.
Different
tissues
make
up
circulatory
words
smallest
into
and
the
ending
correct
with
to
sequence,
the
system
tissue
do
a
which
work
particular
together
function.
largest:
3
organ
same
reproductive
organs
Arrange
the
excretory
2
and
have
exchange
together
organ
and
each
POINTS
function
ovaries,
starting
how
helps.
the
1
3
by
featur
es
right.
heart
kidneys
out
System
and
gullet,
is
functions.
Organs
lungs
cell
pho to
synt
hesis
perform
can
palis
ade
carry
explai
ning
2
a
function
meso
phyl
l
A
you
how
organism
cell
Different
together
organs
as
work
organ
systems.
25
PRACTICE
1
Which
QUESTIONS
structure
is
found
only
in
plant
6
cells?
The
diagram
liver
A
cell
B
chloroplast
C
cytoplasm
D
nucleus
(Paper
shows
a
mitochondrion
1)
Which
[1]
structure
is
not
found
in
animal
cell
membrane
B
cell
wall
C
cytoplasm
D
nucleus
3
Which
the
is
[1]
the
correct
and
sequence,
ending
with
starting
the
7
tissue,
B
cell,
C
tissue,
D
cell,
organ
system,
organ,
organ
system,
×4000
B
×400
D
×40 000
The
(Paper
tissue,
organ,
organ
system
A
out,
A
CO
in,
specimen.
drawing
×40.
A
The
is
is
drawing
length
140
What
a
mm.
the
of
the
The
actual
5600 mm
of
CO
out,
and
out
of
CO
O
8
Cells
in,
nutrients
in
in,
nutrients
out
2
out,
(Paper
in
2
in,
CO
nutrients
O
out,
nutrients
out
2
2)
of
[1]
organisms
contain
classied
which
of
in
the
the
prokaryote
following?
biological
specimen
of
O
2
in
magnication
size
B
a
in
2
2
[1]
makes
O
2
2
1)
student
move
with
kingdom
4
that
are:
D
system
[1]
substances
organ
organ
is:
2)
mitochondria
cell
organ,
diagram
C
largest?
cell,
the
×40
C
tissue,
of
A
B
A
magnication
(Paper
1)
smallest
µm
cells?
The
A
(Paper
a
membrane
1.0
2
from
cell.
the
A
cell
membrane,
B
cell
wall,
enzymes,
nucleus,
vesicles
the
is
cell
membrane,
cytoplasm,
ribosomes
specimen?
C
56 mm
cytoplasm,
DNA,
endoplasmic
DNA,
enzymes,
reticulum,
ribosomes
C
35 mm
D
3.5 mm
D
(Paper
1)
Which
is
cytoplasm,
(Paper
5
not
found
in
an
animal
2)
[1]
cell?
9
A
mitochondria
[1]
The
palisade
mesophyll
cell
is
a
type
of
plant
nucleus
B
permanent
C
ribosomes
D
rough
cell.
A
2)
cell
and
complete
is
a
type
of
animal
cell.
Copy
vacuole
endoplasmic
cells.
Copy
think
reticulum
you
(Paper
liver
the
think
the
the
table
table
structure
it
is
is
to
and
compare
put
present
a
tick
and
a
these
(✓)
if
cross
two
you
(✗)
if
absent.
[1]
palisade
cell
liver
structure
mesophyll
cell
wall
cell
membrane
cell
cell
cytoplasm
nucleus
chloroplast
large
(Paper
26
vacuole
2)
[6]
10
The
diagram
shows
three
animal
(iii)
cells.
the
organ
system
for
transport
in
mammals;
(iv)
the
plant
[1]
tissue
that
transports
sugars.
(b)
Distinguish
[1]
between
the
following
pairs
of
terms.
B
A
(a)
Identify
the
(b)
State
the
(c)
State
where
(i)
Organs
(ii)
Cytoplasm
(iii)
Cell
(iv)
Organ
A,
functions
B
and
of
the
C.
[3]
three
cells.
the
body
these
cells
13
(a)
Five
cell
magnication
of
cell
A
is
system
and
and
cell
wall
[2]
organism
[2]
structures
and
their
functions
are
its
actual
size
in
below.
×1000.
Cell
The
membrane
[3]
Calculate
11
[2]
3)
listed
(Paper
nucleus
are
found.
The
and
[2]
[3]
(Paper
(d)
tissues
C
cells
in
and
millimetres.
structures
[2]
A
nucleus
B
cell
membrane
C
cell
wall
D
large
E
ribosome
F
rough
G
mitochondrion
3)
diagram
shows
three
plant
cells.
D
vacuole
endoplasmic
reticulum
E
Functions
1
controls
into
the
and
movement
out
2
stores
water
3
makes
4
withstands
of
the
and
of
substances
cell
ions
proteins
pressure
of
water
inside
F
the
(a)
Identify
(b)
State
(c)
For
the
each
organ
a
(d)
the
cell,
where
actual
Calculate
D,
functions
different
The
cells
D,
it
E
is
E
of
and
the
and
F,
found.
F.
three
state
In
cells.
a
each
the
5
carries
[3]
6
transports
7
stores
DNA
of
cell
give
organ.
length
[3]
plant
case
[3]
of
cell
D
is
magnication
Match
the
out
each
function
0.05 mm.
of
cell
by
of
(a)
proteins
and
the
within
controls
cell
writing
a
the
the
activities
structures
letter
and
cell
with
a
its
number.
[5]
[2]
(b)
A
student
looked
microscope.
12
respiration
the
drawing.
(Paper
aerobic
She
at
a
cell
made
a
under
a
drawing
light
of
3)
the
cell
the
nucleus
and
showed
the
diameter
of
Name:
(i)
an
animal
cell
which
does
not
have
nucleus;
a
[1]
She
(ii)
a
plant
cell
that
does
not
have
calculated
drawing
size
of
as
the
her
the
drawing
70 mm.
magnication
×10 000.
nucleus
as
in
What
is
the
of
her
actual
micrometres?
Show
a
your
nucleus;
in
working.
[2]
[1]
(Paper
4)
27
3
Movement
3.1
in
out
of
cells
Diffusion
Molecules
LEARNING
Dene
•
Describe
in
the
term
liquid
diffusion
and
do
move
the
importance
about
in
a
random
way.
They
bump
into
one
of
gases
Describe
the
water
a
and
as
in
a
out
well,
gas
to
ll
up
although
is
faster
as
all
it
the
takes
the
space
available.
longer
molecules
for
are
them
more
Molecules
to
ll
the
spread
in
a
space.
out.
The
of
difference
diffusion
spread
this
Movement
in
speed
between
movement
in
gases
and
liquids
is
important
solutes
for
as
gases
OUTCOMES
another
•
•
and
importance
organisms.
This
movement
of
molecules
is
called
diffusion
of
solvent
water
molecules
substance
in
before
Figure
diffusion
after
3.1.1
Diffusion
in
a
gas.
a
coloured
gas
spread
the
TIP
you
write
molecules
of
them
not
as
that
place
to
they
ano th
er
,
that
e
difference
in
A
entrat
one
you
has
a
large
so lu
te
given
disso
lved
high
is
the
ient.
that
are
easily
,
of
vo lu
me
in
a
of
the
where
to
there
where
are
there
low
concentration).
The
difference
between
carry
on
in
two
places
diffusing
molecules
so
until
keep
is
a
they
moving,
diffusion
has
concentration
are
but
spread
there
is
out
no
evenly.
longer
stopped.
movement
to
a
of
molecules
region
of
lower
or
ions
from
a
concentration
region
down
a
the
substances
also
lose
they
some
of
need
their
by
diffusion
waste
from
substances
their
to
their
diffusion.
These
permeable
as
oxygen,
larger
substances
as
they
carbon
molecules.
allow
dioxide
The
have
the
and
to
water
movement
cross
cell
movement
of
to
membranes
of
pass
molecules
small
through
by
diffusion
cell
membranes
is
passive
movement
as
cells
do
not
need
to
use
a
to
move
the
molecules.
the
energy
for
of
diffusion
molecules
comes
and
from
ions.
the
The
kinetic
more
energy
molecules
of
random
present,
the
has
their
kinetic
energy
and
therefore
their
rate
of
movement.
so lu
te
given
that
affect
diffusion
so lven
t.
These
factors
•
distance
The
are
•
The
as
28
by
not
Factors
of
of
They
such
but
across
in
so lu
tion
mas
s
from
of
The
disso
lved
(a
molecules
the
net
partially
molecules
greater
smal
l
out
concentration)
gradient.
some
movement
a
of
concentration
gain
energy
dilu
te
spread
high
say
so lven
t.
A
them
concentrations
concentration
so lu
tion
mas
s
vo lu
me
they
(a
the
grad
conc
entrat
ed
diffuse
volume
alwa
ys
down
ion
liquid.
abou
t
surroundings
conc
of
happens
this
surroundings.
mov
a
are
from
sure
many
When
Cells
mak
e
ions
given
Molecules
of
diffus
ing
or
a
concentration
Diffusion
mo lec
ules
in
gradient.
a
Whe
n
in
container
.
the
STUD
Y
Diffusion
water
diffusion
out
are
through
3.1.2
after
solute
Molecules
lots
of
diffusion
of
through
diffusion
When
Figure
molecules
dispersed
tnemelppuS
before
soluble
water
very
inuence
the
molecules
efciency
have
to
of
travel
diffusion:
–
note
that
cell
membranes
thin.
concentration
quickly
as
gradient
possible,
so
–
they
cells
use
keep
a
the
low
substances
that
concentration
diffuse
inside
the
tnemelppuS
cytoplasm.
because
This
the
means
cell
is
that
molecules
maintaining
a
keep
steep
diffusing
into
concentration
the
cell
red
blood
cells
gradient.
air
•
The
surface
give
•
The
a
area
large
some
surface
temperature
temperature
Gas
–
–
to
have
allow
many
molecules
move
increases.
versus
cells
Diffusion
is
cell
membranes
molecules
faster
faster
to
and
at
that
cross
collide
warmer
are
by
folded
diffusion.
more
often
as
the
temperatures.
liquid
There
Animals
with
the
and
their
gas
plants
page
and
all
exchange
surroundings
exchange
(see
131).
at
surface
the
gas
is
gases
oxygen
exchange
formed
Blood
transports
in
body.
of
surfaces.
the
these
and
alveoli
two
carbon
In
in
gases
dioxide
red
a
short
cells
Magnication
mammals,
the
is
blood
distance
and
very
thin
opposite
cells
layer
of
the
cells
direction.
into
In
the
Breathing
the
alveoli,
blood.
Carbon
constantly
diffuses
dioxide
refreshes
the
blood
constantly
removes
oxygen
and
brings
air
in
in
the
concentration
gradients
are
always
steep.
carbon
There
the
TIP
Alway
s
dioxide,
refer
are
many
give
a
very
large
surface
area
for
gas
dilu
te
plants,
cells
gas
provide
exchange
a
large
spaces
between
this
(see
air
the
page
occurs
surface
cells
64).
in
This
300 000
times
faster
Water
as
solvent
a
inside
area
a
is
than
for
plant
the
the
to
and
efcient
through
‘stro
ng’
exchange.
leaves.
The
exchange
each
cell
because
spongy
of
There
are
exchanges
gases
with
through
the
air
air
is
SUMMARY
QUESTIONS
1
complete
water.
Copy
and
sentences
A
solution
is
made
up
of
two
parts,
the
solute
and
the
solute
dissolves
in
the
solvent.
If
you
dissolve
sugar
using
in
water
a
sugar
solvent.
can
be
The
solution.
solute
solutes
dissolves
in
a
as
is
not
they
solvent
The
always
can
is
sugar
is
a
solid
dissolve
described
the
in
as
solute
like
sugar.
solvents
being
and
the
water
Liquids
too.
random
is
and
gases
Something
is
sometimes
called
the
universal
gas
is
which
of
soluble
solvent.
the
molecules
a
About
75%
is
water
and
it
is
the
main
component
of
of
from
an
blood,
and
xylem
sap
and
phloem
sap
in
transport
plants.
movement
a
or
an
area
area
of
of
of
as
a
result
of
uids
the
like
high
net
concentration
cytoplasm
diffusion
the
to
Water
words:
you
low
make
the
these
solvent.
liquid
The
and
so lu
tions
.
mesophyll
gases.
diffusion
so lu
tions
,
alveoli
‘ weak
’
In
to
so lu
tions
so
neve
r
to
the
alveoli.
alveoli
and
the
the
a
conc
entrat
ed
and
in
lungs
across
diffuses
the
between
air
lungs
between
oxygen
the
×1500.
STUD
Y
the
space
to
movement
of
Everything
molecules.
transported
of
the
water
KEY
1
is
plants
needed
and
reactions
for
animals
that
digestion
has
occur
and
to
in
dissolve
cells
excretion
in
happen
to
take
water
in
and
water.
most
Also,
2
place.
Diffusion
down
of
a
is
the
high
net
movement
concentration
concentration
Factors
that
surface
area,
affect
to
a
molecules
region
of
or
ions
low
from
diffusion
gradient.
are:
and
how
the
size
of
concentration
molecule,
steepness
of
distance,
the
into
a
distance
b
size
c
surface
d
concentration
e
temperature
of
factors
cells:
molecule
area
3
What
do
the
gradient
terms
concentration
the
following
diffusion
a
gradient.
temperature
concentration
of
State
affect
POINTS
region
2
in
chemical
4
Explain
why
important
and
solution
gradient
water
solvent
is
and
mean?
an
for
animals
plants.
29
3.2
Osmosis
Each
LEARNING
of
•
Dene
the
•
Describe
the
term
on
and
osmosis
the
Explain
of
the
water
cells
surrounded
effect
animal
and
tissues
the
out
term
allows
cell
the
by
a
cell
small
outside.
membrane.
The
molecules
membrane
is
cell
It
separates
to
described
membrane
pass
as
through
being
has
the
but
tiny
contents
not
partially
holes
large
in
it
ones.
permeable
osmosis
movement
into
using
of
from
of
Osmosis
occurs
is
a
when
special
two
kind
of
solutions
diffusion
are
involving
separated
by
a
water
molecules.
partially
It
permeable
membrane
water
Osmosis
is
the
diffusion
of
water
from
a
dilute
solution
into
a
more
potential
concentrated
The
tiny
solution
holes
membrane
in
through
a
partially
permeable
membrane.
the
allow
Water
small
molecules
solute
diffuse
water
molecules
to
pass
water
through,
solute
too
the
but
the
molecules
big
to
pass
partially
from
a
high
molecule
large
to
a
concentration
lower
water
concentration
are
through
permeable
fewer
membrane.
Water
is
water
many
diffusing
from
a
place
molecules
water
where
there
is
a
dilute
molecules
STUD
Y
TIP
solution
with
a
high
concentration
of
water
dilute
If
aske
d
to
dene
to
a
place
where
there
is
solution
concentrated
partially
osmos
is
it,
mak
that
of
it
or
e
is
wate
r
write
sure
the
abou
t
you
say
diffus
ion
mo lec
ules.
concentrated
permeable
with
membrane
a
low
concentration
of
Figure
3.2.1
Osmosis.
water
Water
to
potential
move
by
available,
water
a
in
dilute
water
In
the
two
solution
of
water
A
dialysis
to
are
lot
is
a
free
a
of
on
a
of
ability
much
of
water
water
pressure
accurate
molecules)
is
exerted
to
say
has
(containing
potential
molecules
high
partially
water
a
on
that
high
fewer
left
since
hand
through
potential
gradient
diffuse
potential
permeable
through
However,
the
molecules
water
the
more
water
water
move
energy.
is
as
solution
water
region
to
It
the
how
water
potential
The
through
by
such
wall.
a
water
present
water
the
factors
cell
there
about
inuenced
concentrated
from
kinetic
of
down
Dialysis
A
potential
by
the
membrane.
molecules
model
by
above,
the
thinking
is
other
low
molecules
movement
right,
a
gradient,
directions
water
has
of
This
(containing
potential.
potential
way
by
cells
diagram
Water
a
also
plant
sides
lower
is
osmosis.
but
molecules)
30
solution
solution
a
the
the
to
a
this
the
water
region
of
membrane.
membrane
there
side,
between
down
are
there
in
many
will
membrane
both
more
be
from
a
net
left
to
gradient.
cell
tubing
tubing
represent
(Visking
to
the
tubing)
represent
cytoplasm.
the
is
partially
cell
permeable.
membrane
and
We
the
can
sugar
use
solution
tnemelppuS
tnemelppuS
•
is
cell
which
The
plant
cell
OUTCOMES
PRACTICAL
1
Cut
two
pieces
water diffuses
of
into ‘cell’
dialysis
12 cm
tubing,
long.
each
Tie
one
end
sugar
solution
of
each
with
cotton.
dialysis tubing
2
Fill
one
model
cell
with
a
(partially
dilute
sugar
solution
permeable
(cell
membrane)
A).
Fill
the
other
model
water
STUD
Y
cell
with
water
(cell
‘cell
3
Tie
the
other
end
TIP
B).
of
A
’
Y
ou
both
may
be
given
water diffuses
model
cells
and
resul
ts
weigh
out of ‘cell’
them
‘cell
on
A
’
water
a
a
balance.
into
and
beaker
a
Put
beaker
put
‘cell
B’
a
demon
stratio
n
and
into
the
be
resul
ts.
solution
of
30
minutes
to
solution
out
the
model
Mak
e
the
sure
you
den
ition
osmo
sis
and
sugar
permeable
take
osmo
sis
explai
n
dialysis tubing
of
After
to
a
(partially
sugar
.
of
expec
ted
remem
ber
concentrated
the
pract
ical
water
of
containing
of
the
resul
ts
cells
apply
you
it
can
see.
membrane)
Alwa
ys
and
weigh
them
again.
‘cell
resul
ts
‘Cell
A
’
increases
in
mass
explai
n
because
are
molec
ules
capillar y
water
has
diffused
into
the
‘cell’
level
by
that
B’
due
to
the
water
movin
g
by
of
osmo
sis.
tube
sugar
osmosis.
‘Cell
B’
decreases
in
mass
solution
because
water
by
has
the
cell
An
osmometer
diffused
out
of
osmosis.
dialysis
tubing
containing
Y
ou
can
you
set
Fill
the
see
up
the
this
partially
membrane
effects
of
osmosis
water
if
concentrated
apparatus.
sugar
solution
permeable
with
a
very
KEY
concentrated
solution
of
1
Tie
it
to
a
capillary
tube
and
stand
it
in
POINTS
sugar.
Osmosis
water
Very
quickly
measure
your
you
how
ideas
will
fast
about
it
see
is
the
liquid
moving
osmosis
to
moving
using
explain
a
up
ruler
why
is
the
diffusion
of
water.
the
and
the
a
tube.
Y
ou
stopwatch.
liquid
rises
in
of
can
their
(dilute
Use
the
molecules
of
tube.
higher
their
lower
through
a
a
region
concentration
solution)
(concentrated
from
to
a
region
concentration
solution)
partially
permeable
membrane.
SUMMARY
QUESTIONS
2
A
partially
permeable
membrane
1
Dene
the
following
molecules
diffusion
2
Describe
osmosis
practical
osmosis
how
into
you
a
can
sugar
partially
nd
out
solution.
permeable
how
fast
water
Remember
to
membrane
diffuses
include
pass
tnemelppuS
Explain
all
details.
in
terms
water
potential,
how
water
passes
cells
placed
in
distilled
as
but
molecules.
3
Water
molecules
water
a
potential
water
not
to
large
region
of
diffuse
down
gradient
higher
water
into
potential
plant
such
through
solute
a
of
small
by
from
3
allows
terms:
to
a
region
of
lower
water.
water
potential.
31
3.3
Osmosis
animal
LEARNING
•
Describe
enter
OUTCOMES
how
and
water
leave
plant
and
cells
PRACTICAL
can
plant
in
Osmosis
cells
in
potato
cells
by
1
Cut
nine
cores
from
a
potato
so
that
they
are
exactly
the
same
osmosis
length.
•
Describe
affect
how
animal
osmosis
Record
this
length.
can
2
Feel
3
Set
the
cores
to
see
how
rm
and
‘bendy’
they
are.
cells
up
the
following
test-tubes:
B
A
STUD
Y
test-tube
A
test-tube
B
–
distilled
–
dilute
water
distilled
dilute
water
sugar
sugar
TIP
solution
solution
Whe
n
cell
desc
ribin
g
mem
bran
e
say
that
it
is
test-tube
concentrated
the
sugar
4
partia
no t
–
solution.
alwa
ys
Place
three
cores
of
potato
0
1
2
3
4
5
6
7
8
9 10
0
1
2
3
4
5
6
7
8
9 10
lly
into
perm
eable,
C
each
test-tube
and
tissue
swells
up
no
change
semileave
perm
eable.
5
them
Remove
for
the
measure
60
cores
their
minutes.
C
and
concentrated
sugar
lengths.
solution
Calculate
of
cell
the
the
cores
average
in
each
length
test-tube.
membrane
Compared
(partially
to
the
start,
cores
permeable)
will
0
be:
1
tissue
water
A
cytoplasm
–
longer
and
2
3
4
5
6
shrunken
7
8
9 10
and
flaccid
rmer
passes
into
the
B
–
about
the
C
–
shorter
same
length
and
rmness
vacuole
vacuole
by
and
softer
and
‘bendier’.
osmosis
cell
wall
(freely
These
results
are
explained
in
the
text.
permeable)
the
cell
solution
is
less
outside
the
concentrated
Turgidity
than
in
the
vacuole
The
Figure
3.3.1
Osmosis
in
a
plant
cell
sap
inside
cells
are
there
STUD
Y
tnemelppuS
Paper
expec
ted
Y
ou
4
to
you
use
osmo
sis
may
the
As
be
wall
wall
in
and
refer
plan
t
is
plant
a
cell
water,
solution
is
partially
the
of
water
gradient
salts
permeable
enters
so
and
the
that
sugars.
and
cells.
water
When
the
cell
This
is
plant
because
molecules
diffuse
enters
osmosis.
it
makes
water
stops
as
the
it
a
can
cell
the
cell
turgor
hold.
It’s
bursting.
swell
up.
pressure.
like
We
a
say
The
blown-up
that
water
Eventually
the
pushes
the
cell
balloon.
cell
is
against
contains
The
turgid.
strong
This
is
the
as
cell
what
or
to
happened
to
the
cells
in
the
potato
cores
in
tube
A.
The
cells
have
water
,
swollen
and
caused
the
core
to
get
slightly
longer
.
‘ water
T
urgid
cells
plants
upright.
give
the
plant
support.
They
keep
the
stems
of
many
to
This
is
because
the
cells
within
a
stem
are
supported
movem
ent
by
out
by
tissu
es.
grad
ients
’
water
and
tissu
es.
the
potential
developing
absorbed
also
poten
tial
into
in
water
cells
water
cell
term
has
cells
can
explai
n
of
vacuole
placed
a
the
much
abou
t
anim
al
of
cells
turgor
pressure.
The
water
pressure
within
the
cell
acts
against
the
and
inelastic
these
and
32
is
the
TIP
into
In
membrane
cell.
cell
cells
leaves
walls,
lose
that
keeping
water,
have
they
lost
the
are
cells
no
water
turgid
longer
wilt
and
rm
rm.
and
However,
turgid.
when
Plant
stems
tnemelppuS
Plasmolysis
the solution outside the
cell is more concentrated
When
plant
cells
are
placed
into
a
concentrated
sugar
or
salt
solution
than in the vacuole
water
passes
vacuole
limp.
out
starts
We
say
of
to
the
cells
shrink.
that
they
by
These
are
osmosis.
cells
are
accid.
As
As
no
water
longer
more
passes
rm,
water
out,
and
leaves
the
sap
become
the
cells
water
out
the
by
cytoplasm
starts
plasmolysed.
cores
core
in
is
to
test-tube
shorter
move
This
is
C.
than
away
what
The
at
cells
the
from
has
the
cell
happened
have
wall.
to
the
decreased
in
These
cells
cells
in
the
volume
so
are
passes
of
the
cell
osmosis
now
potato
the
whole
as cytoplasm is pulled
start.
away from the cell
The
the
cores
in
water
water
test-tube
potential
potential
overall
about
of
diffusion
the
did
not
change
of
the
sugar
the
cell
sap
of
same
B
water
into
in
solution
in
the
or
out
length
was
potato
of
the
very
about
cells.
cells
much
the
There
so
because
same
has
they
as
been
have
wall, the cell becomes
plasmolysed
the
no
Figure
3.3.2
Water
cell
stayed
passes
by
out
of
a
plant
osmosis.
length.
a
Osmosis
Figure
in
3.3.3
placed
in
animal
shows
different
cell
membrane
The
red
blood
Their
The
cytoplasm
cells
cells
by
them
in
D
in
a
they
so
to
picture
have
cells
has
the
the
blood
blood
salt
been
water.
cells
when
solution.
they
E
same
of
they
are
Remember
passes
not
water
no
blood
shrink
into
proteins,
have
red
have
when
placed
Water
cells
When
(F),
in
red
a
solution
animal
burst.
solution
The
of
that
permeable.
distilled
they
salt
in
the
in
which
are
partially
However,
osmosis.
solution
how
happens
concentrated
were
swelling
by
is
in
a
osmosis.
concentrated
cells
is
what
concentrations
the
cells
cells
as
into
cells
potential
by
and
are
put
size
as
stop
into
out
as
the
blood
sugars.
b
to
passes
in
liquids.
the
wall
water
surrounded
salts
cell
changed
different
a
of
they
cells.
the
are
This
is
plasma.
D
These
(a)
Figure
3.3.3
This
shows
water
as
(D)
they
what
and
a
appear
happens
when
concentrated
when
red
blood
solution
suspended
in
of
cells
salt
blood
are
(F).
E
put
into
shows
KEY
distilled
red
blood
epidermal
turgid
1
plasma.
Water
passes
osmosis.
of
what
is
turgid
water
meant
turgor
Some
potato
dilute
sugar
by
each
of
pressure
these
mass
and
accid
2
plasmolysis
If
plant
cores
were
solution.
dried
on
a
weighed
After
paper
2
and
hours,
towel
then
they
and
placed
were
weighed
into
taken
of
of
the
potato
What
does
sugar
solution?
Explain
tnemelppuS
Explain,
cells
are
passes
turgid.
cells
that
is
T
urgid
cores
remained
this
tell
you
about
the
your
answer
to
part
a
in
using
the
term
water
These
cells
are
shrinks,
unchanged.
concentration
terms
potential,
when
they
are
placed
into
of
what
distilled
for
stems.
of
into
a
solution,
out
by
osmosis.
are
no
happens
to
for
60
accid.
longer
the
cell
away
As
the
rm,
vacuole
membrane
from
the
cell
wall
–
the
3
osmosis.
water
placed
sugar
again.
cell
Animal
cores
is
now
cells
into
plasmolysed.
burst
water
if
they
as
are
they
of
have
potato
cell
support
young
water
placed
3
plant
the
the
b
are
a
out
moves
a
onion
terms:
they
The
red
plant
is
concentrated
solution,
into
A
provide
leaves
2
a
QUESTIONS
cells
Explain
from
plasmolysed.
POINTS
full
1
cells
(b)
cells
by
SUMMARY
and
no
cell
wall
to
resist
the
minutes.
increase
in
size.
33
3.4
Active
Active
LEARNING
Dene
the
term
Look
tnemelppuS
the
Explain
active
the
importance
transport
consuming
•
Describe
of
•
ions
the
by
villi
in
as
an
active
plant
glucose
up
molecules
at
the
and
ions
concentration
concentration
of
and
keep
them
in
high
concentrations.
of
magnesium
magnesium
ions
in
ions
the
in
soil
the
root
hair
cell
and
solution:
of
energy-
process
the
in
Describe
take
active
transport
•
transport
OUTCOMES
Cells
•
transport
vacuole
of
root
hair
cell
transport
roots
active
uptake
epithelial
cells
of
in
soil
and
kidney
tubes
solution
soil
particle
Key:
=
magnesium
Figure
The
of
3.4.1
down
high
root
hair
‘conc
in
of
use
entrat
the
activ
e
of
ion
deni
‘
Aga
inst
of
cell
ions
to
diffusion
cells
magnesium
than
it
gradient.
inside
in
out
ions
the
of
The
the
by
active
is
far
water
the
transport.
greater
in
root
hair
magnesium
root
hair
the
cell
cell
ions
by
a
inside
soil.
We
into
are
the
vacuole
might
the
soil
expect
water
maintained
process
called
at
a
active
the
grad
term
ient’
a
cell
using
transport
through
energy
is
the
the
cell
released
movement
of
membrane
during
ions
against
or
a
molecules
in
or
concentration
out
of
gradient,
respiration.
tion
4000
a
conc
entrat
ion
from
to
cell
in
3000
water
outside
gm
conc
entrat
ion
md
means
3–
a
conc
entrat
ion.
/
high
is
diffuse
inside
low
ions
tran
sport.
grad
ient’
a
absorb
transport
TIP
the
a
hair
concentration
Active
No tic
e
Root
concentration
the
magnesium
STUD
Y
ions
noitartnecnoc
2000
1000
0
+
+
Na
Figure
The
of
a
bar
Ion
chart
against
have
a
the
plant
been
concentration
due
to
in
the
into
active
water
the
gradient
Ca
magnesium
concentrations
and
taken
2+
Mg
potassium
concentration
shows
freshwater
cannot
34
3.4.2
2+
K
sodium
plant
by
Cl
calcium
chloride
transport.
of
in
by
some
which
ions
it
lives.
diffusion.
active
inside
These
They
transport.
the
are
cells
ions
taken
in
tnemelppuS
Active
The
cell
the
with
to
membrane
cell
enter
leave
carrier
change
its
membrane.
and
the
a
and
cell
by
protein.
shape
The
carrier
needs
contains
membrane
or
a
transport
carrier
provide
active
to
carry
protein
proteins.
means
by
transport.
Energy
molecule
energy
from
the
or
reverts
to
First
the
respiration
ion
ion
is
or
to
original
carrier
ions
and
to
the
or
the
the
proteins
molecules
molecule
enables
molecule
released
its
These
which
ion
combines
carrier
inside
inside
of
of
the
span
can
protein
the
membrane
shape.
ions
outside
cell
cell
outside
cell
membrane
+
membrane
energy
inside
3.4.3
Carrier
proteins
in
membranes
carry
out
active
transport.
STUD
Y
Epithelial
absorb
rates
cells
lining
glucose
of
by
the
villi
active
respiration
to
in
the
transport
provide
small
(see
energy
intestine
T
opic
for
and
7.8).
this
the
These
active
kidney
cells
TIP
tubules
have
high
Roo t
hair
transport
against
a
upon
concentration
respiration
oxygen
relies
will
would
also
gradient.
affect
reduce
respiration
the
Any
rate
respiration
of
to
take
factor
active
rate
and
up
that
ions
or
affects
transport.
active
the
So
are
molecules
a
rate
lack
up
increase
to
The
a
in
point,
presence
active
temperature
so
of
transport
SUMMARY
tnemelppuS
1
Explain
2
a
3
would
have
such
stop
as
increase
the
the
same
cyanide
man
y
transport.
rate
effect
can
their
stop
of
on
respiration,
active
to
transport.
respiration,
Make
a
Make
sure
be
is
meant
the
table
to
State
role
to
that
and
of
active
carrier
of
compare
you
have
‘active
from
think
what
transport,
rate
a
lack
proteins
and
respiration
an
c
the
respira
tion
energ
y.
in
active
transport
diffusion
with
taking
active
place.
KEY
of
three
columns
transport’.
the
cell’,
some
For
headed
features
‘concentration
other
features
to
transport.
can
gradient’.
in
your
transport
molecules
include
Y
ou
Active
movement
‘features’,
you
use
POINTS
effect
in
each
each
case
of
the
give
following
reasons
for
would
your
have
answer:
of
is
ions
across
the
or
the
against
concentration
table.
on
of
membrane,
may
from
cell
a
gradient,
using
respiration.
active
2
Active
transport
cells
to
enables
take
up
root
ions,
and
oxygen
epithelial
b
of
in
and
transport.
hair
a
pro tei
ns
mem
bran
es
provi
de
energy
4
havi
ng
altogether.
by
examples
energy
able
villi
activ
e
so
1
‘needs
high
by
carrier
cell
of
for
transport.
two
‘diffusion’
and
QUESTIONS
Describe
Give
also
poisons
what
active
b
would
would
cells
adap
ted
trans
port
of
of
a
An
cells
transport.
epith
elial
Active
cell
tnemelppuS
Figure
cell
increase
in
of
the
villi
to
temperature
take
presence
cells
of
a
poison,
such
as
up
glucose.
cyanide
35
PRACTICE
1
Which
A
is
cell
QUESTIONS
not
partially
membrane
B
cell
membrane
C
cell
wall
D
dialysis
permeable?
of
of
palisade
red
5
mesophyll
blood
cell
Which
A
the
cell
B
1)
A
is
the
best
partially
denition
of
solvent
permeable
concentration
net
of
the
net
molecules
D
through
membrane
down
random
the
of
net
from
molecules
down
of
molecules
against
diffusion
a
a
a
a
movement
of
molecules
in
a
molecules
down
solution
a
membrane
of
water
molecules
permeable
with
with
through
a
a
low
high
membrane
water
water
potential
potential
2)
[1]
Some
fresh
plant
tissue
salt
was
solution
put
for
into
60
a
minutes.
Which
explains
why
the
tissue
became
softer?
liquid
hair
cells
are
surrounded
by
soil
water
,
water
diffused
gradient
[1]
dilute
solution
nitrate
ions
higher
concentrations
hair
water
gas
1)
very
down
gradient
partially
solution
water
cells
and
absorb
of
mineral
magnesium
ions
of
ions.
these
from
soil
ions,
such
Plant
cells
ions.
How
active
B
diffusion
do
C
diffused
water
D
random
into
water
to
the
potential
their
cells
surroundings
so
that
they
out
of
the
cells
so
that
they
plasmolysed
water?
the
cells
lost
turgor
pressure
and
became
accid
(Paper
osmosis
a
cells
turgid
diffused
became
root
transport
C
down
the
as
have
D
A
from
which
became
is
molecules
a
B
Root
a
gradient
A
3
through
a
best
(Paper
water
of
permeable
concentrated
a
molecules
gradient
potential
through
a
6
or
osmosis?
gradient
movement
concentration
D
of
membrane
of
diffusion
water
(Paper
net
water
potential
partially
diffusion?
gradient
movement
concentration
C
of
permeable
diffusion
water
to
B
net
denition
[1]
movement
a
diffusion
the
a
Which
best
tubing
C
2
the
partially
a
(Paper
is
7
(a)
2)
Explain
[1]
the
importance
to
humans
of
the
movement
following:
(Paper
4
A
1)
[1]
student
cut
up
a
potato
into
pieces
(i)
diffusion
of
oxygen
in
the
alveoli
(ii)
diffusion
of
carbon
dioxide
in
[2]
the
that
alveoli
looked
pieces
three
like
as
chips.
‘fairly
different
results
that
the
The
rm’.
student
The
liquids.
pieces
Which
student
described
were
row
[2]
these
put
shows
(iii)
into
absorption
the
the
small
of
glucose
by
diffusion
in
intestine.
[2]
obtained?
(b)
Explain
the
importance
to
plants
of
the
following:
very
very
dilute
salt
salt
(i)
fairly
soft
Osmosis
osmosis
rm
(Paper
swollen
36
soft
fairly
rm
soft
fairly
rm
and
D
of
magnesium
ions
by
cells.
root
[2]
is
a
type
of
diffusion.
Explain
how
and
rm
very
1)
leaves
rm
fairly
soft
absorption
hair
(c)
(Paper
into
[2]
swollen
soft
very
dioxide
and
rm
very
C
carbon
solution
(ii)
B
of
solution
swollen
A
diffusion
water
concentrated
rm
[1]
3)
differs
from
diffusion.
[3]
8
A
group
They
divided
of
of
students
began
10
the
by
peeled
onions
batch
was
and
surface
dried
calculated
The
for
table
small
onions
into
of
salt
two
and
the
50
into
weighed
placed
concentrations
immersion
investigated
peeling
a
hours
reweighed.
their
The
in
B
of
was
the
was
B
mass.
mean
mass
onions
/
set
Some
and
up
bubbled
a
oxygen
A
in
gas
gas
cut
three
solution
with
from
A;
a
solutions,
ions.
rich
a
in
A
each
oxygen
solution
very
solution
mixture.
ions
through
mixture
oxygen;
the
of
potassium
mixture
of
were
in
bubbled
through
gas
investigate
uptake
roots
placed
was
solutions.
to
the
containing
gases
concentration
results.
of
C,
of
received
no
conc.
roots.
and
was
inuencing
washed
mixture
After
students
change
plant
A,
different
batch
factors
plant,
chloride).
each
experiment
by
batches
of
An
the
They
Each
solution
percentage
shows
ve
them.
(sodium
9
osmosis.
onions.
C
The
low
received
roots
were
g
left
for
24
hours
and
then
the
rate
of
uptake
percentage
of
of
salt
before
after
immersion
immersion
2
hours
change
potassium
ions
was
determined.
in
/
−3
mass
The
rate
of
uptake
of
potassium
ions
was
g dm
highest
0
147
173
25
153
165
+
in
solution
+
172
100
154
149
Explain
how
149
142
−4.5
200
183
175
−4.5
The
Journal
(a)
and
data
of
in
Biological
Calculate
used
to
vegetable
compile
Education
the
the
pickling,
(1993)
percentage
supply
uptake
table
Ray
27
W
(2),
change
was
of
of
solution
oxygen
to
C
roots
potassium
repeated
containing
temperatures.
gas
osmosis
the
their
experiment
solutions
150
Practical
in
ions.
[3]
−2.0
The
Information
lowest
8.0
inuences
176
and
18.0
(a)
50
A
mixture
results
They
that
are
roots
were
had
all
been
shown
in
with
kept
at
different
provided
given
the
to
with
the
solution
A.
table.
from
temperature
rate
of
/
ions
uptake
of
potassium
James.
pages
in
°C
/
arbitrary
units
90–91
5
3
10
5
20
10
30
20
40
15
mass
−3
for
the
onions
solution.
(b)
State
why
the
percentage
(c)
Plot
(d)
Use
a
which
(Paper
of
is
the
the
to
no
100 g dm
salt
working.
students
graph
there
in
your
change
graph
your
kept
Show
in
[2]
calculated
the
mass.
[1]
results.
nd
the
change
[5]
salt
in
solution
mass.
in
(b)
Draw
a
graph
(c)
Describe
of
the
results.
[6]
[1]
the
results
shown
in
your
graph.
[4]
4)
(d)
Explain
uptake
(Paper
10
the
of
effect
Explain
the
(b)
Explain
why
Some
term
resources
and
concentrations
Describe
absorb
by
the
concentration
of
in
is
on
the
roots.
[3]
are
their
by
or
cells,
often
in
as
the
ions.
such
very
[2]
as
low
surroundings.
epithelial
molecules
gradient. [2]
described
molecules
required
ions,
how
contents.
(Paper
ions
diffusion
movement
molecules
(c)
temperature
4)
(a)
net
of
potassium
of
cells
glucose
of
the
from
villi
the
gut
[5]
4)
37
4
Biological
4.1
molecules
Biological
Biological
LEARNING
List
in
the
elements
for
present
carbohydrates,
fats
Describe
large
the
synthesis
molecules
from
place
energy
of
cells.
Green
smaller
need
how
They
of
raw
Describe
are
in
different
sequences
give
in
plants
from
the
Relate
proteins
chemicals
of
the
that
we
body.
protein
are
mean
These
synthesis,
needed
all
the
by
reactions
and
living
chemical
the
include
growth
organisms
reactions
the
and
release
repair
the
raw
for
complex
chemical
materials.
Carbon
photosynthesis.
compounds
dioxide
The
simple
wide
range
and
that
they
water
sugars
are
the
produced
in
need
are
used
minerals
to
to
make
make
a
some
of
these
of
other
complex
compounds.
compounds.
shapes
the
structure
shape
eat
of
plants
and/or
other
animals
that
feed
on
plants.
and
protein
molecules
that
animals
require
are
present
in
their
diet.
The
molecules
different
their
carbohydrates,
different
Biological
to
like
amino
Animals
•
chemicals
metabolism
cells
make
simple
materials
Plants
protein
useful
By
respiration,
photosynthesis
acid
complex
of
molecules
•
fats.
metabolism.
taking
and
proteins
•
are
OUTCOMES
and
•
molecules
molecules
biological
molecules
needed
for
a
balanced
diet
in
humans
function
are
carbohydrates,
proteins,
fats,
vitamins,
minerals,
bre
and
water.
Carbohydrates
These
contain
the
Carbohydrates
a
simple
Glucose
sugar
molecules,
e.g.
in
is
a
b
complex
atoms
sugar
e.g.
and
sugar
and
which
transported
in
(C),
hydrogen
(H)
and
oxygen
(O).
starches.
is
made
the
in
blood.
photosynthesis,
It
consists
of
six
used
carbon
arranged
simple
made
to
is
a
double
sugars
by
bonds.
Plants
catalyse
It
is
stored
Starch
complex
carbohydrate
and
Cellulose
glucose
Figure
4.1.1
Different
types
and
glycogen,
a
units.
unlike
The
of
by
two
They
together
starch)
is
animals
molecules
a
by
have
into
another
as
mo lecules
eaten
to
refer
is
also
to
by
the
used
which
an
are
made
animal.
bio logical
to
refer
of
carbohydrates
together
store.
glucose
animal
store
are
chemical
enzymes
long
chains.
complex
of
energy.
muscles.
sugars,
structural
glucose
up
Complex
molecules
energy
glucose
and
complex,
an
join
called
from
liver
sugar
as
that
made
bonds.
units
are
insoluble
carbohydrate
are
held
and
do
made
together
by
not
up
of
bonds
taste
sweet.
thousands
forming
bres,
chains.
which
give
These
plant
cellulose
cells
walls
molecules
their
are
strength
linked
and
of
long
together
rigidity
.
TIP
Bio logical
ions,
simple
starch
made
the
molecule
chemical
reactions
unbranched
form
when
many
(sometimes
in
is
by
of
carbohydrate.
STUDY
ring.
sugar
store
the
carbohydrate
–
a
joined
joining
Glycogen,
starch
into
sucrose
Sucrose
38
simple
respiration
carbon
sugars
glucose
molecules,
c
elements
include
to
by
such
need
organisms.
term
mo lecules
ions,
organisms
T
he
described
as
from
nutrient
nitrate
their
T
hey
(or
in
only
T
o pics
ions,
become
nutrient
4
.1
sodium
environment.
food
mo lecule)
and
ions
4
.2.
and
mo lecules
is
often
Beware
–
used
it
magnesium
to
Proteins
Proteins
are
complex
oxygen,
but
they
molecules
also
contain
made
up
nitrogen
of
(N)
carbon,
and
hydrogen
many
have
STUD
Y
and
sulfur
Y
ou
(S).
Proteins
are
long-chain
molecules
made
up
of
smaller
TIP
may
compa
re
called
amino
acids.
After
formation
Topic
5.1)
they
are
either
folded
shapes
(see
or
become
arranged
into
long
of
bres.
to
compa
re
peptide
head
ings
bond
of
acid
part
molecules
of
a
protein
4.1.2
How
a
protein
is
made
from
amino
are
about
20
different
types
of
acids.
amino
this
acid.
and
will
Molecules
of
be
table
Whe
n
There
are
made
into
chains
as
you
can
see
in
the
diagram.
It
is
of
the
different
amino
acids
in
the
chain
usin
g
as
‘Nam
e
molec
ules
‘Elem
ents’.
which
able
in
to
add
T
opic
nam
ing
to
7
.2.
the
alwa
ys
use
the
full
sequence
table
amino
elem
ents
acids
such
a
molecule
Y
ou
Figure
Mak
e
them
biolog
ical
grou
p’
amino
to
three
biolog
ical
molec
ules.
different
aske
d
these
into
grou
ps
different
be
molecules
nam
es,
no t
determines
their
their
sym
bo ls.
the
type
the
chain
tnemelppuS
The
of
by
different
molecules.
to
protein
their
that
means
of
a
sequences
These
function.
is
formed.
chemical
of
amino
different
shapes
Enzymes
are
Each
bond
acids
of
individual
called
give
peptide
different
protein
proteins
a
amino
that
a
joins
bond.
shapes
molecules
provide
acid
can
to
be
surface
protein
related
fatty
acid
glycerol
molecule
for
molecule
reactions
are
to
take
proteins
enables
with
them
pathogens
place
to
and
a
called
structure
bind
with
make
the
the
‘active
that
has
chemicals
pathogens
site’
(see
binding
called
stick
page
sites
on
antigens
together
47).
its
on
(see
Antibodies
surface.
the
page
This
surface
of
120).
Figure
KEY
Fats
Fats
and
Each
to
fat
this
these
oils
made
molecule
are
can
energy
are
three
form
storage
is
up
made
fatty
the
up
acids.
different
and
of
fats
thermal
of
elements
one
There
with
carbon,
molecule
are
different
different
insulation
of
in
hydrogen
glycerol
types
properties.
the
of
and
and
fatty
Fats
oxygen.
acid
are
1
attached
for
body
.
A
Carbohydrates
up
of
hydrogen
Proteins
of
the
List
the
Give
components
of
a
balanced
diet
for
a
a
fats
are
and
are
made
elements
plus
sulfur.
(e.g.
one
example
of
each
of
the
simple
sugar
ii
a
complex
are
simple
glucose),
and
human.
carbohydrates
such
following:
as
i
same
and
Carbohydrates
complex
b
fat.
QUESTIONS
sugars
a
of
elements
oxygen.
up
2
1
and
the
carbon,
nitrogen
SUMMARY
molecule
POINTS
made
and
used
4.1.3
carbohydrate
found
in
starch,
glycogen
and
plants
cellulose.
iii
a
complex
carbohydrate
found
in
animals
3
2
a
Which
in
elements
are
carbohydrates
present
and
in
proteins,
but
are
not
found
Small
fats?
Name
the
small
molecules
that
are
joined
together
to
Give
d
State
three
examples
of
proteins
that
are
made
in
the
the
Name
made
and
Amino
function
of
each
protein
that
you
named
in
the
molecules
that
are
reacted
together
to
into
acids
are
part
A
molecule
make
of
of
a
fat
is
made
c
combining
three
fatty
acid
a
molecules
molecule
proteins.
body.
by
a
are
glycogen
chain
make
4
3
joined
long
molecules.
made
c
are
make
Sugars
starch,
cellulose.
protein
to
molecules.
into
b
molecules
together
with
a
molecule
of
fat.
glycerol.
b
Give
two
uses
of
fats
in
the
body.
39
4.2
Chemical
tests
biological
Simple
LEARNING
how
the
following
and
are
carried
vitamin
can
be
used
to
identify
starch,
sugars,
proteins,
it
is
important
you
iodine
test
•
Benedict’s
to
carry
out
these
tests
on
pure
forms
of
these
out:
compounds.
•
C.
chemical
First,
tests
tests
molecules
OUTCOMES
fat
State
chemical
for
for
should
For
rst
example,
carry
out
if
you
the
are
testing
chemical
test
a
food
on
a
for
reducing
glucose
sugars,
solution.
starch
Then
test
for
keep
the
results
to
compare
with
your
results
from
testing
other
reducing
materials,
such
as
foods
or
animal
and
plant
tissues.
Y
ou
should
also
sugars
do
•
biuret
test
•
ethanol
for
a
emulsion
test
for
test
for
water
so
that
you
can
see
the
negative
from
the
material
result
as
well.
vitamin
will
need
to
make
an
extract
you
are
testing.
fat
This
DCPIP
with
protein
You
•
test
C
involves
water
The
with
eye
so
a
pestle
chemicals
Safety:
Safety:
grinding
will
Some
always
of
wear
and
be
the
eye
up
a
small
mortar
in
amount
or
solution
chemicals
of
putting
in
the
used
the
it
material
into
a
with
some
blender.
extract.
in
these
tests
are
corrosive,
protection.
protection
T
esting
•
Half
ll
•
Add
two
Iodine
•
Figure
4.2.1
Test
for
A
a
tests
If
drops
usually
result
the
contain
are
for
the
of
food
iodine
looks
starch
extract
if
wish
to
test
for
starch.
solution
yellow
is
you
the
or
light
iodine
brown.
extract
remains
a
yellow
or
solution
light
turns
brown
blue–
colour
it
does
starch.
•
as
they
‘food
can
any
anim
al
be
sugars
Put
a
known
mad
e
in
a
volume
of
the
extract
you
wish
to
test
for
reducing
test-tube.
carried
plan
t
•
Place
a
beaker
•
Carefully
half
(or
the
on
a
heat-proof
mat.
and
or
up
ll
the
beaker
with
boiling
water
from
a
kettle
on
in
place
beaker
on
a
tripod
and
gauze
and
boil
the
water
the
with
labo ra
to ry.
•
Add
a
Bunsen
the
burner).
same
containing
Safety:
reducing
tests’,
mater
ial
so lu
tions
for
of ten
sugars
on
three
with
TIP
know
n
but
or
positive
T
esting
out
test-tube
starch.
not
T
hese
starch
solution
black.
STUD
Y
for
•
Benedict’s
•
A
positive
volume
the
food
solution
test
for
of
Benedict’s
extract
is
and
bright
simple
put
solution
it
into
the
to
the
hot
test-tube
water.
blue.
sugars
is
when
Benedict’s
solution
turns
eye
red
or
orange
(if
you
look
carefully
you
can
see
it
turn
green
and
protection
then
cool
•
d
t
you
can
present.
B
o
You
yellow
t
will
use
If
of
•
Test
for
reducing
colour
If
the
a
reducing
lot
colour
of
a
orange).
If
you
leave
the
test-tube
to
precipitate.
test
to
changes
sugars.
sugars.
reducing
remains
sugars.
reducing
40
see
Benedict’s
the
the
contains
4.2.2
also
turning
tell
to
how
much
green,
the
simple
extract
sugar
is
contains
only
a
o
little
Figure
before
blue
If
it
turns
a
deep
orange
colour
then
sugars.
then
the
extract
does
not
contain
any
it
T
esting
for
protein
Safety:
•
Half
ll
•
Add
ve
copper
a
test-tube
to
six
drops
sulfate
Safety:
T
ake
•
solution
with
of
solution
care
as
the
extract
biuret
and
sodium
you
wish
solution
sodium
to
(this
solution
for
solution
hydroxide
hydroxide
test
protein.
contains
solution).
is
corrosive.
S
od
h
Biuret
•
A
positive
violet
•
If
the
or
usually
test
for
looks
protein
blue
is
if
in
the
colour.
biuret
solution
turns
C
um
yd
ro x
s
o
ut
e
d
s
remains
Fats
will
for
not
solution
of
is
formed.
•
Chop
(Do
•
Put
up
not
the
blue,
then
the
extract
does
not
contain
protein.
Figure
4.2.3
Test
a
Put
•
Add
•
Shake
fat
in
water
ethanol
grind
add
in
a
small
water
extract
is
to
into
a
but
they
added
to
amount
make
clean
of
the
will
dissolve
water
a
material
extract
test-tube
cloudy
you
this
and
in
ethanol.
white
wish
to
If
a
1
emulsion
test
for
Describe
in
each
what
of
stopper
some
the
white
over
the
distilled
test-tube
water
contents
emulsion
positive
test
for
starch
b
a
positive
test
for
protein
c
a
positive
test
for
a
time.)
add
enough
ethanol
to
to
and
make
shake
the
up
the
test-tube
of
the
test-tube
once
d
a
negative
half
e
a
positive
test
for
that
looks
cloudy
does
not
for
Describe
of
is
vitamin
that
loses
C
its
happen,
juices,
can
Put
2
Fill
a
the
white
extract
or
a
milky
colour
is
does
not
contain
such
as
freshly-squeezed
made
from
when
it
volume
or
vitamin
comes
into
C
lemon
tablets.
contact
juice.
DCPIP
with
is
a
A
with
test
an
blue
vitamin
for
of
DCPIP
solution
in
a
dropping
pipette
with
a
a
juice,
the
e.g.
liquid
orange
one
drop
demonstrating
liquid
3
C.
You
the
are
each
the
colour
If
the
blue
of
DCPIP
solution
of
vitamin
C
a
glucose
given
are
a
to
carry
sugar
test
solution
four
a
of
test-tubes
different
glucose.
labelled
you
do
A,
not
B,
C
know
and
the
then
of
glucose
in
time.
the
the
test
test
is
is
positive
for
vitamin
tube.
C.
have
been
told
to
nd
negative.
which
most
is
the
solution
concentrated
least
is
the
and
which
concentrated.
POINTS
Describe
the
procedures
1
Iodine
2
Benedict’s
solution
gives
a
blue–black
colour
when
added
to
solution
turns
orange
when
boiled
with
simple
to
solution
gives
a
purple
or
violet
colour
when
you
would
and
the
observations
sugars.
you
Biuret
practical
that
starch.
follow
3
how
reducing
containing
and
out
KEY
food
juice.
at
disappears
persists
a
sugar
or
You
colour
of
test-tube.
each
If
extract
reducing
concentration
Add
would
the
solution
D
3
of
procedures:
making
out
be
syringe
C
fat.
They
a
vitamin
a
C
colour
known
for
you
each
concentration
1
starch.
fats.
vitamin
in
test
how
out
using
C
for
more.
b
T
esting
test
full.
to
Vitamin
sugar
contents.
a
this
see
a
following
positive
If
would
following:
a
carry
•
you
the
fats.
2
A
protein.
it.
•
•
for
QUESTIONS
reducing
cover
on
fats
dissolve
or
fate
ut
corrosive
SUMMARY
T
esting
op p e
u
s
o
on
purple,
lilac.
colour
eye
protection
added
would
give
expect.
safety
Remember
precautions.
to
protein.
4
Describe
the
4
A
white
emulsion
forms
when
fat
dissolved
in
ethanol
is
you
to
would
use
compare
C
content
of
the
different
water.
fruit
5
test
added
vitamin
to
how
DCPIP
Vitamin
C
decolourises
DCPIP
juices.
solutions.
41
4.3
DNA
tnemelppuS
The
LEARNING
Each
•
Describe
structure
the
structure
of
two
to
form
strands
coiled
chromosome
double
State
that
DNA
chemicals
Describe
called
up
how
in
the
the
how
for
we
eye
the
bases
same
place
in
we
could
DNA
TIP
DNA
of
unravel
The
so
is
the
G,
of
DNA.
show
bases,
A,
each
are
Y
ou
C,
remem
ber
a
The
no t
need
what
colour
we
look
and
like.
height.
For
instance,
Some
genes
there
code
enzymes
that
control
all
the
chemical
reaction
thread
a
chromosome,
would
the
of
long
be
acid).
made
it
would
A
thread
gene
that
up
is
of
a
form
an
chemical
extremely
made
makes
up
up
a
of
a
called
long
short
DNA
length
chromosome
contains
genes.
belongs
to
acids.
a
complex
called
a
Each
DNA
group
of
molecule
biological
nucleotide.
A
single
is
made
up
molecules
nucleotide
of
known
is
thousands
made
up
of
of
as
units
three
phosphate
•
a
sugar
•
a
base
sugar
the
and
DNA
phosphate
strand.
The
molecules
bases
are
join
up
attached
and
to
form
the
the
sugar
backbone
molecules.
struct
ure
nucl
eo tid
e
show
n
you
look
at
Figure
4.3.1
you
will
see
that
DNA
is
made
up
of
two
in
strands
Figu
re
and
hair
to
of
the
like
information
in
If
a
arranged
genetic
T
arrang
ed
do
genes
the
molecules:
•
DNA.
of
block
’
diag
rams
and
of
carry
a
nucleic
how
that
always
hundreds
nucl
eo tid
e
T
he
thousands
way
of
‘build
ing
of
genes
cells.
(deoxyribonucleic
A
up
the
grow
colour,
production
take
thread.
STUD
Y
is
bases
If
pair
made
It
strands
that
•
is
necklace.
affects
genes
for
contain
a
helix
are
•
in
together
that
a
DNA
DNA
beads
as
of
OUTCOMES
of
nucleotides.
It
is
rather
like
a
ladder.
The
whole
molecule
4
.3.2.
is
twisted
bases
as
into
the
a
double
helix
–
a
bit
like
a
spiral
staircase
with
the
steps.
phosphate
base
P
sugar
The
DNA
looks
like
Figure
molecule
a
4.3.2
A
spiral
single
nucleotide.
phosphates
make
The
up
the
sugars
and
‘uprights’
of
staircase
the
ladder
and
the
bases
make
up
the
‘rungs’.
Base
A
T
So
C
G
If
how
you
Each
T
A
G
C
on
Figure
42
4.3.1
A
DNA
model.
of
bases
the
the
the
look
pair
at
of
The
DNA
don’t
bases
molecule
Figure
bases
bases
thymine
(You
pairs
is
different
•
form
pairing
in
4.3.3
held
you
together?
can
together
see
by
that
weak
•
have
to
adenine
(A)
remember
pair
up
in
•
each
the
of
same
the
•
cytosine
(A)
(C)
pairs
pairs
with
with
thymine
guanine
(T)
(G)
(C)
names,
way:
steps
adenine
bases
bonds.
cytosine
staircase
•
the
join
There
together.
are
four
DNA:
(T)
always
is
held
•
guanine
just
their
(G)
letters.)
are
the
weak,
double
bonds
there
helix
in
are
holding
many
of
the
two
them.
chains
So
of
nucleotides
altogether
they
tnemelppuS
Although
together
keep
the
DNA
shape.
cytosine
guanine
adenine
thymine
A
student
shows
(guanine)
thymine
examines
the
pairs
is
of
yellow
a
model
bases.
and
C
In
of
DNA
this
that
model
(cytosine)
is
G
red.
adenine
phosphate
guanine
cytosine
sugar
weak
Figure
4.3.3
How
SUMMARY
1
Figure
4.3.4
of
bases
pair
up
in
DNA.
QUESTIONS
molecule.
letters
the
bonds
shows
Copy
the
a
and
partially
completed
complete
missing
the
section
diagram
by
of
the
writing
DNA
in
the
bases.
James
the
They
G
Figure
2
The
table
DNA
below
from
four
C
A
T
Watson
structure
they
are
and
of
posing
made
in
Francis
DNA
with
by
Crick
worked
building
their
Cambridge
nal
in
the
out
models.
model
early
that
1950s.
4.3.4
shows
the
different
percentages
of
the
four
bases
in
KEY
POINTS
organisms.
1
percentage
of
each
base
The
two
DNA
molecule
strands
coiled
consists
of
together
organism
to
A
C
G
T
human
31
19
19
31
locust
29
21
21
29
2
form
Each
a
double
strand
chemicals
and
yeast
32
18
18
32
bacterium
15
35
35
15
3
A
C
a
Explain
b
In
A.
c
an
the
pattern
organism
What
Explain
shown
26%
percentage
how
organisms
it
is
such
percentages
of
of
the
DNA
be
to
humans
bases.
the
table.
bases
would
possible
as
in
C?
have
and
in
4
DNA
Show
two
yeast
are
your
very
with
found
to
very
similar
called
always
bonds
bonds
chromosome
long
bases
bond
with
with
is
A,
C,
G
together.
T;
G.
made
super-coiled
up
strand
of
of
DNA.
working.
different
contains
which
always
A
a
be
T
,
helix.
5
A
gene
that
of
a
is
a
codes
length
for
particular
the
of
DNA
production
protein.
43
PRACTICE
1
What
QUESTIONS
are
the
chemical
A
carbon,
hydrogen
B
carbon,
hydrogen,
elements
and
in
Use
proteins?
the
nitrogen
and
molecules
molecules
oxygen
shows
carbon,
hydrogen,
of
nitrogen,
oxygen
a
are
known
questions
6–8.
small
part
of
sub-unit
nucleotides.
of
a
DNA
The
diagram
molecule.
and
B
carbon,
(Paper
for
composed
as
sulfur
D
DNA
oxygen
DNA
C
diagram
nitrogen,
oxygen
and
sulfur
1)
[1]
C
A
2
The
small
proteins
molecules
that
are
built
up
into
are:
A
amino
B
fatty
acids
acids
(Paper
1)
Which
row
C
glucose
D
glycerol
[1]
D
3
four
gives
chemical
the
positive
results
for
the
tests?
Benedict’s
biuret
iodine
emulsion
test
test
test
test
green
violet
yellow
Adenine
no
A
X
suspension
6
Which
of
the
labelled
parts
of
DNA,
A,
B,
C
or
D,
no
B
blue
blue
indicates
yellow
a
base
pair?
suspension
(Paper
2)
Which
of
[1]
cloudy
C
yellow
red
blue
suspension
D
orange
7
indicates
blue-
cloudy
black
suspension
4
Water
1)
is
because
[1]
an
it
important
is
molecule
in
8
organisms
a:
A
solute
C
solvent
B
solution
D
suspension
What
9
5
1)
Enzymes
regions
that
form
[1]
and
of
bind
antibodies
these
to
parts
of
DNA,
A,
B,
C
or
proteins
other
specic
are
proteins.
have
molecules.
shapes
A
molecules
of
B
molecules
with
because
D,
different
[1]
the
structure
labelled
X?
A
adenine
(A)
C
guanine
(G)
B
cytosine
(C)
D
thymine
(T)
The
2)
[1]
diagram
molecule
below
increases
shows
in
how
specic
a
starch
length.
A
Special
Proteins
they
2)
is
(Paper
(Paper
labelled
nucleotide?
violet
(Paper
(Paper
the
a
shapes
can
have:
lengths
different
numbers
of
amino
(a)
Name
molecule
(b)
Name
two
A.
[1]
acids
C
molecules
with
different
sequences
places
where
starch
is
stored
plants.
amino
[2]
acids
(c)
D
molecules
with
other
molecules
or
Describe
to
plant
would
nd
out
whether
tissue
contained
details
of
the
starch.
test
in
Include
your
the
answer.
[4]
[1]
(Paper
44
you
them
practical
2)
how
ions
a
attached
(Paper
in
of
3)
10
The
diagram
shows
a
protein
5
molecule:
Repeat
steps
1
to
4
with
the
juices
to
be
tested.
The
(a)
Name
the
sub-unit
molecules
that
results
are
shown
in
the
table.
are
volume
assembled
into
the
protein.
added
to
DCPIP
[1]
3
test
(b)
Name
two
proteins
found
in
the
solution
substance
/
cm
human
body.
1
2
3
mean
1.8
1.9
2.1
1.9
2.4
2.6
2.3
2.4
3.2
3.1
2.9
3.1
9.6
9.1
9.4
9.4
[2]
−3
(c)
(d)
State
two
places
many
proteins
Some
seeds
the
are
are
chemical
in
the
body
in
that
10 g dm
where
made.
rich
test
human
proteins.
orange
Describe
would
use
juice
to
grapefruit
determine
whether
different
types
of
rich
details
in
of
proteins.
the
test
Include
in
your
the
answer.
[4]
The
Explain
why
readings
3)
(b)
11
juice
practical
(a)
(Paper
juice
seed
apple
are
diagram
shows
a
molecule
of
a
Use
the
the
for
results
(Paper
13
juices.
Name
the
(a)
components
of
the
DNA
of
vitamin
Show
molecules
X
and
Y.
the
your
C
in
the
three
working.
[3]
two
places
are
stored.
State
in
the
human
body
a
double
what
this
helix
means.
[2]
the
precise
site
of
DNA
in
an
cell.
[2]
where
The
sequence
of
bases
in
a
small
sample
[2]
of
three
have
Explain
[2]
animal
State
calculate
[3]
molecule
(b)
labelled
(c)
substance.
4)
structure.
fats
three
Y
X
List
to
test
took
fat.
fruit
(b)
student
each
concentration
(a)
C
solution
[2]
you
vitamin
roles
of
fats
in
the
DNA
is:
human
ATAGATCCCGAA
body.
[3]
(c)
(d)
Oils
have
the
same
molecular
structure
Write
out
opposite
fats.
Many
seeds
are
rich
in
oils.
chemical
test
to
nd
out
whether
different
owering
plant
The
oil
or
not.
Include
strand
DNA
of
of
the
test
in
your
A
student
the
used
vitamin
the
C
is
DCPIP
test
present
in
answer.
to
The
concentration
of
nd
out
different
the
the
DNA
molecule.
[1]
determines
of
a
a
small
protein.
above
to
explain
Use
how
determine
the
sequences
base
of
[4]
acids
in
a
protein.
[1]
how
In
2007,
scientists
compared
the
degree
fruit
of
juices.
in
practical
(e)
much
this
structure
sequence
amino
12
in
sequence
the
sequences
details
bases
species
the
contain
of
seeds
part
from
sequence
Describe
(d)
a
the
as
DCPIP
similarity
between
some
of
the
DNA
solution
taken
from
the
nuclei
of
white
blood
cells
−3
was
10 g dm
.
The
student
followed
these
of
a
domesticated
cat
and
several
other
instructions.
mammalian
species.
The
results
are
below.
3
1
Put
2
Use
2 cm
of
DCPIP
solution
into
a
test
tube.
percentage
a
graduated
pipette
or
burette
to
similarity
between
add
domesticated
cat
and:
−3
a
10 g dm
vitamin
C
solution
drop
by
wild
drop
to
the
DCPIP
solution.
Shake
the
tube
human
dog
cow
rat
mouse
90
82
80
69
67
cat
gently
add
of
after
the
the
adding
vitamin
DCPIP
C
each
drop.
solution
solution
Continue
until
the
to
colour
99
disappears.
What
3
Record
that
4
the
was
Repeat
of
vitamin
C
a
(Paper
procedure
mean
two
more
do
you
conclude
from
these
results?
[3]
solution
added.
the
calculate
volume
times
4)
and
volume.
45
5
Enzymes
5.1
Structure
and
action
of
enzymes
A
LEARNING
catalyst
end
•
Dene
the
substance
term
that
catalyst
speeds
chemical
reaction
changed
by
the
and
as
up
is
a
of
speed
Dene
enzymes
the
up
act
not
How
as
as
speed
biological
up
the
tnemelppuS
Explain
using
rate
how
the
an
‘lock
enzyme
and
key’
works
too
catalyses
many
of
in
Breaking
is
2
They
take
keep
are
different
of
3
of
storage
are
known
place
in
organisms
many
as
at
organisms,
biological
organisms.
alive
different
reaction.
shows
its
(see
we
will
Topics
of
3D
enzymes
Most
discuss
7.5
and
up
in
nutrition
the
large
cell
the
one
when
that
they
These
unless
types
they
of
enzymes
the
that
catalysts
reactions
are
enzyme
speeded
as
work
each
inside
cells,
here
work
outside
cells,
for
7.7).
gut
for
as
work
of
large
to
down
small
cells
and
types.
and
their
are
broken
then
food
used.
and
we
reason.
joined
inside
starch,
three
molecules
absorbed
break
from
into
ones
food
be
same
are
divided
ones
together
to
speed
structural
to
up
make
the
large
formation
molecules
such
as
plants.
small
chemical
as
be
small
the
glucose,
such
can
can
enzymes
enzymes
walls
into
molecules
such
molecules,
for
so
release
into
These
catalyse
molecules
ones
fungi
Converting
molecule
reactions
that
into
occur
another
inside
cells
involve
small
an
changes
right)
that
molecules,
Many
image
that
gut
enzymes
cellulose
computer-generated
those
large
and
molecules.
to
molecules,
such
as
adding
or
removing
atoms
or
groups
shape.
of
atoms.
from
For
example,
compounds
Figure
5.1.1
breakdown
shows
of
a
there
during
the
are
enzymes
that
remove
hydrogen
respiration.
way
in
which
an
enzyme
catalyses
the
molecule.
TIP
writi
ng
enzy
mes
abou
t
alwa
ys
enzy
mes
reactio
ns.
say
enzyme
substrate
substrate
active
cata
lyse
Figure
Figure
from
46
to
There
small
Building
Small
that
reactions
important
into
release
Whe
n
a
the
reactions
Bacteria
STUD
Y
unchanged
by
model
down
the
remains
produced
work
slowly
enzymes.
example
This
(on
and
reactions
1
enzyme
reaction
proteins,
of
The
This
reactions.
enzymes
chemical
by
but
•
chemical
are
catalysts
one
chemical
chemical
proteins
up
to
a
Enzymes
reaction
happen
that
up
reaction.
a
Many
•
speeds
OUTCOMES
in
enzyme
products
site
released
5.1.1
5.1.2
two
shows
smaller
how
an
enzyme
molecules.
is
involved
in
building
a
molecule
Enzymes
are
made
All
enzymes
have
1
They
are
all
2
Each
enzyme
3
They
can
4
They
are
inuenced
by
temperature.
5
They
are
inuenced
by
pH.
ve
of
protein
important
properties.
proteins.
be
catalyses
used
one
again
reaction.
and
again.
active
site
substrate
Enzymes
are
made
of
protein
molecules.
These
molecules
can
be
enzyme
folded
a
into
shape
many
that
explains
different
makes
why
there
it
shapes.
suitable
are
many
for
Each
type
catalysing
different
of
enzyme
one
enzymes
type
–
one
molecule
of
has
reaction.
enzyme
for
This
each
substrate
in
reaction.
active
Enzymes
catalyse
products.
Look
reactions
at
enzyme
matches
and
substrate
the
together.
Once
Figure
the
t
which
5.1.1.
shape
have
they
in
of
Notice
the
shapes
substrates
that
together
that
substrate
are
the
the
are
converted
shape
molecule.
of
part
The
complementary
reaction
can
take
site
into
of
the
enzyme
so
place.
they
t
product
Other
released
substrates
involved
have
in
the
the
wrong
reaction
shape
catalysed
to
t
by
into
this
the
enzyme
enzyme.
so
When
will
the
not
be
reaction
is
Figure
5.1.2
This
shows
enzyme
over
the
product
or
products
leave
the
enzyme
and
another
tnemelppuS
As
you
an
join
two
substrate
molecules
molecule
how
can
together.
enters.
can
substrate(s)
This
way
of
key’
model.
lock
to
see
t
in
Figure
and
describing
The
form
an
5.1.2
where
the
how
enzyme
the
part
reaction
enzymes
and
of
work
substrate
enzyme-substrate
the
takes
is
enzyme
place
is
known
combine
like
where
the
as
a
the
active
the
key
site.
‘lock
substrate
A
substrate
B
and
entering
a
complex
enzyme
Figure
5.1.3
Only
the
SUMMARY
Copy
and
complete
the
sentences
using
these
words:
1
Enzymes
catalysts
proteins
are
biological
that
up
the
rate
.
type
Enzymes
of
are
the
meant
3
Use
a
terms
by
the
why
the
‘lock
each
all
and
each
enzyme
why
an
rate
Enzymes
catalyse
in
substrate
reactions
acts
which
complementary
and
key’
enzyme
key’
model
will
and
active
model
act
to
of
site
to
enzyme
explain
what
is
only
on
molecules,
action.
explain:
3
one
converted
or
breaking
All
enzymes
molecules.
substrate
enzyme
can
be
used
to
catalyse
a
large
quantity
to
molecules
the
product
either
up
where
b
the
.
‘lock
and
increase
reactions.
by
building
down.
are
Part
protein
of
the
reaction
enzyme
occurs
has
of
a
complementary
shape
to
substrate
the
c
why
high
destroying
the
temperature
active
stops
site
the
by
heating
enzyme
from
the
enzyme
working
to
substrate
molecule(s).
a
4
The
of
active
the
site
enzyme
substrate
reaction
ts
is
the
part
where
and
tnemelppuS
tnemelppuS
Use
biological
that
chemical
are
2
are
of
2
chemical
one
t
site.
reactions
of
on
will
POINTS
catalysts
speed
Enzymes
A
active
QUESTIONS
KEY
1
substrate
enzyme’s
the
where
the
occurs.
47
5.2
Factors
affecting
action:
The
LEARNING
activity
Carry
the
out
an
effects
enzyme
investigation
of
into
temperature
on
reaction
measuring
substrate
the
activity
Describe
enzyme
the
effects
temperature
on
that
how
is
e.g.
the
is
determined
enzyme
much
used
reaction
time,
•
an
temperature
by
measuring
the
rate
of
OUTCOMES
the
•
of
enzyme
product
over
a
measured
per
catalyses.
is
period
in
This
formed
of
time.
quantity
of
may
or
by
The
done
either
measuring
rate
product
be
or
is
like
how
the
substrate
by
much
speed
per
of
unit
of
minute.
of
enzyme
Effect
of
temperature
on
enzymes
activity
Explain
the
effects
activity
of
enzymes
is
inuenced
of
6.0
by
temperature
on
temperature.
This
graph
shows
enzyme
effect
of
increasing
temperature
nim
the
1–
activity
on
the
rate
of
an
enzyme-catalysed
tcudorp
reaction.
the
can
reaction:
slow
are
use
this
some
from
the
answ
er
.
say
the
low
temperatures,
10 °C
desc
ribin
g
•
like
at
at
increases
as
the
increases
to
40 °C
etar
alwa
ys
your
of
observe
4.0
3.0
2.0
fo
you
grap
h
take
n
rate
and
noitcaer
is
e.g.
a
graph
TIP
•
Whe
n
the
/
that
STUD
Y
at
gm
Look
5.0
temperature
one,
1.0
gu
res
grap
h
Here
•
reaches
a
maximum
•
decreases
at
0
40 °C
in
10
at
5.6
mg
min
ute
at
high
es
greater
t
prod
uct
per
•
is
zero
the
than
be
describ
e the
tempe
rature
enzy
mes,
4
aske
d
40 °C
and
effec
t
and
but
will
explai
n,
enzyme.
fungal
•
human
•
some
which
Here
and
plant
are
the
some
maximum
37 °C
enzymes
rate
This
examples
enzymes:
enzymes:
of
the
temperature.
of
is
20 °C
temperature
produced
by
reaction
best
optimum
approximately
(body
of
the
–
bacteria
for
is
for
temperatures:
(see
see
occurs
temperature
page
T
opics
use
in
250)
7.5
and
industry:
7.7)
90 °C.
be
saw
in
the
T
opic
5.1,
an
enzyme
substrate
molecules.
by
between
molecule
The
shape
is
of
folded
an
into
a
enzyme’s
shape
active
that
site
bonds
different
parts
of
the
molecule.
is
Remember
that
the
shape
into
the
enzyme
of
the
active
site
determines
whether
the
substrate
will
t
on
for
the
reaction
to
occur
.
in
aske
d
At
rst,
will
increasing
increase
have
the
greater
there
are
the
rate.
kinetic
more
temperature
This
is
energy.
chances
of
of
because
They
them
an
enzyme-controlled
enzyme
move
and
around
colliding,
the
substrate
more
reaction
molecules
quickly
substrate
tting
and
into
remem
ber
the
are
tempe
ratures
of
we
of
pH
pH.
active
site
and
a
reaction
taking
place.
protei
ns
denat
ured
extrem
es
by
and
At
higher
together
site,
We
so
say
temperatures
start
the
to
break
substrate
that
catalyse
48
at
optimum
maintained
only
you
enzy
mes
are
the
to
inu
ence
enzy
mes.
Whe
n
high
5.2.1
60 °C.
temperature
accepts
to exp
lain ho
w thes
e fact
ors
that
at
•
As
you
60
°C
TIP
may
Paper
50
/
40 °C
.
called
Y
ou
40
rate
The
STUD
Y
30
temperature
Figure
is
20
temperatures
you
the
the
the
no
enzyme
reaction.
bonds
down.
This
longer
has
holding
the
changes
enzyme
the
shape
molecule
of
the
active
no
longer
ts.
been
denatured
and
it
can
tnemelppuS
tnemelppuS
The
•
PRACTICAL
Investigating
Amylase
is
changes
iodine
iodine
an
the
enzyme
like
not
temperature
breaks
down
blue-black.
change
starch
When
colour.
on
enzyme
to
starch
Draw
a
action
maltose.
is
broken
table
for
Starch
down,
your
this.
temperature
and
will
of
that
solution
solution
results
effect
starch
at
which
was
kept
/
amylase
time
°C
taken
fully
for
broken
starch
down
/
to
be
min
Figure
5.2.2
T
esting
starch
the
in
solution
for
iodine.
3
1
Put
A,
5cm
B,
C,
of
starch
and
solution
into
each
of
four
test
tubes
labelled
D.
2
Put
test
tube
A
into
the
refrigerator
3
Put
test
tube
B
into
a
test
4
Put
test
tube
C
into
a
water
tube
and
note
the
temperature.
and
note
the
temperature.
rack
bath
at
about
35°C
and
note
the
temperature.
5
Put
test
tube
D
into
a
water
bath
at
about
80°C
and
note
the
temperature.
3
6
Collect
7
Put
a
of
10cm
drop
spotting
of
amylase
iodine
solution
solution
into
in
a
clean
each
of
boiling
the
wells
tube.
on
a
tile.
3
8
Add
2cm
note
9
At
the
amylase
test
iodine
When
solution
to
each
of
the
four
tubes
and
KEY
time.
two-minute
the
10
of
intervals
solution
solution
the
from
on
each
the
amylase
use
a
clean
test
tube
spotting
solution
pipette
and
to
remove
add
it
to
a
some
drop
of
1
of
has
broken
down
all
the
Increasing
of
tile.
POINTS
an
iodine
solution
will
no
longer
turn
blue-black.
temperature
reaction
increases
reaction
up
to
a
the
rate
of
maximum,
starch
which
the
the
enzyme-controlled
They
occurs
at
the
optimum
will
temperature.
brown.
on
What
the
does
this
tell
you
about
the
effects
of
amylase?
This
is
because
energy
SUMMARY
QUESTIONS
is
number
enzyme
1
a
Sketch
a
graph
temperature
to
on
show
the
rate
the
of
effect
a
of
increasing
reaction
catalysed
enzyme,
such
as
salivary
Describe,
in
words,
what
is
Suggest
what
each
reaction
catalysed
of
by
the
shown
a
following
human
At
higher
by
your
a
temperature
below
b
a
temperature
of
c
a
temperature
of
temperatures
the
would
do
of
reaction
decreases
graph.
to
the
rate
of
it
stops
acting
as
a
catalyst.
enzyme:
This
a
between
substrate
amylase.
until
2
collisions
and
kinetic
greater
a
rate
b
of
a
molecules.
by
2
human
greater
causing
tnemelppuS
light
temperature
tnemelppuS
stay
10 °C
is
shape
37 °C
due
of
to
the
means
the
longer
t.
a
change
active
site
substrate
The
in
can
enzyme
the
which
is
no
now
50 °C
tnemelppuS
denatured.
3
Use
the
‘lock
enzymes
are
and
key’
model
denatured
at
to
high
explain
what
happens
when
temperatures.
49
5.3
Enzymes
The
LEARNING
Describe
enzyme
•
Carry
the
effects
of
pH
enzymes
on
i.e.
action
out
the
an
at
a
that
low
of
pH
tnemelppuS
Explain
active
in
the
is
can
be
present
affected
stomach
work
in
the
by
the
best
stomach,
pH
in
acidic
so
of
the
conditions,
pH.
bile
is
that
present
are
in
active
the
rst
here
part
work
of
best
the
in
small
alkaline
intestine,
so
conditions,
the
i.e.
at
a
activity
the
effects
of
pH
pH.
on
Most
enzyme
enzymes
work
best
inside
cells
where
the
conditions
are
neutral.
action
The
optimum
Enzymes
Enzymes
Many
pH
of
and
are
these
is
therefore
about
pH
7.0.
pH
inuenced
enzymes
enzymes
work
by
best
the
in
pH
of
neutral
their
surroundings.
conditions,
but
some
work
best
substrate
enzyme
in
Enzyme
–
the
acidic
conditions
and
some
in
alkaline
conditions.
denatured
substrate
fits
Figure
are
acid
on
high
•
reaction
Hydrochloric
investigation
effects
enzymes
enzyme
enzyme-controlled
surroundings.
Alkaline
into
of
pH
OUTCOMES
its
•
rate
and
no
active
longer
site
Look
and
at
the
graph
in
Figure
5.3.2
showing
the
action
of
enzymes
X
Y
.
5.3.1
•
Enzyme
•
The
•
Up
X
works
optimum
best
pH
for
at
pH
2.0
enzyme
Y
–
is
that
pH
is
its
optimum
pH.
8.0.
6.0
to
pH
2.0
the
rate
of
reaction
increases
for
enzyme
X
and
then
5.0
between
pH
2.0
and
pH
5.5
it
decreases.
There
is
no
reaction
above
1–
fo
tcudorp
noitcaer
nim
pH
5.5.
4.0
•
3.0
Between
Y
and
pH
then
gm
etar
reaction
4.5
and
between
below
pH
pH
pH
4.5
8.0
the
8.0
and
rate
and
pH
above
of
reaction
10.0
pH
it
increases
decreases.
for
There
enzyme
is
no
10.0.
2.0
enzyme
X
enzyme
Y
As
we
vital
0
0
1
2
3
4
5
6
7
8
9
10
11
pH
if
have
it
is
structure
seen,
to
of
the
three-dimensional
function.
the
Many
enzyme
are
of
the
weak
shape
chemical
bonds.
If
of
an
bonds
these
enzyme
holding
bonds
is
the
that
acid
Figure
5.3.2
STUD
Y
TIP
hold
the
enzyme
then
the
shape
reaction
is
that
substrate
At
is
say
kille
d’.
no t
enzy
me
Enzy
mes
orga
nism
s.
are
pro te
in
T
he
co rrec
t
dena
tured.
50
‘the
are
T
hey
mo lec
ules.
wo rd
to
use
is
at
the
these
can
Never
molecule
of
values
affect
the
zero,
the
the
of
rate
extremes
denatures.
the
of
in
active
shape
of
molecules
pH
of
its
shape
site
the
will
enzymes
reaction
pH
are
can
be
active
no
are
an
by
altered.
site
longer
has
the
changed
Small
denaturing
enzyme
changes
When
in
pH,
rate
so
of
much
t.
denatured.
without
range
broken
changes
the
becomes
in
enzyme,
unstable
pH
but
and
tnemelppuS
/
1.0
PRACTICAL
The
effect
Egg
white
egg
pH
on
contains
investigate
in
of
the
white.
a
lot
effect
You
the
of
will
action
of
protein.
protease
also
of
see
a
In
this
from
how
protease
the
pH
experiment
stomach
affects
the
you
on
will
the
way
protein
the
enzyme
works.
1
Set
up
a
water
bath
2
Using
syringe
put
3
Add
2 cm
4
Add
2 cm
at
40 °C
and
label
three
test
tubes
1–3.
3
a
of
5 cm
egg
white
into
each
test
tube.
3
of
sodium
of
water
carbonate
(an
alkali)
to
tube
1.
This
is
a
model
of
protease
that
breaks
3
to
tube
2.
down
proteins
intestine.
It
to
amino
works
best
acids
at
a
in
pH
the
of
small
about
8.5
3
5
Add
2 cm
6
Compare
each
of
the
tube
to
dilute
hydrochloric
pH
each
of
dip
into
test
the
acid
tube
by
solution
to
tube
using
and
a
then
3.
and
clean
touch
glass
the
rod
pH
at
37 °C.
for
test
KEY
POINTS
paper.
7
Place
all
three
8
Add
9
Compare
test
tubes
in
the
water
bath
at
40 °C
for
ve
1
minutes.
Most
one
enzymes
value
of
work
best
at
pH.
3
of
protease
to
each
test
tube.
2
the
appearance
of
the
tubes
every
minute
until
At
either
side
optimum
is
no
further
the
table
pH
value,
enzyme
At
some
shape
white
appearance
+
changes
5
plus:
values
of
the
of
pH
active
the
site
after
pH
tube
protease
decreases.
below.
3
egg
their
change.
activity
Complete
of
there
tnemelppuS
1 cm
so
that
substrate
minutes
molecules
no
longer
t.
3
2 cm
of
sodium
1
carbonate
solution
3
2
2 cm
of
water
3
2 cm
of
3
hydrochloric
SUMMARY
1
Sketch
the
a
QUESTIONS
graph
optimum
2
Use
3
An
the
‘lock
to
pH
and
investigation
Eight
The
test
acid
tubes
show
is
7.0
key’
was
were
concentration
of
the
and
effect
there
model
carried
set
up
to
reducing
increasing
no
explain
out
at
of
is
a
into
activity
what
the
sugar
pH.
a
Plot
a
b
Explain
of
graph
the
reducing
to
show
effects
of
sugar
these
pH
produced
of
was
the
pH
pH
They
(product)
pH
concentration
on
happens
effects
different
pH
below
rate
4.0
when
on
were
then
of
and
an
enzymes
the
action
incubated
estimated.
4.0
5.0
6.0
1
12
26
enzyme-catalysed
none
are
of
in
above
The
enzyme
water
bath
results
are
reaction,
where
10.0.
denatured
the
a
pH
at
extremes
amylase
at
30 °C
shown
6.5
7.0
8.0
9.0
32
33
27
13
on
for
in
of
pH.
starch.
1
the
hour
.
table.
10.0
5
results.
on
the
action
of
amylase
in
this
investigation.
51
PRACTICE
QUESTIONS
1
the
Which
is
correct
statement
about
enzymes?
5
In
an
enzyme-catalysed
binds
A
Enzymes
are
biological
catalysts
to
B
inside
Enzymes
only
C
are
outside
catalysts
function
Enzymes
and
are
inside
are
used
they
catalyse.
up
of
protein
Enzymes
only
substances
catalyse
are
made
the
by
cells
reactions
reactions
broken
substrate
down
in
into
site
B
complementary
as
C
reaction
D
substrate
site
site
site
2)
[1]
which
smaller
6
Albumen
and
in
1)
is
the
at
a
protein
blood.
75 °C
A
and
found
solution
then
in
egg
of
added
white
protease
to
a
was
solution
of
[1]
albumen.
The
the
molecule
the:
active
kept
2
enzyme
that
molecules.
(Paper
as
A
(Paper
D
reaction,
the
that
cells.
during
of
cells.
made
continually
they
part
that
known
function
the
equation
shows
a
reaction
catalysed
by
No
reaction
occurred.
an
Which
is
the
most
likely
explanation?
enzyme.
A
75 °C
is
below
the
optimum
temperature
lipase
of
fat
+
water
→
fatty
acids
+
B
The
progress
of
the
reaction
the
protease
glycerol
can
be
albumen
cannot
be
broken
down
by
followed
proteases
by
detecting
the
decrease
in
pH.
This
is
C
the
protease
D
there
is
denatured
because:
A
fat
is
an
acidic
the
B
fatty
acids
they
lower
are
one
of
the
products
the
no
D
the
reaction
is
a
1)
Starch
and
kinetic
energy
for
2)
[1]
stops
when
the
pH
decreases
7
The
diagram
possible
shows
an
enzyme
and
four
substrates.
reactant
A
(Paper
enough
pH
further
water
not
reaction
and
(Paper
C
was
substance
C
B
D
[1]
enzyme
3
together
human
at
salivary
different
temperature
will
amylase
were
temperatures.
give
the
fastest
mixed
Which
rate
of
starch
digestion?
A
20 °C
B
60 °C
C
37 °C
Which
of
substrate
D
(Paper
1)
shown
is
the
enzyme?
pH
2)
of
enzyme-controlled
reactions
changed
affect
the
from
rate
of
pH
the
A
always
increases
B
always
decreases
C
has
effect
D
may
the
(Paper
no
change
on
the
7
to
pH
8.
How
does
The
optimum
reactions?
the
the
the
rate
rate
rate
rate
or
have
no
temperature
effect
reaction
is
the
for
an
enzyme-
temperature
at
which:
this
on
rate.
1)
[1]
may
catalysed
52
substances
this
[1]
8
The
be
for
10 °C
(Paper
4
the
[1]
A
least
B
most
C
the
D
the
(Paper
substrate
product
rate
of
is
broken
is
down
formed
reaction
reaction
2)
is
is
at
completed
its
in
fastest
the
longest
time
[1]
9
(a)
Explain
the
following
statements.
A
(i)
Only
small
required
(ii)
Cells
quantities
inside
make
of
enzymes
cells.
many
B
are
[2]
different
types
of
1
3
enzymes,
The
the
table
shows
relative
solution
at
not
the
activity
pH
just
one.
effect
of
an
of
[2]
temperature
enzyme
kept
in
on
C
a
7.
2
relative
temp
/
°C
activity
5
4
15
8
(a)
State
(b)
Use
the
the
when
25
16
35
32
45
30
55
7
(c)
(d)
the
when
(b)
Explain
why
kept
the
at
all
the
same
reaction
mixtures
were
pH?
Draw
a
graph
(d)
Describe
of
the
results
in
the
table.
results
Hydrogen
shown
in
the
graph. [4]
(a)
model
to
is
what
a
happens
reaction.
known
explain
enzyme
what
molecule
temperatures
peroxide
is
produced
metabolism.
as
[4]
‘lock
or
happens
changes
extremes
of
shape
pH.
[4]
is
a
very
toxic
substance
The
by
cells
enzyme
peroxide
and
as
part
of
catalase
is
found
their
breaks
in
down
organisms
in
3)
all
10
model
[3]
4)
hydrogen
(Paper
describe
catalyses
C.
[6]
which
the
and
[2]
12
(c)
the
B
[2]
the
high
(Paper
to
enzyme
why
A,
key’.
Use
in
of
diagram
an
Explain
and
names
Explain
the
following
kingdoms.
statements.
catalase
(i)
Amylase
digests
starch,
but
proteases
Hydrogen
do
not.
Human
enzymes
catalyse
reactions
student
but
not
at
73 °C.
table
shows
enzyme
kept
35 °C.
the
in
relative
solutions
activity
of
investigated
in
yeast
by
the
activity
measuring
of
the
the
enzyme
volume
of
a
different
collected
over
time.
The
graph
of
shows
the
results.
pH
3
human
water
[2]
oxygen
The
+
at
catalase
37 °C,
oxygen
[1]
A
(ii)
peroxide
mc
at
7
/
relative
3
detcelloc
pH
activity
5
32
9
10
emulov
7
fo
14
negyxo
5
6
5
4
3
2
1
×
0
0
11
20
40
60
80
time
(a)
(b)
Explain
why
all
the
reaction
mixtures
Use
at
35 °C?
Draw
a
graph
Describe
the
results
catalase
of
the
results
in
the
table.
140
on
shown
to
hydrogen
describe
the
[4]
Explain
results
shown
in
the
why
catalyse
catalase
the
is
the
breakdown
only
of
enzyme
hydrogen
graph. [4]
peroxide.
(Paper
3)
(c)
Describe
catalyses
11
The
diagram
reaction.
effect
peroxide.
[6]
to
(d)
120
s
[3]
(b)
(c)
the
/
were
of
kept
100
4
shows
an
[2]
what
a
happens
reaction.
when
an
enzyme
[4]
enzyme-catalysed
(Paper
4)
53
Plant
nutrition
6.1
Photosynthesis
The
LEARNING
process
When
•
•
Dene
State
the
the
term
Describe
leaf
tnemelppuS
•
for
State
photosynthesis
word
how
equation
for
look
round,
green
energy
to
into
to
test
a
green
starch
the
you
at
cells
Photosynthesis
raw
is
called
carbon
sugars.
This
the
materials
dioxide
process
process
using
Describe
the
by
can
role
of
chlorophyll
carbon
be
dioxide +
balanced
+
equation
This
is
full
of
not
that
TIP
tnemelppuS
this
is
there
of
the
balanced
write
it
out.
are
the
atoms
their
see
use
many
light
surroundings
photosynthesis
plants
make
carbohydrates
light.
in
of
and
this
word
equation:
chlorophyll
glucose
equation
6H
for
photosynthesis
and
a
case.
H
6
There
different
photosynthesis
are
oxygen
is:
C
that
+
chlorophyll
O
suggests
the
by
energy
transferred
sure
you
plants
many
is
one
reactions
in
O
12
+
6O
6
simple
2
reaction.
photosynthesis,
each
enzyme.
chloroplasts.
Light
Make
from
2
This
catalysed
STUDY
from
Green
water
2
are
called
summarised
chemical
6CO
cells
microscope
water
which
energy
light
plant
the
photosynthesis
The
These
and
is
light
•
under
chloroplasts.
chemical
Photosynthesis
for
leaf
structures
convert
simple
from
balanced
equation
some
photosynthesis
photosynthesis
•
of
OUTCOMES
equation
when
you
Make
same
form
the
The
becomes
sure
are
the
carbon,
As
by
to
a
is
a
water
used
to
are
the
bond
Glucose
as
chemical
from
is
result,
starch
chlorophyll.
as
ions
chemical
produced.
converted
energy
hydrogen
carbohydrate.
number
absorbed
chlorophyll
carbohydrates
process
oxygen.
is
by
used
to
in
simple
store
of
energy
to
the
energy
in
carbon
simple
that
During
leaves
that
produced;
and
and
to
chlorophyll
sugars
is
ions
dioxide
by
is
reactions
hydrogen
absorbed
sugar
light
the
dioxide.
into
reduce
from
drive
carbon
water
energy
energy
one
and
split
light
The
energy
other
it
is
parts
of
plants.
hydrogen
and
both
of
sides
oxygen
the
on
Photosynthesis
arrow.
that
feed
show
that
oxygen
carbon
dioxide
on
where
in
it
provides
plants
oxygen
its
is
is
own
used
energy
directly
or
produced
respiration
by
other
for
plants
indirectly
as
or
it
a
and
(see
for
by-product.
may
all
page
diffuse
other
244).
The
out
plant
into
organisms
The
equations
may
the
use
atmosphere
organisms.
Sun
oxygen
chlorophyll
Investigating
photosynthesis
light
traps
light
energy
energy
Green
if
too
a
very
plants
much
make
sugar
simple
is
sugars
dissolved
in
from
the
carbon
cell
sap
of
dioxide
plant
and
cells
water
.
it
However
,
would
make
sugar
cells
to
concentrated
by
osmosis
make
very
together
effect
starch
Figure
6.1.1
A
simple
overview
photosynthesis.
54
of
out
on
in
to
and
thick
form
leaves.
cause
cell
Y
ou
As
you
This
the
walls.
larger
osmosis.
whether
solution.
will
cells
T
o
starch
can
to
see
iodine
in
has
so
this,
water
much
glucose
which
solution
Topic
been
make
swell
prevent
molecules
use
photosynthesis
would
6.2
are
to
we
that
in
they
insoluble
for
use
or
from
the
this
not.
other
would
molecules
test
can
happening
move
are
and
need
linked
have
presence
test
to
no
of
nd
tnemelppuS
6
PRACTICAL
T
esting
a
leaf
for
starch
Safety:
eye
1
Submerge
This
it
kills
easier
a
leaf
in
the
leaf
as
to
extract
boiling
it
water
destroys
the
for
one
wear
At
this
boil
3
Put
point,
the
the
turn
is
ethanol
ammable
minute.
membranes,
making
chlorophyll.
boiling
2
Safety:
protection
off
any
Bunsen
burners
used
water
ethanol
to
water.
leaf
into
chlorophyll
is
a
test-tube
extracted
by
of
ethanol.
dissolving
The
into
the
ethanol.
4
Stand
the
test-tube
in
a
beaker
of
hot
water
for
turn
about
10
off
Bunsen
burner
minutes.
iodine
5
Wash
the
ethanol
makes
6
some
7
If
and
it
Spread
leaf
the
leaf
stays
to
leaf
drops
cold
water.
rehydrates
easy
the
in
of
out
there
is
SUMMARY
QUESTIONS
1
complete
and
oxygen
on
plants
chloroplasts
for
this
made
make
the
process
in
the
are
leaves
white
on
softens
surface
is
own
leaves
and
present.
and
put
If
it
Safety:
using
chlorophyll
food
traps
these
careful
2
To
nd
carry
of
this
out
out
a
if
process
is
the
by
the
are
.
Green
Sun’s
.
.
changed
gas
photosynthesis
to
burn
yourself
dioxide
in
Raw
Simple
to
.
the
materials
sugars
The
are
waste
KEY
product
not
words:
carbon
and
some
be
photosynthesis
carbon
and
it
starch.
water
their
the
it.
sentences
starch
of
which
starch
no
the
energy
Green
a
solution
blue-black,
red/brown
Copy
leaf
removes
out.
at
iodine
goes
the
spread
This
has
POINTS
.
taken
place
in
a
leaf
we
can
1
test.
Chlorophyll
absorbs
energy
is
that
used
light
in
photosynthesis.
Copy
out
correct
the
stages
reason
on
listed
the
on
the
left.
Match
each
one
with
the
right.
2
Photosynthesis
by
Stage
in
test
which
the
leaf
in
cold
water
to
test
for
to
soften
to
remove
raw
the
leaf
add
drops
in
ethanol
iodine
solution
the
ethanol
the
glucose
leaf
rehydrate
using
from
light.
Carbon
the
dioxide
and
water
and
are
to
materials
it
3
of
process
starch
energy
boil
the
make
Reason
from
wash
is
plants
the
raw
materials
for
leaf
photosynthesis.
dip
the
leaf
in
boiling
water
to
extract
the
chlorophyll
4
3
Write
out
the
word
equation
for
photosynthesis
and
The
are
the
raw
materials
and
Using
only
information
in
this
topic,
explain
why
plants
to
our
of
and
photosynthesis
oxygen.
A
leaf
that
has
been
exposed
are
to
vital
glucose
products.
5
4
products
identify
light
will
give
a
positive
survival.
test
for
starch.
55
6.2
What
is
needed
for
photosynthesis?
The
LEARNING
requirements
Green
•
List
the
raw
needed
•
for
Describe
materials
that
plants
need
for
the
following
in
order
to
carry
out
photosynthesis:
•
light,
which
provides
•
chlorophyll,
energy
for
the
process
photosynthesis
the
that
dioxide
photosynthesis
are
experiments
chlorophyll,
and
light
are
a
green
pigment
that
absorbs
the
energy
from
light.
that
Chlorophyll
prove
for
OUTCOMES
is
in
the
chloroplasts
of
the
leaf
carbon
•
carbon
•
water,
dioxide,
which
diffuses
into
the
leaves
from
the
air
needed
photosynthesis
Water
which
and
If
a
needed
plant
them
To
as
be
starch.
certain
leaves
the
dark
is
then
that
given
we
out
If
are
cannot
the
no
all
the
that
plant’s
raw
roots
from
materials
chlorophyll,
the
of
as
will
investigation
48
at
things
(It
the
hours.
is
that
plant
is
is
for
carbon
make
the
soil.
photosynthesis.
dioxide
it
is
to
water
do
so
a
you
sugars
will
not
must
and
this,
a
and
make
make
light
plant
that
plant
can
for
the
water
for
so
hardly
store
starch.
sure
is
left
de-starching.
except
show
by
it
we
called
needs
required
is
To
simple
then
valid,
start.
This
difcult
water
the
it
photosynthesise
starch
testing.
most
are
the
photosynthesis
least
photosynthesis,
things;
it
that
at
by
photosynthesis.
have
for
dioxide
demonstrate
for
carries
the
absorbed
carbon
Investigations
are
is
that
in
The
plant
substance
is
needed
many
‘take
it
for
other
away’.)
PRACTICAL
Showing
T
ake
as
a
a
that
de-starched,
leaves
is
important
affect
to
understand
photosynthesis
in
the
order
to
factors
that
variegated
needed
plant
for
photosynthesis
such
are
means
white
chlorophyll
some
because
parts
there
of
is
the
no
there.)
increase
Place
crop
is
geranium.
(‘Variegated’
It
chlorophyll
the
plant
in
sunlight
for
about
6
hours.
yields.
Draw
one
leaf
to
show
the
white
and
green
parts.
Now
STUD
Y
TIP
the
test
this
starch
variegated
test
described
leaf
in
for
starch
T
opic
using
6.1.
Variegated
No te
and
that
carb
on
wate
r
mater
ials;
sour
ce
no t
a
of
are
the
ligh
t
dioxid
e
raw
is
energy
,
the
and
Y
ou
should
The
green
that
parts
photosynthesis
only
contain
to
make
the
green
parts
chlorophyll
of
the
which
is
leaf
needed
blue-black.
for
starch.
white
parts
contain
no
chlorophyll,
so
no
photosynthesis
mater
ial.
occurs
here.
Therefore
the
starch
the
white
parts
of
the
leaf
give
a
negative
result
with
test.
Safety:
56
go
leaves.
is
The
raw
nd
geranium
wear
eye
protection
STUD
Y
Showing
for
You
that
carbon
dioxide
and
light
are
Y
ou
needed
photosynthesis
could
own
prove
food
except
by
that
a
carbon
it
dioxide.
mus
t
explai
n
plant
providing
TIP
needs
with
Then
carbon
everything
test
to
see
if
dioxide
it
needs
it
has
to
for
make
in
we
to
need
these
experim
ents
.
photosynthesis
made
able
why
cont
ro ls
its
be
starch.
PRACTICAL
Showing
1
T
ake
a
that
de-starched
absorbs
2
Leave
carbon
carbon
the
plant
described
in
dioxide
plant.
dioxide.
in
the
Topic
needed
Enclose
(Soda
light
6.1.
is
for
The
a
leaf
it
in
lime
a
for
plastic
absorbs
few
hours.
should
photosynthesis
bag
Test
show
with
carbon
a
a
a
chemical
that
dioxide.)
leaf
negative
for
starch
result
for
as
the
plastic
starch
bag
test.
Deprived
make
of
carbon
dioxide
the
leaf
is
unable
to
photosynthesise
and
starch.
soda
lime
elastic
band
A
control
the
soda
carbon
can
This
dioxide
dioxide
Y
ou
experiment
lime.
that
also
should
means
removed.
caused
show
the
that
a
be
the
Then
lack
we
of
plant
set
plant
up
in
can
starch,
needs
in
exactly
the
be
sure
and
light
the
control
it
not
to
same
was
the
keeping
carry
way
experiment
out
but
does
absence
the
plant
without
not
of
have
carbon
inside
the
plastic
bag.
photosynthesis.
PRACTICAL
Showing
that
light
is
needed
for
photosynthesis
aluminium
1
T
ake
a
de-starched
plant.
Cover
part
of
the
leaf
with
some
foil
aluminium
2
Leave
3
T
est
the
the
foil
to
plant
leaf
for
of
the
test
leaf
of
the
leaf
that
prevent
in
the
starch
that
light
light
as
were
for
getting
a
few
described
left
in
through.
hours.
T
opic
uncovered
6.1.
go
Only
the
blue-black.
parts
The
parts
starch
carry
out
covered
photosynthesis
SUMMARY
1
were
did
and
so
not
receive
could
not
light
make
and
could
no
Describe
b
Explain
how
why
show
that
c
What
is
d
Describe
you
it
is
would
de-starch
necessary
plants
need
to
light
use
to
a
a
plant.
de-starched
carry
out
plant
to
photosynthesis.
KEY
a
variegated
how
carbon
you
could
dioxide
POINTS
leaf?
carry
out
an
investigation
to
show
1
is
needed
for
Plants
need
in
State
whether
the
following
light,
chlorophyll,
photosynthesis.
carbon
2
starch
starch.
QUESTIONS
a
that
present
not
statements
are
true
or
dioxide
order
to
and
carry
water
out
false.
photosynthesis.
a
Plants
get
all
b
Plants
need
their
food
from
the
soil.
2
chlorophyll
to
carry
out
We
can
light,
c
Water
d
Leaves
for
photosynthesis
is
are
de-starched
absorbed
give
a
to
see
through
the
chlorophyll
blue-black
colour
with
are
needed
Explain
what
is
by
for
not
giving
iodine.
plants
3
carbon
when
photosynthesis
tested
that
and
leaves.
dioxide
that
test
photosynthesis.
meant
by
a
control
experiment
each
testing
of
leaves
these
for
and
starch.
57
6.3
Products
of
photosynthesis
The
LEARNING
products
and
•
State
the
products
in
outline
that
how
show
they
the
are
used
procedures
oxygen
of
the
is
such
as
glucose,
of
the
glucose
•
Some
of
the
glucose
in
•
Some
for
of
make
use
the
cell
Glucose
plant
needs
for
food
are
made
in
the
leaves.
is
used
for
respiration
in
the
leaf.
in
is
the
changed
future,
into
e.g.
at
starch
and
stored
in
the
night.
is
plant
•
Plants
get
•
Glucose
•
Plants
also
to
to
make
sucrose
phloem
be
(see
converted
nitrogen
and
Sugars
The
these
the
need
energy
used
cellulose,
which
is
needed
to
by
nitrate
and
Topic
to
other
absorbing
are
used
transported
to
to
other
parts
of
8.4).
substances:
nitrate
form
ions
amino
from
the
acids,
soil.
which
are
built
proteins
enzymes
•
is
converted
in
can
into
glucose
walls.
Glucose
up
in
a
that
produced
food
which
Some
the
makes
sugars
•
•
proteins
and
are
in
for
growth
and
cell
repair
and
for
making
hormones.
converted
to
oils,
which
are
an
efcient
way
to
store
seeds.
importance
of
photosynthesis
wheat
plants.
Think
what
soya
STUD
Y
sugars,
in
photosynthesis
Photosynthesis
simple
and
leaves
Describe
are
are
photosynthesis
plants.
•
photosynthesis
oxygen.
Most
formed
of
OUTCOMES
TIP
If
about
you
beans
you
eat
the
eat
food
comes
and
meat
you
have
from
eaten
plants
like
in
the
rice,
last
24
maize,
hours.
wheat,
A
lot
of
potatoes,
nuts.
or
sh
then
that
comes
from
animals
that
have
eaten
plants.
Mak
e
conc
how
a
diag
ram
map
plan
ts
simpl
e
to
use
a
you
learn
mad
e
T
his
them
Oxygen
Some
is
58
is
is
is
a
a
by-product
product
used
upon
plants?
so
why
are
made
from
plants.
of
photosynthesis
by
the
of
photosynthesis.
plant’s
It
respiration,
is
but
not
the
usually
main
there
product.
is
most
it
is
diffuses
called
a
out
of
the
leaves
into
the
more
than
atmosphere.
by-product.
products
provide
more
about
also
timber
depends
is
needed,
Plants
food
margarine
all.
Plants
this
and
will
Plant
of
oil
in
That
much
cooking
the
is
How
like
show
Oxygen
suga
rs
pho to
synt
hesis.
help
or
Products
ept
and
us
with
this
on
provide
a
cotton.
including
digitalis,
extracted
from
the
our
food
page
range
Many
which
rosy
and
of
raw
food
materials
medicines
is
also
for
our
livestock.
There
248.
a
heart
periwinkle
have
drug,
from
for
been
and
industry,
such
discovered
two
in
anti-cancer
Madagascar.
as
plants
drugs
Plants
are
the
dominant
organisms
in
almost
all
environments.
As
DID
such
they
provide
rainforests
support
make
more
habitats
up
than
only
half
for
6%
the
animals
of
the
and
microorganisms.
Earth’s
world’s
land
species
of
surface,
animals
but
and
YOU
Plants
they
plants.
provide
everything
works
The
concentrations
of
gases
in
the
atmosphere
are
kept
constant
Without
green
plants,
the
concentration
of
of
in
the
air
would
increase
and
the
concentration
of
art.
Lignum
The
for
of
to
that
the
grows
in
is
the
hardest
wood
used
oxygen
Fast-growing
trees
decrease.
provide
is
PRACTICAL
Oxygen
1
timber
wood
vitae
commercially.
would
with
construction
carbon
Jamaica
dioxide
us
from
by
tree
photosynthesis.
KNOW?
The
Set
the
collect
in
of
as
fossil
a
biofuel
form
fuels
of
(see
that
energy,
page
282).
photosynthesis
apparatus
bubbles
wood
renewable
unlike
produced
up
a
to
gas
gas
rich
in
oxygen
given
off
by
the
Canadian
collecting
pondweed
(Elodea
canadensis).
light
Canadian
A
lamp
provides
the
light
STUD
Y
pondweed
energy
that
the
plant
Plasticine
Carbon
in
the
dioxide
water.
sodium
is
to
to
dioxide
Rem
embe
r
dissolved
Add
of
some
hydrogencarbonate
powder
This
is
the
water
make
in
the
sure
TIP
needs.
and
that
the
in
stir
to
there
dissolve.
is
always
by
the
respira
tion.
carbon
that
water.
some
produc
ed
If
there
is
not
enough
carbon
dioxide
then
produc
ed
the
down.
plan
t
T
his
is
fo r
its
means
oxyg
en
is
no t
photosynthesis
into
slows
some
pho to
synt
hesis
used
enough
that
oxyg
en
relea
sed
atmos
phere
or
wate
r
.
2
Place
gas
3
Test
the
to
apparatus
the
gas
Standing
dioxide
for
the
the
oxygen
funnel
dissolved
photosynthesis
A
in
light
and
allow
a
few
hours
for
the
collect.
water
plant
downward
in
on
the
does
is
with
glowing
plasticine
water
not
used
a
slow
because
displacement
of
to
splint.
gives
reach
a
gap
the
to
allow
pondweed
carbon
so
down.
it
is
easy
to
collect
the
gas
by
water.
KEY
SUMMARY
1
QUESTIONS
POINTS
Products
include
1
What
a
are
the
glucose
following
b
starch
products
c
made
cellulose
in
d
plants
used
protein
e
to
for?
photosynthesis
glucose,
make
amino
oils
of
starch,
acids
which
is
used
cellulose,
(and
then
proteins).
2
a
Describe
as
a
how
you
by-product
practical
of
would
show
that
photosynthesis.
plants
produce
Remember
to
oxygen
include
all
2
Photosynthesis
it
details.
provides
medicines;
b
How
would
you
show
that
light
is
necessary
for
us
it
is
important
with
helps
food
to
as
and
keep
oxygen
constant
concentrations
of
production?
carbon
3
Plants
are
important
because
they
provide
us
food
Give
three
b
fuels
examples
c
of
building
plants
materials
that
provide
d
us
and
oxygen
in
with:
the
a
dioxide
atmosphere.
medicines
with
each
of
these.
59
6.4
Rate
When
LEARNING
plants
Describe
how
effect
varying
of
temperature
dioxide
rate
of
to
investigate
light
and
the
much
by
carbon
concentration
the
products
intensity
,
on
photosynthesis
describe
carry
photosynthesis
out
photosynthesis
they
produce
oxygen.
We
can
OUTCOMES
determine
•
of
the
as
by
results
that
starch
nding
use.
and
how
can
are
or
out
Instead,
we
or
slow
oxygen
the
an
is
dioxide
in
conditions
be
Starch
as
such
as
done
but
it
oxygen
by
the
light
is
is
described
measuring
concentration
occurs
by
an
be
in
T
opic
rate
of
is
6.3.
method
much
This
oxygen
is
to
easier
done
produced.
temperature
of
the
how
measured
easy
produced
volume
the
can
not
intensity,
inuence
measuring
measuring
production
mass,
much
plant
by
can
dry
how
aquatic
or
This
made.
change
bubbles
Environmental
photosynthesis
produced.
measuring
use
counting
carbon
fast
and
photosynthesis.
PRACTICAL
Photosynthesis
Y
ou
the
can
use
rate
1
Cut
2
Put
of
a
this
and
light
apparatus
intensity
to
measure
the
effects
of
light
intensity
Canadian
on
photosynthesis:
piece
of
pondweed
about
5 cm
in
length.
stream
a
paperclip
on
the
pondweed
to
stop
it
oating
to
the
surface.
of
bubbles
3
Put
a
lamp
close
to
the
plant
and
measure
the
distance
between
the
metre
plant
4
and
Count
times
5
the
and
Repeat
The
less
number
this
the
of
of
bubbles
lamp
is
close
photosynthesis
energy
bubbles
the
for
the
released
over
5
minutes.
with
the
should
to
is
plant
the
high.
and
lamp
at
decrease
plant
As
the
the
the
rate
different
as
of
sis ehtnysotohp
of
In
the
light
lamp
distance
intensity
is
moved
graph
are
dark
very
fo
the
rate
as
the
the
This
away
some
plant.
lamp
gives
the
results
intensity
is
no
and
the
light
the
plant
plant
lots
intensity
etar
investigating
an
the
oxygen
intensity
increase
energy
on
of
of
increases.
energy
decreases;
experiment
rate
of
photosynthesis.
of
light
not
the
so
the
there
is
any
available
the
effect
At
further
.
light
The
until
the
of
different
the
plant
for
intensities
rate
at
a
Increasing
to
measure
effect
photosynthesis.
low
produced.
increases
to
of
photosynthesis
certain
the
there
light
light
intensity
intensity
photosynthesis.
light
intensities
it
is
intensity
important
The
effect
light
of
increasing
intensity
on
the
to
T
emperature
keep
can
the
be
other
kept
environmental
constant
by
conditions
putting
a
the
same.
thermometer
into
rate
the
beaker
of
water
and
adding
hot
or
cold
water
if
the
temperature
photosynthesis.
changes.
The
by
The
lamp
concentration
adding
dissolve.
60
high.
bubbles
the
from
decreases.
light
does
increases
of
is
there
few
increases
6.4.1
several
between
further
shows
increasing
the
When
Figure
distances
photosynthesis
The
light
Repeat
average.
procedure
of
rule
lamp.
calculate
number
When
rate
the
sodium
This
may
of
give
carbon
off
heat,
dioxide
so
in
hydrogencarbonate
ensures
that
the
plant
the
the
to
will
temperature
water
the
not
can
water
run
out
be
and
of
may
kept
increase.
constant
letting
carbon
it
dioxide.
PRACTICAL
Photosynthesis
and
To
of
nd
the
of
beakers
of
different
lamp
water
kept
at
one
The
to
similar
into
a
range
all
the
of
time
hydrogencarbonate
make
number
of
apparatus
test-tubes
temperatures.
across
distance
Sodium
test-tubes
constant.
placed
different
temperatures
constant.
the
at
are
sure
carbon
bubbles
of
The
10 °C
so
is
about
the
added
dioxide
be
are
used.
put
minimum
to
that
oxygen
can
which
ve
40 °C.
light
to
is
the
The
intensity
water
concentration
produced
inside
at
etar
in
temperature
fo
is
is
effect
pondweed
sis ehtnysotohp
Pieces
temperature
is
different
temperature
temperatures
can
be
counted
in
the
same
Figure
Figure
6.4.2
shows
the
results
you
might
/
˚C
way.
expect.
The
6.4.2
The
effect
of
increasing
maximum
temperature
rate
of
photosynthesis
occurs
at
the
optimum
temperature.
on
photosynthesis.
actual
temperature
depends
on
the
plant
that
is
used.
Plants
in
lower
temperate
than
those
latitudes
that
grow
have
in
optimum
the
temperatures
The
rate
of
rate
that
decreases
grow
the
The
that
are
because
at
chloroplasts
tropics.
high
enzymes
are
temperatures
in
the
denatured.
PRACTICAL
The
same
Adding
water
of
carbon
apparatus
different
increases
dioxide
can
be
the
modied
quantities
the
on
of
for
sodium
concentration
of
rate
this
of
photosynthesis
investigation.
hydrogencarbonate
carbon
dioxide.
At
to
least
the
ve
deewdnop
The
effect
fo
sodium
test-tubes
You
can
intensity
see
that
and
the
the
light
intensity.
photosynthesis.
If
As
is
is
a
different
mass
of
added.
of
the
there
the
with
temperature
effect
photosynthesis
each
must
increasing
same
no
carbon
as
carbon
the
carbon
dioxide
be
effect
dioxide
kept
constant.
dioxide
of
on
the
etar
the
used
increasing
there
can
concentration
be
fo
light
of
be
hydrogencarbonate
The
rate
can
sisehtnysotohp
different
no
carbon
Figure
there
is
an
increase
in
the
rate
of
photosynthesis.
dioxide
concentration
increases
Above
a
6.4.3
The
on
concentration
SUMMARY
the
rate
remains
List
the
the
of
rate
carbon
of
dioxide
photosynthesis.
constant.
QUESTIONS
KEY
1
effect
certain
main
environmental
factors
that
inuence
the
rate
POINTS
of
1
The
release
of
oxygen
photosynthesis.
from
2
A
student
used
the
distances
25,
30 cm
the
and
and
apparatus
the
24,
shown
numbers
40 cm
and
of
18,
opposite.
bubbles
60 cm
per
and
He
wrote
minute:
10,
20 cm
100 cm
to
down
and
Explain
how
the
student
kept
other
conditions
Make
a
c
Explain
table
of
the
results
and
plot
them
as
a
constant.
line
Light
and
intensity,
the
your
graph
does
not
look
like
Figure
is
used
of
temperature
concentration
dioxide
are
of
three
graph.
environmental
why
rate
6.
carbon
b
plants
the
photosynthesis.
and
2
a
aquatic
measure
6.4.1.
that
inuence
factors
the
rate
of
photosynthesis.
3
Describe
carbon
the
effect
dioxide
on
the
rate
concentration,
of
photosynthesis
and
b
increasing
of
the
a
increasing
temperature.
61
6.5
Glasshouse
tnemelppuS
We
LEARNING
•
Dene
•
Identify
the
OUTCOMES
the
term
and
limiting
environmental
in
of
the
enrichment,
use
light
of
•
Temperature
•
Carbon
carbon
and
in
inuences
dioxide
These
to
three
intensity,
the
rate
determines
concentration
enzymes
light
inuence
intensity
is
a
use
to
raw
temperature
of
activity
there
is
and
photosynthesis
energy
material
make
are
the
the
increases
factors
available
of
for
carbon
in
to
enzymes
photosynthesis.
in
the
photosynthesis,
more
of
it
dioxide
plants.
available
chloroplasts.
so
if
for
the
chloroplast
carbohydrates.
limiting
factors
optimum
Limiting
temperature
that
Light
conditions
dioxide
seen
•
different
Explain
optimum
factor
explain
photosynthesis
•
limiting
factors
have
concentration
production
factors
glasshouse
systems
A
limiting
short
Light
dioxide
sisehtnysotohp
CO
2
is
of
In
of
fo
CO
etar
2
something
it
restricts
does
water
and
energy
this
case
increases
increases
also
see
because
that
the
warm
rate
environment
of
if
in
photosynthesis.
the
is
the
6.5.1
of
plant
temperature
intensity
light
rate
rate
matter
Figure
the
the
photosynthesis
light
In
in
such
processes.
the
not
a
for
present
life
influences
it
photosynthesis.
intensity
0.04%
Y
l o w,
and
shortage
high.
is
that
intensity
intensity
0.4%
factor
supply
and
can
photosynthesis
intensity
becomes
is
the
rate
that
constant
for
as
however
is
very
rate
light
The
Yo u
much
a
be
the
the
f a c t o r.
light
carbon
there
increases.
limiting
the
of
cannot
factor
see
If
lots
because
the
limiting
you
has
rate
can
the
light
X
light
Figure
6.5.1
The
is
f a c t o r,
must
it
dioxide
intensity
effect
intensity
of
be
on
the
photosynthesis
concentrations
of
at
carbon
on
page
certain
reactions
move
61
grap
h
and
you
a
the
ruler
from
lines
the
rate
a
grap
h
alon
g
left
The
substrates
and
more
can
the
rate
see
rate
by
as
enzymes
from
of
when
longer
the
temperature
the
increase
graph
in
photosynthesis
the
increases
enzymes
often
at
(see
to
higher
are
or
limiting
carbon
with
Figure
6.4.2
in
rate
reaches
because
the
To p i c
the
The
of
and
a
and
energy
increase
rate
until
maximum
kinetic
chloroplast
5.2).
increases
a
of
then
the
they
photosynthesis
Here
on
you
because
To p i c
the
enzymes
in
5.3).
Look
at
the
graph
in
Figure
6.5.1.
rate
of
photosynthesis
at
point
X.
rate
of
photosynthesis
at
point
Y
.
Light
intensity
Another
is
factor
limiting
is
the
limiting
This
could
be
carbon
the
dioxide
right
or
temperature.
or
H o w e v e r,
can
grap
h
cond
ition
s
to
(see
the
trend
s
the
temperatures
denatured
to
alwa
ys
concentration
the
starts
cons
tant
.
62
use
ques
tion,
follo
w
nd
such
no
TIP
patte
rns.
rule
that
decreases.
chloroplasts
a
catalysed
Yo u
temperature
decreases
Whe
n
else
now
two
collide
answ
er
something
is
rate
dioxide.
STUD
Y
intensity
increasing
intensity
temperature.
of
Light
concentration.
Chemical
light
increased.
to
carbon
there
is
you
can
dioxide
more
see
that
the
concentration
of
this
raw
rate
is
of
photosynthesis
increased
material
from
available.
This
remai
n
factor
at
Y
is
carbon
dioxide
to
means
when
limiting
increases
0.04%
concentration.
0.4%
that
if
as
the
Growers
best
try
to
possible
Conditions
earlier
•
grow
in
•
improve
inside
grow
The
production
the
conditions
•
in
a
yield
for
of
their
crops
photosynthesis
glasshouse
the
places
following
tnemelppuS
Glasshouse
allow
to
plants
by
giving
take
them
the
place.
to:
year
where
they
conditions
would
inside
not
normally
glasshouses
are
grow
well.
controlled.
T
emperature
Sunlight
The
heats
glass
up
stops
a
the
lot
inside
of
this
of
the
heat
glasshouse.
from
escaping.
Glasshouses
Electric
heaters
Ventilator
•
glass
when
and
lets
light
in
opened
in
sunlight.
intensity
shading
cold
to
weather.
cool
dioxide
Growers
can
gas
pump
dioxide
which
the
too
the
as
glasshouse
of
lighting
low.
Blinds
temperature
carbon
dioxide
concentration.
provides
temperature
Articial
gets
lowers
Carbon
carbon
•
are
used
on
hot
can
temperature,
control
light
limiting
intensity
factors,
and
such
humidity.
days.
Light
The
•
aps
are
carbon
They
in
cold
used
out
also
grow
plants
strong
light
countries.
burn
also
to
very
glasshouses
can
and
be
keep
tropical
into
dioxide
glasshouses
in
can
heat
to
increase
butane
to
raise
or
natural
the
weather.
Water
Many
and
All
glasshouses
humidiers
these
factors
concentration,
process
data
which
are
automatic
ensure
monitored
humidity,
from
SUMMARY
have
the
light
watering
plants
and
sensors
and
always
controlled
intensity
systems
and
control
get
by
using
enough
all
heating,
Water
so
detect
few
staff
changes
ventilation,
QUESTIONS
are
in
lighting
needed.
these
and
Explain
process
2
State
what
of
is
meant
by
the
photosynthesis
which
factors
term
to
would
help
be
limiting
explain
limiting
factor.
your
of
shading
Give
your
reasons
in
each
glasshouse
Use
A
for
factors.
in
crop.
the
carbon
dioxide
Computers
glasshouse.
POINTS
limiting
factor
is
a
factor
the
in
the
in
such
environment
that
is
answer.
photosynthesis
in
short
supply
that
it
the
restricts
following.
a
Sensors
limiting
KEY
1
1
misting
water.
computers
temperature
sprinklers
a
life
process,
such
as
case.
photosynthesis.
a
Plants
growing
on
a
high
mountainside
early
in
the
2
Light
intensity,
temperature
morning.
and
b
Plants
c
A
d
The
e
A
growing
in
a
dense
tropical
forest
at
carbon
dioxide
midday.
concentration
eld
of
same
maize
eld
early
late
on
in
a
the
very
bright
morning.
factors
plant
in
a
photosynthesis.
shaded
position
in
a
warm
room.
Carbon
light
dioxide
intensity,
temperature
3
Explain
how
each
of
the
following
can
be
controlled
to
give
optimum
conditions
for
carbon
b
light
dioxide
and
controlled
glasshouse
in
systems
give
optimum
conditions.
concentration
This
intensity
humidity
are
growth:
to
a
concentration,
in
modern
glasshouses
limiting
afternoon.
3
house
of
are
c
ensures
that
the
rate
of
temperature
photosynthesis
is
plants
maximum
produce
kept
high
so
yield.
63
6.6
Leaves
The
LEARNING
of
•
Identify
a
tnemelppuS
•
and
label
the
parts
of
a
and
Leaves
Explain
how
leaf
of
absorbing
into
leaf
of
shape
a
leaf
makes
it
ideally
adapted
to
carry
out
its
functions
OUTCOMES
is
the
out
light
of
for
the
photosynthesis
leaf
and
allowing
gases
to
diffuse
tissues.
have:
structure
adapted
•
a
large
•
a
thin
•
many
surface
area
–
to
absorb
light
rays
for
shape
–
so
gases
can
diffuse
in
and
out
easily
photosynthesis
place
•
veins
the
leaf
–
to
nd
–
to
absorb
light
for
the
reactions
that
take
photosynthesis
to
leaf
Inside
To
chloroplasts
in
support
cells,
all
a
and
other
the
to
leaf
take
parts
of
surface
sucrose
the
and
and
to
carry
amino
water
acids
and
away
ions
from
to
the
plant.
leaf
out
how
a
leaf
works
we
can
look
at
the
structure
of
a
typical
leaf.
A
leaf
has
an
ideal
shape
for
photosynthesis.
upper
layer
epidermis:
of
cells
with
chloroplasts.
cuticle:
down
waterproof
the
water
layer
lost
by
that
also
straight
cuts
lots
of
Most
mesophyll:
air
spaces
more
rounded
between
cells
vein:
with
and
lower
epidermis:
no
thick
cuticle.
Has
here
contains
that
ions
tiny
holes
called
stomata
(singular:
allow
gases
to
diffuse
in
and
the
water
leaf
tubes
that
and
take
stoma)
away
These
to
xylem
bring
lots
phloem
of
the
contain
chloroplasts.
vessels
them
mesophyll:
cells
photosynthesis
occurs
of
goes
evaporation
palisade
lots
Light
through
palisade
spongy
single
no
sucrose
and
amino
out
acids
stoma
guard
6.6.1
Leaf
cell
structure.
Some
of
the
internal
features
are
adaptations
for
photosynthesis.
PRACTICAL
•
Palisade
upper
Looking
at
a
leaf
surface
Observe
a
transverse
a
leaf
on
a
the
are
leaf
to
packed
tightly
maximise
together
absorption
near
of
light
the
slide
is
where
its
highest.
section
•
of
of
cells
section
intensity
1
mesophyll
under
There
are
many
chloroplasts
in
the
palisade
mesophyll
cells
to
the
absorb
as
much
light
as
possible.
microscope.
•
Look
for
the
tissues
in
Stomata
dioxide
6.6.1
under
low
(usually
in
the
lower
epidermis)
open
to
allow
carbon
Figure
to
diffuse
into
the
leaf.
Carbon
dioxide
is
a
raw
material
for
power
.
photosynthesis.
Now
look
tissue
64
at
under
each
high
type
of
power.
•
Leaves
the
are
thin
so
atmosphere
that
to
the
carbon
cells
of
dioxide
the
does
palisade
not
and
have
to
spongy
diffuse
far
mesophyll.
from
tnemelppuS
Figure
There
are
large
intercellular
air
spaces
within
the
spongy
tnemelppuS
•
mesophyll
palisade
layer.
This
makes
mesophyll
from
cell
cells.
to
it
easy
for
Diffusion
carbon
through
dioxide
air
is
to
diffuse
much
faster
to
all
than
cells
the
diffusion
cell.
spongy
•
Xylem
in
veins
bring
water
and
ions
to
the
mesophyll
cells.
Water
is
cells
CO
a
raw
by
material
the
cells
to
for
photosynthesis
make
and
magnesium
ions
are
2
needed
chlorophyll.
CO
2
•
The
sugar
produced
in
photosynthesis
is
converted
to
sucrose
lower
and
epidermis
transported
away
from
the
leaf
in
the
phloem
in
CO
veins.
guard
cell
2
Figure
6.6.2
Carbon
into
Stomata
the
dioxide
leaf
diffuses
for
photosynthesis.
Stomata
to
are
diffuse
small
into
epidermis,
pores
and
but
out
some
(holes)
of
the
plants
in
the
leaf.
like
epidermis
Stomata
water
lilies
are
that
allow
usually
have
them
in
in
gases
the
the
lower
upper
closed
stoma
epidermis.
guard
pore
In
cells
partly
closed
sunlight:
•
carbon
dioxide
•
oxygen
made
•
water
diffuses
in
vapour
in
for
photosynthesis
photosynthesis
diffuses
diffuses
out
out.
chloroplast
Opening
and
closing
pore
Stomata
are
Stomata
usually
cells
by
opened
open
osmosis.
Carbon
dioxide
diffuses
out.
and
during
This
into
vapour
by
the
makes
diffuses
Water
closed
guard
day.
them
the
also
Water
bend
leaf
for
so
passes
the
into
stoma
the
guard
opens.
photosynthesis
diffuses
and
oxygen
out.
Figure
At
night
osmosis
the
and
stomata
prevent
stomata
they
pores.
the
SUMMARY
Water
straighten
The
plant
close.
stomata
passes
and
move
also
close
out
closer
in
of
the
guard
together
hot,
dry
so
cells
closing
weather
to
6.6.3
Closed
by
Match
function
on
the
STUD
Y
the
leaf
See
parts
on
the
left
with
their
open
help
wilting.
of
and
the
QUESTIONS
each
stoma
stoma.
TIP
T
opic
your
self
1
open
cells
which
correct
into
right:
is
3.2
to
abou
t
how
and
remin
d
osmo
sis,
water
out
of
moves
guar
d
cells.
stomata
palisade
spongy
carry
mesophyll
water
allow
mesophyll
up
gases
to
from
pass
the
into
stem
and
out
of
leaf
contain
chloroplasts
for
photosynthesis
cuticle
contain
chloroplasts
for
photosynthesis
veins
prevent
too
much
water
being
lost
KEY
2
a
Which
gas
would
pass
b
Which
gas
passes
out
into
a
leaf
during
1
of
a
leaf
during
POINTS
daylight?
The
diagram
structure
3
Leaves
Lay
a
have
leaf
area
by
Find
out
same
a
large
onto
graph
counting
if
leaf
leaves
area.
surface
the
area
paper,
to
draw
absorb
around
light.
it
different
and
work
out
have
its
carry
squares.
from
Record
the
top
your
and
results
bottom
and
of
the
internal
daylight?
of
a
explain
plant
them.
have
the
2
a
leaf
important
shows
which
each
functions
to
out.
Stomata
of
of
tissues
gases
control
into
the
and
diffusion
out
of
a
leaf.
65
6.7
Mineral
Plants
LEARNING
need
Describe
the
nitrate
ions
ions
plant
in
importance
and
Explain
the
They
Nutrients
of
magnesium
active
are
light,
need
absorbed
transport
effects
of
carbon
in
the
mineral
dioxide
from
roots
salts
and
the
soil
(see
(also
water
in
Topic
called
for
small
plant
healthy
quantities
nutrients).
as
ions
by
3.4).
nutrients
nitrate
Nutrients
and
also
nutrition
Plant
•
than
OUTCOMES
growth.
•
more
requirements
magnesium
deciency
are
needed
for
healthy
growth
of
plants.
They
are
used
for
on
a
variety
of
purposes
in
plants.
If
these
nutrients
are
lacking
in
the
soil
plants
then
Use
do
not
grow
well
and
show
certain
symptoms
known
as
hydrogencarbonate
solution
to
exchange
kept
in
investigate
of
the
an
light
aquatic
and
deciency
symptoms.
which
are
used
plants
decient
Plants
need
nitrate
ions
to
make
amino
acids
gas
in
to
make
proteins.
As
proteins
are
required
for
growth,
plant
the
in
nitrate
show
poor
growth.
dark
Magnesium
Leaves
as
for
the
may
ions
plants
chlorosis.
and
If
of
are
absorbed
decient
Plants
need
in
by
plants
chlorophyll
phosphate
for
and
look
used
to
yellow,
making
a
make
chlorophyll.
condition
compounds
known
such
as
DNA
respiration.
soil
does
add
more
not
as
contain
enough
fertiliser
to
nutrients,
replace
the
farmers
missing
and
growers
nutrients.
tnemelppuS
•
plants
PRACTICAL
The
effects
Some
of
plants
grown
in
culture
nutrients
on
growth
are
water
to
show
that
cotton
seedling
plants
need
different
wool
nutrients.
1
Set
up
some
normal
test-
culture
tubes
as
shown
solution
here.
This
plant
has
magnesium
deciency.
Cover
the
tubes
1
with
black
black
paper
to
to
prevent
growing
YOU
in
3
4
no
distilled
magnesium
nitrates
water
keep
algae
out
DID
2
no
paper
light
the
KNOW?
water.
Legume
plants,
such
as
peas
and
Each
beans,
have
bacteria
in
their
has
that
are
able
nitrogen
plants
(see
can
page
clover
back
are
into
nitrogen
66
into
to
a
use
‘x’
252).
that
make
Plants
grown
the
soil
content
all
of
lacks
a
certain
nutrient
except
test-tube
1
which
them.
atmospheric
form
to
solution
roots
and
to
for
the
3
Leave
4
After
5
Y
ou
the
apparatus
in
good
light
for
6
weeks.
proteins
such
ploughed
increase
crops.
6
weeks
you
could
examine
the
colour
and
size
of
leaves.
as
the
could
growth.
measure
length
of
stems
and
roots
to
compare
All
exchange
living
in
organisms,
plants
including
plants,
carry
out
respiration
all
the
time.
tin
Plants
they
are
need
waste.
At
During
In
no
a
supply
night,
the
bright
different
day,
light,
of
from
plants
when
other
oxygen
plants
tnemelppuS
Gas
and
exchange
carry
there
out
is
organisms.
a
they
T
o
produce
these
gases
carry
carbon
with
photosynthesis,
high
rate
of
out
dioxide
their
as
foil
respiration
as
pond
weed
a
surroundings.
well
as
respiration.
photosynthesis,
some
of
hydrogen
the
oxygen
aerobic
of
is
the
produced
respiration.
plant.
used
by
The
in
The
their
rest
carbon
chloroplasts
chloroplasts
of
the
dioxide
for
is
oxygen
used
is
produced
photosynthesis.
not
by
by
mitochondria
required
so
mitochondria
However
,
this
is
for
diffuses
in
carbonate
indicator
out
respiration
not
enough
Test
so
carbon
dioxide
diffuses
in
from
the
tube
Figure
Gas
exchange
in
aquatic
plants
is
1
Test
carbon
solution.
dioxide
This
and
solution
investigated
two
pH
contains
with
it
dissolves
in
water
indicators.
it
forms
Carbon
dioxide
is
an
to
Hydrogencarbonate
carbonic
atmospheric
air
through
indicator
it.
This
acid,
solution
gives
which
is
acid
a
the
is
prepared
indicator
a
by
red
Explain
why
in
Set
up
three
test
tubes
as
shown
colour
.
2
3
plants
in
Figure
Describe
a
the
plant
Add
3
Cut
in
hydrogencarbonate
two
each
pieces
of
test
of
indicator
pondweed
tubes
1
and
to
in
to
each
length
test
and
tube.
place
plant
at
growth
and
Put
test
5
Leave
If
carbon
tube
1
in
darkness
test
tubes
near
a
ii
is
added
hydrogencarbonate
to
by
covering
it
in
carbon
dioxide
is
light
the
indicator
taken
up
carbonate
for
water
solution
from
indicator
2–3
In
test
tube
dioxide
1,
was
the
the
by
the
will
plant,
turn
water
solution
indicator
released
by
the
Plant
from
for
the
by
the
red
to
plant,
roots
will
turned
turn
yellow
pondweed
In
test
tube
2,
the
indicator
turned
was
taken
up
by
the
from
red
because
during
purple
pondweed
nutrients
ions
needed
growth.
Nitrate
ions
are
to
amino
needed
acids;
to
magnesium
purple.
are
make
carbon
used
by
the
plants
to
chlorophyll.
respiration.
because
for
nitrate
healthy
yellow.
If
mineral
ions
are
lacking,
carbon
a
dioxide
absorb
the
3
•
i
sunshine.
hours.
ions
•
surroundings
bright
POINTS
make
hydrogen
its
in
foil.
2
If
gas
between
2.
including
dioxide
the
occurs
one
1
the
without
explain
that
and
night,
KEY
4
appearance
6.7.1.
solution
10 cm
likely
ions.
Describe
a
2
need
ions.
exchange
1
plants
bubbling
nitrate
respiration
QUESTIONS
gas.
of
and
3
weak
PRACTICAL
Photosynthesis
tube
provide
mineral
acid.
Test
hydrogencarbonate
hydrogencarbonate
1
When
2
6.7.1
SUMMARY
indicator
tube
surroundings.
plant
develops
deciency
photosynthesis.
symptoms.
•
The
purpose
of
test
tube
3
was
to
act
as
a
control.
4
The
indicator
The
colour
the
plant
oxygen
to
solution
changes
in
the
light
dissolves
monitor
the
in
only
are
or
to
absorbed
water
changes
responds
nothing
it
in
does
by
not
oxygen
to
do
changes
with
the
the
plant
change
in
carbon
oxygen
in
the
dark.
and
by
pH.
If
you
concentration
you
would
have
an
oxygen
probe
and
a
data
pond
weed
solution
remains
same.
at
is
low
red
as
kept
light
the
in
a
test
intensity,
rates
of
carbon
photosynthesis
by
oxygen.
only
At
night
carbon
respiration.
Hydrogencarbonate
indicator
logger
.
solution
If
up
to
5
use
in
use
produce
dioxide
wanted
plants
release
plants
When
the
light
dioxide
dioxide.
released
In
tube
the
of
hydrogencarbonate
colour
of
photosynthesis
the
and
solution
indicator
usually
respiration
are
the
changes
is
in
used
carbon
concentrations
of
gas
to
as
exchange
detect
dioxide
a
by
result
aquatic
plants.
67
PRACTICE
1
Photosynthesis
cells.
out
Which
occurs
in
structure
palisade
inside
mesophyll
these
cells
light
carbon
intensity
concentration
A
chloroplast
B
cytoplasm
C
nucleus
D
vacuole
The
1)
raw
materials
A
carbon
B
light
energy
/
A
high
low
30
B
low
high
20
C
low
low
30
D
high
high
35
for
photosynthesis
dioxide
C
light
energy,
D
water
and
nitrate
(Paper
2)
(Paper
and
ions
Which
feature
good
and
carbon
carbon
supply
a
dioxide
and
ions
cellulose
B
chlorophyll
large
B
many
C
thin
are
used
by
plants
for
D
xylem
internal
air
a
cells
spaces
chloroplasts
cuticle
on
in
the
and
and
palisade
lower
phloem
mesophyll
cells
epidermis
in
veins
2)
[1]
Hydrogencarbonate
atmospheric
indicator
air
is
solution
bubbled
is
red
through
it.
A
oils
placed
a
piece
1)
[1]
tube
Y
that
contained
T
ube
Y
was
covered
was
Which
represents
the
movement
of
of
pondweed
inside
test
through
the
open
stomata
of
a
repeated
leaf
uncovered.
indicator
completely
test
tube
Z,
in
but
solution.
foil.
the
This
tube
Both
tubes
were
left
in
was
bright
during
sunshine.
the
for
this
gases
left
After
60
minutes
the
colour
of
the
day?
indicator
gas
into
leaf
gas
out
of
was
leaf
A
A
oxygen
carbon
in
B
water
vapour
carbon
tube
purple.
pondweed
carbon
D
oxygen
dioxide
Which
does
water
vapour
pondweed
dioxide
had
the
in
and
in
tube
reason
absorbed
for
Z
this?
pondweed
in
carbon
Z
had
dioxide
Y
had
the
produced
pondweed
in
carbon
Z
had
oxygen
[1]
not
occur
during
pondweed
dioxide,
photosynthesis?
A
absorption
of
light
by
B
conversion
of
glucose
to
carbon
dioxide
to
of
molecules
using
light
9
energy
The
see
2)
Which
row
would
provide
in
Y
pondweed
in
carbon
Z
had
dioxide
had
in
Z
produced
had
oxygen,
absorbed
but
oxygen
2)
[1]
diagram
transverse
(Paper
carbon
pondweed
(Paper
water
produced
pondweed
a
carbohydrate
splitting
had
sucrose
the
of
Y
the
chlorophyll
D
reduction
in
but
absorbed
it
in
a
on
the
section
next
page
through
a
shows
leaf
as
a
you
would
microscope.
[1]
of
the
table
the
(top
of
conditions
next
for
(a)
Name
photosynthesis
of
a
the
tropical
the
(b)
Describe
tissues
labelled
E,
F,
G
and
H. [4]
column)
the
functions
of
the
parts
of
the
highest
leaf
of
and
correct
oxygen
C
rate
Y
yellow
the
carbon
produced
1)
was
is
dioxide
B
(Paper
in
and
produced
C
Y
What
dioxide
dioxide
labelled
I
and
J.
[3]
plant?
(c)
Explain
and
68
ensure
the
proteins
(Paper
6
to
to
making:
student
D
dioxide
leaf?
A
when
C
adaptation
dioxide
8
5
an
carbon
water
(Paper
4
is
of
[1]
A
fats
[1]
water
1)
Magnesium
D
°C
are:
inside
C
temperature
[1]
7
3
dioxide
carries
photosynthesis?
(Paper
2
QUESTIONS
G
how
are
cells
in
adapted
the
for
tissues
labelled
photosynthesis.
F
[3]
I
(a)
State
how
the
student
would:
E
(i)
vary
the
light
(ii)
determine
intensity;
the
rate
of
[2]
photosynthesis;
[2]
F
(iii)
maintain
constant
a
constant
carbon
throughout
the
temperature
dioxide
and
concentration
investigation.
[4]
G
(b)
J
for
3)
plants,
several
K
and
days.
L,
were
They
placed
were
then
in
the
placed
dark
into
carbon
L
was
the
student’s
results.
the
light
apparatus
if
shows
etar
T
wo
below
fo
10
graph
sisehtnysotohp
H
(Paper
The
shown
dioxide
provided
below
is
in
the
required
with
for
carbon
K
light
to
nd
photosynthesis.
Using
dioxide.
the
L
(Paper
12
the
limiting
shown
in
the
factors,
explain
graph.
[4]
4)
groups
that
were
M
group
term
results
T
wo
Group
bag
intensity
out
N
of
seedlings
decient
was
was
in
grown
grown
were
two
grown
ions
without
without
that
in
solutions
plants
nitrate
need.
ions;
magnesium
ions.
bag
Group
O
received
all
the
ions
that
plants
require.
soda
lime
The
band
results
are
shown
in
the
table.
band
group
of
colour
of
growth
seedlings
(a)
Explain
why
the
plants
were
put
in
leaves
reduced
the
growth
yellow
dark
for
several
days.
but
[2]
(especially
M
Explain
why
the
plants
were
well
watered
lower
kept
in
bright
light.
Describe
how
you
did
not
carry
would
out
any
show
that
leaves
–
plant
photosynthesis
inside
the
bag,
but
plant
L
did.
Explain
why
plant
L
was
included.
A
student
investigated
intensity
the
effect
of
varying
normal
growth
Explain
the
on
the
apparatus
rate
of
shown
the
effects
of
the
deciencies
of
the
ions
and
magnesium
ions
as
shown
photosynthesis
in
using
green
green
nitrate
light
reduced
growth
3)
(a)
11
–
[2]
O
(Paper
leaves
[4]
pale
(d)
severely
N
upper
while
N
[2]
yellow
K
in
leaves)
lower
(c)
much
seedlings
group
and
as
the
as
(b)
not
the
table.
[4]
below.
(b)
Why
was
seedlings
(c)
Many
it
in
crops
grown
in
(Paper
group
to
achieve
the
yields.
world
Explain
controlled
high
the
[2]
throughout
are
include
O?
glasshouses.
conditions
to
necessary
in
are
how
glasshouses
[6]
4)
69
7
Animal
nutrition
7.1
A
A
LEARNING
balanced
balanced
Dene
what
balanced
•
Describe
and
provides
an
adequate
intake
of
the
biological
OUTCOMES
molecules
•
diet
diet
is
meant
by
a
health
and
and
energy
needed
to
sustain
the
body
and
ensure
good
growth.
diet
how
activity
age,
affect
gender
dietary
needs
•
Describe
the
pregnancy
on
•
the
diet
Describe
effects
and
of
the
of
breast-feeding
the
mother
effects
malnutrition
on
of
heart
disease
Figure
STUD
Y
A
TIP
7.1.1
balanced
Which
diet
carbohydrates,
Rem
embe
r
bala
nced
energy
that
die t
as
Each
of
well
as
•
T
o
these
carries
provide
and
T
o
fats.
diet
proteins
energy
one
released
will
keep
from
the
brain
T
o
(see
The
if
you
to
energy
in
8-year-old
a
the
in
are
this
or
is
used
and
more
mainly
for
of
three
the
energy
role
only
development,
repair
source
and
bre
basic
functions.
of
of
body
amino
if
of
repair
cells
acids
for
carbohydrates
they
are
and
and
in
excess
replacement.
tissues.
cells
of
to
Proteins
make
their
in
own
4.1).
body’s
very
small
aged
14
a
used
day
/
kJ
8 500
8 500
12 500
9 700
11 000
9 800
little
Diet
worker
have
manual
worker
woman
breast-feeding
mother
15 000
in
The
about
you
your
still
metabolism
quantities
have
for
a
and
in
–
vitamins
the
diet
and
repair,
these
varies
per
body
from
day.
energy.
on
age,
greater
your
chemical
this
basal
completely
beating,
The
7000 kJ
need
higher
bed
heart
BMR
depends
a
in
growth
required
(BMR).
requires
lying
constant.
involved
Children
70
one
growth,
Topic
keep
energy
rate
pregnant
water
to
and
help
minerals
regulate
our
metabolism.
active
those
adult
minerals,
hour.
temperature
office
–
are
growth
needed
energy
adult
for
provide
regulate
are
one
Even
teenager,
vitamins,
KNOW?
•
for
components:
fats,
out
energy
Proteins
allow
the
peanut
meal?
provid
es
•
The
better-balanced
these
proteins,
requirements
YOU
has
the
a
nutr
ients
.
DID
is
So
sex
energy
metabolic
inactive
lungs
reactions
are
functions
even
and
if
to
your
is
the
lie
are
and
still
but
down
body
such
require
basal
using
your
body,
and
person,
you
as
energy.
metabolic
an
and
adult
do
very
activity
requirement
rate
working
in
occurring
person
you
than
adults
because
they
(BMR).
12 500
10 000
11 500
A
young
BMR
per
child
may
kilogram
weigh
per
day
less
than
because
an
adult
they
are
but
still
may
have
growing.
a
higher
Y
oung
they
children
are
people
lower
stay
constantly
generally
BMR.
men.
tissue
have
has
a
Figure
The
Fat
a
they
daily
and
a
energy
to
of
and
eat
relatively
fat
tissue,
rate
per
need
to
to
occupations
body
new
mass
cells.
needs
fat
and
diet
if
under
so
because
Elderly
have
they
content
example
muscle,
than
the
make
higher
for
of
balanced
a
are
to
in
their
bodies
the
skin.
Fat
women
generally
men.
requirements
explain
unit
protein
a
than
requirement
try
needs
and
need
have
in
protein
energy
metabolic
energy
the
lower
stored
lower
7.1.2
energy
is
more
developing
have
Women
lower
Compare
need
However
,
healthy.
than
also
of
the
people
shown
in
differences.
that
involve
physical
activity
pregnant
are
10 000
greater
who
than
take
and
high
less
part
they
months
9 MJ
pregnancy
can
fat
provides
proteins.
that
The
extra
need
us
be
with
However
,
may
for
a
protein
extra
about
at
a
required
during
a
desk.
require
0.8 MJ
more
teenage
day
fat:
saturated
fat
that
in
the
that
comes
energy
is
a
of
the
from
sh
be
per
the
woman.
gram
aware
comes
and
concentration
from
plants.
chemical
made
cholesterol
genes
that
that
determine
tend
to
high
concentration
High
in
increase
the
we
the
than
that
carbohydrates
there
animals
Saturated
risk
concentrations
cholesterol
liver
and
produce
our
in
of
of
found
depends
metabolism
of
the
are
two
or
main
and
male
types
manual
girl,
producing
in
fats
in
our
the
upon
in
the
which
more
blood.
blood.
our
we
8 500
developing
types
of
of
the
high
blood
cholesterol
(see
in
page
pressure
fat.
diet
diet
The
cholesterol
per
cholesterol.
concentrations
the
blood
108),
and
an
heart
Monounsaturated
Polyunsaturated
which
will
7.1.2
Typical
energy
a
b
What
High
and
as
fat
the
diets
having
a
are
linked
increased
to
risk
a
disease.There
fats
have
little
of
are
thick,
inner
of
sur face
two
effect
Figure
7.1.3
A
healthy
and
on
help
to
fats
may
reduce
help
heart
an
artery
artery
to
reduce
State
meant
how
following
who
the
will
does
not
by
term
protein
differ
take
and
from
much
balanced
energy
those
of
diet?
16-year-old
of
A
balanced
an
iii
a
elderly
person
pregnant
mother
and
minerals,
the
correct
female
the
fat
wall.
diet
provides
proteins,
fats,
water
and
vitamins,
bre
in
the
quantities.
exercise:
2
i
(left)
with
POINTS
carbohydrates,
requirements
a
layer
deposit
cholesterol
1
the
in
rough
fatty
disease.
QUESTIONS
is
needs.
quantity
well
energy
1
day
may
KEY
SUMMARY
per
day
Cholesterol
as
inherit.
kJ
deposited
blood
years
blood.
arteries
unsaturated
8
kJ
unsaturated
smooth
narrowing
years
day
three
than
Figure
increase
14
per
and
last
15 000
fat
kJ
energy
worker
of
boy,
12 500
muscle
pregnancy
woman
per
People
high
for
woman
us?
energy
should
is
example,
non-pregnant
more
also
nutrients
For
for
sitting
sports
require
bad
we
involve
physical
breast-feeding.
recommended
Why
Fat
of
diets.
Women
are
jobs
vigorous
protein
development.
when
active
in
kJ
ii
a
2-year-old
iv
a
male
child
Requirements
depend
gender
athlete
on
a
and
of
the
diet
person’s
how
age,
active
they
are.
2
a
What
are
b
Explain
the
health
risks
associated
with
a
diet
high
in
fat?
3
how
a
person
may
reduce
the
fat
content
of
Saturated
fats
cholesterol
diet.
(You
may
nd
it
useful
to
look
at
pages
73
and
answering
this
blood
which
is
linked
to
74
narrowing
before
increase
their
of
the
arteries
and
question.)
heart
disease.
71
7.2
Sources
Eating
LEARNING
•
State
of
nutrients
healthily
OUTCOMES
some
good
components
of
and
the
describe
sources
a
of
balanced
Diets
in
different
from
each
parts
of
the
world
vary.
However,
we
should
all
eat
the
of
the
food
groups
shown
in
the
food
guide
pyramid.
diet
importance
of
Carbohydrates
them
Carbohydrates
•
Describe
the
source
symptoms
due
to
lack
mineral
C
sugars
and
starches,
which
provide
us
with
a
ready
of
energy
and
salts
D,
iron
and
and
that
is
easily
respired.
Simple
sugars
are
absorbed
almost
of
immediately
vitamins
include
deciency
by
the
stomach
into
the
blood
to
give
an
immediate
result
of
respiration.
source
the
of
energy
.
of
carbohydrates
This
energy
is
released
as
a
Good
sources
calcium
are
rice,
potatoes,
bread,
yams,
sugar
and
honey
.
Proteins
fats,
oils,
sweets
In
it
order
needs
protein
meat,
poultr y,
yogurt,
beans,
cheese
your
protein
into
body
to
to
grow
make
amino
new
acids
and
and
cells.
then
develop,
You
use
digest
these
to
fish,
make
milk,
for
eggs,
your
own
proteins.
There
are
20
different
nuts
types
of
fruit
of
these
Cell
amino
to
acid
make
membranes
and
its
your
own
and
body
protein
cytoplasm
must
(see
have
Topic
contain
a
all
4.1).
great
vegetables
deal
bread,
or
cereal,
pasta,
rice
of
protein.
damaged
your
food
growth
daily
Figure
7.2.1
exercise
The
food
and
guide
weight
energy.
control
for
and
Y
our
cells
so
this
as
repair
Good
it
body
you
well.
may
sources
may
need
If
protein
be
are
need
to
enough
is
respired
meat,
sh,
replace
protein
not
to
old
in
used
for
provide
milk
and
nuts.
pyramid.
Fats
Fats
are
under
the
releases
one
STUD
Y
can
now
infor
mation
you
each
(e.g.
in
starte
d
featu
re
energy
kJ)
write
mak
e
0
add
to
in
(e.g.
provi
de
gram
the
Fats
are
Fats
also
a
4
.1.
long-term
around
than
twice
the
as
carbohydrate
energy
heart
much
or
store.
and
kidneys.
energy
protein.
The
than
When
One
can
we
fat
be
are
is
stored
gram
of
fat
released
short
of
from
thick
you
uses
also
energy
fat.
good
give
layer
the
thermal
buoyancy
of
blubber.
to
insulators,
marine
Good
since
animals,
sources
are
they
for
cut
down
example
butter,
heat
whales
cheese,
fat
in
loss.
have
meats
For
sh,
nuts.
inclu
de
sure
and
if
Water
you
for
Water
when
the
you
up
drink
two-thirds
or
of
your
body
mass.
You
take
in
water
eat.
answ
er
vitam
ins,
water
makes
each
do
energy
).
not
You
could
in
few
to
a
take
go
without
food
days
without
water.
place
in
water.
in
the
that
your
in
Waste
urine,
faeces,
72
of
and
a
conten
t
bre
,
any
table
body
and
even
min
erals
more
T
opic
someth
ing
nutri
ent
is
skin
more
as
TIP
our
Y
ou
important
solution.
intake
sweat
water
of
and
in
water
are
our
number
is
blood
day
of
weeks,
needed
for
transports
passed
sweat
each
breath.
a
Water
The
chemicals
and
for
out
of
cools
equals
bodies
down.
your
you
substances
our
us
but
chemical
loss
It
of
in
is
would
die
reactions
dissolved
solution
important
water
in
urine,
Vitamins
We
be
of
need
and
small,
healthy.
If
minerals
regular
these
deciency
amounts
are
lacking
of
in
vitamins
the
diet
and
we
minerals
can
develop
if
we
are
to
symptoms
diseases:
deciency
rich
symptoms
food
use
name
in
body
(deciency
source
disease)
oranges,
tissue
lemons,
resistance
repair,
bleeding
vitamin
C
other
gums
to
(scurvy)
citrus
sh
fruits
oil,
butter
vitamin
disease
milk,
D
made
strengthens
soft
by
bones
bow
the
and
outwards
T
angerines
are
a
good
source
of
vitamin
C.
(rickets)
Sun)
used
in
formation
liver,
legs
skin
teeth
in
bones,
(also
meat,
of
haemoglobin
in
tiredness,
lack
of
DID
YOU
KNOW?
iron
cocoa,
eggs
red
blood
cells
energy
(anaemia)
In
for
transport
1747,
James
Lind,
a
Scottish
of
ship’s
surgeon,
was
able
to
oxygen
show
weak,
milk,
sh,
strengthens
green
bones
teeth
The
Fibre
bre
cabbage,
the
The
or
bulk
gut
muscles
helps
the
plant
part
to
of
the
the
and
our
from
comes
cell
of
sweetcorn
adds
entire
roughage
from
important
Fibre
disease
preventing
the
citrus
walls.
diet.
food.
gut
Although
High-bre
Since
to
wall
of
plants.
it
It
is
made
cannot
foods
be
up
digested,
include
bran
Fibre
from
diet
it
anus
need
food
constipation
bacteria
lowers
reduces
the
the
in
is
not
and
digested,
does
something
the
not
to
alimentary
it
passes
provide
fruits
provided
C
the
push
canal
down
any
energy.
against.
by
Fibre
KEY
(see
Topic
7.3).
Fibre
POINTS
peristalsis
absorbs
Carbohydrates
in
our
gut.
Many
doctors
believe
concentration
risk
of
heart
of
disease
cholesterol
and
bowel
in
that
the
List
the
a
each
of
an
balanced
diet
and
give
a
2
good
source
one.
2
Explain
why
3
Explain
the
quick
of
energy,
energy
while
fats
store.
blood.
cancer.
Protein
is
needed
repair
Lack
can
a
a
high-
QUESTIONS
components
are
poisonous
3
SUMMARY
of
on
vitamin
it
and
1
sailors
years;
cereals,
are
bre
for
mainly
source
wastes
affected
voyages
celery.
mouth
movement
from
1
so
as
successfully
remedy.
cellulose
an
lemons,
cramps
in
is
and
(rickets),
long
of
such
weakness
teeth
and
Dietary
fruits,
and
muscle
vegetables
citrus
bones
oranges
and
calcium
brittle
that
of
of
calcium
cause
lack
of
and
lack
and
rickets
iron
of
for
growth
tissues.
vitamin
(soft
causes
D
bones);
anaemia
vitamin
C
causes
scurvy.
the
diet
must
contain
each
component.
4
Roughage
of
term
deciency
food
helps
through
the
the
passage
gut.
disease
73
7.3
Balancing
Getting
LEARNING
the
reasons
why
put
• Describe
on
food
as
a
result
If
health
in
a
day
should
provide
you
with
enough
energy
to
day.
risks
happens
if
we
eat
too
much?
of
malnutrition
the
eat
that
and
What
you
eat
more
food
than
you
need,
your
body
stores
the
extra
as
fat.
associated
Your
with
you
through
weight
obesity
constipation
• List
right
some
get
people
balance
needs
OUTCOMES
The
• State
the
energy
energy
intake
is
the
energy
you
get
in
your
food
in
a
day
in
obesity
proteins,
• Explain
the
role
of
Your
(bre)
in
the
carbohydrates
and
fats.
roughage
energy
output
is
the
energy
your
body
uses
in
a
day.
If
diet
energy
body
intake
and
body
overweight
page.
that
or
People
become
greater
mass
even
with
diet
foods
low
or
a
energy
increases.
We
Obesity
basal
obese
contains
with
than
obese.
a
overweight
their
rened
is
of
may
is
run
than
the
rate
those
foods,
added
then
dened
metabolic
fattening
lot
output,
risk
in
stored
box
high
in
the
becoming
are
higher
as
is
of
the
(BMR)
with
such
fat
on
the
more
BMRs.
fat
next
likely
It
is
foods
to
likely
and
sugar.
Obesity
In
rich,
suffer
if
Many
children
do
not
eat
this
sort
of
meal
a
industrialised
from
person
countries,
overeating
takes
in
than
more
like
from
energy
Britain
eating
in
and
too
food
the
little.
than
they
USA,
As
more
we
use,
have
then
people
seen,
the
at
excess
is
stored
as
fat.
T
aken
to
extremes,
people
can
put
on
so
much
lunchtime!
weight
Major
•
high
that
of
obesity
intake
of
fatty
•
too
•
social
People
Exercise
helps
ght
heart
disease
and
74
growing
and
rened
foods
containing
a
lot
emotional
are
people
9.5),
sugar
stress,
overweight
to
have
high
(see
Topic
and
health
blood
leading
obese
and
‘comfort
are
problems
pressure,
10.3)
to
eat
•
take
of
much
such
as
diabetes
arthritis
eating’.
more
heart
caused
(worn
likely
than
disease
by
high
joints).
could
someone
lose
weight?
could:
•
A
a
foods
obesity.
They
is
and
Topic
How
Obesity
include:
exercise
who
thinner
obese.
sugar
little
blood
become
causes
added
(see
they
less
high-energy
more
sensible
exercise
approach
•
a
balanced
•
a
gradual
•
having
diet
foods
(increase
to
with
increase
(lower
slimming
a
in
their
lower
their
energy
energy
should
intake
of
intake)
output).
combine:
energy
exercise
problem.
an
ideal,
but
achievable,
target
for
weight
reduction.
DID
YOU
KNOW?
Obesity
STUD
Y
There
are
two
ways
in
which
people
can
identify
being
Y
ou
• being
20%
above
the
recommended
weight
for
his
or
TIP
obese:
her
do
no t
remem
ber
• having
a
body
mass
index
(BMI)
greater
than
body
mass
index
mass
/
inde
x,
kg
be
2
/
the
but
metres
awar
e
person
with
a
BMI
of
less
than
20
is
underweight;
between
is
severely
body
overweight;
obese.
mass
These
same
is
If
in
your
the
calculations
way
for
more
BMI
than
is
in
acceptable
are
for
children
30
the
the
obese;
range
of
more
20
to
than
24,
40
then
or
indigestible
but
is
grea
ter
is
The
BMI
is
calculated
interpretation
important
is
bulk
to
our
in
the
for
a
healthy,
balanced
diet.
It
TIP
is
food.
This
is
important
for
moving
down
the
alimentary
canal.
The
muscles
of
the
gut
die ts
that
to
squeeze
the
food
along.
Soft
foods
do
not
stimulate
to
contract
as
effectively
as
the
harder,
indigestible
too
little
foods
muc
h
that
form
roughage.
If
the
movement
of
food
is
slow
it
will
result
making
it
difcult
to
defecate.
or
A
diet
containing
fruit
and
vegetables
contains
lots
of
certai
n
far
are
the
best
foods
to
relieve
complete
Copy
and
the
exercise
sentences
energy
you
take
.
long
by
in
more
than
Eating
periods
eating
of
foods
time
can
less
lead
foods
using
muc
h
is
to
the
List
four
health
problems
that
are
A
is
stored
added
Calculate
person
can
more
as
KEY
lose
weight
1
the
the
body
BMI
mass
category
index
in
for
each
linked
the
.
to
people
their
a
man
1.70 m
b
a
woman
in
1.75 m
height
in
is
following
people
a
man
a
State
1.85 m
in
height
a
body
with
a
mass
body
of
mass
110 kg
of
Obesity
and
a
50 kg
with
a
body
mass
of
two
good
sources
of
Explain
the
effects
of
a
roughage
lack
output
can
lot
intake
rened
of
in
the
than
(in
their
(in
their
exercise).
be
of
roughage
in
of
caused
fatty
by
a
foods
added
of
too
foods
containing
sugar
little
plus
the
exercise.
A
diet
lacking
in
roughage
diet.
(bre)
b
greater
weight
75 kg
3
4
on
intake
and
effects
c
put
energy
case:
with
height
roug
hage
.
obesity.
high
a
of
die t
POINTS
Some
if
2
name
fo rm
the
over
energy
3
as
words:
excess
with
.
taking
in
a
fatty
use,
foods
lack
ing
food)
2
of
obesity
fat
you
and
and
these
sugar
high-energy
If
shor
tage
constipation.
is
1
too
compo
nent
s.
malnu
trition
QUESTIONS
or
compo
nent
s
Cons
tipat
ion
SUMMARY
a
roughage;
those
these
too
there
energy
energy
,
in
of
constipation
no t
beca
use
the
is
muscles
are
wall
bala
nced
contract
refers
keeping
to
food
their
30.
different.
Malnu
trition
adds
is
your
STUD
Y
bre
if
than
is
Constipation
Roughage
someo
ne
obese
range.
adults.
but
is
as
mas
s
shou
ld
25
BMI
30
body
you
that
classi
ed
and
to
to
=
height
A
how
30.
calcul
ate
body
have
height
the
can
lead
to
diet.
constipation.
75
7.4
Starvation
and
nutrient
deciency
People
can
water.
•
Describe
the
effects
upon
of
are
starvation
This
its
no
tnemelppuS
Describe
•
Discuss
the
effects
of
of
many
weeks
causes
vitamin
without
and
in
the
The
During
body
muscles
wasting
energy
by
to
a
lack
the
to
are
of
the
dietary
food
fat
food,
provided
starvation,
and
protein
starvation
uses
stored
use
as
a
the
fat
source
the
they
for
basal
and
body
have
energy,
draws
but
metabolic
then
breaks
there
rate
down
of
energy.
This
leads
to
In
(swelling
abdomen
legs);
hair;
appearance.
that
and
(PEM).
energy
or
with
shown
lack
on
the
In
which
of
so
its
worst
terms
are
food.
in
suggests,
are
These
two
In
given
have
The
protein
form
to
is
it
caused
can
describe
lead
the
ways
conditions,
However,
adapted
food.
is
this
different
both
marasmus.
marasmus
when
undernutrition
term
protein.
more
with
better
of
the
PEM.
to
though
children
are
and
marasmus,
responds
respond
form
As
it
better
is
to
symptoms
in
children
of
lack
of
these
left.
of
kwashiorkor:
and
emaciated
common
children
body
conditions
the
of
underweight,
thought
oedema
an
most
kwashiorkor
which
Symptoms
and
malnutrition
appearance
sparse,
aky
both
cases,
frequent
causes
children
servings
cells
enzymes
of
are
of
the
are
small
in
pancreas
secreted
danger
quantities
and
and
the
and
of
feeding
food.
intestine
surface
to
area
should
This
die,
for
is
so
involve
because
fewer
absorption
PEM
digestive
of
digested
skin;
food
is
reduced.
During
starvation,
there
are
deciencies
of
the
accumulation
protective
in
water.
reduced.
Worldwide,
fat
carbohydrate,
of
iron
deciencies
dry
of
periods
and
D
of
of
during
scurvy
muscle
effects
for
because
stores
is
protein
the
is
stores
(BMR)
•
survive
OUTCOMES
vitamins;
people
are
at
risk
of
developing
infectious
communities
in
developing
diseases.
liver.
Dietary
shown
of
surveys
that
cells,
with
has
these
Children
such
as
of
with
to
poor
be
which
used
conditions
who
these
other
and
are
protein
as
are
develop
cassava
content,
Symptoms
of
protein,
an
the
in
foods.
be
energy
suffering
potato;
protein,
Staple
used
for
source.
from
symptoms
sweet
low
should
a
may
while
so
This
lack
be
fed
need
such
on
a
have
and
that
energy
in
be
wheat
repair
children
the
tropical
high
to
as
nations
growth
shows
of
having
they
foods
the
diet.
crops
energy
supplemented
and
rice
will
marasmus:
satisfy
very
low
mass;
energy
legs;
muscle
we
also
76
is
found
seen,
symptoms
protein
of
two
energy
This
can
Vitamin
protein
malnutrition.
C
have
calcium
of
needs
a
in
oranges,
deciency
of
lemons
and
vitamin
C
other
leads
citrus
to
the
fruits.
disease
called
face.
gums.
forms
protein.
old-
scurvy.
Typical
enough
fat;
As
7.4.1
provide
arms
Vitamin
wizened,
Figure
also
little
or
looking
and
body
thin
Nutrient
and
intake
by
C
helps
bones
used
helps
cause
in
to
and
make
the
bleeding
bond
teeth.
skin,
healing
of
in
cells
parts
of
together
Vitamin
tendons,
wounds
C
is
the
body,
and
helps
used
ligaments
and
the
to
particularly
in
form
and
the
an
blood
formation
of
use
the
of
important
vessels.
scar
It
tissue.
tnemelppuS
LEARNING
It
is
also
D
needed
needed
Deciency
rickets
is
in
children.
children
body.
Rickets
the
of
can
Iron
bones
is
found
iron.
It
Foods
needed
in
red
is
to
rich
in
a
of
iron
iron
grow
the
the
of
by
In
bend
carry
oxygen
day.
liver,
At
is
puberty,
rich
soft,
weight
in
leads
protein
the
of
vitamin
gives
to
a
so
the
D
like
rise
to
softening
which
combined
is
with
body.
If
occur.
girls
become
the
cells.
causing
haemoglobin
a
cocoa.
can
bone
fractures.
around
meat,
in
bones
deciency
which
protein
anaemia
in
and
foods
of
calcium.
calcium
with
adults,
chance
blood
of
absorb
calcium
eating
milk.
to
properly
bones
Haemoglobin
called
each
to
fail
increased
include
disease
lack
and
cells.
to
deposition
osteomalacia,
make
blood
needed
diet,
16 mg
an
as
intestine
the
prevented
eggs
known
and
the
walking
be
small
include
Bones
start
butter,
condition
the
the
oil,
the
regulate
symptoms
when
sh-liver
to
for
there
An
need
to
is
a
adult
make
lack
of
needs
sure
iron
in
about
they
have
An
enough
iron
in
their
diet
as
they
start
to
menstruate
(have
X-ray
bowed
The
lack
The
main
of
iron
shortness
of
breath,
SUMMARY
1
a
leads
symptoms
to
of
a
reduction
anaemia
heart
are
in
the
number
tiredness
palpitations
and
a
and
pale
of
red
lack
of
blood
the
main
inadequate
are
causes
the
of
symptoms
kwashiorkor
Explain
why
frequent
starvation
in
terms
of
servings
of
of
very
below
is
mouth
are
these
small
two
conditions
/
amounts
of
as
a
box
containing
breakfast
Fat
/
/
g
per
a
result
much
energy
would
How
c
The
to
3
Make
the
in
a
this
table
fat
of
How
get
diet.
the
much
protein
much
mass
to
2
Scurvy
be
in
a
150 g
serving
of
the
is
to
body,
in
good
with
a
cereal
in
a
75 g
adult
serving
female
would
a
of
the
needs
female
cereal?
per
have
day
to
3
iron,
table
dietary
The
fallen
C
in
in
a
very
of
the
eat
vitamin
C
and
and
the
vitamin
about
D
their
deciency
in
roles
diseases
4
cause
bones
a
parts
iron
in
of
of
D
by
can
the
anaemia
Vitamin
plus
a
low
fat
and
lack
of
a
vitamin
and
in
ability
of
infections.
of
diet
transport
information
sources
nutrient.
Lack
cause
is
protein?
your
each
be
young
more
of
have
vitamin
lack
caused
bleeding
the
with
wasting,
deciency
there
there
compare
Include
associated
would
enough
results
mass
particularly
mass
60 g.
not
resistance
cereal?
b
scurvy.
POINTS
muscle
3
How
of
Starvation
in
a
has
teeth
100 g
83
g
the
cereal.
6
Carbohydrate
who
and
food.
1800
g
person
diet.
body
Protein
a
involves
1
kJ
of
inamed
marasmus?
from
Amount
/
and
of:
ii
treatment
information
Energy
bones
rickets.
an
KEY
The
weakened
with
diet.
the
2
the
child
complexion.
out
c
a
cells.
gums
i
of
energy,
The
What
legs
QUESTIONS
Explain
b
showing
periods).
C
cause
of
the
body,
gums.
the
diet
which
the
tnemelppuS
tnemelppuS
Vitamin
can
affects
blood
to
oxygen.
deciency
softening
causing
of
can
the
rickets
and
osteomalacia.
77
7.5
Digestion
During
LEARNING
the
different
•
Dene
mechanical
Dene
ingestion,
Ingestion
the
and
be
along
the
alimentary
canal,
a
number
of
identied.
the
taking
and
of
lipase,
amylase,
Digestion
into
of
substances
(food
and
drink)
into
the
mouth.
is
the
and
soluble
breaking
the
molecules
down
so
that
of
large
they
can
insoluble
pass
molecules
through
the
into
gut
wall
blood.
listing
•
substrates
the
egestion
function
protease
the
is
through
small
State
food
absorption,
•
assimilation
•
of
can
digestion
body
•
processes
and
•
chemical
passage
OUTCOMES
the
Absorption
is
the
movement
of
small
food
molecules
and
ions
endthrough
the
wall
of
the
intestine
into
the
blood.
products
•
Assimilation
cells
•
of
the
Egestion
is
absorbed,
The
large
gut,
food
which
system
the
the
as
mechanically
is
body
out
are
of
with
2.4).
food
the
This
the
digestive
used,
that
has
proteins
happens
liver
and
the
food
When
food
molecules
becoming
part
not
of
been
into
the
the
cells.
digested
or
anus.
starch,
chemically.
Topic
of
are
through
molecules
and
they
passing
faeces
together
(see
movement
where
in
and
the
pancreas
has
fats.
form
been
Digestion
alimentary
your
occurs
canal,
or
digestive
digested,
it
is
absorbed
mouth
through
the
molecules
wall
can
of
go
the
small
through
intestine
the
gut
into
wall
the
they
blood.
must
be
Before
the
dissolved.
food
Large
food
food
molecules
through
the
molecules
wall
of
another
digestive
are
the
are
wall
insoluble;
of
the
soluble.
small
body
They
intestine
uid
that
they
small
will
not
intestine.
will
and
dissolve
enter
absorbs
the
and
dissolve,
On
so
the
therefore
other
they
blood
can
and
transports
fat
hand,
get
the
cannot
small
through
lymph,
(see
page
get
food
the
which
is
114).
enzymes
gut
Mechanical
digested
digestion
food
Mechanical
smaller
digestion
pieces
of
food
is
the
breakdown
without
changing
of
the
large
food
pieces
of
food
molecules.
into
This
anus
starts
in
pieces
7.5.1
Digestion
in
the
alimentary
canal.
STUD
Y
that
continue
faeces
Figure
broken
about
n
‘diges
deni
tions
tion’
dige
stion’
prepar
,
‘mec
the
hani
‘chem
to
e
the
betw
een
body
Muscular
small
globules
digestion
can
into
use
by
in
food
small
digestion
into
contractions
intestine,
large
emulsication
the
next
few
by
into
of
the
globules
bile.
smaller
stomach
of
There
fat
is
are
more
topics.
that
has
been
eaten,
the
food
must
be
molecules.
is
smaller
the
breakdown
soluble
of
molecules
the
by
large
the
insoluble
action
of
food
enzymes.
be
occurs
in
the
mouth,
stomach
and
small
intestine.
Mechanical
distin
guis
h
differ
them
.
ence
gives
a
larger
surface
area
for
the
enzymes
to
work
on.
s)
The
three
types
carbohydrases
specic
to
remind
of
enzymes
and
enzyme
lipases.
because
yourself
breakdown
78
the
food
ical
digestion
(giv
In
down
digestion
down
molecules
and
swallowed.
breaks
cal
This
ed
chewing
of
Chemical
and
be
where
process.
smaller
Chemical
TIP
stion’
can
this
into
broken
dige
mouth
mechanical
Before
Lear
the
about
proteins,
in
the
Each
they
the
alimentary
type
have
of
food
different
reason
carbohydrates
for
and
canal
are:
molecule
shapes.
having
fats.
proteases,
needs
See
different
Topic
a
5.1
enzymes
to
a
protein
many
molecule
different
is
amino
made
up
amino
of
protease
down
a
starch
molecule
acids
acids
is
made
up
enzymes
protein
break
molecules
of
glucose
many
glucose
molecules
amylase
starch
a
fat
fatty
molecule
acid
and
is
made
glycerol
up
to
maltose
break
(a
down
sugar)
of
fatty
molecules
lipase
fatty
enzymes
acid
down
enzymes
fat
acids
break
molecules
glycerol
glycerol
Figure
The
7.5.2
The
chemical
carbohydrase
breakdown
enzyme
that
of
protein,
breaks
starch
down
and
starch
fat.
is
called
amylase
KEY
SUMMARY
POINTS
QUESTIONS
1
Mechanical
the
1
Name
the
enzymes
and
end-products
involved
in
the
particles
starch
b
protein
c
surface
a
Explain
why
b
Explain
the
digestion
is
necessary.
of
large,
is
difference
between
mechanical
digestion
chemical
what
happens
to
food
after
it
has
been
graph
into
food
smaller,
molecules
by
water-
the
shows
the
activity
of
the
enzymes
of
enzymes.
digested.
2
The
Chemical
breakdown
digestion.
action
Outline
the
and
soluble
3
increase
insoluble
molecules
c
to
area.
fat
digestion
2
of
of:
their
a
is
breakdown
chemical
food
digestion
digestion
physical
amylase
Amylase
breaks
down
and
starch
molecules
to
glucose
pepsin.
molecules.
a
i
At
what
ii
How
pH
does
pepsin
work
best?
Protease
does
hydrochloric
acid
in
the
stomach
breaks
molecules
pepsin
to
What
are
formed
when
pepsin
breaks
down
i
At
what
ii
What
is
amino
protein
acids.
pH
does
formed
amylase
when
the
work
breaks
down
fats
to
proteins?
fatty
b
to
work?
Lipase
iii
down
help
acids
and
glycerol.
best?
amylase
breaks
down
starch?
iii
Why
is
it
useful
that
saliva
contains
an
alkali?
emyzne
pepsin
fo
ytivitca
amylase
2
3
4
5
acid
6
7
pH
8
9
10
11
12
alkaline
79
7.6
T
eeth
The
LEARNING
teeth
breaks
The
•
Describe
the
structure
in
teeth
and
mechanical
surface
their
State
the
decay
care
mechanical
area
into
of
smaller
digestion
food
is
pieces
increased
so
when
chewing
so
making
making
it
food.
it
easier
This
easier
to
swallow.
for
enzymes
catalyse
the
reactions
needed
for
chemical
digestion.
digestion
causes
and
of
out
food
function
Adult
•
down
of
to
human
carry
OUTCOMES
of
describe
tooth
the
They
humans
have
have
different
32
teeth,
shapes
but
for
not
all
of
performing
the
teeth
different
are
the
same.
functions:
proper
•
incisors
are
chisel-shaped
•
canines
are
pointed
•
premolars
•
molars
for
biting
and
cutting
teeth
are
Counting
there
8
teeth
During
teeth,
small.
to
be
the
uneven
‘cusps’
premolars
number
4
in
of
and
each
and
for
are
type
tearing
grinding
for
of
and
chewing
tooth,
chewing
up
you
food.
should
nd
that
our
are
canines,
lives
back
we
small
Between
will
8
premolars,
and
12
molars,
which
makes
all.
replaced
teeth
our
like
piercing
are:
incisors,
32
have
for
the
by
come
have
teeth
two
and
ages
our
of
or
6
of
and
when
wisdom
teeth.
are
only
12
permanent
through
molars
sets
there
we
8
these
teeth.
are
at
The
rst
molars
teeth
The
least
set,
as
or
our
gradually
last
18,
of
if
our
at
milk
jaws
fall
are
out,
permanent
all!
These
are
teeth
enamel
pulp
A
child
usually
has
20
milk
cavity
crown
teeth.
dentine
canine
molar
gum
premolar
root
STUD
Y
Mak
e
TIP
sure
iden
tify
type
s
from
of
you
ner ves
can
the
differ
ent
hum
an
tee th
pho to
grap
hs
their
and
Figure
7.6.1
Adult
Figure
teeth.
7.6.2
Vertical
section
through
molar.
and
Enamel
the
tions
part
forms
above
the
hard,
the
gum.
outer
layer
Inside
this
of
is
the
crown
softer
of
the
dentine,
tooth,
which
is
which
more
is
like
in
bone
in
bony
socket
structure.
A
layer
of
cement
xes
the
root
of
the
tooth
into
a
dige
stion.
The
pulp
blood
Tooth
to
in
the
cavity
jaw.
is
a
The
root
space
in
is
the
the
part
tooth
that
is
below
containing
the
gum.
nerves
and
vessels.
Healthy
80
vessels
socket
incisor
a
can
func
mecha
nica
l
and
bony
blood
diag
ram
s
state
that
teeth
decay
form
is
and
caused
plaque,
by
which
gums
bacteria
is
a
layer
in
your
that
mouth.
sticks
to
They
your
mix
teeth
with
and
saliva
gums.
decay
enamel
dentine
DID
pulp
YOU
KNOW?
Periodontal
abscess
No
pain
Slight
toothache
Severe
toothache
the
7.6.3
Stages
in
tooth
if
space
between
get
tooth
to
the
forming
base
an
of
abscess
can
make
The
bacteria
holding
decay.
and
After
a
meal,
Bacteria
in
respiring
of
a
this
be
be
this
will
your
should
plaque
and
acid
will
make
the
of
very
The
starts
attack
red
food
the
acid
off
the
painful
gums
sugary
changes
anaerobically.
tooth
away,
particles
tooth
and
cause
may
sugar
can
dentine.
and
the
between
acid
the
the
7.6.4
on
the
degrees,
your
brush
teeth
with
up-and-down
at
the
45
Clean
gentle,
of
your
short
the
gently
movements.
sure
inside
teeth
back
not
surface
moving
to
and
your
the
The
shows
of
Brush
brush
forwards.
forget
the
also
the
is
worn
pulp
acid
how
both
Be
with
the
teeth.
short,
and
the
make
gums
They
can
rot
teeth
them
unhealthy.
the
in
fall
bres
position
out.
STUD
Y
TIP
cavity
can
our
biting
upper
the
are
No te
also
surfaces
lower
scrubbing
that
uo rid
e
streng
then
s
teeth
of
outside
the
can
into
surface
brushed.
clean
get
teeth.
they
the
enamel
reaches
toothache.
Figure
your
because
enamel
When
cavity
severe
swollen.
left
into
attack
decay.
If
be
a
Holding
bacteria
Agony!
bacteria
Figure
disease
occur
the
tee th
,
hard
the
exterio
r
KEY
POINTS
KEY
POINTS
enam
el
giving
them
surf
ace.
of
teeth
strokes.
1
back
Incisors
are
cutting,
for
biting
canines
for
and
piercing
teeth.
Figure
7.6.4
Make
SUMMARY
sure
you
clean
all
surfaces
of
your
Copy
tearing,
and
molars
and
complete
the
and
chewing.
sentences
using
these
Tooth
decay
bacteria
words:
in
changes
dentine
crown
mechanical
bite
enamel
chew
are
of
is
used
to
digestion.
gum
and
the
a
hard,
which
is
and
Each
which
outer
similar
layer
of
to
tooth
is
tted
the
your
consists
into
tooth;
a
of
food.
a
is
above
bony
inside
This
this
.
is
the
a
a
Name
b
For
c
What
the
The
softer
3
Tooth
by
each
is
type
the
permanent
d
Describe
e
State
in
part
types
a,
difference
of
caused
to
by
which
acid
that
the
of
enamel
the
and
tooth.
decay
good
can
be
brushing
toothbrush,
foods
and
avoided
with
a
avoiding
visiting
the
regularly.
teeth.
describe
between
its
the
shape
milk
and
teeth
its
function.
and
the
teeth?
the
three
main
sugar
regular
sugary
.
four
is
plaque,
type
the
dentist
2
grinding
bone
dentine
teeth
premolars
for
socket
attacks
root
The
and
are
QUESTIONS
2
1
and
teeth.
stages
ways
in
of
tooth
which
decay.
tooth
decay
can
be
prevented.
81
7.7
Mouth,
and
stomach
Chewing
LEARNING
Describe
the
events
that
during
the
and
of
chewing
food,
of
Describe
Describe
in
the
the
digestion
of
TIP
rst
our
enzy
me
food
amyl
ase.
what
starch
,
they
mou
th
smal
l
the
are
is
Mak
e
and
pieces.
digestion
the
moistened
into
a
ball
molar
It
easier.
food
or
salivary
through
and
the
canine
mouth.
teeth
bite
When
it
into
is
teeth
grind
important
to
these
chew
chunks
your
of
food
food
well
The
tongue
mixes
the
food
with
as
saliva
is
chewed
by
the
teeth.
The
food
is
then
bolus
mucus,
to
act
a
glands
slimy
down
amylase,
the
pro te
in
pass
to
the
saliva,
that
which
contains:
lubricates
the
passage
of
the
food
throat
enzyme
that
catalyses
the
breakdown
of
starch
to
maltose.
no te
s
nasal
to
and
from
end
intest
ine.
wher
e
make
substance
the
ball
prod
uced
they
body
teeth
saliv
ary
happ
ens
enzy
mes
them
,
premolar
smaller
makes
bolus
•
as
The
much
rolled
food
•
on
the
stomach
STUD
Y
on
into
incisor
peristalsis
The
T
he
the
saliva
and
•
ingested
mouth,
including
this
•
are
the
and
into
action
drink
enters
chunks.
swallowing
the
swallowing
take
food
place
and
OUTCOMES
Food
•
oesophagus
the
passage
food
fat
the
of
The
food
soft
palate
pushes
your
the
List
that
of
act
This
stops
going
on
up
upwards.
the
food
your
hard
nose!
palate
enzy
mes
Before
and
you
swallow,
what
your
tongue
food
into
rolls
the
do.
epiglottis
opening
So
food
the
The
covers
to
food
your
your
doesn’t
wrong
the
trachea.
go
and
down
a
soft
pushes
back
of
it
your
ball
to
the
mouth
way!
squeezes
epiglottis
oesophagus.
into
past
trachea
your
Gulp!
oesophagus
Figure
7.7.1
Events
during
swallowing.
muscle
direction
The
oesophagus
Food
passes
contracting
food
is
moving
stomach.
ball
longitudinal
of
down
The
the
oesophagus
oesophagus
muscles
in
its
(also
from
known
as
the
the
mouth
gullet)
to
the
has
circular
and
wall.
food
The
movement
muscular
of
food
contraction
down
called
the
oesophagus
peristalsis.
The
occurs
circular
by
a
wave
muscles
of
contract
muscles
and
relaxing
it
the
along.
longitudinal
In
front
longitudinal
Figure
7.7.2
Peristalsis
in
contraction
the
82
the
muscles
relax
bolus,
contract
the
to
behind
circular
widen
the
food
muscles
the
bolus
relax
oesophagus
to
and
to
push
the
allow
the
the
bolus
oesophagus
of
muscles
is
to
stomach.
a
wave
pass
of
food
to
move
along.
Movement
of
food
in
the
small
and
of
food
to
large
intestines
also
occurs
by
peristalsis,
though
to
a
lesser
extent.
The
oesophagus
stomach
liver
stomach
The
stomach
food
but
can
stomach
The
a
walls
juice.
tnemelppuS
Gastric
a
muscular
stretch
number
of
This
proteins
is
the
smaller
juices
also
the
that
usually
accommodate
things
stomach
contains
to
to
of
bag
happen
make
a
molecules
contain
more.
to
pepsin
called
about
When
1
food
litre
of
reaches
the
it.
digestive
protease
holds
juice
which
known
starts
as
the
gastric
digestion
of
polypeptides.
hydrochloric
acid
which
carries
out
gall
two
bladder
important
functions
due
to
its
low
pH.
pyloric
•
It
kills
any
bacteria
in
the
food.
The
low
pH
denatures
the
sphincter
enzymes
pancreas
in
any
harmful
microorganisms
in
the
food.
bile
duct
pancreatic
•
The
the
acid
pH
action
of
of
about
the
1.5
to
protease
2.0
gives
enzyme
the
optimum
conditions
for
small
pepsin.
duct
intestine
Figure
7.7.3
Upper
part
of
the
digestive
system.
The
mixture
chyme.
making
is
a
of
The
sure
type
of
contents
of
food,
gastric
muscular
that
it
is
walls
mixed
mechanical
the
juice
of
and
the
well
with
digestion.
stomach
are
like
a
hydrochloric
stomach
the
After
juices.
2–3
runny
churn
acid
up
This
hours
of
is
the
called
food
muscular
KEY
POINTS
action
churning,
1
the
Food
by
A
ring
of
muscle
called
the
pyloric
sphincter,
is
teeth.
liquid.
opens
to
let
the
the
a
little
at
a
time
into
the
duodenum
which
is
the
rst
is
up
then
actions
by
the
swallowed
of
the
tongue,
food
saliva,
pass
chewed
It
part
soft
pallette
and
of
epiglottis.
the
small
intestine.
2
Peristalsis
of
that
3
In
the
the
carrying
oesophagus
mouth
a
wave
contractions
squeeze
bolus,
salivary
involves
muscular
it
to
food
down
the
stomach,
the
stomach.
food
is
churned
gland
up
and
and
mixed
with
hydrochloric
gastric
acid.
juice
This
oesophagus
starts
liver
SUMMARY
the
digestion
of
proteins.
QUESTIONS
stomach
1
With
reference
events
that
to
take
the
place
following,
when
describe
food
is
the
chewed
pancreas
and
swallowed:
a
saliva
c
the
tongue
b
mucus
d
the
epiglottis
a
Describe
small
2
one
function
of
the
muscle
layers
in
intestine
the
b
i
stomach
Name
wall.
the
type
of
protease
produced
large
by
the
walls
of
the
stomach.
intestine
ii
Describe
the
function
of
this
type
of
enzyme.
c
Explain
briey
why
a
different
enzyme
is
rectum
appendix
required
anus
food
Figure
7.7.4
The
digestive
for
the
digestion
of
each
type
of
substance.
system.
83
7.8
Small
intestine
and
absorption
The
The
•
Describe
small
the
digestion
small
in
the
small
the
emulsifying
its
role
of
bile
Dene
the
The
fats
term
Describe
how
intestine
is
efcient
after
the
the
absorption
for
of
food
•
amylase
•
trypsin
lipase
Bile
a
globules
emulsied
globules
to
of
of
are
to
increase
Bile
is
fo r
TIP
lipas
e
no t
a
incr
eases
of
of
as
chan
ged
it
is
the
about
large
6
metres
intestine.
long;
The
rst
duodenum
that
leads
into
the
ileum
to
the
down
duodenum
the
duct
to
by
meet
the
pancreatic
food
arriving
duct.
juice
from
contains:
to
protease
starch
that
to
breaks
maltose
down
proteins
and
polypeptides
do
the
enters
the
not
also
stomach.
to
the
made
fatty
well
in
in
an
and
acidic
glycerol.
environment,
hydrogencarbonate.
along
the
a
liver
neutralises
This
acids
duodenum
duodenum
uid
and
to
sodium
enters
the
fats
work
alkali,
which
alkaline
in
down
gives
from
tube
and
the
the
stored
the
in
for
bile
the
which
pH
so
pancreatic
neutralises
the
stomach.
called
acid
best
the
This
duct.
gall
was
is
bladder
added
enzymes
Bile
in
to
the
the
small
work.
emulsies
Cells
globules.
over
fat
fats
which
into
fatty
lining
the
by
breaking
These
the
minute
enzyme
acids
ileum
and
down
large
droplets
lipase
can
globules
have
act
to
a
much
break
of
fats
larger
down
into
surface
molecules
glycerol.
make
enzymes
that
complete
the
digestion
of
food.
fat
•
Proteases
•
Sucrase
•
Maltose
which
break
down
peptides
to
amino
acids.
act
which
breaks
down
sucrose
to
glucose
and
fructose.
is
chem
ical
the
a
down
fats
Emul
sica
tion
dige
stion
no t
area
enzy
mes
type
ows
breaks
food
intestine
of
upon
.
as
of
area.
area
surf
ace
the
connected
breaks
enzymes
smaller
Emul
sica
tion
–
–
also
food
smaller
fat
surface
fat
–
yellow-green
Bile
the
is
Pancreatic
contains
acidic
STUD
Y
small
that
peptides
juice
their
is
juice
stomach.
These
Large
so
than
small
adapted
•
7.8.1
really
less
stomach,
pancreas
to
Figure
is
absorption
the
•
not
in
Pancreatic
•
is
diameter
intestine,
part,
including
intestine
of
however
food
intestine
OUTCOMES
of
the
is
broken
epithelium
down
lining
by
maltase
the
small
to
glucose
on
the
membranes
intestine.
is
chem
ically
.
Absorption
Absorption
the
microvilli
wall
of
the
the
movement
intestine
into
of
the
digested
blood
or
food
the
molecules
lymph.
through
Digested
food
forming
includes
brush
is
simple
sugars,
amino
acids,
fatty
acids
and
glycerol.
These
border
molecules
goblet
diffusion
cell
The
small
pass
or
by
through
active
intestine
is
the
wall
of
the
small
intestine
either
by
transport.
adapted
for
efcient
absorption
of
food
as
it
has:
nucleus
•
a
very
large
•
a
thin
lining
surface
area
of
about
9
square
metres
basement
membrane
the
Figure
7.8.2
Detailed
structure
epithelial
small
84
cells
of
lining
intestine.
the
the
wall
into
(only
the
one
cell
blood
thick),
and
so
lymph.
digested
food
can
easily
cross
tnemelppuS
LEARNING
It
is
possible
because
has
villi
a
the
such
lining
villus).
called
a
large
intestine
inner
(singular:
cell
t
small
folded
projections
the
to
is
of
the
area
long
millions
epithelial
microvilli.
membrane
very
with
The
surface
cells
These
epithelial
(at
of
least
tiny,
tnemelppuS
wall
cell
is
small
metres
in
space
an
adult).
projections
the
villi
have
the
absorptive
(see
Figure
acids
It
called
microscopic
area
of
7.8.2).
and
sugar
molecules
only
are
one
6
a
increase
amino
villus
such
nger-like
lining
vastly
cells
into
absorbed
through
the
thin
villus
thick
wall
into
the
blood
capillar y
Villi
increase
the
surface
area
of
the
small
intestine.
blood
capillar y
fatty
acids
absorbed
and
into
glycerol
the
are
lacteal
lacteal
(lymph
blood
pick
coming
up
lymph
food
to
capillar y)
villus
blood
to
coming
to
takes
away
molecules
to
lymph
villus
fluid
glycerol
Figure
The
7.8.3
digested
capillaries)
to
the
in
liver
lymph
walled
result,
the
lymph.
slowly
veins,
the
food
portal
through
enter
to
the
and
molecules
body
carries
away
to
vein.
of
Fatty
the
lymphatic
enter
lacteals
molecules
Movement
eventually
not
capillaries
Absorbed
hepatic
the
does
reaches
villi.
moves
like
fat
the
in
of
fatty
rest
of
acids
and
body
villus.
food
by
transported
the
A
food
rest
into
acids
gut
blood
too
(lymph
transported
and
glycerol
empties
vessels,
the
bloodstream
are
the
which
near
quickly
(see
are
lacteal
are
the
quickly
and
thin-
heart.
page
As
a
115).
KEY
1
SUMMARY
POINTS
Bile
fat
1
Match
with
each
its
part
correct
of
the
emulsies
duodenum.
QUESTIONS
digestive
function
in
oesophagus
makes
bile
stomach
moves
food
the
system
second
in
the
rst
lipase
column:
2
from
the
stomach
to
globules
surface
column
the
area
can
Enzymes
intestine
liver
makes
pancreatic
in
the
smaller
have
a
upon
larger
which
act.
produced
pancreas
ileum
fats
The
and
the
by
the
small
complete
chemical
juice
digestion.
gall
bladder
carries
pancreas
mixes
duodenum
food
food
stores
to
the
with
stomach
gastric
by
peristalsis
3
juice
bile
Absorption
is
of
food
digested
through
2
a
State:
i
the
components
of
bile,
ii
the
organ
where
bile
iii
the
organ
where
bile
is
wall
movement
molecules
of
the
is
intestine
produced,
the
the
into
the
blood
and
stored.
lymph.
b
Describe
two
ways
in
which
bile
aids
the
digestion
of
fats.
4
3
a
How
are
conditions
conditions
in
the
in
the
small
stomach
different
from
the
The
for
small
absorption
long,
intestine?
lining
b
State
the
composition
of:
i
gastric
juice,
ii
pancreatic
intestine
having
with
a
by
is
adapted
being
folded
millions
of
very
inner
tiny
villi.
juice.
85
7.9
Large
intestine
intestinal
The
LEARNING
Describe
the
large
its
Describe
diarrhoea
symptom
intestine
the
is
about
appendix,
1.5
the
metres
colon
long
and
and
the
can
be
divided
into
rectum.
Explain
as
of
cholera
how
cholera
the
time
food
gets
to
the
colon
there
is
not
much
useful
food
left.
a
It
is
now
it
has
mainly
been
bre,
absorbed
dead
in
cells,
the
bacteria
small
and
some
water,
as
most
of
intestine.
bacteria
3
cause
diarrhoea
The
and
small
food
dehydration
intestine
passes
absorbs
along
the
about
colon,
5 – 10 dm
more
water
of
is
water
every
absorbed
into
day.
the
As
blood
–
3
about
The
0.3 – 0.5 dm
solid
faeces
waste,
are
per
or
egested
day.
faeces,
through
are
stored
the
anus.
in
the
The
rectum.
passing
Eventually
out
of
the
digestible
stomach
food
liver
through
the
anus,
in
the
form
of
faeces,
is
called
egestion
Cholera
Cholera
is
cholerae.
a
water-borne
The
dehydration.
main
Diarrhoea
Some
people
suffer
from
infected
the
disease
symptom
is
the
with
disease
of
loss
the
and
caused
cholera
of
the
called
bacterium
diarrhoea
watery
cholera
are
by
is
faeces
bacterium
as
a
from
may
symptomless
Vibrio
result
the
not
of
body.
actually
carriers
colon
Transmission
caecum
small
Cholera
tends
sanitation,
anus
The
large
that
of
the
is
people
is
transmitted
Almost
acidic
seen
in
an
on
all
the
cholera
and
mucous
as
in
reach
lining
by
by
occur
food
conditions
survive
cholerae
can
handling
Effects
where
supply
there
or
is
a
lack
of
contaminated
proper
food.
Water
when
their
infected
people
pass
out
large
faeces.
the
by
or
drinking
water
or,
containing
contaminated
utensils
more
the
water
,
without
rarely,
food
bacteria.
by
washing
infected
their
hands.
body
the
the
the
of
material
cooking
bacteria
in
ingestion
faecal
ingested
stomach.
small
wall
of
by
However,
intestine.
the
humans
Here
intestine
some
they
and
are
killed
pathogens
burrow
start
by
to
the
may
through
produce
a
the
toxin.
electron
Molecules
of
this
toxin
enter
the
epithelial
cells
of
the
intestinal
wall.
(×13 000).
Here
they
epithelial
the
from
and
disrupt
cells.
intestine
lumen
cells
water
functioning
a
ions
intestinal
water
and
from
of
the
Chloride
(the
creates
the
symptoms
86
areas
contaminated
bacteria
contaminated
T
ransmission
microscope
in
water
intestine.
Cholera
Vibrio
occur
unclean
become
numbers
7.9.1
an
rectum
supplies
Figure
to
intestine
appendix
tnemelppuS
tnemelppuS
•
large
caecum,
function
By
•
intestine
intestine
the
and
disease
OUTCOMES
The
•
large
and
the
blood
cholera
–
of
This
cell
surface
the
cells
the
into
Water
the
lumen
dehydration
and
membrane
into
the
accumulation
gradient.
blood
into
the
out
lumen).
potential
from
the
pass
of
ows
lumen.
of
the
of
space
ions
by
diarrhoea.
the
inside
in
the
osmosis
Movement
intestine
of
of
cause
ions
the
tnemelppuS
Oral
To
rehydration
treat
diarrhoeal
infected
not
people
effective
drinking
being
and
An
lost.
because
or
to
water
to
•
sodium
•
glucose
bottled
is
like
is
not
water,
treated
This
cholera
possible.
is
by
is
important
giving
absorbed
does
not
giving
oral
it
Just
by
them
the
contain
people
a
rehydration
to
rehydrate
water
is
intestine,
the
ions
solution
therapy
and
that
of
are
salts
(ORT).
contains:
rehydrate
ions
as
water
drink.
solution
•
soon
Cholera
glucose
ORT
diseases
as
water,
therapy
to
the
blood
replace
the
and
ions
other
lost
tissues
from
blood
and
tissue
uid
Cholera
to
provide
energy
for
the
active
uptake
of
sodium
there
from
the
other
is
a
most
lack
easily
of
transmitted
clean
water
and
where
sanitation
is
intestine
poor
•
is
ions
ions
such
as
potassium
and
chloride
to
replace
ions
lost
or
non-existent.
in
diarrhoea.
and
made
a
a
cholera
glucose
into
person
until
are
a
to
solution
water
ions
cells
that
with
boiling
and
is
with
The
a
water.
given
powder
contents
This
regularly
of
containing
each
takes
and
sachet
little
in
salts
are
training
large
for
volumes
recover.
these
epithelial
sachets
available.
administer
people
When
outbreak,
made
are
reabsorbed,
decreases
was
lost
in
and
the
water
water
is
potential
absorbed
to
of
make
the
up
for
the
diarrhoea.
A
child
during
SUMMARY
1
a
What
QUESTIONS
sort
of
receives
the
KEY
organism
causes
1
cholera?
How
does
c
What
are
the
the
organism
symptoms
enter
of
the
Diarrhoea
a
What
b
How
sort
of
conditions
2
cholera?
encourage
the
spread
of
effective
treatment
of
drinking
water
help
control
sewage
the
is
the
Why
are
these
developing
measures
not
put
and
the
spread
of
is
tnemelppuS
Explain
in
how
th e
into
place
in
a
Diarrhoea
be
disease
caused
treated
The
diarrh o ea
and
loss
bact eriu m
of
br in g s
s a lts
f rom
caused
by
by
by
cholera
using
oral
the
a
bacterium
toxin
that
causes
a bout
blo od
ions
to
pass
into
the
in
intestine.
the
watery
therapy.
cholera
chloride
dehydration,
of
some
4
cholera
loss
intestine.
cholera?
countries?
detail
2010.
chlorination
produces
3
in
bacterium.
rehydration
c
the
from
Cholera
can
of
therapy
Haiti
cholera?
3
can
in
body?
a
2
rehydration
epidemic
POINTS
faeces
b
oral
cholera
tnemelppuS
During
This
causes
water
to
intestine.
pass
out
resulting
the
in
by
osmosis,
diarrhoea
dehydration
the
cells
loss
of
and
ions
from
blood.
87
PRACTICE
1
The
QUESTIONS
breakdown
of
large,
insoluble
food
vitamin
molecules
into
small,
water-soluble
molecules
C
vitamin
D
calcium
gums
bowing
of
bleed
leg
iron
is:
muscle
A
absorption
B
digestion
C
egestion
D
ingestion
weakness
A
(Paper
and
1)
[1]
tiredness
bones
cramps
bowing
muscle
gums
B
2
Which
is
a
correct
description
of
the
action
of
leg
tiredness
of
weakness
bleed
bones
a
and
cramps
protease?
A
breaks
down
fat
into
fatty
B
breaks
down
protein
C
breaks
down
starch
D
converts
acids
and
C
scurvy
rickets
D
tiredness
rickets
anaemia
soft
gums
glycerol
muscle
into
amino
acids
bones
bleed
weakness
amino
into
acids
glucose
into
proteins
(Paper
(Paper
1)
The
an
[1]
[1]
6
3
2)
drawing
incisor
shows
a
vertical
section
The
drawing
shows
part
of
the
digestive
system.
1
through
tooth.
1
2
2
3
3
4
What
part
is
1,
the
function
stored
in
A
to
digest
B
to
increase
C
to
acidify
D
to
digest
of
part
proteins
the
the
2
liquid
and
to
produced
released
amino
surface
into
by
part
3?
acids
area
of
fat
droplets
4
Which
parts
row
is
shown
the
in
correct
the
identication
drawing
of
(Paper
above?
2
3
fats
contents
to
fatty
of
part
acids
4
and
glycerol
the
7
1
the
The
2)
[1]
following
events
occur
during
the
passage
4
of
A
cement
pulp
enamel
dentine
B
dentine
enamel
pulp
cement
1
starch
through
Amylase
is
the
alimentary
secreted
in
saliva
canal.
from
salivary
glands.
C
enamel
dentine
pulp
cement
D
pulp
cement
dentine
enamel
2
4
1)
A
C
is
a
anaemia
rickets
symptom
B
D
Which
to
4
Glucose
enters
5
Glucose
is
into
epithelial
the
surface
of
intestine.
breakdown
of
glucose.
the
blood
plasma.
absorbed
by
active
transport
cholera
the
cell.
scurvy
1)
Amylase
catalyses
the
breakdown
of
starch
[1]
row
the
the
small
of
of
the
table
(top
of
next
deciency
symptoms
for
maltose.
column)
Which
gives
onto
the
catalyses
to
5
in
maltose
6
(Paper
secreted
cells
Maltase
[1]
Diarrhoea
is
epithelial
3
(Paper
Maltase
vitamin
is
the
correct
sequence
for
these
C,
events?
vitamin
D,
calcium
and
iron?
A
1,6,2,3,5,4
B
6,1,3,2,4,5
C
2,3,1,6,5,4
D
3,2,6,1,4,5
(Paper
88
2)
[1]
8
Which
area
of
a
villus
increases
12
surface
The
diagram
alimentary
capillaries
B
goblet
C
lacteal
D
microvilli
Copy
its
absorption?
A
(Paper
9
feature
for
shows
a
villus
from
the
canal.
cells
2)
[1]
the
diagram
from
question
6.
A
(a)
On
the
diagram
oesophagus,
label
the
stomach,
following:
pancreas
and
(a)
duodenum.
Copy
and
(b)
Draw
arrows
on
the
diagram
to
show
taken
by
food
as
it
passes
the
parts
of
the
alimentary
canal
on
(c)
State
the
diagram
use
label
lines
and
lacteal.
the
part
villi
F
an
letters
site
of
Name
three
to
the
secretion
of
hydrochloric
H
the
With
that
secretes
molecules
of
place
13
with
organ
A
State
diet
what
provided
It
is
is
an
that
alkaline
stores
essential
reference
A
meal
in
a
an
balanced
State
three
increased
that
they
that
a
increased
components
[4]
(a)
starch,
Describe
good
should
health.
The
be
diet.
[4]
when
woman’s
quantity
she
is
components
and
explain
should
be
diet
of
the
in
bread
diagram,
the
from
A
[3]
explain
alimentary
and
cheese.
cheese
starch
canal.
In
that
diagram
is
the
canal.
[6]
Bread
contains
digested
your
and
molecule
where
molecule
you
shows
molecule
in
answer
protein.
the
state
where
the
to
describe
a
small
places
1
break
place.
[5]
protein
along
proteases
help
take
the
and
it
2
act
on
down.
should
1
certain
2
1
breast-feeding.
that
why
it
should
is
be
important
increased.
(b)
[6]
How
many
after
the
two
fragments
molecule
will
has
be
been
produced
digested
by
proteases?
[1]
3)
(c)
The
to
villi
and
how
changes
the
11
of
contains
contains
pH
bile
for
components
important
include
(Paper
pass
villus.
4)
the
(b)
that
the
3)
balanced
(a)
into
a
the
10
canal
[1]
substances
diagram
alimentary
(Paper
alimentary
acid
protease
a
the
located.
show:
(Paper
organ
G
[2]
of
are
signicance
the
capillaries
the
(d)
following
E
the
[2]
on
On
label
the
diagram.
(c)
and
through
where
the
diagram
the
(b)
direction
the
[4]
liver
performs
important
functions
in
Suggest
protein
digestion
and
assimilation
of
food.
One
why
protease
2
cannot
act
on
the
the
in
the
same
places
as
protease
1.
of
[4]
these
is
the
production
of
an
alkaline
digestive
(d)
juice
that
breaks
down
large
globules
of
State
the
where
(a)
(i)
Name
the
digestive
juice
secreted
liver.
proteases
Explain
how
The
this
digestive
alimentary
canal
protein.
[2]
fragments
produced
by
digestion
by
the
food
in
the
1
and
2
are
not
absorbed
into
juice
the
reaches
the
[1]
proteases
(ii)
in
digest
by
(e)
the
organs
fat.
small
blood.
Explain
why
this
is
so.
[2]
intestine.
(f)
Describe
what
happens
to
these
fragments
[3]
so
(iii)
Explain
why
this
digestive
juice
that
alkaline.
down
(b)
Explain
(Paper
how
large
what
is
completely
broken
[2]
[2]
(Paper
Outline
protein
is
down.
(iv)
the
is
this
digestive
globules
meant
by
of
juice
4)
breaks
fat.
assimilation.
[4]
[2]
4)
89
8
Plant
transport
8.1
Transport
Most
LEARNING
living
organisms
State
and
•
the
and
functions
of
xylem
the
positions
phloem
sections
of
transport
rely
phloem
Identify
in
of
xylem
stems
on
and
such
diffusion
Vertebrates
so
transport
system.
tube.
This
blood
systems:
and
have
for
throughout
water
root
Only
very
from
of
transport
regnans
is
the
tallest
in
the
so
remove
as
food
systems
same
and
and
move
up
to
90
two
of
a
dioxide.
have
water,
uids
through
within
pump
separate
are
plant
body
in
in
from
upwards
xylem,
to
Topic
in
and
the
the
unlike
These
stems
mineral
soil.
stem
in
composed
2.3).
roots,
water
ions
stem
tissues
(see
each
(the
heart)
transport
the
the
in
The
enter
phloem,
is
that
are
are
found
in
roots
the
leaves,
absorb
xylem
owers
one
in
the
the
and
fruits.
direction
only
–
leaves.
Phloem
xylem
sucrose
cells
leaves.
ions.
These
to
of
tissues
and
tissue
transports
phloem
sucrose,
owering
acids
and
bud
metres.
hormones
sunlight
YOU
have
can
ow
leaf
DID
not
they
carbon
amino
growing
do
that
direction
consisting
have
worms,
at,
organisms
such
mass
system
or
phloem
plant
the
via
large
in
plants
some
and
transport
called
circulatory
Flowering
and
are
moves
is
and
small,
substances,
These
uid
transports
water
of
a
so
oxygen
plants
transport
mineral
roots
uptake
the
are
obtain
carry
transport
travel
Transport
plant,
small
phloem
the
tissue
and
and
of
phloem
specialised
Xylem
to
vessels.
and
to
bodies.
of
xylem
Xylem
Xylem
all
type
Vertebrates
and
their
protoctists
bodies
owering
systems
that
bacteria,
Their
alone
and
throughout
tubes
as
systems.
transport
transverse
roots,
leaves
Eucalyptus
a
OUTCOMES
organisms,
•
need
systems
the
throughout
plant.
Sucrose
is
KNOW?
energy
a
carbon
The
world’s
redwood
It
is
in
114 m
tallest
tree
is
a
giant
dioxide
California.
tall.
simple
made
simple
made
sugars
sugars
from
and
the
minerals
soil
sugar
which
made
especially
for
transporting
energy.
It
leaves
is
made
with
the
from
moves
growing
root
growing
bud
down
or
up
and
to
to
in
sugars
photosynthesis
from
storage
as
water
is
by
into
sucrose
complex
photosynthesis
sucrose
water
soluble,
starch
organs,
swollen
roots
in
such
and
and
stems.
minerals
taken
by
up
roots
Figure
8.1.1
Substances
from
leaves
buds;
90
also
Transport
are
to
in
the
transported
roots
from
and
storage
xylem
in
the
upwards
organs
to
and
phloem.
phloem
from
new
in
two
leaves
stems
to
directions:
owers,
and
leaves.
downwards
fruits
and
Hormones
They
also
Inside
control
control
the
cell
the
nd
the
to
give
transverse
root
and
growth
root
To
and
transport
hairs
for
of
growth
owers
of
and
the
stem,
fruits
roots
(see
and
page
leaves.
170).
stem
tissues
of
roots
and
stems,
we
cut
across
them
sections.
absorb
mineral
division
water
ions
cortex
stores
some
food
This
as
starch
phloem
amino
transports
acids
from
sucrose
the
are
used
to
make
at
root
as
it
Figure
the
root
cap
the
through
8.1.2
transports
ions
up
The
root
the
root
tip
tip
cells
the
grows
internal
structure
of
a
make
new
red
dye
the
for
xylem
with
dye.
water
root
as
the
cells
divide
vascular
phloem,
bundle
is
cambium
made
and
up
xylem
new
The
and
a
are
root.
of
xylem
in
strands
soil
a
cambium
lled
standing
red
tip
protects
grows
vessels
left
The
new
and
cells
was
hours.
leaves
xylem
which
celery
several
and
tissue
in
the
centre
of
this
root
is
phloem
cortex
as
the
plant
xylem,
grows
which
between
the
is
stained
xylem
are
red.
The
phloem
green
areas
tissue.
pith
epidermis
is
a
single
layer
phloem
of
cells
on
the
outside
amino
the
stem
which
the
stem
and
acids
See
up
xylem
loss
8.1.3
Topic
sucrose
to
the
and
roots
to
the
flowers
and
fruits
reduces
transports
mineral
Figure
down
protects
and
water
transports
of
The
6.6
for
internal
the
structure
positions
of
of
a
ions
up
water
to
the
and
leaves
stem.
xylem
and
phloem
in
the
leaves.
A
transverse
Note
SUMMARY
QUESTIONS
1
complete
the
KEY
Copy
and
the
sentences
using
these
sucrose
water
amino
ions
fruits
blood
heart
have
a
Flowering
transport
plants
system
have
two
Xylem
vessels
mineral
made
up
transport
of
a
the
transports
and
up
the
,
owers
and
.
and
acids
Phloem
the
stem
from
the
Phloem
tissue
from
leaves
to
all
parts
Using
the
roots
leaves.
vessels
made
transport
in
the
leaves
photosynthesis
and
in
transports
of
the
organs,
to
other
parts
plant,
the
plant.
organs.
3
2
to
roots
of
as
water
the
Xylem
storage
such
from
and
systems.
during
to
transport
ions
stem
sucrose,
tissue
stem.
storage
2
.
young
vessels
up
Vertebrates
a
POINTS
and
mineral
through
bundles.
words:
1
leaves
section
vascular
the
diagrams
above,
state
the
functions
of
each
of
Xylem
and
phloem
are
these
distributed
in
a
central
core
issues:
inside
a
phloem
e
root
b
xylem
c
cambium
d
f
root
cortex
root.
Inside
a
stem
epidermis
they
cap
a
are
vascular
organised
into
bundles.
91
8.2
LEARNING
Water
uptake
Water
by
The
•
Identify
root
hairs
as
the
main
microscope
take
their
structure
to
hairs.
Soil
water
such
State
the
pathway
taken
through
root,
of
and
roots
are
mineral
to
anchor
ions.
Just
the
plant
behind
the
in
the
root
soil
tip
and
are
small
Water
passes
into
the
root
hairs
by
osmosis
as
is
a
dilute
nitrate
and
solution
of
potassium.
various
Root
solutes
hairs
including
have
thin,
mineral
permeable
ions,
cell
by
walls
water
water
water
uptake
•
functions
up
and
root
relate
roots
seen
to
under
uptake
OUTCOMES
stem
and
provide
a
large
surface
area
to
absorb
water
.
The
cell
sap
and
in
the
root
hair
cells
is
a
more
concentrated
solution
than
soil
water
.
leaf
This
is
because
solutes
water
particle
soil
as
diffuses
hair
sugars.
from
cells
The
the
water
also
cell
soil
cell
then
Most
walls
From
the
hair
cells
of
here
stem
enters
cortex
water
passes
up
in
the
by
by
the
other
permeable
so
osmosis.
cortex
of
the
the
in
water
the
moves
spaces
through
between
the
the
a
from
xylem
water
and
to
cell
in
the
cell
to
the
moves
the
Water
centre
up
leaves
cells.
walls,
cell.
cells.
the
of
the
xylem
where
Much
eventually
of
evaporates
it
through
enters
the
to
root.
the
water
form
water
and
then
diffuses
through
stomata
to
xylem
the
water
across
mesophyll
vapour
stem
of
cells
have
the
airspace
Absorption
of
and
the
spongy
8.2.1
hair
passes
moves
reaches
Figure
root
partially
and
B
Some
root
the
is
ions
vessel
root.
A
mineral
membrane
into
Water
xylem
absorb
atmosphere.
root.
We
describe
and
into
Water
a
hair
movement
xylem
passes
potential
root
the
in
vessel
down
the
cell.
potential
lower
water
in
in
in
the
potential
in
cells
soil
the
to
a
root
hair,
potential
gradient,
lower
from
cortex
xylem
a
water
passes
of
the
of
into
potential
the
turn,
in
water
terms
water
solution
Water
water
a
of
the
and
(see
from
water
root
across
a
the
Topic
high
potential
hair
cell
eventually
to
to
an
cortex
3.2).
water
in
a
tnemelppuS
soil
such
root
the
lower
even
vessel.
PRACTICAL
Look
then
with
at
Root
hairs
on
as
can
a
a
92
hairs
of
a
germinating
bean
seed.
a
at
a
root
are
also
section
have
of
a
hairs.
long
look
germinating
or
a
osmosis
hairs
microscope.
the
bean
They
by
root
closely
Look
You
Root
at
a
and
at
thin.
root
hairs
seedling
such
radish.
large
and
surface
mineral
area
ions
through
are
which
absorbed
by
water
active
is
absorbed
transport.
tnemelppuS
Looking
Xylem
that
vessels
lls
instead
are
them.
it
is
like
pipes
Water
pulled
is
by
as
not
the
they
are
pushed
empty
from
evaporation
of
the
except
roots
for
up
the
to
water
the
leaves,
water.
tnemelppuS
STUD
Y
Transpiration
pull
Mak
e
T
ranspiration
cells
in
the
vapour
is
leaves
can
the
evaporation
and
diffuse
TIP
the
out
loss
of
the
of
of
water
water
leaf
from
vapour
when
the
the
to
surfaces
the
stomata
of
mesophyll
atmosphere.
are
sure
the
correc
t
We
say,
leaves
The
is
by
This
•
is
As
from
up
the
xylem
transpiration
water
wilting.
up
‘pulled’
used
water
the
mass
for
is
xylem
ow
cohesion
–
of
the
stem
from
the
roots
to
the
and
the
photosynthesis
up
vessels,
lost
rather
up
water
or
the
and
from
like
xylem
molecules
to
stop
the
water
relies
tend
being
on
to
the
leaves,
plant
more
‘ water
vapo
ur
each
of
‘ water
the
leaf’
goes
out
of
leaf’.
sucked
up
properties
attract
not
out
from
is
sucked
two
use
Water
pull
used
water
the
in
you
term
inolog
y.
open.
diffus
es
Water
that
a
straw.
of
other,
water:
sticking
together
adhesion
the
So
xylem
there
is
a
–
the
water
molecules
also
tend
to
stick
to
the
inside
of
vessel.
continuous
ow
of
water
from
the
roots
to
the
leaves.
This
STUDY
movement
of
water
up
the
xylem
is
called
the
transpiration
When
SUMMARY
QUESTIONS
1
complete
TIP
stream
you
and
the
sentences
using
these
in
stomata
osmosis
large
transpiration
are
for
2
into
taken
taking
leaves
of
passes
also
up
a
.
root
A
water
by
the
Look
up.
cell
root
and
This
is
hair
hair
cell
mineral
ions.
controlled
ions
the
.
a
water
xylem,
Mineral
leaf
water
of
that
from
with
water
pulls
the
in
the
roo ts.
surface
Water
by
the
start
evaporation
area
by
has
how
words:
always
Water
are
explaining
moves
Copy
tnemelppuS
•
the
is
lost
from
opening
and
the
closing
.
at
the
diagram
of
the
root
hair
in
the
soil:
A
B
KEY
1
POINTS
Water
enters
osmosis.
the
cells
osmosis
It
a
root
then
of
the
hair
passes
root
before
cell
by
across
cortex
passing
by
into
the
C
xylem
D
F
the
and
then
up
the
stem
to
leaves.
E
2
a
Name
the
parts
labelled
A
to
Root
the
b
Explain
c
Give
how
water
gets
into
tnemelppuS
3
Explain,
root
using
hair
vessels
other
cells,
and
up
the
functions
term
across
to
the
water
the
cells
leaves,
of
a
root
root
hair
hair
potential,
of
are
well
cell
from
the
absorption
the
where
cells.
how
cortex,
it
is
lost
to
have
have
water
into
passes
the
the
of
adapted
water
for
since
soil.
they
two
hairs
F
.
into
xylem
atmosphere.
3
Loss
a
of
‘pulls’
stem
thin
large
water
more
from
cell
walls
surface
from
water
the
transpiration
the
up
roots
and
area.
leaves
the
in
the
stream.
93
8.3
Transpiration
Plants
absorb
water
•
Dene
•
Describe
the
term
transpiration
passes
where
it
is
diagram
how
water
is
related
to
cell
lost
of
are
spaces
Describe
and
how
temperature,
light
from
humidity
can
There
and
affect
rate
tnemelppuS
how
a
the
leaf
atmosphere
you
will
see
through
the
soil.
as
that
stems
Much
water
there
and
of
vapour.
are
many
If
enters
this
you
air
leaves
look
spaces
at
a
by
mesophyll
cells
which
have
damp
cell
inside.
walls.
from
this
huge
internal
surface
so
the
air
spaces
Water
become
wilting
with
water
vapour.
in
is
usually
the
outside
the
air.
more
Describe
water
up
stomata
variations
intensity
transpiration
•
of
moves
surfaces,
saturated
•
quantities
roots,
to
lined
evaporates
air
into
vapour
These
loss
large
OUTCOMES
The
air,
more
so
water
water
from
water
water
lost
the
vapour
vapour
from
the
in
the
diffuses
spongy
air
spaces
through
than
the
mesophyll
there
stomata
cells
is
is
in
into
replaced
by
xylem.
occurs
Transpiration
evaporation
the
of
diffusion
is
the
loss
water
of
at
water
of
water
the
vapour
surfaces
vapour
of
through
from
the
the
plant
mesophyll
leaves
cells,
by
the
followed
by
stomata.
Wilting
More
the
T
wo
open
transpiration
stomata
are
open
the
Carbon
during
place
during
the
dioxide
the
day
is
a
during
so
raw
day
that
the
and
day
closed
carbon
material
than
at
at
night.
dioxide
for
night
can
because
The
diffuse
photosynthesis
into
and
stomata.
diffuses
The
STUD
Y
into
stomata
chloroplasts
close
as
Whe
n
form
s
refer
water
evapor
ates
water
vapo
ur
.
to
at
night
in
mesophyll
to
reduce
cells.
the
volume
of
water
lost
by
TIP
transpiration.
xylem
open
stomata
leaf.
takes
it
as
just
Do
air
lost
in
may
also
close
transpiration
is
in
not
hot,
being
dry
conditions
replaced
by
during
water
the
from
day
the
soil.
it
not
‘ water
vessel
water
They
’.
space
The
stomata
enough
so
much
are
rm
plant
close
water
it
water
and
that
give
becomes
up
will
reduce
they
the
soft.
to
start
to
are
plant
The
transpiration.
wilt
no
(see
longer
support.
stem
is
above
no
If
If
the
plant
on
the
right).
turgid
the
or
cells
longer
full
of
become
upright
and
still
Its
does
cells
water
.
T
urgid
accid
the
not
then
leaves
get
have
lost
cells
the
droop.
water
evaporates
off
cell
wall
stoma
vapour
Wilting
is
not
a
bad
thing.
The
leaves
move
downwards
so
are
diffuses
out
of
the
direct
rays
of
the
Sun
so
do
not
get
as
hot.
When
the
out
temperature
Figure
8.3.1
Loss
a
94
of
leaf.
water
vapour
decreases
and
they
can
absorb
from
by
transpiration
the
leaves
will
recover.
more
water
than
is
lost
tnemelppuS
LEARNING
Factors
As
factors
see
the
light
intensity
of
In
very
humidity
is
a
dry
the
is
of
the
measure
is
of
rate
high.
of
the
are
air
rate
and
the
of
the
transpiration
Figure
the
other
Y
ou
8.3.2.
increases
conditions,
temperature.
the
air
in
transpiration
by
quantity
when
As
environmental.
factors
determined
conditions
transpiration
humid,
that
these
of
water
humidity
becomes
is
etar
the
Humidity
air
.
increases,
maximum
as
of
etar
such
a
transpiration
two
fo
to
of
fo
up
affecting
effects
noitaripsnart
can
transpiration
noitaripsnart
Other
affecting
vapour
low,
more
the
and
in
the
25
rate
more
50
75
humidity
decreases.
Figure
8.3.2
10
100
/
15
T
wo
20
temperature
%
factors
affecting
the
rate
/
25
°C
of
transpiration.
The
rate
of
transpiration
increases
as
the
air
temperature
increases.
KEY
Transpiration
evaporation
Light
causes
stomata
to
open.
As
the
light
intensity
increases,
wider
.
As
light
intensity
decreases
when
it
is
cloudy
or
stomata
close
so
that
less
water
is
lost
by
transpiration.
conditions,
there
may
be
nearly
as
much
water
vapour
followed
in
water
as
concentration
low.
In
dry
vapour
cell
out
rate
the
surfaces
water
air
conditions
the
inside
the
gradient
diffuses
inuences
cells
in
of
leaf.
have
of
inside
for
the
water
vapour
the
concentration
the
leaves
of
temperature
more
kinetic
This
so
the
the
water
rate
and
is
that
of
from
very
enter
the
is
steep
so
such
molecules
air
2
is
inside
as
the
not
easy
velocity
the
leaf
the
If
water
water
rate
of
transpiration
but
you
can
use
to
water
lost
slightly
roots.
This
and
in
is
is
measure
less
because
keeping
cells
the
rate
than
some
the
of
of
water
volume
the
water
uptake.
of
is
water
used
The
taken
up
in
volume
in
by
potometer
shown,
is
making
allowed
bubble
is
is
to
a
sure
form
in
loss
of
by
the
in
increasing
the
greater
plants
lack
of
of
rate.
than
wilt
and
turgor
in
leaves.
of
photosynthesis
the
of
submerging
stem
in
the
capillary
the
rate
of
it
in
water.
stopper
tube.
The
water
is
It
is
set
air-tight.
distance
up
An
air
moved
cut
by
bubble
1
How
you
rate
shoot
of
State
a
capillar y
rate
set
measure
how
explain
a
the
by
it
a
cut
works.
how
conditions
of
up
uptake
Explain
and
an
to
water
these
the
reser voir
would
potometer
the
uptake.
air
QUESTIONS
as
of
A
rate
the
2
8.3.3
the
while
is
stems
shoot?
Figure
Increasing
wind
turgid.
lled
measure
and
decreases
SUMMARY
The
increases
rate.
uptake,
opens
a
cells
potometer
diffusion
intensity
and
transpiration,
as
transpiration
measure
the
through
increases
humidity
to
the
atmosphere.
light
stomata
because
is
the
temperature
the
on
to
transpiration
3
It
by
vapour
Increased
the
water
vapour
.
Measuring
at
mesophyll
no
T
emperature
surfaces,
water
there
transpiration
stomata.
increases,
energy
means
gradient
through
evaporation
As
leaves.
water
the
stomata
atmosphere
of
the
In
of
humid
of
towards
cells
evening,
the
stomata
surfaces
open
is
tnemelppuS
tnemelppuS
1
Explanations
POINTS
each
affects
transpiration:
increase
in
light
intensity
tube
bubble
b
a
decrease
c
an
in
increase
temperature
in
humidity
potometer.
95
8.4
Translocation
tnemelppuS
Food
LEARNING
is
made
in
include
•
Dene
•
State
that
the
term
acids
move
parts
translocation
sucrose,
of
the
•
to
Explain
plant
a
sink
the
sucrose
a
in
at
phloem
from
a
The
act
as
a
parts
a
of
Compare
transport
source
times
to
growth
a
and
during
the
take
converted
plant
photosynthesis.
in
solution
which
and
in
means
fatty
the
acids.
The
soluble
These
phloem.
‘from
place
to
This
are
products
carried
transport
is
to
all
called
place’.
food
regions
place.
in
where
of
the
takes
of
The
leaves
growth
place
storage
simple
into
or
from
or
to
regions
sugars
sucrose.
storage
regions
to
is
production
where
produced
This
occur
of
by
respiration
or
photosynthesis
transported
provide
(the
to
energy.
parts
are
of
Sucrose
the
is:
plant
•
•
by
acids
amino
leaves)
some
different
of
and
sink
that
may
life
leaves
amino
plant
translocation
source
the
OUTCOMES
transpiration
with
broken
down
by
an
enzyme
to
give
simple
sugars
that
are
used
in
respiration
translocation
•
changed
•
used
and
•
to
Leaves
in
use
make
are
also
DID
tissues.
make
where
If
the
the
the
and
can
stylet
sap
so
be
of
stylet
collected
above
for
96
are
crop
on
phloem
their
piercing
pests.
sap
They
by
using
mouthparts.
the
at
the
and
photosynthesis
cells
are
are
cuticle
for
isotope
of
and
in
seeds
growing
root
tip
all
over
made
stored
on
the
and
the
in
in
attract
nitrate
plant
shoot
many
upper
animals.
to
and
seeds
surface
ions
make
root
as
of
tips.
oils
the
and
leaves.
to
some
the
and
sap
insert
of
maple
tubes
trees.
through
which
buckets.
feed
the
the
study
on
the
called
stem
into
the
sap
stylets
a
phloem
aphid
aphid
single
tube
with
cut,
the
phloem
which
can
phloem
causes
it
be
tube.
to
of
plants.
inserted
The
pass
along
food.
transport
is
in
the
of
sugars
sugary
sap
in
the
will
phloem.
pass
out
time.
sucrose
aphid
and
in
that
inside
phloem
tree
transport
the
feeding
below
from
the
collects
provide
used
a
from
and
cortex
sweet
needed
mouthparts
surface
Isotopically-labelled
feed
into
insects
piercing
of
root
walls
them
that
waxy
prepared
holes
small
the
stylet
the
of
Aphids
new
phloem
pressure
cell
from
are
acids
and
Aphids
8.4.1
These
Aphids
the
Figure
sugars
fatty
for
is
drill
have
the
KNOW?
syrup
are
in
new
make
and
through
living
acids.
to
ows
They
are
for
sap
Aphids
tubes
simple
needed
Farmers
Phloem
fruits
especially
Maple
the
the
YOU
storage
cellulose
some
also
for
tip
amino
proteins,
Leaves
starch
make
shoot
stored
to
to
stylets,
leaf.
the
can
be
that
The
injected
have
been
contents
passage
of
the
of
into
a
leaf
inserted
the
sucrose
sap
and
into
can
traced.
be
samples
the
stem
analysed
In
plant
transport,
journey
Water
empty
relies
a
is
called
and
owers
and
ions
and
upon
tension
The
the
in
part
of
absorbed
(the
the
The
sinks).
by
plant
part
roots
Xylem
where
where
(the
are
of
water
in
evaporation
of
water
vapour
xylem.
stream.
This
pulls
up
T
ranspiration
xylem
water
is
it
a
substance
ends
source)
vessels
movement
the
transpiration
translocation
source.
are
fruits
cells.
the
a
tnemelppuS
Transpiration
its
and
from
from
greatest
travel
columns
vessels
the
the
on
is
(or
to
leaves
dry
is
to
a
its
sink
leaves,
pipes)
passive,
roots
hot,
begins
journey
of
dead,
since
it
producing
give
and
the
windy
days.
Black
Translocation
is
an
active
process
which
occurs
in
phloem.
The
food
are
the
source
of
food
substances
and
the
sinks
are
the
bean
and
tissues,
regions
of
growth
(root
and
shoot
tips)
cells
active
tubes
the
such
that
as
the
contain
transport
to
build
sinks.
root
some
of
up
cortex
sucrose
a
and
cytoplasm.
head
Translocation
at
of
is
the
the
source.
pressure
most
seeds.
Movement
Water
that
active
Phloem
in
on
the
regions
tubes
forces
sunny,
the
are
phloem
enters
the
days
very
spraying
are
producing
increased
levels
of
rapidly.
sap
Movem
ent
in
sugar.
is
the
way
–
roots.
in
the
b
What
the
term
translocation
substances
are
translocated
in
the
T
he
What
are
the
materials
transported
in
the
phloem
both
used
and
for?
leave
s
2
3
Draw
a
table
Substances
the
xylem
to
are
and
compare
transpiration
transported
in
plants
with
from
translocation.
sources
to
sinks
to
grow
th
in
sink
of
for
substances
substances
substances
in
in
in
the
from
stem
In
it
is
leave
s
tips,
and
to
from
wher
e
and
this
of
phloe
m
season
fruits
ques
tion
only
from
trans
port
occu
rs,
owe
rs,
is
upwa
rds
answ
ering
source
them
and
direct
ions.
Rem
embe
r
phloem.
water
xylem
upwa
rds
down
ward
s
phloem?
of
grow
ing
roots
c
control
to
when
QUESTIONS
Dene
Farmers
TIP
subs
tanc
es
a
of
aphids
insecticide.
STUD
Y
the
1
plenty
living
one
SUMMARY
is
requires
ions
plants
there
favourable,
of
phloem
phloem
warm
are
respiring
and
by
storage
When
conditions
reproduce
plant
aphids.
leaves
to
seeds.
when
Sum
mary
3b.
transported
transport
in
the
plant
the
plant
the
KEY
POINTS
xylem
1
transport
Translocation
movement
the
is
the
in
of
sucrose
and
phloem
amino
acids
from
the
leaves
(translocation)
to
regions
growth
a
Copy
are
in
and
complete
transported
each
in
the
each
table
tissue
by
giving
and
one
two
substances
source
and
one
Explain
2
Regions
called
case.
how
a
root
tuber
can
be
a
source
and
a
sink
times
of
the
Aphids
feed
on
storage,
How
are
b
Suggest
are
are
regions
respiration
called
and
sinks.
Transpiration
is
a
passive
plants.
they
used
to
investigate
movement
in
involving
why
farmers
and
growers
control
dead
tissue.
phloem?
Translocation
spraying
and
year.
process
a
production
at
3
4
of
sources
growth
different
respiration,
storage.
that
sink
of
b
of
and
aphids
by
process
is
an
involving
active
living
tissue.
insecticides.
97
PRACTICE
1
In
QUESTIONS
which
water
conditions
by
would
a
plant
lose
of
most
environmental
caused
transpiration?
A
cool
and
dry
C
hot
and
dry
B
cool
and
humid
D
hot
and
humid
it
to
conditions
is
likely
to
have
wilt?
air
light
2
(Paper
1)
Which
row
transported
in
describes
the
the
phloem
amino
B
amino
D
glucose
(Paper
3
acids
sucrose
Which
is
and
molecule
A
root
leaf
B
and
and
and
and
of
ions
sucrose
sucrose
ions
water
and
and
amino
sucrose
correct
water
ions
it
taken
moves
xylem
cell,
mesophyll
pathway
as
mesophyll,
hair
D
low
B
low
low
high
C
high
low
high
D
low
high
low
water
acids
and
(Paper
water
and
7
Which
water
ions
air
cortex,
root
moves
in
by
Which
through
root,
root
cortex,
air
spaces
spaces
hair
root
in
leaf,
xylem
a
phloem
C
xylem
down
in
xylem,
cortex,
leaf
D
xylem
from
water
potential
a
down
a
a
water
water
low
in
2)
mesophyll,
8
Which
statement
xylem,
mesophyll
the
from
root
water
from
B
mesophyll
D
xylem
of
spaces
best
the
to
high
which
the
water
pathway
is
lost
water
vapour
from
stomata
intercellular
into
the
from
of
water
and
mesophyll
diffusion
cells
of
through
soil?
into
the
atmosphere.
hairs
Evaporation
and
vessel
of
diffusion
into
water
of
the
from
water
mesophyll
vapour
cells
through
the
atmosphere.
[1]
potato
plant
grows
in
a
eld
Evaporation
sunlight.
Which
row
shows
the
of
carbohydrate
in
the
source
destination
carbohydrate
A
glucose
leaves
tubers
B
glucose
tubers
leaves
C
sucrose
leaves
tubers
D
sucrose
tubers
leaves
9
The
A
diffusion
of
water
stomata
into
2)
water
for
6
days.
vapour
the
from
air
spaces
atmosphere.
[1]
diagrams
root,
B
show
stem
and
transverse
C
after
being
Which
leaf.
B
[1]
wilted
cells
2)
A
has
mesophyll
of
carbohydrate
plant
from
phloem?
(Paper
of
water
correct
through
movement
of
in
and
left
combination
C
98
gradient
potential
describes
by
through
Evaporation
D
without
gradient
leaves?
air
cell,
1)
potted
potential
potential
water
mechanism
cuticle
A
gradient
[1]
Diffusion
C
6
potential
atmosphere.
root
(Paper
water
[1]
absorbs
type
down
(Paper
atmosphere
C
bright
of
leaf
1)
sweet
movement
cells?
stem,
A
cuticle
A
the
leaf
from:
B
stomata
5
into
plant?
cell
A
(Paper
explains
stem
a
water
4
the
mesophyll
B
(Paper
statement
atmosphere
cells,
stoma,
stoma,
[1]
A
and
xylem,
2)
from
Water
water
stoma
C
high
[1]
cortex,
root
xylem?
1)
the
high
xylem
acids
C
A
substances
phloem
A
humidity
temperature
[1]
best
intensity
sections
of
(a)
Copy
that
the
diagrams
represent
phloem
in
A,
the
B
and
shade
positions
and
the
of
11
areas
xylem
and
C.
[3]
A
leafy
into
Copy
and
complete
functions
term
sap
of
the
refers
xylem
table
to
the
and
to
was
a
balance.
uptake
two
from
and
Topic
The
the
a
plant
8.3)
table
rate
and
which
shows
of
placed
was
the
rate
transpiration
the
leafy
shoot
during
a
hot,
dry
day.
The
transported
in
rate
these
cut
(see
compare
phloem.
liquid
on
water
by
the
shoot
potometer
placed
of
(b)
a
tissues.
time
/
of
water
rate
of
water
h
–1
loss
feature
phloem
composition
direction
of
of
the
ow
/
g
–1
h
absorption
/
g
h
xylem
midnight
4
7
0300
6
9
0600
12
12
0900
18
14
1200
24
17
1500
22
19
1800
18
20
2100
8
14
midnight
6
10
sap
in
the
stem
destinations
[6]
(c)
Describe
how
pathway
through
above
(Paper
10
A
you
taken
the
would
by
parts
water
of
the
discover
as
it
the
travels
plant
that
are
ground.
[3]
3)
potometer
measure
(see
water
Topic
uptake
8.3)
by
a
was
used
leafy
to
(a)
Plot
(b)
Calculate
rate
shoot.
a
of
1200
time
the
Describe
move
A
cool,
humid
air
in
B
cool,
dry
/
min
(d)
Explain
daylight
C
warm,
dry
D
warm,
humid
air,
in
daylight
E
warm,
humid
air,
at
night
in
air,
the
daylight
in
of
percentage
loss
your
the
change
between
Show
in
0600
table.
in
[5]
the
hours
working.
and
[2]
the
changes
over
the
in
water
24-hour
loss
and
water
period.
[4]
the
how
stem
water
to
the
moves
from
atmosphere.
the
cut
end
[4]
4)
6
daylight
rate
data
2
(Paper
air
the
100
of
Calculate
hours.
absorption
mm
(a)
the
water
show
water
conditions
to
to
taken
(c)
for
graph
1
3
60
water
movement
in
−1
mm min
E,
(b)
and
Draw
the
for
each
present
a
ve
bar
of
your
chart
to
conditions
the
conditions,
answers
show
on
the
in
the
a
table.
effect
rate
of
A
From
the
of
movement
(d)
State
two
shoot
with
(Paper
a
[5]
results,
conditions
that
state
affect
through
ways
would
[3]
water
movement.
(c)
to
be
in
three
the
the
of
water
plant.
which
affected
transparent
environmental
rate
the
if
plastic
it
air
[3]
around
was
bag.
the
covered
[2]
3)
99
9
Transport
9.1
Describe
The
circulatory
Most
animals
the
one-way
ow
around
the
Describe
the
of
pump
the
ow
heart
of
as
a
of
valves
blood
to
and
circulatory
system
vessels.
that
consists
Circulatory
systems
of
in
blood,
some
animals
useful
permit
substances
surface
and
such
nutrients
as
oxygen
from
the
absorbed
part
of
the
from
gut
a
gas
that
is
the
for
absorption.
Circulatory
systems
also
transport
waste,
only
such
one-way
a
blood
pump
adapted
role
and
body
exchange
for
have
of
transport
•
system
OUTCOMES
sort
blood
humans
Circulation
LEARNING
•
in
as
carbon
dioxide,
from
all
over
the
body
to
the
gas
exchange
ow
surface.
•
Describe
of
•
a
the
single
circulation
sh
Describe
Blood
the
circulation
double
of
a
The
mammal
heart
its
the
blood
very
ows
body.
close
their
The
flow
let
the
Valves
towards
blood
close
to
stop
heart
from
The
wastes
from
blood
delicate
so
helps
to
the
they
blood
the
through
blood
vessels.
heart
to
the
different
organs
the
and
a
blood
so
heart
to
in
veins
a
veins.
are
good
can
have
The
smallest
capillaries.
supply
their
of
Cells
oxygen
carbon
are
and
dioxide
and
efciently.
allows
to
the
receive
one-way
giving
maintain
capillaries,
capillaries
reduce
to
arteries
removed
pumps
this
back
capillaries
system
heart
getting
arterioles
ows
these
circulatory
small
pressure
a
but
it
ow
pressure
one-way
high
the
blood
so
that
ow.
pressure
muscular
before
of
it
This
vessels
blood
enters
ows
is
blood
blood
around
inside
good
will
the
for
damage
known
as
capillaries
(you
flowing
nd
out
more
about
arterioles
on
page
107).
When
blood
leaves
backwards
capillaries
Figure
circulates
away
connect
capillaries
and
can
the
that
arteries
the
blood
which
arteries
Blood
to
other
body.
to
pump
in
vessels
nutrients
open
a
advantages
of
Valves
is
and
Blood
explain
circulation
9.1.1
How
semi-lunar
permit
one-way
the
blood
pressure
is
even
lower.
valves
ow
of
There
are
semi-lunar
valves
in
veins
to
make
sure
blood
does
blood.
not
ow
backwards
happens,
valve
of
gills
has
the
back
veins
swell
three
blood
to
ll
away
of
and
these
pushes
the
from
the
the
blood
pockets.
against
heart
is
The
them,
(see
not
circulated
valves
but
Figure
open
they
9.1.1).
when
close
If
properly.
when
the
this
Each
pressure
blood
ows
pockets.
arteries
heart
A
semi-lunar
the
between
heart
the
single
Fish
body
9.1.2
Fish
have
a
circulation
ows
once
the
100
are
valves
chambers
chambers
of
in
to
the
heart
enter
the
at
the
arteries.
heart
(see
places
There
page
are
where
also
blood
valves
102).
circulation
veins
organs
Figure
leaves
single
in
in
a
body.
the
circuit
a
single
during
from
the
oxygen
which
through
have
once
it
a
organs
and
circulation
complete
is
ows
called
because
circuit
into
the
of
the
heart
blood
body
from
deoxygenated
ows
(see
veins.
blood.
through
Figure
This
The
the
9.1.2).
blood
heart
heart
Blood
has
little
pumps
blood
blood
into
blood
ows
an
artery
that
takes
it
to
the
gills
to
be
oxygenated.
heart
around
on
from
the
gills
in
arteries
to
the
body
organs.
The
tnemelppuS
detanegyxo
detanegyxoed
doolb
doolb
chambered
There
tnemelppuS
A
double
circulation
lungs
Mammals
twice
have
during
a
one
this
by
The
mammalian
is
a
circulation.
complete
following
septum
double
the
heart
thick
circuit
pathway
wall
Blood
around
that
blood
ows
the
through
body.
takes
is
divided
into
two
of
muscle
that
separates
You
around
halves:
right
the
the
can
heart
conrm
Figure
and
two
9.1.3.
left.
halves
The
of
the
right
heart
that
stops
blood
in
the
right
side
mixing
with
blood
in
the
side
left
side
left
of
heart
of
heart
side.
Blood
circulation
•
right
The
and
side
back
to
has
of
the
two
the
functions:
heart
heart
pumps
again.
The
deoxygenated
pressure
blood
required
to
to
the
force
lungs
blood
the
to
the
the
lungs
lungs
occurs
as
as
absorbs
returns
is
not
they
blood
the
are
a
ows
oxygen
to
very
and
high
spongy
in
a
is
little
lled
capillaries
carbon
vein.
there
tissue
through
loses
heart
since
with
in
dioxide.
This
blood
resistance
the
The
is
air.
Gas
lungs.
to
red
heart
in
exchange
Blood
oxygenated
bright
ow
in
blood
colour
rest
and
of
body
is
•
shown
The
of
left
the
red
side
body
leaving
is
in
the
much
of
on
the
and
left
more
diagrams
heart
back
side
to
is
the
pumps
the
much
resistance
of
to
circulation.
oxygenated
heart
again.
greater
ow
than
than
blood
The
on
there
to
pressure
the
is
right
through
the
of
rest
Figure
9.1.3
Mammals
side
the
as
exchange
such
and
as
occurs
muscles,
carbon
capillaries
the
dioxide
and
as
blood
gut,
liver
enters.
ows
ows
and
The
through
through
kidneys.
capillaries
Oxygen
deoxygenated
veins
is
dark
blood
red
in
in
leaves
that
colour,
shown
as
ows
through
twice
in
but
may
and
be
complete
KEY
2
the
sentences
using
these
words
body
veins
The
heart
right
.
The
is
Here
of
it
gas
blood
it
side
of
tissues
left
lungs
deoxygenated
the
pumped
to
to
mammalian
absorbs
is
returns
and
carbon
right
dioxide
3
oxygen
heart
and
removed
from
the
the
side
the
is
of
where
pumps
now
blood
the
it
to
in
complete
circuit
valves
up
lungs.
and
from
its
of
ensure
a
a
around
system.
single
passes
once
the
blood
circulation,
through
during
one
the
circuit
body.
Blood
ows
heart
the
twice
during
body
in
a
th ro u gh
one
circuit
m a mmal.
the
blood.
the
have
blood
the
called
heart
gives
blood
ow
circulatory
Fish
of
The
a
body.
POINTS
heart
(some
twice):
oxygenated
the
blue.
QUESTIONS
used
blood
heart
is
so
Copy
the
blood
leaves
the
1
double
organs
the
one-way
SUMMARY
a
which
lungs.
1
always
in
there
of
Gas
have
circulation
blood
4
The
heart
pumps
low
pressure
to
blood
the
at
lungs
The
and
at
rest
of
high
pressure
to
the
here
and
the
body
in
a
double
is
circulation.
now
the
2
3
called
heart
blood.
in
what
double
circulation
Explain
the
Blood
b
Blood
c
Veins
passes
back
to
the
side
of
.
Explain
a
It
is
5
meant
following
the
terms
statements
on
the
right
on
the
left
contain
by
side
side
of
of
semi-lunar
the
the
single
about
heart
heart
is
circulation
the
is
at
low
high
ows
in
from
the
veins
towards
arteries
heart.
Blood
away
ows
in
and
mammalian
at
Blood
the
heart.
heart.
pressure.
pressure.
valves.
101
9.2
The
Heart
LEARNING
Describe
the
four
human
the
heart
and
locate
of
blood
vessels
and
•
State
that
the
with
the
place
The
page
one
heart
consists
of
that
away
from
blood
the
two
pumps
and
the
lying
left
side
side
of
by
the
side.
The
heart
is
almost
entirely
of
cardiac
muscle
tissue
one
to
is
aorta
pumped
heart
body
body
vena
cava
(main
into
vein)
pulmonary
arteries
heart
•
and
in
Explain
of
the
returns
to
to
right
lung
importance
septum
to
left
oxygenated
deoxygenated
lung
in
pulmonary
separating
artery
the
veins
the
right
another
events
during
from
State
of
pump
24).
heartbeat
•
consists
is
heart
sequence
take
heart
valves
(see
associated
the
the
pump.
major
heart
chambers
side
of
structure
OUTCOMES
The
•
heart
veins
and
blood
from
•
Locate
the
and
name
the
valves
heart
right
atrium
left
•
Explain
why
ventricles
those
of
the
are
the
walls
thicker
atria
of
left
than
ventricle
than
and
the
is
why
thicker
valve
right
cava
TIP
left
Whe
n
tendons
valve*
vena
STUD
Y
atrium
the
atrioventricular
the
lungs
in
you
look
at
ventricle
a
right
diag
ram
the
it
hear
t
from
or
draw
ing
you
of
ventricle
from
are
*Supplement
septum
the
fron
t
of
the
Figure
body
the
–
so
hear
t
side
of
the
is
the
lef t
on
the
side
YOU
9.2.1
The
septum
right
draw
ing.
KNOW?
Al-Nas
physician
was
the
the
the
side
On
each
are
called
have
was
He
an
of
13th
the
suggested
puried
in
the
show
how
the
blood
moves
through
the
heart.
(wall
mixing
of
tissue)
side
of
atria
When
much
prevents
the
oxygenated
heart
(singular:
the
atria
more
they
with
deoxygenated
there
contract
the
are
atrium).
muscular
pump
blood
blood
out
the
into
left
empties
pump
than
the
chambers.
Blood
they
walls
two
on
blood
on
the
blood
atria.
arteries
side.
The
into
into
chambers
from
ventricles,
When
at
upper
them
the
higher
which
ventricles
pressure.
Arab
person
functions
lungs.
102
of
rst
was
arrows
righ
t
contract
Ibn
The
of
veins.
DID
body
view
ing
century.
to
He
connect
heart
that
lungs.
and
blood
Between
prevent
right
walls
each
the
and
blood
left
than
further
atrium
owing
ventricles
the
than
and
atria
the
ventricle
back
–
into
contract.
because
atria
to
a
right
to
or
left
have
pump
lungs
valve.
and
ventricles
have
the
one-way
the
The
they
either
is
to
The
valves
atrium
more
when
the
muscular
the
blood
the
tissues
much
of
the
body.
The
left
ventricle
because
more
it
tnemelppuS
contract,
The
at
more
pump
to
pumps
the
muscular
blood
around
wall
the
than
body
the
right
and
has
ventricle
to
from
from
heart
relaxation
overcome
ow.
two
sides
same
blood
chamber
chamber
the
a
action
heart
each
to
resistance
Heart
The
has
has
when
gets
contracts
of
the
time.
it
heart
The
its
smaller
relaxes
work
the
relaxation
phase,
During
the
contraction
and
so
it
contract.
squeezes
lls
together.
ventricles
During
muscles
contract
blood
up
the
with
The
and
ows
When
relax
into
the
blood
blood
atria
the
out.
the
atria
phase
filling
After
again.
contract
at
muscles
and
same
from
relax
right
left
atrium
atrium
time.
the
veins.
left
phase:
ventricle
•
The
atria
between
against
contract
and
force
the
and
ventricles
atria
blood
into
open
the
due
ventricles.
to
the
The
valves
pressure
of
blood
right
them.
ventricle
heart
•
Then
The
The
the
valves
right
artery.
aorta
The
ventricles
close
left
(main
phase
They
they
prevent
pumps
ventricle
to
force
blood
blood
owing
to
pumps
blood
the
blood
out
into
the
arteries.
back
into
the
atria.
lungs
to
the
in
the
rest
of
of
full
blood
to
to
lungs
body
pulmonary
the
body
in
the
artery).
semi-lunar
arteries.
to
ventricle
The
contract
valves
act
shut,
like
occur
the
at
the
ones
preventing
in
base
of
Figure
back
ow
the
aorta
9.1.1.
of
and
During
blood
into
pulmonary
the
the
relaxation
ventricles.
heart
During
the
the
lungs
contraction
and
the
phase
they
open
allowing
blood
to
leave
to
contraction
body.
Figure
Deoxygenated
blood
returns
to
the
right
atrium
in
the
vena
9.2.2
The
cardiac
changes
cava
heart
(main
vein).
pulmonary
phase
pumping
Oxygenated
blood
returns
to
the
left
atrium
in
cycle
that
during
–
the
occur
one
in
the
heartbeat.
the
veins.
KEY
1
POINTS
The
heart
muscular
consists
pumps
of
two
divided
by
a
septum.
SUMMARY
QUESTIONS
2
1
a
What
are
the
two
upper
b
What
are
the
two
lower
chambers
chambers
of
of
the
the
heart
heart
called?
Ventricles
blood
make
called?
one
c
What
is
the
function
of
the
Explain
each
The
atria
The
left
blood
ows
in
The
atria
have
less
muscular
statement.
have
less
muscular
walls
than
the
ventricle
has
a
much
more
than
the
ventricles,
as
ventricles.
they
b
that
force
valves
direction.
walls
a
sure
to
arteries;
septum?
3
2
contract
into
muscular
wall
than
only
force
blood
into
the
the
ventricles.
right
ventricle.
4
3
In
each
of
the
following
cases,
which
blood
vessel
The
right
blood
a
blood
to
the
rest
of
the
blood
from
the
lungs
c
blood
from
the
body
to
to
to
the
forces
lungs,
then
the
body
left
b
ventricle
carries:
the
the
left
atrium
right
atrium
as
a
ventricle
it
has
to
pressure
greater
is
more
pump
that
muscular,
blood
at
overcomes
resistances.
103
9.3
Heart
There
LEARNING
•
State
can
be
to
the
activity
in
monitored
pulse
rate
sounds
of
the
by
heart
monitored.
These
listening
the
Investigate
listening
valves
of
The
the
state
physical
pulse
Explain
control
activity
variety
the
activity
of
the
sounds
of
the
heart
valves
(ECGs),
heart
pulse
may
rate
be
and
closing.
(ECG)
of
of
the
heart
heartbeat
disorders
depends
can
upon
produce
electrical
activity.
irregularities
in
this
activity.
on
electrocardiogram,
or
ECG,
is
a
useful
diagnostic
tool
that
can
rate
the
effect
of
on
the
these
defects.
Electrodes
are
taped
at
various
positions
on
the
physical
body
activity
to
electrocardiogram
detect
•
which
and
The
the
by
electrocardiograms
closing
A
effect
methods
include
ECG,
and
The
•
different
exercise
OUTCOMES
that
taking
are
and
heart
and
the
electrical
activity
of
the
heart
is
then
displayed
on
a
rate
monitor.
ECGs
The
its
Figure
for
a
9.3.1
heart
resultant
trace
characteristic
contracting,
the
P
,
the
ventricles,
shows
a
normal
ECG,
while
Figure
9.3.2
shows
disorder.
can
be
QRS
QRS
and
compared
and
T
‘spike’
the
T
waves.
with
The
immediately
wave
represents
the
P
normal
wave
ECG
shows
precedes
the
ventricles
with
the
atria
contraction
of
relaxing.
R
egnahc
lacirtcele
A
boy
an
using
ECG
to
an
exercise
monitor
his
bicycle
heart
while
T
P
P
having
Q
function.
S
0
0.1
0.2
0.3
0.4
0.5
0.6
time
Figure
Heart
ECG
A
normal
(ECG)
the
of
the
this
example
one
heart
0.9
1.0
s
beats
takes
0.8
seconds.
sounds
The
heart
The
noise
of
During
fibrillation
contractions
In
0.8
trace
sound
ventricular
9.3.1
/
0.7
ventricles
are
extremely
valves
of
the
your
the
respond
blood
contraction
to
force
blood
pressure
of
blood
pressure
when
heartbeat
contract
to
–
the
changes
valves
open
during
and
a
close
cardiac
make
cycle.
the
‘lub-dub’.
phase,
out
of
the
muscular
the
pulmonary
walls
of
the
artery
and
ventricles
aorta.
The
irregular
shut,
rst
complete
heart
the
ventricles
atria
and
part
During
block
are
preventing
beating
independently
high
of
the
9.3.2
A
normal
ECG
trace
ECG
traces
disorders.
for
in
the
the
going
sound
from
back
–
phase,
arteries
blood
atrioventricular
into
the
valves
atria.
causes
This
them
produces
to
the
‘lub’.
the
ventricles
causes
going
the
relax.
The
semi-lunar
backwards
into
blood
valves
the
to
under
shut,
ventricles.
produces
the
second
part
of
the
heart
sound
–
‘dub’.
Doctors
are
heart
able
any
104
heart
the
and
This
two
blood
relaxation
pressure
preventing
Figure
the
against
to
listen
to
irregularity
these
in
the
heart
sounds
heartbeat.
with
a
stethoscope
and
identify
tnemelppuS
The
heart
During
order
exercise,
to
muscles
These
and
your
contract.
dilate
changes
exercise
muscles
So
the
increase
the
an
increase
in
supply
•
an
increase
in
removal
can
time
you
can
wrist.
the
detect
the
left
same
the
You
as
the
The
resting
The
tter
The
same
energy
faster
are,
of
of
and
carbon
blood
a
and
from
respiration
arteries
in
supplying
muscles
and
result
in:
glucose
through
arteries
passes
pulse
per
to
dioxide.
wave
your
pulses
heart
ow
oxygen
nd
of
pulse
you
blood
beats,
can
number
of
ow
ventricle
feel.
The
more
beats
(widen).
•
You
need
heart
by
minute
along
feeling
is
your
as
a
the
an
‘pulse’.
arteries
artery
pulse
at
rate
Each
which
your
and
this
is
rate.
rate
the
A
gives
lower
a
good
your
indication
resting
pulse
of
a
rate
person’s
(see
person
minute
but
with
of
blood
fewer
is
being
passed
out
of
the
heart
and
shows
levels
of
the
taken.
POINTS
per
heartbeats.
ECG
traces,
sounds
table
pulse
tness.
1
The
their
table).
KEY
volume
having
general
relationship
between
resting
pulse
rate
used
of
to
pulse
valves
monitor
rate
and
closing
heart
the
can
be
activity.
tness.
2
pulse
less
rate
than
level
50
of
tness
Pulse
rate
and
then
resting
pulse
with
decreases
to
rate.
outstanding
3
50–59
Physical
activity
increases
the
excellent
heart
60–69
good
70–79
fair
ow
80
increases
activity
and
over
rate,
to
more
muscles,
oxygen
removing
poor
increasing
blood
supplying
and
carbon
glucose
and
dioxide.
PRACTICAL
Investigating
the
Sit
a
still
and
get
effect
partner
of
to
exercise
measure
on
your
pulse
pulse
SUMMARY
rate
rate
at
rest.
1
Try
doing
step-ups
for
1
minute
(light
QUESTIONS
a
State
pulse
exercise).
what
rate
happens
when
a
to
person
exercises.
As
soon
as
you
have
nished,
sit
down
and
count
your
pulse
rate.
b
Wait
until
your
pulse
returns
to
the
resting
rate.
Explain
pulse
how
rate
and
why
changes
with
exercise.
Now
do
(heavy
step-ups
exercise).
Remember
have
the
exercise
until
that
same
each
your
as
quickly
Then
to
make
person
time,
pulse
as
count
this
doing
rest
returns
for
to
you
your
a
valid
the
5
its
can
pulse
for
3
minutes
rate.
2
investigation
exercise,
minutes
resting
do
the
between
you
should
same
each
type
can
your
also
results
repeat
more
the
tests
and
Draw
b
Explain
to
of
exercise
T
or
calculate
an
average
to
make
Pulse
can
explain
how
reliable.
the
results
in
terms
the
normal
what
heart
ECG
is
at
trace.
happening
P
,
QRS
and
waves.
of
supplying
substances
rate
certain
be
You
a
rate.
3
You
a
is
risk
some
the
affected
factors.
of
result
these
of
a
by
Explain
can
person’s
to
lifestyle.
your
muscles
and
removing
their
wastes.
105
9.4
Blood
Blood
LEARNING
ows
them
arteries
Name
to
the
and
and
arteries
to
all
main
from
blood
the
in
and
veins.
This
table
organs
shows
of
you
the
body
some
of
and
the
heart,
organs
vessel
Describe
the
function
of
structure
arteries,
lungs
liver
kidneys
and
veins
and
vena
cava
right
atrium;
to
hepatic
artery;
bringing
blood
renal
pulmonary
hepatic
(see
pulmonary
the
functions
vein
artery
vein
arterioles,
venules
page
(see
146)
of
and
artery
portal
to
organ
State
away
important
veins.
lungs
kidney
capillaries
•
ows
most
vessels
heart
•
the
OUTCOMES
from
•
in
vessels
to
left
atrium
page
144)
shunt
taking
pulmonary
blood
artery
away
right
from
aorta
organ
ventricle
vessels
tnemelppuS
from
hepatic
vein
renal
vein
pulmonary
•
Explain
how
the
structure
of
ventricle;
(see
page
(see
page
vein
arteries,
are
veins
adapted
and
for
capillaries
their
functions
from
left
144)
head,
and
vena
thick
146)
neck
arms
cava
outer
layer
lungs
pulmonar y
pulmonar y
vein
arter y
aorta
vena
which
blood
thick
and
right
left
atrium
atrium
cava
flows
layer
elastic
of
right
left
ventricle
ventricle
hepatic
muscle
vein
fibres
liver
hepatic
arter y
Figure
9.4.2
An
artery.
hepatic
portal
vein
renal
gut
vein
renal
kidneys
body
arter y
and
legs
two
are
outer
layers
thinner
outer
layer
Figure
than
9.4.1
Main
blood
vessels
of
the
body.
arteries
Structure
large
space
When
which
and
function
of
blood
vessels
through
blood
your
heart
muscles
contract
they
force
blood
into
at
muscle
and
a
high
the
pressure.
blood
to
Arteries
ow
have
along.
quite
They
a
have
narrow
thick
space
walls
and
9.4.3
in
made
fibres
106
arteries
the
centre
elastic
for
Figure
the
flows
A
vein.
elastic
bres
to
withstand
the
pressure
of
blood.
of
muscle
Veins
have
thinner,
veins
is
walls.
that
The
a
less
There
squeeze
are
in
branch
so
tnemelppuS
blood
and
than
one
it
is
less
valves
times
very
wall
easy
elastic
at
–
the
a
do
to
substances
adapted
to
such
veins
to
(see
cell
can
from
to
a
and
their
inside
thick
ensure
page
branches
blood
are
pressure
heart
pass
and
need
along
the
made
to
The
not
smallest
red
is
arteries
walls.
intervals
capillary
are
than
they
back
until
a
ow
so
narrow;
of
for
vessels
to
arteries
direction
are
The
blood
have
in
many
Capillaries
cells
for
semi-lunar
through.
thin
How
lower
ows
arteries
capillaries.
space
muscular
much
blood
very
wider
100).
form
only
single
from
just
layer
the
of
blood.
functions
red
The
like
elastic
a
bres
piece
original
of
where
it
the
elastic
length.
maintaining
in
The
its
walls
when
recoil
enters
an
you
of
pressure.
As
organ
is
of
the
stretch
elastic
a
arteries
a
and
bres
result
only
it
the
little
stretch
then
helps
less
let
to
pressure
than
and
then
recoil
it
return
to
push
blood
along
at
the
when
end
it
left
of
is
estimated
that
there
are
over
80
000
km
of
capillaries
so
heart.
in
9.4.4
A
capillary
body.
These
tiny
vessels
provide
a
huge
surface
area
magnied
capillary
between
blood
and
cells.
Blood
ows
through
slowly
(about
substances
cells
the
with
diffusion
This
makes
and
to
it
the
by
pressure
mm
As
to
of
from
second)
walls
blood
the
oxygen
dioxide
in
and
the
blood
is
for
from
and
exchange
one
cells
nutrients,
other
of
time
made
and
veins
contraction
giving
are
between
supply
carbon
pressure
per
the
distance
easy
remove
As
1
cells.
is
layer
very
such
as
of
surround
the
are
other
wastes.
very
body
low,
it
is
muscles
squeezed
and
other
along
KEY
POINTS
organs
Arteries
in
the
circulatory
system.
elastic
blood
have
much
small
subdivisions
of
arteries
that
carry
blood
blood
networks.
from
ow
blood
pressure.
hormones
in
Like
They
the
arteries,
transport,
order
through
muscular
receive
to
they
have
arterioles
nerve
regulate
are
muscle
important
impulses
their
in
and
diameter.
their
in
withstand
less
tissue
Blood
Veins
muscle
and
have
pressure
and
thin
in
veins
low.
walls.
regulating
respond
This
to
pressure.
to
is
Apart
thick
walls
high
walls.
capillary
have
veins.
vessels
the
removed
cells).
short.
elastic
are
blood
glucose,
Arterioles
Arterioles
section
red
of
and
There
view
thin
1
that
actually
capillaries
to
very
is
for
cylindrical,
exchange
×2500
the
(the
human
cells
capillar y
artery
Figure
It
a
its
an
the
blood
inside
to
2
are
various
regulates
Capillaries
one
have
cell
substances
blood
and
capillaries.
out
of
walls
thick
can
the
so
that
that
pass
easily
blood
in
in
body
tissues.
Venules
Venules
are
from
the
veins
which
small
blood
capillary
beds.
transport
vessels
These
whose
function
thin-walled
deoxygenated
is
vessels
blood
back
to
collect
then
to
blood
unite
the
to
SUMMARY
QUESTIONS
form
1
heart.
Make
a
table
differences
Shunt
and
vessels
veins.
columns:
A
shunt
vein,
allowing
Shunt
In
vessel
vessels
is
the
can
endotherms
response
and
to
a
blood
vessel
to
control
thereby
heat
that
bypass
blood
(warm-blooded
cold,
reducing
blood
links
the
ow
off
artery
capillaries
by
directly
in
certain
constriction
animals),
cutting
an
the
shunt
blood
and
vessels
ow
to
areas.
dilation.
the
show
Include
feature,
the
main
arteries
three
artery,
vein.
a
constrict
to
to
between
in
extremities
2
In
what
well
ways
adapted
materials
and
body
are
for
the
capillaries
exchange
between
the
of
blood
tissues?
loss.
107
9.5
Coronary
heart
disease
(CHD)
You
LEARNING
need
muscle
•
Describe
the
coronary
State
nature
heart
the
of
disease
possible
preventative
coronary
•
Describe
CHD
(CHD)
causes
measures
heart
the
may
get
then
blocked
to
be
in
could
the
and
heart
heart
cause
in
the
blood
heart
to
around
keep
coronary
could
it
7.2
arteries.
die
Slowing
Healthy
which
the
arteries
However,
people
from
each
cause
countries.
death
The
become
is
for
one
starved
have
a
smooth
cholesterol,
This
can
condition
narrow
is
which
the
called
lining,
is
letting
made
artery
and
in
the
slow
blood
liver,
down
death
It
rate
in
is
with
can
from
has
the
CHD
There
are
these
differences
of
atherosclerosis
Fatty
deposits
break
Fatty
deposit
of
a
–
blood
9.5.1
The
artery
clot
and
the
healthy
Blood
walls
block
108
blocked
formed
with
of
is
if
can
the
the
become
vessel.
artery
gets
or
angina.
rough,
The
coronary
activity
called
flow
arter y
along
stops.
Atherosclerosis.
coronary
heart
blockage
artery
partly
emotion
It
is
which
is
causes
caused
by
cause
called
a
serious
blocked
makes
can
it
the
not
can
blood
to
thrombosis
problems.
cause
heart
the
work
enough
chest
pains,
harder.
oxygen
getting
to
by
to
fatty
deposits.
further
the
narrow
healthy
artery
muscle.
Angina
should
a
attack.
heart
total
act
blockage
and
the
unless
as
or
a
warning
thrombosis
supply
the
beating
follow
Compare
arter y.
artery.
stop
has
the
flow
chest
artery
blocks
them.
happens,
it.
their
blood.
many
A
above
to
of
is
the
artery.
stick
ow
lowest
This
the
easily.
the
especially
clot
and
the
If
blood
oxygen
many
Narrowing
coronary
are
arteries
in
Figure
A
of
ow
the
the
A
these
ow
3
Cross-section
If
coronary
year.
country
Japan
rate.
reasons
diet
of
death
Ukraine;
Heart
These
attack
2
highest
body.
and
treated
million
disease
leading
your
contracting.
KNOW?
world
heart
the
muscle
a
1
Around
pump
oxygen
of
disease
ways
This
This
YOU
heart
glucose
to
walls.
DID
healthy
needs
transported
die.
•
a
OUTCOMES
of
affected
oxygen
part
altogether
the
heart
–
of
this
starts
to
the
can
is
cause
cut
the
is
sufferer
off.
heart
called
beating
a
It
is
because
heart
attack.
causes
a
again
The
arrest.
within
may
lead
When
severe
damaged.
cardiac
it
this
pain
heart
Death
minutes.
to
in
the
may
will
Risk
These
•
factors
are
factors
eating
can
less
a
diet
increase
page
71).
fresh
being
•
smoking
People
•
These
age
•
sex
fruit
–
too
increase
much
concentration
diet
–
down
and
of
eating
on
fried
–
but
other
inherited
the
from
control
chances
men
risk
are
parents
the
of
more
likely
to
getting
the
reduce
little
or
fat,
which
blood
sh,
less
CHD:
red
the
no
(see
which
meat
are
and
risk.
exercise
stress
risk
cannot
–
CHD
metabolism
getting
to
taking
these
factors
in
and
eating
helps
of
(animal)
poultry
foods;
•
about
chance
cholesterol
more
vegetables
something
the
saturated
•
genes
–
the
good
do
life,
genes
•
with
to
overweight
can
of
CHD
thought
cutting
•
way
A
fatty;
more
for
CHD
get
factors
be
avoided
tends
of
fat
to
than
changing
such
run
and
increase
CHD
by
in
their
as:
families.
cholesterol
with
age
women.
tnemelppuS
Figure
Treatment
of
9.5.2
Three
you
A
coronary
of
CHD.
the
arm
below
A
artery
blood
or
the
leg,
bypass
vessel
and
is
narrowed
is
can
taken
attached
or
relieve
from
to
blocked
patients
another
the
coronary
area.
with
part
of
the
the
artery
Depending
on
above
the
CHD,
a
number
of
separate
grafts
may
be
there
is
just
one
incidence
of
narrowing,
or
severity
STUD
Y
angioplasty
widen
open.
it.
and
A
This
tube
Antiplatelet
the
arteries.
people
with
angina,
involves
small
metal
is
may
be
inating
tube
called
a
medicines,
T
aking
CHD,
attack,
SUMMARY
is
then
carried
out.
This
is
a
less
ao rta
a
small
then
balloon
inserted
to
inside
help
like
the
keep
artery
the
aspirin
stroke
coronary
or
prevent
daily
other
stent
and
is
blood
part
forms
of
of
bypass
clots
the
forming
treatment
heart
Dene
d
a
T
hey
a
If
the
disease,
tissu
es
in
vent
for
of
ricles
blood
the
to
atria
the
and
.
e.g.
surgery.
heart
disease
b
thrombosis
c
angina
1
arrest
heart
POINTS
Coronary
caused
is
full
of
blood,
then
why
does
it
need
its
heart
by
disease
blockage
arteries
of
that
is
the
supply
own
the
blood
the
tran
sport
coronary
2
of
QUESTIONS
coronary
cardiac
base
abov
e
valv
es.
to
artery
oxyg
enat
ed
aspirin,
the
just
complex
KEY
1
put
a
stent
low-dose
known
heart
can
disease.
arterie
s
from
semi-l
unar
operation
that
heart
TIP
co rona
ry
the
coronary
of
of
needed.
blockage,
risk
usually
and
bran
ch
If
at
symptoms
body,
T
he
the
activities
CHD
heart
with
glucose
and
supply?
oxygen.
b
How
c
Why
is
the
heart
muscle
supplied
with
oxygenated
blood?
2
does
the
heart
muscle
need
this
oxygenated
Risk
factors
control
3
There
are
getting
risk
heart
factors
that
can
increase
the
of
a
person
sex.
disease.
List
some
of
the
factors
that
cannot
b
List
some
of
the
factors
that
can
c
What
advice
would
attack?
are
you
give
to
a
be
be
controlled.
person
recovering
diet,
exercise
controlled.
3
from
a
genes,
Avoidable
include
a
heart
chances
which
we
cannot
blood?
CHD
and
may
aspirin
be
and
angioplasty
risk
age
and
factors
stress,
lack
of
smoking.
treated
surgery
and
by
(stents,
bypass).
109
9.6
Blood
Blood
LEARNING
•
List
as
the
red
components
blood
cells,
of
Y
ou
have
and
cell
•
platelets
white
Identify
cells
as
red
and
and
seen
microscope,
5
litres
fragments
of
blood
suspended
in
in
your
a
body.
yellow
Blood
liquid
is
called
made
of
plasma.
cells
The
red
blood
of
blood
is
due
to
the
pigment
haemoglobin
in
red
blood
cells.
plasma
white
under
in
about
blood
colour
cells,
composition
OUTCOMES
blood
the
light
plasma
photographs
–
liquid
part
of
blood
(55%
of
blood
volume).
3
Plasma
10 cm
and
•
in
consists
of
water
with
chemicals
dissolved
in
it:
diagrams
Describe
cells
and
that
they
the
the
role
of
red
•
nutrients,
•
wastes,
•
blood
•
hormones,
and
blood
such
mineral
as
ions,
such
as
glucose,
e.g.
urea
amino
sodium
and
acids,
and
carbon
lipids,
chloride
vitamins
ions
dioxide
haemoglobin
contain
in
proteins,
such
as
albumen
and
antibodies
oxygen
such
as
insulin,
glucagon,
and
adrenaline.
transport
3
5 cm
•
State
the
roles
of
white
blood
and
cells,
platelets
and
red
Figure
9.6.1
When
it
Blood
There
Red
are
they
shows
cells
red
with
smear
blood
their
seen
cells
nuclei
with
and
a
light
two
stained
are
white
in
in
three
no
of
a
centrifuge
(or
left
to
stand
for
24
hours),
is
full
layers.
have
cell
nuclei
molecules
a
colourless
shown
the
blood
in
bacteria
process
group
as
nuclei.
they
do
the
and
of
centrifuge
in
blood.
have
cytoplasm
haemoglobin
They
(see
not
look
Figure
have
for
white
that
transporting
when
9.6.1).
separated
Under
haemoglobin
of
oxygen.
or
a
by
microscope
see
them,
stain
has
to
be
added
as
in
the
any
blood
other
of
photograph.
and
is
takes
known
white
blood
One
them
as
group
into
white
vacuoles
phagocytosis
cells
of
makes
where
(see
protein
blood
cells
smear
they
Figure
are
9.7.1).
molecules
searches
digested.
Another
called
antibodies
cells
to
protect
that
us
invade
Platelets
example
transport
dioxide
against
the
are
as
of
and
different
types
of
disease-causing
organisms
body.
tiny
when
substances
fragments
you
cut
listed
ions,
in
of
yourself.
Figure
nutrients,
cells
which
The
9.6.1.
such
as
cause
plasma
Among
glucose
blood
contains
its
to
functions
and
clot,
many
amino
are
for
soluble
the
acids,
carbon
hormones.
platelets
Red
Red
and
white
and
platelets.
blood
blood
cells
transport
oxygen
cells
Red
a
blood
large
to
110
types
have
of
cells
blood
To
This
9.6.2
spun
blood
phagocyte
Figure
main
cells
pigment.
out
lymphocyte
is
into
microscope
blue.
red
three
blood
spinning
blood
cells
blood
separates
thousands
White
blood
cells
blood
many
This
platelets
plasma
cells
surface
absorb
are
disc-shaped
area
oxygen.
compared
with
with
the
their
middle
pushed
volume
and
in.
this
They
helps
have
them
Haemoglobin
have
red
this
enough
blood
is
in
(see
more
Haemoglobin
special
iron
cells
makes
a
type
of
protein
diet
to
make
your
anaemia
space
for
combines
on
page
that
contains
enough
77).
As
iron.
You
haemoglobin
the
cells
have
for
no
must
your
nuclei
haemoglobin.
easily
with
oxygen
in
the
lungs
to
form
oxyhaemoglobin:
haemoglobin
Look
at
the
+
→
oxygen
diagram
oxyhaemoglobin
below:
There
are
5
million
red
blood
cells
like
these
3
in
molecules
an
of
in
the
Oxygen
the
to
diffuses
blood.
the
The
from
oxygen
haemoglobin
in
the
alveoli
attaches
the
red
millimetre
(mm
)
of
blood.
in
lung
the
1
cubic
alveolus
capillaries
oxygen
every
lungs
into
temporarily
cells
making
red
blood
cell
oxyhaemoglobin.
4
The
cells
for
red
blood
return
more
to
the
lungs
oxygen.
haemoglobin
cell
membrane
2
The
carr y
the
red
the
cells
blood
cells
oxygen
which
to
Figure
need
9.6.3
Red
blood
cells
magnied
it.
×2500.
red
blood
cells
3
The
oxygen
leaves
oxyhaemoglobin
out
The
of
the
blood
and
to
just
diffuses
the
oxyhaemoglobin
now
the
cells.
is
haemoglobin
again.
SUMMARY
capillaries
body
cells
in
body
tissues
1
a
List
9.6.4
Transport
of
oxygen
from
the
lungs
to
body
Notice
that
capillaries
•
oxyhaemoglobin
in
the
alveoli
Oxyhaemoglobin
capillaries
in
gives
body
in
forms
the
out
while
blood
ows
found
as
blood
ows
c
through
a
a
the
is
cell
white
white
How
ways
blood
Name
of
tissues.
three
red
from
lungs.
oxygen
plasma.
Give
a
through
2
KEY
chemicals
tissues.
b
•
four
tisses
in
Figure
QUESTIONS
in
which
blood
two
main
blood
the
in
differs
cell.
types
cell.
red
blood
POINTS
cell
adapted
for
oxygen
transport?
1
The
main
components
of
blood
are
plasma,
red
blood
cells,
b
white
visible
blood
under
cells
and
the
light
platelets.
Red
and
white
blood
cells
i
What
microscope.
ii
Where
with
2
Red
blood
cells
contain
haemoglobin
which
combines
is
haemoglobin?
are
does
oxygen
to
form
combine
and
what
with
molecule
oxygen
it
is
formed?
oxyhaemoglobin.
111
9.7
Blood
tnemelppuS
White
LEARNING
how
white
such
as
blood
lymphocytes
them
protect
cells
than
the
red
defend
blood
us
against
cells.
The
disease.
two
There
groups
of
are
far
white
fewer
blood
cells
and
described
phagocytes
from
cells
blood
of
cells
blood
defence
OUTCOMES
White
• Describe
in
in
T
opic
9.6
are
phagocytes
and
lymphocytes
body
disease
Phagocytes
•
State
in
•
the
role
producing
Describe
of
lymphocytes
These
antibodies
the
process
of
are
white
blood
cells
that
ingest
pathogens,
such
as
bacteria.
blood
They
surround
the
pathogens,
ingest
them
and
take
them
into
food
clotting
vacuoles.
The
Then
process
is
they
called
entrapment
food
digest
them
by
using
enzymes
and
this
kills
them.
phagocytosis
of
formation
particle
food
of
vacuole
within
cell
nucleus
tiny
vacuoles
filld
with
food
enzymes
vacuole
cell
membrane
cytoplasm
bacteria
This
image
was
microscope
computer
blood
The
It
image
a
and
then
program.
cells
shows
taken
and
can
white
was
phagocyte
an
with
see
in
ingesting
red
cells.
the
a
ingested
a
two
blood
taken
being
electron
coloured
Y
ou
three
below
with
same
yeast
way.
cell.
digestion
of
enzymes
added
to
bacteria
the
Figure
When
They
Find
9.7.1
A
white
pathogens
can
out
squeeze
about
blood
invade
the
through
tissue
cell
destroys
body,
on
vacuole
bacteria.
phagocytes
capillary
rejection
some
food
move
towards
them.
walls.
page
151.
Lymphocytes
Lymphocytes
enters
not
Like
112
be
the
are
body
there.
a
type
the
white
Lymphocytes
enzymes,
antibodies
Enzymes
have
active
Similarly,
each
type
one
of
type
of
blood
lymphocytes
sites
of
then
are
make
with
combine
has
When
that
proteins
proteins
that
antibody
pathogen.
cell.
recognise
a
it
a
is
called
many
with
bacterium
‘foreign’
binding
site
virus
should
antibodies
different
their
or
and
shapes.
substrates.
that
combines
with
attack
•
they
make
•
they
dissolve
•
they
neutralise
some
There
After
a
you
produce
the
have
their
Blood
again.
in
together
cell
the
a
number
of
ways:
(agglutinate)
membranes
toxins
(poisons)
that
some
pathogens,
such
as
produce.
had
of
pathogens
stick
different
more
body
When
them
bacteria,
is
the
tnemelppuS
Antibodies
type
a
antibody
disease,
the
This
of
such
appropriate
makes
you
as
for
each
measles,
antibodies
immune
to
type
of
pathogen.
lymphocytes
should
that
the
are
ready
pathogen
particular
to
enter
disease.
clotting
you
cut
yourself
you
Like
the
two
white
white
Before
long,
platelets
help
the
thicken
and
the
bleeding
thickened
clot.
blood
Without
has
clotting,
formed
blood
lost
and
pathogens
cell
in
this
of
smear
is
a
is
another
way
would
that
The
skin
the
in
blood
of
is
a
cells.
are
They
small
the
the
is
cut
are
body.
and
blood
blood
However
starts
called
come
there
like
fragments
made
the
in
blood
the
The
fibrinogen.
in
contact
with
a
blood
vessel
is
The
of
the
fibrinogen
threads
make
into
a
threads
net
over
of
Whe
n
they
the
white
fibrin
writi
ng
blood
to
plasma
into
sure
you
use
‘phag
ocyt
es’
are
bres.
which
Red
forms
blood
a
these
The
threads
cells
clot
to
the
get
hardens
to
time
keeps
the
the
skin
cut
heals
a
clean.
and
no t
blood
their
call
cells
’.
Red
blood
cells
get
caught
in
the
net
clot.
scab
and
make
cut.
The
the
New
With
a
blood
clot
skin
dries
clot
to
which
make
a
seals
the
grows
under
the
scab.
POINTS
scab.
scab
1
Figure
falls
when
of
KEY
which
e
trapped
the
make
mak
nam
es
and
do
‘ white
protein
meshwork
make
–
the
2
in
,
desc
ribin
g
the
in
them
brin,
abou
t
cells
platelets
change
insoluble
cell
When
brinogen
the
white
cut.
func
tions
protein
smaller
bone
cells.
damaged,
substances
soluble
larger
blood
When
air
you
release
a
TIP
protein
‘lym
phoc
ytes
’
a
of
leaking
is
scab
marrow
photograph
phagocyte.
disease.
turn
Platelets
these
The
enter
.
platelets
against
110,
stained.
lymphocyte.
STUD
Y
defends
page
a
out
This
on
been
would
1
be
have
stops.
fibrin
The
smear
cells
blood
threads
to
blood
bleed.
9.7.2
Blood
Phagocytes
ingest
pathogens
clotting.
off.
and
digest
them
using
enzymes.
2
SUMMARY
Lymphocytes
that
protect
pathogens
1
a
b
State
where
Explain
how
white
blood
cells
lymphocytes
act
are
to
defend
the
body
from
3
After
a
how
a
disease,
person
can
become
immune
to
an
the
to
like
a
b
Explain,
What
has
had
a
lymphocytes
for
that
more
pathogen
measles.
in
detail,
would
exposed
c
body.
infectious
if
3
the
produce
antibodies
disease
in
person
remain
Explain
antibodies
against
made.
pathogens.
2
make
QUESTIONS
Describe
to
role
happen
the
the
the
air
at
process
if
a
of
a
of
platelets
person’s
in
the
blood
cut?
phagocytosis.
clotting
did
not
of
clot
disease
again.
blood.
when
the
4
This
Platelets
encountered
called
help
brinogen
blood
is
is
to
to
immunity
convert
brin
during
clotting.
113
9.8
Lymph
tnemelppuS
Tissue
LEARNING
Describe
the
exchange
between
tissue
blood
Describe
tissue
the
lymphatic
functions
of
gaps.
the
vessels
lymphatic
and
lymph
uid
the
may
protect
uid.
from
our
disease
immune
Experiments
have
all
able
to
cells
stable
the
cells.
squeeze
stay
in
the
environment
substances
glucose
and
Most
Fluid
but
know
cut
of
is
and
waste
to
White
out
of
blood.
for
diffuse
the
oxygen
found
is
blood
the
cells,
which
capillaries
Tissue
uid
through
‘bathes’
the
and
tissue
of
it
uid
like
then
owing
drains
from
out
of
urea
pass
passes
from
into
tissue
cells.
our
the
uid
Useful
out
back
of
into
plasma
lymphatic
into
cells.
cells
the
and
into
the
blood
back
into
system.
system
produced
white
not
cells
a
the
so
stress,
than
is
circulatory
our
heart
system
beating
–
we
and
videos.
Not
glucose,
all
taken
amino
vitamins,
Our
other
But
feel
circulatory
system
the
beneath
glands
–
the
fluid
and
tonsils
lymphatic
–
these
vessels.
In
are
the
Unit
7,
lymph
page
lower
nodes
85,
leaves
at
the
This
is
a
thin-walled
vessel
that
absorbs
part
of
the
lymphatic
when
veins
system
jaw,
think
you
that
saw
are
a
fat
from
the
lacteal
gut
system.
of
in
the
tissue
one-tenth
of
capillaries.
(e.g.
acids,
ions)
oxygen,
fatty
acids,
uid
it
returns
enters
Once
a
to
plasma
separate
inside
these,
waste
(e.g.
the
products
carbon
metabolites,
in
blood
system
of
tissue
given
dioxide,
excess
capillaries.
capillaries
uid
is
called
called
lymph
out
unwanted
ions)
the
venule
arteriole
capillary
network
back
arteriole
the
rest
enters
lymph
The
blood
our
lymphatic
your
some
9.8.1
see
see
those
nutrients
the
by
another
lymph
of
skin.
obvious.
adenoids
villus.
About
end
feel
and
non-humorous
capillaries
blood
can
signicantly
and
tissue
our
we
humorous
blood
reduced
about
that
in
114
the
form
them.
into
pass
chemicals
constantly
some
ourselves,
connected
Figure
of
to
and
about
watching
watching
walls
systems.
–
had
a
lymphatic
through
more
constituents
capillary
our
we
videos
the
the
KNOW?
We
people
surrounds
are
blood
helps
like
plasma,
The
boost
Red
dioxide
capillaries.
bodies
of
in
nodes
tissue
Laughter
some
gaps
system
Carbon
YOU
that
shape,
providing
substances
DID
tissues,
small
system
Tissue
as
body
through
the
cells
Outline
out
uid
change
these
•
reaches
move
uid
can
•
uid
capillaries
the
and
uid
of
plasma
materials
tissue
OUTCOMES
When
•
and
formation
of
tissue
uid
and
vessel
lymph.
of
the
the
tissue
lymph
fluid
capillaries
tissue
into
fluid
the
passes
capillaries
but
capillaries
will
lymph
not
the
vessels.
thin-walled
ows
let
in
and
one
have
tiny
lymph
These
valves
pass
have
contain
a
that
out
allow
again.
structure
semi-lunar
the
They
similar
valves
to
tissue
join
to
uid
up
to
veins;
make
sure
to
tnemelppuS
Lymph
enter
form
they
are
lymph
direction.
The
lymphatic
The
contraction
system
of
has
no
pump
surrounding
so
the
muscles
ow
helps
of
to
lymph
make
it
is
slow.
ow.
STUD
Y
right
into
lymphatic
the
right
duct
empties
subclavian
left
vein
TIP
subclavian
vein
Plas
ma,
lym
ph
that
tissu
e
are
are
very
compo
sitio
n,
in
the
the
thoracic
duct
out
differ
ent
body
.
text
uid
three
uids
simila
r
but
Read
e
they
in
occu
r
places
in
throug
h
carefu
lly
wher
and
to
are
nd
and
remem
ber!
lymphatic
from
of
lymph
Figure
Lymph
join
9.8.2
to
subclavian
the
blood
lymphatic
from
form
the
two
veins,
before
lacteals
small
in
villi
intestine
nodes
The
ows
up
vessels
system.
tissues
large
under
joining
to
lymph
the
the
the
heart.
vessels
collar
vena
The
which
bones.
cava
smaller
empty
Here
just
the
before
lymph
into
lymph
it
vessels
the
mixes
enters
the
with
heart.
KEY
At
intervals
along
the
length
of
the
lymph
vessels
are
lymph
1
There
are
many
lymphocytes
in
the
nodes
and
during
an
POINTS
nodes.
When
tissue
lymph
they
multiply
by
cell
division
and
make
antibodies.
Some
uid
enters
the
infection
capillaries
it
is
termed
leave
lymph
lymph
nodes
patrolling
an
and
for
important
circulate
fresh
part
around
invasions
of
the
of
body’s
the
body
pathogens.
immune
in
the
The
blood,
constantly
lymphatic
system
is
2
system.
Lymph
and
has
SUMMARY
QUESTIONS
a
What
is
tissue
uid
no
large
3
1
and
what
are
its
The
consists
white
red
What
is
lymph
and
what
are
its
Explain,
in
as
much
detail
as
you
slow
and
how
the
circulation
can,
is
What
main
are
lymph
function?
nodes,
where
are
proteins.
lymphatic
why
the
ow
of
lymph
system
circulation
has
a
which
lymph
to
the
blood.
is
Lymphocytes
are
in
lymph
maintained.
nodes
3
but
or
functions?
4
so
cells
functions?
returns
2
plasma
cells,
blood
plasma
separate
b
of
blood
they
found
and
what
is
their
during
where
an
produce
they
multiply
infection
and
antibodies.
115
PRACTICE
1
Which
the
QUESTIONS
chamber
of
the
heart
pumps
blood
into
4
Which
row
shows
components
aorta?
A
left
atrium
B
left
ventricle
of
the
the
correct
functions
of
the
blood?
red
plasma
blood
platelets
cells
C
right
atrium
D
right
ventricle
antibody
oxygen
formation
transport
A
(Paper
1)
clotting
[1]
B
2
The
plan
system.
diagram
Which
is
shows
the
the
human
pulmonary
antibody
oxygen
formation
transport
clotting
circulatory
transport
artery?
of
oxygen
C
clotting
ions
transport
A
head
and
oxygen
antibody
fore-limbs
D
clotting
transport
(Paper
formation
1)
[1]
D
5
In
a
single
through
circulation
the
circulation
C
leaves
the
heart
of
the
of
once
body.
a
sh,
the
during
What
a
blood
ows
complete
type
of
blood
heart?
B
lower
and
A
deoxygenated
blood
at
high
B
deoxygenated
blood
at
low
C
oxygenated
blood
at
high
D
oxygenated
blood
at
low
pressure
pressure
pressure
pressure
body
hind
limbs
(Paper
2)
[1]
Key
oxygenated
deoxygenated
3
(Paper
1)
Which
is
owing
A
B
6
blood
blood
blood
the
correct
body
→
the
vena
pathway
human
cava
taken
ventricle
→
lungs
left
ventricle
→
aorta
cava
lungs
→
→
atrium
right
body
(Paper
1)
arteries
to
veins
B
arteries
to
capillaries
that
transport
C
capillaries
to
veins
left
D
capillaries
to
venules
system?
atrium
→
(Paper
right
→
body
2)
pulmonary
→
left
ventricle
→
right
artery
ventricle
→
[1]
→
Blood
capillaries
are
exchange
vessels.
They
atrium
aorta
→
→
→
the
exchange
of
substances
between:
left
A
cells
and
lymph
B
plasma
and
lymph
C
plasma
and
tissue
D
lymph
aorta
lungs
→
uid
atrium
and
tissue
uid
[1]
(Paper
116
vessels
A
permit
D
blood
blood
circulatory
→
left
by
7
C
are
from:
[1]
through
vena
Arterioles
2)
[1]
8
Prevention
of
coronary
heart
disease
may
11
The
diagram
shows
the
heart.
involve:
A
A
angioplasty
B
eating
C
putting
D
taking
B
(Paper
9
This
saturated
stents
more
into
fats
coronary
arteries
exercise
C
2)
is
seen
more
a
[1]
drawing
with
a
light
made
of
a
blood
smear
as
microscope.
E
F
H
D
(a)
(i)
Name
(ii)
Give
A
to
the
E.
[5]
letters
from
the
diagram
that
G
indicate
(a)
(i)
Name
(ii)
State
the
the
cells
F,
G
functions
and
of
H.
the
oxygenated
[3]
cells
F
to
(b)
H
The
magnication
×1100.
(c)
Calculate
Show
your
Some
blood
separate
of
the
the
drawing
diameter
(c)
is
of
cell
was
the
in
a
components.
centrifuge
The
to
(Paper
the
why
lower
rest
of
vessels
contain
blood.
happens
capillaries
blood
[1]
to
in
blood
the
owing
pressure
the
that
than
as
it
ows
lungs.
to
the
blood
[4]
lungs
owing
body.
is
to
[3]
3)
(a)
Copy
and
complete
the
table
to
compare
results.
arteries,
(i)
what
the
blood
diagram
12
shows
a
the
[2]
spun
Explain
at
H.
working.
Describe
through
[3]
(b)
the
Identify
the
veins
and
capillaries.
cells
J
that
would
found
in
feature
be
regions
arteries
veins
capillaries
K
relative
and
L.
Give
reasons
thickness
for
your
answer.
[3]
of
(ii)
Name
the
uid
at
thin
very
thin
some
none
K
wall
J
muscle
and
describe
its
role
tissue
in
the
body.
L
[5]
elastic
some
(Paper
10
3)
tissue
T
aking
the
health
of
pulse
is
one
way
to
monitor
direction
the
heart
the
of
heart.
to
arteries
to
blood
organs
veins
ow
(a)
What
is
(b)
Describe
during
the
pulse?
what
and
[2]
happens
after
to
the
pulse
exercise.
rate
[5]
[4]
(b)
(c)
State
of
two
the
other
heart
can
ways
be
in
which
monitored
the
health
helps
3)
it
how
to
the
carry
structure
out
its
of
an
artery
function.
[3]
[2]
(c)
(Paper
Explain
Describe
muscle
(Paper
how
cells
substances
by
are
capillaries.
provided
to
[4]
4)
117
10
Diseases
10.1
and
immunity
Disease
Pathogens
LEARNING
that
•
Dene
and
the
terms
Describe
cause
disease
how
pathogens
are
spread
from
person
that
The
Outline
the
against
disease
body’s
humans
cause
fungi,
protoctists
transmissible
or
are
disease.
transmitted,
bacteria
and
diseases
from
one
and
Most
of
worms.
because
person
viruses.
the
organisms
The
the
to
Other
diseases
that
pathogens
another.
They
they
are
are
also
infectious
diseases.
to
person
•
are
in
can
called
be
organisms
disease
pathogens
pathogen
transmissible
cause
passed,
•
are
OUTCOMES
table
shows
different
ways
in
which
diseases
are
transmitted.
defences
method
examples
of
of
description
diseases
transmission
pathogens
are
in
tiny
droplets
inuenza,
of
through
the
liquid
from
the
airways
and
air
tuberculosis,
lungs
of
infected
people
(see
common
photo
people
not
preparing
wash
contaminated
are
food
human
not
their
food
hands;
cooked
do
foods
properly;
cholera,
and
drink
water
direct
contact
faeces
supplies;
insect
uninfected
people
people,
infected
people
the
e.g.
droplets
her
of
nose
she
is
water
and
using
a
are
bodies
touch
or
items,
have
of
an
that
athlete’s
foot
used
feed
infected
malaria,
dengue
vectors
and
then
feed
on
an
fever
person
handkerchief,
containing
mouth
transfer
mosquitoes,
blood
uninfected
though
their
infected
person
Even
ies
on
insects,
typhoid
contaminate
pathogens
on
cold
opposite)
pathogens
entering
the
blood
from
air
and
from
person
an
enters
infected
the
blood
of
HIV/AIDS,
may
be
inhaled
by
others.
body
uids
an
uninfected
person,
an
unsterilised
e.g.
in
hepatitis
between
drug
pathogens
sexual
activity
person
blood,
Defences
We
have
prevents
three
These
houseies
may
have
picked
up
third
their
and
bodies
human
them
118
to
while
wastes
uncooked
feeding
and
are
meat.
on
bacteria
now
rubbish
transferring
that
line
pathogens.
on
different
pathogens
pathogens
The
against
to
break
pass
semen
shared
addicts
from
sexual
or
infected
HIV/AIDS,
partner
in
specic
vaginal
uid
(NSU),
non-
urethritis
chlamydia
disease
lines
entering
of
defence
the
through
produces
needle
body;
the
antibodies
rst
that
against
the
line
disease.
second
and
defend
line
enters
us
The
rst
destroys
the
against
line
any
blood.
specic
Barriers
to
infection
STUD
Y
The
defences
chemical
we
have
against
entry
of
pathogens
are
mechanical
barriers.
Y
ou
Mechanical
The
•
The
dead
barriers:
outer
layers
of
the
skin
form
a
barrier
to
entry
(see
T
opic
in
the
nose
trap
larger
particles
that
you
breathe
are
The
•
Topic
Cells
that
small
from
The
If
dust
is
a
Blood
White
enter
and
The
are
is
and
and
know
diseas
es
show
n
in
How
ever
,
you
in
the
acid
that
kills
pathogens
in
up
(trachea
and
bronchi)
microorganisms.
to
swallowed
the
and
throat
any
by
The
cilia
make
mucus
(see
pathogens
are
mucus
is
Topic
moved
easier
me th
ods
food
that
it
you
fo r
traps
of
may
learn
the
tran
smis
sion
learn
each
to
an
exam
ple
one.
away
11.3).
destroyed
by
acid.
get
second
through
line
of
these
barriers
to
enter
the
blood,
then
defence.
defences
blood
the
cells
body’s
viruses
into
process
white
during
airways
particles
pathogens
there
hydrochloric
if
the
lungs
mucus
any
makes
7.7).
line
the
stomach
to
barriers:
stomach
(see
the
tran
smitt
ed
ways
nd
•
have
of
in.
table.
Chemical
no t
14.8)
the
hairs
do
exam
ples
that
•
TIP
and
of
a
line
or
vacuoles
of
the
cells
infection
which
by
defence
blood.
where
phagocytosis
blood
an
form
tissues
they
is
against
are
digested
described
produce
pathogens
any
Phagocytes
in
and
T
opic
antibodies.
they
produce
pathogens
engulf
that
bacteria
destroyed.
9.7.
Lymphocytes
When
activated
antibodies
which
are
All
proteins
that
have
a
variety
of
effects,
such
as
stopping
outdoor
activities
involve
some
risk
of
pathogens
infection.
moving
engulf
through
them.
antibodies
the
body
Vaccination
and
give
and
is
a
making
way
long-term
to
it
easier
make
protection
for
phagocytes
lymphocytes
against
to
produce
certain
KEY
POINTS
diseases.
1
A
pathogen
causing
SUMMARY
Copy
and
complete
the
Pathogens
from
following:
one
through
Pathogens
are
that
cause
disease.
Human
diseases
by
bacteria,
and
.
The
airways
have
that
make
to
trap
kills
.
any
pathogens
form
in
The
pathogens
stomach
that
the
a
.
barrier
lining
enter
the
Dead
to
cells
makes
on
the
Explain
why
you
always
b
never
c
always
d
use
e
never
wash
share
and
your
hands
towel
your
surface
of
the
3
The
are
pathogens.
before
with
hands
handling
skin
and
of
Explain
how
dog
the
and
vectors
in
the
barriers
nose
to
pathogens.
Mucus
in
acid
the
in
lick
climber
in
airways
stomach
and
are
someone
after
when
your
the
going
to
the
barriers.
toilet
Phagocytes
are
white
blood
sneezing
face
that
digest
engulf
them;
antibodies
3
hairs
mechanical
cells
a
food
animal
food
5
handkerchief
let
by
mosquitoes).
chemical
a
droplets,
in
should:
a
wash
in
contact,
which
4
a
air
transmitted
another
body
entry
2
be
to
cells
(e.g.
people
can
host
the
direct
water
when
disease-
are
by
caused
a
QUESTIONS
2
1
is
organism.
the
photograph
is
at
risk
of
to
pathogens
lymphocytes
attack
and
make
pathogens
infection.
that
enter
the
blood.
119
10.2
Defence
tnemelppuS
If
LEARNING
pathogens
Explain
has
that
each
antigens,
own
specic
pathogen
each
with
Explain
that
specic
is
their
provided
antibodies
shapes
that
to
have
by
the
our
help
the
blood
mechanical
and
chemical
may
and
destroy
in
order
antibodies
to
engulf
defences,
nd
and
produced
by
engulf
them.
Many
are
the
shapes
of
these
have
are
chemicals
made
lymphocytes
respond
the
on
Describe
how
antigens
are
help
lymphocytes.
the
of
by
on
their
protein.
making
surface
of
surface
When
you
antibodies,
the
called
antigens.
catch
which
a
disease
can
‘lock
your
on’
to
pathogens.
They
active
cause
for
Some
This
STUD
Y
•
TIP
no t
becom
e
be tw
een
is
a
all
begin
Unit.
helps
Bacteria
prod
uce
secre
ted
help
are
‘anti-’
antibody
molecules
attack
•
such
as
group
stick
together
to
nd
agella
can
them
in
a
and
to
to
group.
engulf
that
This
much
them.
that
the
to
and
blood.
combine
them
move
and
stop
Each
have
pro te
ins
that
destro
y
If
Antito
xins
that
type
shapes.
a
mak
e
a
is
walls.
kill
bacteria
This
causing
the
you
of
The
3
shape
have
that
an
and
and
healthy
antigens
diphtheria
with
cells
the
by
cell
the
‘punching’
to
burst.
its
own
walls
so
on
bind
receptors
on
ts
a
If
again,
to
toxins
through
enters
by
you
Lymphocytes
week
strain
will
are
or
which
against
antigen.
have
each
The
specic
type
of
antibody
antigen
has
a
shape
as
the
common
symptoms.
two
you
of
the
virus
not
get
the
responsible
for
will
that
same
this
You
be
cold,
will
back
causes
you
then
to
the
are
be
your
to
You
will
activated
ill
for
feel
normal,
common
symptoms.
and
will
begin
cold
not
be
during
an
response
virus
are
large
4
lymphocytes
born
with
number
of
a
very
different
lymphocytes
are
activated
and
types
5
divide
active
secrete
of
lymphocytes.
lymphocytes
antibodies
These
to
6
to
antibodies
virus
are
different
the
specic
antigens
surfaces
of
of
bacteria,
particles
throughout
particles
bind
cells
the
body
viruses
and
other
throughout
pathogens.
body
pathogen
When
invades,
lymphocytes
antibodies
person
10.2.1
so
to
virus
the
are
antigen.
such
of
antigens
made
the
the
variety
a
the
are
around
infection,
have
within
self.
has
that
specific
inhaled
spread
the
moving.
release
holes
water
You
particles
virus
them
harmless.
directly
weakens
pathogen
antibodies
complementary
while
better
harm
less.
2
through
Antitoxins
immune
Figure
it
that
ill.
measles
makes
bacteria.
tetanus
into
making
use
agella
these
cause
antibodies
and
they
the
destroy
substances)
of
them
which
attach
those
antibodies
cells
osmosis
lym
phoc
ytes
antib
odies
Some
their
lym
phoc
ytes
to
have
(poisonous
special
invades
particles
pathogens.
in
antig
en
are
by
path
ogen
s.
toxins
which
wo rd
s
antib
odies
.
Antib
odies
that
to
phagocytes
neutralising
with
chem
ical
a
conf
used
the
An
stim
ulates
to
in
phagocytes
Antibodies
toxins
this
bacteria
bacteria
body.
that
ways
immunity
•
Do
several
pathogens
easier
Dene
120
That
antibodies
•
1
However
,
pathogens.
antigens
destroy
•
need
pathogens
There
•
in
shapes
complementary
of
phagocytes
phagocytes
All
•
through
disease
OUTCOMES
then
•
get
against
Active
immunity
–
the
body’s
response
to
a
measles
infection.
help
recover
divide
to
of
same
some
respond
make
more
the
the
a
type.
and
cells
of
these
lymphocytes
become
bigger
and
ll
many
ribosomes
lymphocytes
which
are
attached
to
a
very
extensive
network
of
endoplasmic
secreted
into
antigens
and
reticulum.
The
antibody
molecules
are
blood
and
on
release
recognise
bacteria
specific
lymph
antibodies
to
be
the
distributed
specic
Other
throughout
antigens
lymphocytes
on
are
the
the
body.
The
pathogens
activated
to
antibodies
that
have
‘lock
invaded
patrol
the
body
infected
cell
they
on’
the
looking
to
body.
for
antibodies
infected
cells.
When
they
nd
an
destroy
it
to
stop
attach
to
it
antigens
on
bacteria
molecules
producing
is
that
much
The
it
more
pathogens.
destroys
of
our
the
body’s
defence
response
to
the
The
HIV
lymphocytes
against
rst
reason
infectious
infection
is
is
such
that
are
diseases
very
slow.
a
serious
infection
responsible
(see
This
Topic
is
why
for
16.14).
you
have
phagocytes
fallen
is
ill.
much
The
response
faster;
so
fast
to
the
that
second
you
are
infection
unlikely
to
by
the
have
same
any
pathogen
attracted
bacteria
symptoms.
engulf
This
process
of
def en ce
again st
th e
pa thog en
by
small
a ntibo dy
is
catching
a
gain
type
this
During
an
called
active
transmissible
of
immunity .
disease
an d
Becoming
being
ill
is
a
immune
na tur a l
enzymes
a f ter
way
to
bacteria
within
immu nity.
immune
response,
many
lymphocytes
of
the
specic
types
Many
of
these
cells
develop
into
antibody-producing
cells,
do
not.
These
other
cells
remain
in
the
blood
and
the
10.2.2
circulating
respond
throughout
whenever
there
the
same
antigens.
the
same
way
response
to
produced
body
antibodies.
faster
and
are
far
The
store
in
the
more
cells
do
more
body
,
so
to
any
These
invasion
not
the
next
with
a
same
memory
of
a
ability
cells
of
the
infection
easier
secrete
for
ingest
bacteria
and
destroy
phagocytes
them.
in
immune
lymphocytes
is
it
with
antigen
each
pathogen
to
make
which
pathogen
During
these
time
the
subsequent
memory
the
brain.
more
that
are
by
have
in
and
lymphocytes
response
much
body
.
memories
antigens,
remain
the
another
Memory
we
specic
to
there
that
is
Lymphocytes
that
lymphatic
to
system
digested
vacuoles
but
antibodies
some
are
food
are
Figure
produced.
and
them
vacuoles
contain
production
are
towards
are
invades
produce
the
therefore
the
right
much
greater
.
KEY
1
POINTS
Antibodies
‘lock
onto’
Vaccination
antigens
It
is
This
possible
is
done
to
by
promote
injecting
active
a
immunity
vaccine
that
without
contains
having
live
to
be
ill.
pathogens,
or
antigens
taken
from
the
surface
of
pathogens.
Each
pathogen
stimulates
immunity
to
a
specic
disease,
such
as
and
mumps.
In
some
cases,
the
vaccine
provides
a
vaccines.
specic
strain
Vaccination
is
of
an
that
disease
articial
as
way
is
to
the
gain
case
with
active
which
specic
Explain
3
Active
what
is
antigen
active
meant
4
by:
a
Memory
b
antibody
c
a
immunity
Outline
how
e
memory
someone
transmissible
b
Explain
Describe
the
rst
shapes
is
a
pathogen
defence
by
antibody
why
how
becomes
naturally
immune
to
a
and
response.
body
.
remain
lymph
in
after
the
response
to
an
provide
much
faster
to
and
greater
subsequent
infections.
vaccination
second
the
cells
response
disease.
the
in
cells
is
a
form
of
active
immunity.
5
3
the
antitoxin
a
2
t
immunity
immune
d
own
specic
QUESTIONS
blood
a
its
have
antibodies.
production
1
has
inuenza
immunity.
against
SUMMARY
which
protection
of
against
the
measles,
shapes
rubella
to
pathogens.
Each
antigens
vaccine
of
dead
2
pathogens
leading
destruction
response
to
an
antigen
differs
from
Active
after
immunity
an
is
infection
pathogen
or
by
gained
by
a
vaccination.
121
tnemelppuS
Many
10.3
Aspects
tnemelppuS
So
LEARNING
far
we
Dene
•
Explain
passive
during
During
immunity
an
stimulate
that
passive
a
short-term
using
another
an
defence
immune
the
passive
immunity
importance
of
the
to
Type
how
a
immune
1
to
of
immunity
pathogen
response
follows
that
and
vaccination.
enters
the
body
antigens
of
which
involving
the
production
secrete
antibodies
and
of
others
many
which
cells.
immunity
protection
is
required
in
a
hurry,
then
antibodies
may
be
given
by
breast-
This
provides
only
temporary
immunity,
but
should
be
sufcient
give
system
leads
Antibodies
giving
diabetes
the
symptoms
of
Type
1
a
TIP
not
cross
to
lym
phocyt
es
the
the
later
milk
.
the
antib
odies
mothe
r
.
It
baby
imm
une
develo
ped
and
to
fe tus
and
the
so
is
babies
can
which
placenta
against
will
baby’s
rst
are
cause
vaccination
them.
much
immunity
way
and
are
diseases
have
body
The
safer
usually
deaths
lasts
is
passive
present
that
immunity
treats
the
immunity
than
active
immune
of
until
against
immunity
are
at
wounds.
as
soon
immunity
are
in
in
breast
the
against.
milk,
so
environment
This
mother’s
is
also
antibodies
to
these
time
gained
without
immunity.
tetanus
children.
the
is
as
The
Amongst
and
they
other
measles,
protection
when
exposure
both
gained
should
from
receive
their
diseases.
used
when
In
tetanus
people
these
cases,
possible
that
can
to
bacteria
are
involved
health
workers
neutralise
cause
entering
muscle
the
the
in
will
toxins
body
nasty
accidents
inject
through
tetanus
produced
by
open
antibodies
these
paralysis.
venom
from
snakes
and
other
animals,
such
as
spiders
and
has
acts
far
too
quickly
for
active
immunity
to
be
of
any
use.
own
People
can
is
of
until
The
its
risk
as
bacteria
wait
system
before
the
destroys
of
scorpions,
lym
phocyt
es
this
in
‘borr
ow ’
from
has
in
placen
ta
T
he
baby
the
mother
as
diseases,
and
breast
his/her
antigens,
Passive
pass
across
protection
temporary
passive
mothe
r ’s
gained
diabetes
to
T
he
pass
baby
which
foreign
STUD
Y
Immunity
and
only
treatment
protection.
malfunction
and
Outline
the
type
that
of
to
or
the
or
babies
Describe
do
some
memory
injection.
•
immunity,
infection
from
If
•
the
an
person
Explain
fed
active
of
against
antibodies
Passive
•
at
course
immunity
become
disease
the
infection
lymphocytes,
is
looked
immunity
OUTCOMES
occurs
•
have
of
produ
ce
who
injection
of
have
been
antivenom
bitten
by
quickly.
the
venomous
Antivenom
animals
contains
need
an
antibodies
to
the
antib
odies
.
molecules
these
prompts
the
of
an
blood,
people
No
in
are
at
risk
cells
immunity
is
is
in
Sometimes
are
–
of
one
many
the
antibodies
infectious
122
advantages
most
to
of
important
protect
diseases.
the
is
baby
and
made
being
the
body
but
of
by
in
it
they
the
is
collect
horses
to
and
to
the
from
sheep.
This
collected
in
areas
from
where
animals.
instantaneous.
antigens
are
immunity,
available
venom
or
hospitals
venomous
passive
are
into
antibodies
available
bitten
produced
arrival
active
the
and
companies
quantities
response
are
the
Malfunction
There
of
Specialist
small
short-term,
enter
between
there
inject
immune
memory
wait
venom.
and
processed
antibodies
as
the
animals
be
so
As
this
soon
used.
production
type
as
the
There
of
is
no
antibodies
immunity.
of
the
immune
immune
system
does
system
not
work
perfectly.
When
this
breast-feeding
happens
it
prompts
an
detects
our
own
antigens
as
something
foreign
and
this
providing
immune
response.
As
a
result
tissues
mistake.
against
and
destroys
healthy
by
the
immune
system
attacks
are
of
collectively
these
and
T
ype
1
1
immune
known
diseases:
Type
the
as
system
cause
autoimmune
examples
are
a
variety
diseases.
rheumatoid
arthritis,
of
diseases
There
are
multiple
tnemelppuS
Malfunctions
that
many
of
sclerosis
diabetes.
diabetes
This
type
and
destroys
happens
of
diabetes
the
rapidly
is
cells
and
caused
of
the
often
when
the
pancreas
before
immune
that
the
age
make
of
system
insulin.
attacks
This
usually
20.
Milking
Insulin
helps
to
control
the
concentration
of
glucose
in
the
The
It
is
made
in
response
to
an
increase
in
the
glucose
the
concentration
venom
blood
usually
while
a
meal
is
being
absorbed.
Insulin
liver
This
needed
The
•
cells
loss
–
due
lowers
tiredness
One
to
of
–
to
store
glucose
is
release
Type
cells
1
use
glucose
not
stored
energy
in
diabetes
protein
as
glycogen
for
times
(see
when
Topic
it
to
the
its
due
provide
increased
water
to
antibodies
will
bites
of
this
snake.
antigen
to
give
protection
to
species
of
against
snake.
respiration.
are:
and
fat
instead
of
glucose
as
sources
of
concentration
of
glucose
in
the
blood
of
glycogen
between
diabetes
is
that
can
be
converted
to
glucose
meals.
the
presence
of
glucose
in
the
urine.
with
diabetes
are
treated
with
regular
injections
of
people
drug
is
manufactured
using
techniques
of
genetic
Topic
diabetics
20.4)
can
SUMMARY
What
is
and
many
control
their
different
blood
types
glucose
are
with
programmable
insulin.
diabetes
pumps
into
to
body
use
deliver
fat
insulin
through
a
tube
engineering
known
2
an
14.7).
continuously
1
dangerous
be
Many
(see
a
as
potential
lack
energy
indicator
People
The
from
used
energy
thirst
to
muscles
that
symptoms
that
•
by
weight
of
•
and
means
be
stimulates
the
the
will
in
produce
the
venom
blood.
available
so
concentrations
as
a
catheter.
that
efciently.
QUESTIONS
meant
a
passive
a
Use
b
Explain
an
by
the
immunity
example
why
b
to
your
following
Type
explain
terms?
1
the
example
is
diabetes
advantages
only
a
of
passive
short-term
immunity
.
form
of
immunity.
3
a
Explain
Type
1
the
cause
and
describe
the
symptoms
of
diabetes.
Figure
b
Suggest
why
insulin
has
to
be
injected
or
delivered
10.3.1
Human
cells
catheter
KEY
1
not
taken
orally
(by
made
mouth).
genetically
by
make
this
modied
human
to
protein.
POINTS
Passive
immunity
against
another
2
and
insulin
by
No
is
pathogens
a
short-term
using
defence
antibodies
3
from
milk.
individual.
memory
immunity.
cells
are
Antibodies
its
produced
in
passive
4
These
mother
T
ype
cross
1
release
protect
has
had
diabetes
destroying
the
cells
insulin
is
in
to
placenta
a
baby
or
the
against
been
caused
and
by
in
the
the
blood
against.
immune
that
breast
diseases
vaccinated
pancreas
control
are
system
make
and
glucose.
123
10.4
Controlling
of
•
Explain
good
food
spread
of
tnemelppuS
Explain
in
in
Personal
hygiene
infectious
diseases.
hygiene,
and
proper
•
sewage
preventing
the
role
controlling
important
in
preventing
the
spread
of
some
•
of
all
urinate
Hair
ages
or
should
should
defecate
be
wash
and
washed
also
with
their
hands
before
after
handling
shampoos
to
going
or
to
the
eating
prevent
toilet
food.
dandruff
and
headlice.
of
the
People
to
disease
the
is
of
preparation,
disposal
treatment
•
importance
personal
waste
infection
OUTCOMES
the
hygienic
spread
disease
Preventing
LEARNING
the
vaccination
spread
•
Everyone
•
Dental
should
wash
themselves
frequently,
especially
in
hot
weather
.
of
hygiene
is
most
important
in
ghting
dental
caries
disease
(see
•
Topic
Cuts
and
applied
bruises
to
Hygienic
•
Food
•
Kitchen
•
Food
as
•
should
Water
is
important
the
hands
spread
that
with
of
everyone
soap
and
learns
water
to
to
Proper
•
Household
•
be
keep
ies
cleaned
plasters
away.
with
thoroughly
going
to
disinfectants
make
sure
to
any
kill
bacteria.
bacteria,
such
be
to
be
eaten
cold
should
be
kept
separate
meat.
and/or
water
drinking
purication
should
tablets
if
be
it
boiled
comes
or
from
contaminated.
attract
Toilet
often
by
found
bacteria,
to
be
such
•
safe
to
eat
if
it
a
buried
and
may
houses
health
in
into
and
covered
bins
businesses
hazard.
properly
tips
ies
also
put
and
collected
at
contain
should
regulated
where
which
It
it
is
not
spread
harmful
should
be
landll
buried
disease.
sites.
disposed
Putting
carefully
The
chemicals
be
recycled,
means
efuent
that
it
from
cause
pollution.
treatment
is
a
serious
drainage
wastes
pathogens
pipes
are
works
health
to
broken
(see
that
a
down
Topic
cause
hazard
sewage
by
if
it
is
not
treatment
disposed
properly
works.
microorganisms
in
sewage
21.8).
typhoid
and
cholera
are
transmitted
as
faeces
and
transmitted
is
contaminated
thoroughly.
from
not
be
weekly.
rubbish
rats
tips
through
is
is
or
waste
Human
The
it
onto
treatment
is
should
e.g.
collected
through
•
waste
so
Sewage
124
and
disposal
correctly
rubbish
cooked
is
might
Garbage
will
It
antiseptic
killed.
cooking
intervals,
garbage
Salmonella.
to
especially
waste
incinerated
meat
an
disease.
regular
contaminated
cooked
adding
that
with
wash
prevent
•
Chicken
should
that
for
by
washed
preparation
are
food,
used
be
covered
be
food
raw
sources
their
be
surfaces
Cooked
should
wounds.
food
should
sterilised
It
open
Salmonella,
from
•
7.6).
with
raw
sewage.
to
people
who
drink
food
or
water
•
Thorough
and
sewage
cholera
so
treatment
these
breaks
diseases
are
the
transmission
unknown
in
of
typhoid
countries
with
proper
sanitation.
tnemelppuS
The
role
of
Vaccination
protection
children
and
Many
e.g.
it
of
the
was
programmes
offered
are
were
vaccination
by
these
last
declared
interrupted.
against
for
diseases
case
of
the
important
are
ill
now
in
still
of
in
polio
exists
in
the
used
and
rare
of
citizens.
that
Americas
transmission
part
their
health
very
the
disease
to
diseases
much
polio
that
But
an
governments
vaccinated
responsible
are
many
be
and
very
common
deaths.
parts
was
in
had
been
other
Infants
to
many
health
1991,
of
the
and
in
world,
1994
successfully
regions
of
the
world
Household
and
could
be
introduced
into
the
Americas
by
travellers.
In
in
there
were
countries
can
follow
whole
93
because
are
small
transmit
people
into
vaccines
DID
of
campaign
online
to
for
vaccination
give
active
coming
Careful
all
with
2015);
vaccines,
around
infectious
into
them
people
infected
in
neighbouring
and
the
is
used
in
immunity
they
Kenya.
polio
to
bins
overowing
from
substance
health
and
be
as
many
enters
to
SUMMARY
a
health
hazard.
and
can
neighbourhood
HIV
,
For
some
Ebola
disease
will
limited
who
dengue
not
identies
be
diseases
and
Mass
may
there
or
have
are
no
fever
.
as
100
million
different
lymphocytes
that
the
destroy
body,
there
will
be
a
lymphocyte
with
the
against
teach
it
is
Quetta,
Pakistan
right
1
important
children
POINTS
The
spread
to
wash
to:
waste
into
is
personal
their
food
hands
covered
of
transmissible
prevented
hygiene,
preparation,
waste
food
in
it.
QUESTIONS
why
polio
2014.
diseases
Suggest
put
becoming
protected
the
workers
spread
ways.
KEY
b
kept
before
the
in
a
be
You
Vaccination
1
should
collected
KNOW?
may
specicity
and
everyone.
be
with
immunity
their
two
can
contact
by
and
people.
are
in
eradicate
but
have
surveillance
diseases
examples
to
more
Somalia
covered
‘polioeradication’.
of
them
with
Africa,
to
people
contact
(as
Pakistan
West
respond
disease.
have
the
attempt
vaccinating
YOU
There
not
most
the
by
do
in
of
programmes
chances
who
stopped
come
as
of
searching
schemes
the
polio
parts
progress
by
people
of
Syria,
eradication
vaccination
Some
in
the
world
During
cases
and
garbage
2013,
disposal
by
good
hygienic
proper
and
sewage
bins
c
connect
d
cook
toilets
to
the
main
drainage
system
2
chicken
Vaccination
tnemelppuS
used
2
The
Americas
children
were
declared
throughout
the
free
of
Americas
polio
in
receive
1994.
polio
Why
do
Why
is
offered
it
important
by
their
that
everyone
country’s
health
receives
service?
the
to
prevent
transmissible
the
are
spread
of
diseases.
vaccinations?
3
3
programmes
thoroughly
vaccinations
Many
diseases
effectively
by
vaccination
are
controlled
mass
of
children.
125
tnemelppuS
treatment.
PRACTICE
1
A
QUESTIONS
pathogen
A
feeds
is
on
an
organism
dead
B
lives
in
an
C
lives
inside
and
decaying
organism
6
that:
and
A
organisms
causes
During
host
organism
harm
make
all
lymphocytes
spreads
disease
organisms
specic
phagocytes
divide
antibodies
disease
divide
to
produce
cells
that
without
C
D
response:
and
to
make
causing
immune
lymphocytes
B
a
an
from
infected
antibodies
phagocytes
engulf
and
completely
digest
to
bacteria
uninfected
people
D
(Paper
1)
specic
that
2
Which
is
a
transmissible
cholera
B
coronary
B
rickets
D
scurvy
7
heart
make
Which
Passive
[1]
immunity
A
being
bitten
B
being
treated
barrier
to
cholera
of
B
skin
C
stomach
infection
is
most
effective
D
phagocytosis
is
gained
by:
a
venomous
snake
antibodies
to
the
injecting
snake
The
in
a
quantity
of
antivenom
snake
with
venom
antibodies
horse
2)
[1]
second
the
rst
A
[1]
immune
measles
invasion
the
response
people
long-term
transmissible
is
virus
many
much
concentration
measles
gives
small
to
an
invasion
acid
1)
hand
venom
spider
D
by
A
snake
with
a
produced
8
against
a
by
injecting
bacteria?
mucus
Which
to
C
(Paper
4
cells
[1]
A
(Paper
produce
disease
1)
against
to
2)
venom
3
divide
antibodies
disease?
(Paper
A
(Paper
lymphocytes
[1]
remains
months
faster
of
antibodies
high
after
the
because:
from
the
specic
rst
to
response
protection
B
lymphocytes
respond
C
lymphocytes
specic
faster
with
age
diseases?
to
other
viruses
washing
B
garbage
C
sewage
D
vaccination
respond
as
well
memory
cells
collection
D
are
present
in
the
blood
and
treatment
lymph
(Paper
(Paper
1)
9
5
An
antigen
2)
[1]
[1]
is:
Some
that
A
a
disease-causing
B
a
molecule
and
organism
produced
by
a
(a)
lymphocyte
microorganisms,
cause
cause
State
cholera,
such
enter
as
the
the
body
bacteria
in
our
food
disease.
the
term
given
to
a
disease-causing
organism.
C
any
substance
that
stimulates
an
[1]
immune
(b)
response
State
two
ways
contaminated
D
a
which
food
can
become
microorganisms.
[2]
pathogen
(c)
(Paper
2)
Explain
how
the
stomach
provides
a
[1]
defence
(d)
(e)
against
microorganisms.
Microorganisms
may
Explain
body
in
the
Some
and
how
(Paper
diseases
water.
3)
the
enter
the
prevents
[2]
blood.
their
spread
blood.
infectious
126
in
with
[4]
are
State
transmitted
four
diseases
other
can
be
in
ways
food
in
which
transmitted.
[4]
10
(a)
Explain
the
importance
maintaining
(i)
good
personal
of
the
following
in
12
The
diagram
and
health:
an
shows
antibody
four
different
antigens
molecule.
hygiene
Y
W
(ii)
sewage
(iii)
proper
treatment
Z
(b)
Rubella
by
a
is
virus.
against
11
A
disposal
transmissible
Many
rubella.
provides
(Paper
a
waste
disease
children
Explain
protection
[6]
are
how
against
X
caused
vaccinated
vaccination
disease.
[3]
3)
child
received
measles
at
booster
at
four
a
eight
antibodies
to
rst
vaccination
months
of
months.
measles
is
age
The
against
and
then
(a)
a
concentration
shown
in
the
The
the
of
graph.
(i)
Which
(ii)
Explain
doolb
There
has
antibody
forms
a
complex
with
one
of
antigens.
is
no
been
one?
[1]
your
vaccine
for
vaccinated
eht
including
measles,
answer.
[1]
chicken
against
tetanus
pox.
several
and
A
child
diseases
rubella.
ni
noitartnecnoc
The
child
catches
symptoms
(b)
Use
of
the
ydobitna
explain
many
(c)
3
4
5
6
7
8
9
10
the
it
is
diseases,
Explain
such
how
eradicate
a
pox
and
has
the
disease.
information
why
disease,
0
chicken
in
the
possible
but
as
still
be
chicken
be
ill
to
immune
with
to
another
pox.
vaccinations
disease
diagram
to
from
[4]
can
a
be
used
to
country.
[3]
months
(d)
Suggest
must
(a)
Explain
why
no
antibodies
were
present
blood
for
the
rst
vaccination
to
be
against
carried
out
diseases
even
if
in
there
the
why
continue
week.
are
no
cases
of
the
disease
for
many
[3]
years.
(b)
The
response
vaccine
is
to
the
different.
the
graph
the
booster
to
two
Use
describe
infections
the
how
of
information
the
response
(Paper
in
eight
months
differs
4)
to
13
at
(a)
The
lymphatic
response
to
the
rst
injection
at
and
Describe
why
the
response
to
the
the
is
different
to
the
and
response
to
The
injection.
Suggest
why
further
boosters
of
how
may
be
given.
(i)
lymphatic
(ii)
lymph
nodes
[4]
system
consists
lymphocytes
of
and
the
immune
antibodies.
system
this
us
against
infection
by
bacterial
[2]
pathogens.
(Paper
of
[4]
defends
vaccine
functions
immune
Explain
(d)
lymphatic
the
phagocytes,
rst
of
second
(b)
injection
consists
nodes.
[4]
vessels,
Explain
lymph
four
months.
(c)
system
from
vessels
the
[3]
the
[5]
4)
(Paper
4)
127
11
Gas
exchange
11.1
The
in
humans
gas
exchange
system
Structure
LEARNING
•
Identify
name
on
the
bronchi,
lungs,
•
diagrams
larynx,
associated
capillaries
the
need
We
breathe
to
breathe
air
of
The
lungs
form
The
lungs
are
surrounded
and
functions
in
We
The
the
thorax
the
volume
part
into
our
of
spongy
and
from
of
our
lungs
the
gas
organs
protected
is
a
the
the
intercostal
enters
larynx
lungs
to
in
get
order
rid
of
exchange
found
by
sheet
of
the
inside
ribs
brous
abdomen.
lungs
to
which
the
the
enter
Its
move
to
get
carbon
oxygen.
dioxide.
system
and
the
chest
the
sternum
tissue
and
movement
air
exchange
The
lungs
which
appear
tubes
It
throat
or
to
which
through
deep
nose
then
the
lung.
takes
between
during
mouth
each
bronchioles,
gas
muscles
especially
(voice-box).
connects
healthy
air
of
(thorax)
muscle
up
and
and
are
(breastbone).
that
down
separates
when
you
breathe
out
changes
and
in.
trachea
Air
of
system
the
breathing,
X
-ray
out
diaphragm
The
An
exchange
alveoli,
ribs,
muscles
cartilage
gas
trachea,
diaphragm,
the
the
and
bronchioles,
intercostal
State
of
OUTCOMES
and
the
lungs.
It
in
move
air
through
trachea
branches
continue
tiny
ribs
passes
enters
These
end
the
the
ribs
during
the
throat
breathing.
to
sacs
(windpipe),
to
divide
called
form
to
two
form
alveoli.
It
to
the
which
bronchi
many
is
small
here
that
place.
which
air
moves
are
often
called
airways.
black.
nasal
lar ynx
(voice
box)
C -shaped
cartilage
trachea
(windpipe)
intercostal
muscle
right
left
bronchus
left
lung
lung
epiglottis
(cut
open)
lar ynx
bronchioles
trachea
rib
oesophagus
Figure
11.1.1
Entry
and
of
air
into
the
nose
rib
trachea.
heart
diaphragm
Figure
128
11.1.2
The
gas
exchange
system.
tnemelppuS
The
larynx
make
This
to
sounds.
is
down
You
because
cover
The
contains
the
your
the
cannot
when
you
opening
trachea
trachea
is
vocal
kept
to
(see
cords.
breathe
by
a
larynx.
page
open
and
swallow,
your
When
air
passes
swallow
ap
at
called
This
stops
over
the
the
any
these
same
time.
epiglottis
food
trachea
you
from
bronchiole
moves
going
82).
C -shaped
rings
of
cartilage.
The
‘arms’
of
left
the
C
are
joined
by
prevents
the
pressure
decreases.
Deeper
There
is
surface
trachea
into
a
very
area
diffusion).
capillaries
muscle
the
back
collapsing
of
as
the
you
trachea.
breathe
The
in
lung
cartilage
when
the
air
lungs
number
diffusion
Each
for
the
large
for
from
at
alveolus
efcient
of
(see
is
gas
alveoli
page
in
28
surrounded
exchange
the
to
remind
by
into
lungs
a
to
yourself
network
and
give
out
of
of
a
huge
about
blood
the
blood.
bronchiole
The
alveoli
short
have
distance
thin
for
walls
made
diffusion.
of
They
a
are
single
moist
layer
so
of
cells,
oxygen
so
there
dissolves
in
is
a
alveoli
(air
capillar y
watery
uid
before
diffusing
through
the
walls
into
the
network
blood.
Figure
SUMMARY
sacs)
this
11.1.3
Describe
the
route
taken
by
inspired
air
(air
we
breathe
the
nasal
cavity
to
the
alveoli
in
the
The
lung.
diagram
shows
the
human
TIP
a
simpl
e
lungs.
of
2
a
in)
Draw
from
of
QUESTIONS
STUD
Y
1
Structure
breathing
system:
the
gas
syst
em
some
diag
ram
exchan
ge
and
no te
s
label
to
the
A
explai
ning
B
of
E
C
the
By
F
are
the
this
Add
func
tions
differ
ent
doin
g
it.
labels
parts.
you
anno
tatin
g
your
diag
ram
.
D
G
KEY
a
Name
structures
A
to
1
G.
POINTS
The
the
b
Match
parts
A
to
G
with
these
inspired
larynx,
sheet
ii
one
of
muscle
forming
the
oor
of
the
these
enters
each
contains
iv
exible
v
where
the
vocal
Cartilage
kept
open
by
rings
of
slippery
vii
an
of
gases
takes
made
of
the
trachea
passes
spongy
Gas
exchange
air
blood
tissue
it.
occurs
between
place
membranes
organ
air
cartilage
the
vi
alveoli.
cords
3
exchange
the
keeps
when
through
tube
to
lung
open
iii
down
bronchi,
thorax
2
of
passes
descriptions:
bronchioles
i
air
trachea,
and
found
in
the
chest
in
in
the
the
alveoli
and
the
surrounding
capillaries.
129
11.2
Gas
exchange
Breathing
LEARNING
Carbon
• Compare
the
composition
and
expired
the
dioxide
features
exchange
of
if
dioxide
it
is
builds
a
up
waste
in
gas
made
in
respiration.
can
become
breathe
out
in
order
to
get
rid
of
the
carbon
dioxide.
gas
surfaces
composition
• Describe
It
cells.
air
We
• List
carbon
of
toxic
inspired
out
OUTCOMES
gas
exchange
at
the
gas
inspired
air
/
%
expired
air
alveolus
(breathing
oxygen
carbon
dioxide
page
28
to
16
0.04
4
78
78
abou
t
conc
vapour
variable
saturated
remin
d
The
your
self
and
out)
TIP
water
See
(breathing
21
nitrogen
STUD
Y
in)
table
shows
that
we
breathe
out
more
carbon
dioxide
than
we
diffus
ion
entrat
breathe
in.
We
and
air
that
breathe
in
more
oxygen
than
the
air
we
breathe
out,
ion
the
we
breathe
out
has
a
lot
more
water
vapour.
grad
ients
.
The
following
more
carbon
practical
demonstration
conrms
that
we
breathe
out
dioxide.
PRACTICAL
Carbon
mouthpiece
limewater
1
Set
2
Then
up
the
apparatus
breathe
gently
as
in
you
breathe
in
•
When
you
breathe
out
•
The
limewater
more
limewater
The
carbon
turns
limewater
in
A
and
the
will
Figure
of
the
comes
air
expired
go
in
air
air
11.2.1.
mouthpiece
in
goes
rst
also
expired
in
out
air
the
in
and
shown
cloudy
dioxide
through
through
B,
cloudy
in
if
times.
A.
B.
showing
than
several
that
inspired
you
there
is
air.
breathe
through
11.2.1
apparatus
long
concentration
Gas
STUD
Y
Gas
alveo
li
have
We
and
walls
cells
,
but
have
anim
al
can
say
that
capilla
ries
mad
e
no t
remem
ber
cells
of
exchange
enough,
carbon
showing
dioxide
in
there
is
a
lower
atmospheric
(inspired)
air.
surfaces
TIP
Bewa
re!
cell
only
cell
of
exchange
a
human,
exchange
oxygen
and
as
in
the
gills
common
carbon
of
a
that
sh
and
adapt
alveoli
them
for
(air
sacs)
efcient
dioxide:
•
a
very
•
moist
•
a
large
surface
area
for
the
diffusion
of
gases
surfaces
so
that
gases
can
dissolve
before
diffusion
plan
t
walls
do
such
features
walls
thin
surface
(only
one
cell
thick
in
each
alveolus)
so
the
gases
do
,
not
cells
of
surfaces,
have
of
have
to
diffuse
very
far
no t.
•
a
good
and
blood
lots
of
supply
carbon
concentration
130
inspired
When
the
–
in
•
•
Figure
dioxide
so
that
dioxide
is
gradients
lots
of
oxygen
supplied
for
these
is
quickly.
gases
removed
This
quickly
maintains
the
•
ventilation
is
of
changed;
between
Gas
the
this
air
in
lungs
helps
the
exchange
When
inspired
contains
a
alveolus.
through
lot
It
the
diffusing
at
of
oxygen.
capillary
and
the
diffuses
through
the
that
the
gas
in
air
in
the
air
passages
concentration
the
gradients
blood.
alveolus
in)
air
reaches
Oxygen
into
cells,
the
the
the
the
dissolves
through
wall
two
that
maintain
alveoli
(breathed
then
ensures
wall
blood.
distance
alveoli
in
the
of
the
(air
water
very
it
lining
alveolus
Although
is
sacs)
this
each
SUMMARY
1
involves
List
four
alveoli
small.
them
Each
alveolus
has
a
network
of
capillaries
around
it.
combine
oxygen
from
with
to
the
alveolus
diffuse
haemoglobin.
the
body
The
into
blood
the
cells
is
wall
ver y
of
can
then
cells
the
film
inside
of
of
moisture
the
carbon
O
O
O
adapt
exchange
transport
this
2
Look
on
at
the
apparatus
used
in
experiment:
the
cells
gauze
making
dioxide
O
O
O
O
the
that
alveolus
respiring
using
oxygen
O
efcient
cricket
cells
of
lungs
gases.
this
alveolus
for
the
and
thin
respiring
O
blood
tissues.
thin
the
red
features
of
Oxygen
of
molecules
QUESTIONS
and
O
O
O
O
O
O
O
O
O
O
lime
O
blood
carries
oxygen
blood
carries
carbon
water
dioxide
A
from
the
Figure
the
lungs
to
from
the
cells
to
the
B
lungs
cells
11.2.2
Gas
exchange
at
an
alveolus.
After
an
hour
the
tubes
were
examined.
There
is
a
lot
of
carbon
dioxide
in
the
capillary.
in
the
blood
It
has
been
carried
a
there
from
the
respiring
tissues
plasma.
It
diffuses
in
What
result
would
you
the
expect?
opposite
into
the
Alveoli
direction,
space
are
through
inside
the
surrounded
by
the
capillary
alveolus.
elastic
From
tissue.
wall
here
This
across
it
is
the
alveolar
breathed
stretches
when
wall
b
Explain
your
c
Explain
why
answer.
out.
you
tube
B
is
breathe
included.
in
and
recoils
when
you
breathe
out
to
help
remove
air
from
the
lungs.
3
The
air
we
breathe
out
is
saturated
with
water
vapour
that
Give
of
evaporated
from
the
moist
walls
of
the
an
the
When
to
There
is
a
you
cold
droplets
POINTS
b
1
more
carbon
dioxide,
less
oxygen
and
more
water
Expired
expired
air
than
in
inspired
Gas
area
exchange
and
a
surfaces
good
blood
are
Alveoli
are
well
adapted
moist,
thin,
have
a
large
surface
supply.
for
and
are
gas
surrounded
on
form.
air
turns
cloudy
c
Alveoli
thin,
exchange
as
they
have
inspired
by
many
(air
have
quicker
and
air.
sacs)
a
are
large
have
very
surface
walls
with
these
elastic
features
out
water
air
.
area
3
each
vapour
than
2
breathe
surface,
limewater
in
for
following.
alveoli.
a
KEY
explanation
has
bres.
capillaries.
131
11.3
Breathing
tnemelppuS
When
LEARNING
ribs
•
you
Describe
how
pressure
changes
ventilation
of
volume
your
and
lead
the
outwards.
Explain
cells,
the
dust
role
mucus
protecting
system
it
lungs
to
so
inside
lungs
of
and
the
from
This
diaphragm
they
the
moves
•
breathe
feels
as
if
the
lungs
are
expanding
to
push
your
OUTCOMES
in
is
and
to
through
so.
When
ribcage
occupy
lungs
not
a
move
larger
below
your
the
volume.
the
nose
you
chest
This
pressure
and/or
breathe
of
in,
cavity
movements
and
decreases
pull
the
atmospheric
on
air
air
of
the
pressure
so
that
air
mouth.
goblet
cilia
gas
in
When
exchange
pathogens
relax
and
you
and
pressure
particles
is
forced
alone
This
when
in
out,
causes
the
out.
(try
is
breathe
this
lungs
You
ne
you
for
quiet
exercise
diaphragm
chest
cavity
increases
can
breathing
the
the
do
this
without
to
the
by
moving
but
intercostal
intercostal
decrease
above
just
breathing,
and
to
in
atmospheric
movement
your
The
pressure
your
air
so
air
diaphragm
ribs).
during
muscles
of
muscles
volume.
deep
breathing
contract
to
and
move
the
ribs.
PRACTICAL
(Intercostal
the
A
model
of
the
external
Obtain
a
model
like
the
one
diagram.
The
rubber
the
that
are
ribs.)
closer
There
to
the
are
two
layers
skin,
and
the
of
these:
that
are
deeper
into
the
chest
wall
(see
Figure
internal
11.3.3).
diaphragm
is
made
of
tough
brous
tissue
in
the
centre
and
sheet
strong
represents
muscles
the
in
The
the
between
chest
muscles
1
means
muscles
that
connect
to
the
backbone,
the
lower
ribs
and
the
diaphragm.
sternum
glass
(breastbone).
tube
passage
bell
of
air
jar
muscles
contract
balloon
ribs
lungs
move
up
and
out
the
volume
the
chest
of
ribcage
rubber
sheet
cavity
increases
diaphragm
diaphragm
contracts
and
2
Pull
and
the
rubber
then
sheet
push
it
front
up.
Figure
3
Do
this
watch
a
few
what
times
moves
down
down
view
of
chest
side
view
of
chest
11.3.1
and
happens
to
the
balloons.
Inspiration
This
model
shows
•
movement
of
the
in
the
the
the
volume
thorax
bell
jar
.
As
the
and
the
inate
lungs
increase
in
pressure
the
132
in
The
external
in
as
the
intercostal
muscles
contract
and
the
internal
a
result
space
relax,
raising
the
ribs
upwards
and
outwards.
•
At
the
•
Both
same
time,
the
diaphragm
contracts
and
attens.
by
the
downwards,
and
muscles
pressure
diaphragm
moves
volume
balloons.
and
represented
contracts
in)
diaphragm
intercostals
changes
(breathing
how
of
an
decrease
around
•
of
these
pressure
Since
they
actions
inside
atmospheric
inate.
increase
the
thorax
pressure
is
the
to
volume
inside
the
thorax,
causing
decrease
greater,
air
moves
into
the
lungs
and
(breathing
passage
of
tnemelppuS
Expiration
out)
clavicle
air
trachea
external
intercostal
muscles
relax
breastbone
internal
ribs
move
down
intercostal
ribs
lungs
muscles
and
in
ribcage
the
volume
the
chest
of
cavity
external
diaphragm
decreases
intercostal
muscles
relaxes
and
diaphragm
bulges
upwards
front
view
Figure
•
The
This
•
The
chest
side
view
of
chest
11.3.2
internal
muscles
•
of
intercostal
muscles
contract
and
the
external
intercostal
relax
lowers
the
muscle
pressure
ribs
downwards
in
the
diaphragm
from
the
organs
and
inwards.
relaxes
below,
for
and
it
bulges
example
the
up
due
to
liver
and
stomach,
internal
and
•
contraction
Both
of
these
of
the
actions
abdominal
decrease
the
volume
external
intercostal
muscles.
inside
the
muscles
intercostal
muscles
thorax,
cilia move
dust
ciliated
causing
the
pressure
inside
the
thorax
to
particles
cells
•
Elastic
recoil
Cleaning
of
the
As
you
by
evaporation
the
air,
The
the
breathe
trachea,
helps
to
force
air
out
of
the
in
through
water
particles
bronchi
your
from
and
nose,
the
and
air
lining.
some
is
warmed
Hairs
and
inside
moistened
the
nose
lter
goblet cells
pathogens.
bronchioles
are
lined
with
ciliated
epithelial
Figure
11.3.4
Goblet
cells
epithelial
cells
and
goblet
cells
which
secrete
mucus.
Dust
particles
become
trapped
in
the
slimy
mucus.
The
cilia
and
cells
ciliated
keep
the
and
lungs
pathogens
make mucus
lungs.
air
of
removing
alveoli
these cells
increase
beat
free
of
dust
and
to
pathogens.
carry
a
stream
particles
and
of
mucus
pathogens
up
to
your
which
you
nose
then
and
throat,
removing
the
swallow.
KEY
SUMMARY
1
QUESTIONS
POINTS
Inspiration
occur
1
When
a
person
breathes
in,
describe
what
happens
due
volume
in:
and
to
and
expiration
changes
pressure
of
in
the
thorax.
a
the
intercostal
volume
inside
muscles
the
b
thorax
the
e
ribs
the
c
the
diaphragm
pressure
inside
the
d
the
thorax
2
The
internal
muscles,
2
Look
at
the
model
of
the
chest
in
the
Practical,
Which
part
of
the
model
the
lungs
ii
the
and
the
diaphragm
represents:
control
i
intercostal
opposite.
muscles
a
intercostal
external
diaphragm
iii
the
these
changes
during
ribs?
ventilation.
b
Make
some
criticisms
of
the
model
as
a
way
of
3
representing
the
changes
that
occur
during
Goblet
which
3
Explain
free
the
from
role
dust
of
mucus
particles
and
and
cilia
in
keeping
pathogens.
cells
produce
mucus
breathing.
the
air
passages
traps
pathogens
beat
the
to
dust
in
the
remove
particles
air
and
mucus
and
cilia
from
airways.
133
11.4
Rate
and
depth
of
breathing
Breathing
LEARNING
At
•
Investigate
and
describe
exercise
rest
effects
of
on
rate
physical
and
you
probably
take
between
12
and
16
breaths
per
minute.
the
When
the
and
OUTCOMES
you
exercise
this
breathing
rate
changes.
exercise
depth
of
breathing
tnemelppuS
PRACTICAL
•
Describe
of
how
exercise
dioxide
the
effects
increase
carbon
concentration
The
You
the
blood
and
how
effects
the
rate
and
exercise
on
breathing
rate
can
measure
your
breathing
rate
by
counting
the
number
of
this
times
affects
of
in
depth
that
you
breathe
out
in
a
minute.
of
breathing
You
could
record
your
results
in
a
table
like
this:
–1
breathing
at
rate
/
breaths
per
min
light
heavy
exercise
exercise
rest
1
2
3
average
•
Try
•
As
=
doing
soon
as
you
breathing
rate.
•
Wait
until
your
•
Now
try
(heavy
•
Then
•
You
for
have
1
minute
nished,
breathing
doing
step-ups
sit
rate
as
(light
exercise).
down
returns
quickly
as
and
to
its
you
count
your
resting
can
for
value.
3
minutes
exercise).
count
will
change
Performing
step-ups
your
notice
after
breathing
that
doing
your
rate
when
breathing
you
rate
have
and
nished.
depth
of
breathing
exercise.
step-ups.
•
Repeat
this
twice
and
calculate
averages.
plastic
container
breathe
out
The
here
are
rate
and
working
They
also
depth
hard,
of
breathing
your
produce
muscles
more
carbon
increase
need
with
more
dioxide
in
exercise.
oxygen
for
When
they
respiration.
respiration.
rubber
tubing
Increasing
blood
and
continue
a
trough
Figure
11.4.1
This
apparatus
used
to
capacity
can
measure
(see
top
of
vital
heart
134
to
rid
respire
Your
of
and
of
quite
oxygen
pulse
beating
depth
more
fast
rate
to
of
breathing
carbon
fast
after
and
they
remains
deliver
dioxide
exercise
still
high
plenty
gets
the
nishes.
have
carbon
after
of
more
from
They
to
this
extra
oxygen
and
have
their
carbon
dioxide
the
need
to
because
your
into
Muscles
still
dioxide
exercise
blood
oxygen
blood.
be
your
muscles
next
gain
page).
is
rate
gets
supply
removed.
be
your
good
the
removed.
so
they
oxygen
delivered
muscles
rate
of
respiration
rate
in
and
depth
more
to
STUD
Y
quickly
TIP
of
exercise
muscles
breathing
increases
See
increases
carbon
page
your
self
removed
muscles
11.4.2
The
effect
of
exercising
on
to
diffus
ion.
quickly
Com
pare
resu
lts
with
you
go t
inve
stigat
ing
(pag
is
adult
their
out
can
vital
after
105)
take
in
about
capacity
breathing
in
–
5
the
as
litres
of
air
maximum
much
air
as
in
their
volume
possible.
deepest
of
air
At
breath.
that
rest,
is
This
on
breathed
about
half
a
effect
s
the
the
air
is
breathed
in
and
out.
During
exercise
approximately
four
litres
of
extra
air
can
be
taken
in
during
a
deep
and
body
add
tnemelppuS
You
don’t
happens.
exercise?
you
So
exercise
dioxide
about
what
the
more
your
makes
brain
which
become
Y
ou
some
(see
has
lowers
you
a
tissues
respire
pH
They
–
breathe
special
the
acidic).
breathing
part
more
in
the
may
most
faster
for
the
and
time
deeper
controlling
quickly
tissues
also
of
and
and
make
page
brain
gluc
ose
when
of
the
more
blood
blood
acid
(i.e.
which
When
STUDY
they
does
TIP
the
this
rise
in
carbon
dioxide
and
the
lowering
of
are
reaching
it.
The
brain
sends
nerve
impulses
to
and
to
the
increase
dioxide
turn
and
in
this
through
more
the
has
intercostal
the
rate
rapidly,
blood
the
them.
muscles!
muscles
so
they
contract
and
depth
of
breathing.
By
and
same
This
is
you
this
effect
an
lower
raises
on
the
the
example
the
concentration
blood
tissues
of
pH
back
because
homeostasis
the
hard
faster
require
work.
the
extra
and
and
glucose
and
breathing
of
carbon
to
normal.
the
–
organs
the
need
deeper
the
the
the
oxygen
to
14
.
carbon
T
hey
further
and
Unit
140).
detects
diaphragm
in
you
doing
pH
able
abou
t
just
breathing.
make
the
lactic
it
T
hey
Your
and
be
more
tempe
ratu
re
Remember
same
hear
t
will
breathing
think
The
ise
includ
ing
breath.
blood
of
mar
exerci
se
a
body
Control
of
rate
litre
to
half
Sum
mus
cles,
lung
s.
of
.
breathing
the
An
e
when
puls
e
tnemelppuS
of
the
breathing.
resu
lts
Depth
remin
d
abou
t
from
more
your
Figure
28
dioxide
blood
see
page
to
taken
In
have
away.
answer
ows
the
166.
in
on
wastes
Start
this
changes
the
their
that
muscles
any
topic
with
occur
during
exercise.
1
When
a
2
QUESTIONS
you
the
exercise,
rate
Describe
of
what
describe
breathing
happens
what
b
to
the
happens
the
to:
depth
of
concentration
breathing
of
carbon
KEY
dioxide
1
in
the
blood
when
you
POINTS
Exercise
rate
tnemelppuS
3
a
Explain
how
the
brain
monitors
and
controls
the
rate
when
you
and
depth
Explain
what
happens
An
increase
to
the
following
when
you
the
intercostal
iii
the
heart
the
breathing.
in
the
muscles
ii
the
of
carbon
exercise:
dioxide
i
both
exercise.
concentration
b
of
of
2
breathing
increases
exercise.
diaphragm
the
in
brain
changes
the
blood
triggers
in
reaching
these
breathing.
rate
135
tnemelppuS
SUMMARY
PRACTICE
1
Which
QUESTIONS
is
a
pathway
that
air
takes
from
the
tube
atmosphere
to
the
gas
exchange
surface
in
A
tube
B
the
A
cloudy
cloudy
B
cloudy
no
C
no
change
cloudy
D
no
change
no
lungs?
A
mouth
larynx
bronchiole
B
alveolus
mouth
nose
alveoli
C
nose
trachea
bronchus
larynx
trachea
(Paper
bronchus
trachea
bronchiole
bronchus
What
A
1)
many
lled
a
conical
ask
with
lime
put
student
water
cross
the
a
drawing
then
to
test
of
a
breathed
nd
out
became
after
features
of
a
gas
exchange
how
The
three
beneath
the
long
invisible.
doing
cross
into
it
ask
took
thick-walled,
C
area,
small
surface
area,
capillaries
thin-walled,
many
the
repeated
of
surface
The
lime
before
student
minutes
it.
of
large
capillaries
water
few
and
the
thick-walled,
[1]
student
are
alveolus
B
2
[1]
surface?
A
(Paper
1)
alveolus
4
nose
change
bronchiole
bronchiole
D
change
bronchus
D
large
few
area,
capillaries
thin-walled,
strenuous
surface
small
surface
area,
capillaries
exercise.
Which
describes
the
time
taken
for
the
5
to
become
invisible
in
the
test
after
(Paper
1)
Which
is
The
cross
became
invisible
in
a
the
function
of
the
cartilage
in
exercise?
the
A
[1]
cross
trachea?
shorter
A
cleans
the
B
contracts
C
increases
air
as
it
moves
to
the
lungs
time.
B
The
cross
become
took
three
times
as
long
to
move
air
into
the
lungs
to
resistance
to
air
owing
to
the
invisible.
lungs
C
The
cross
took
twice
as
long
to
become
D
prevents
the
trachea
collapsing
invisible.
D
The
(Paper
time
was
the
same.
(Paper
1)
[1]
6
The
act
3
The
diagram
shows
apparatus
to
2)
[1]
diaphragm
together
production
of
carbon
dioxide
the
intercostal
expiration
at
muscles
the
end
of
investigate
strenuous
the
and
during
exercise.
Which
of
the
following
during
occurs?
respiration
to
see
in
of
insects.
tubes
A
and
What
would
B
minutes
ve
you
expect
after
intercostal
setting
up
the
apparatus?
muscles
diaphragm
internal
external
relax
contract
relax
contract
contract
relax
contract
relax
moves
A
contracts
down
B
contracts
C
relaxes
moves
up
moves
down
limewater
D
relaxes
moves
up
limewater
(Paper
potassium
living
hydroxide
animals
solution
carbon
136
(absorbs
dioxide)
air
flow
2)
[1]
7
The
gas
photograph
exchange
shows
some
cells
from
the
(b)
(i)
Calculate
system.
the
(ii)
(c)
changed
minute.
per
of
of
in
same
class.
so
What
A
is
cell
X?
alveolar
B
ciliated
C
goblet
D
muscle
cell
10
The
the
cell
(a)
cell
(b)
cell
2)
50
step-
of
exercise
on
the
to
on
that
between
the
two
they
they
investigate
boys
features
would
could
the
the
and
have
make
boys
of
to
the
keep
valid
and
girls.
3)
[2]
diagram
thorax
Name
(i)
shows
from
A
to
the
the
ribs
and
muscles
of
side.
C.
Describe
the
(Paper
to
the
[2]
State
that
comparisons
(Paper
rest
in
when
[2]
effect
exercise
investigation
the
from
decided
this
the
the
change
breath
breathing.
students
effect
girls
each
ups
Describe
The
percentage
of
student
rate
X
the
volume
[3]
how
structures
[1]
shown
8
The
it
percentage
passes
composition
through
the
lungs
of
air
changes
bring
as
about
breathing
because:
A
movements
A
carbon
dioxide
and
water
vapour
are
C
during
absorbed
from
the
air
inspiration
B
carbon
dioxide
is
absorbed
and
and
oxygen
expiration.
[6]
excreted
(ii)
C
oxygen
is
absorbed
and
carbon
Explain
how
dioxide
B
the
movements
excreted
you
D
oxygen
(Paper
is
absorbed
and
nitrogen
excreted
2)
air
move
into
Some
students
investigated
the
effect
Here
on
are
the
the
rate
results
and
for
volume
activity
each
depth
one
of
of
of
the
and
lungs.
[5]
3)
breathing.
the
students.
number
breaths
breath
of
of
(Paper
exercise
to
[1]
out
9
describe
cause
11
Look
(a)
of
at
the
table
Describe
the
student’s
taken
of
results
effect
of
in
question
exercise
on
9.
the
breathing.
[5]
3
/
cm
rest
20
minute
500
18
750
25
1200
34
(b)
50
Explain
why
changed
(Paper
step-ups
per
the
during
student’s
exercise.
breathing
[6]
4)
minute
step-ups
per
(a)
per
minute
(i)
Calculate
of
each
the
change
breath
changed
from
when
20
to
in
the
the
50
volume
student
step-ups
minute.
(ii)
[1]
Describe
volume
per
the
of
effect
each
of
exercise
breath.
on
the
[2]
137
12
Respiration
12.1
Aerobic
Aerobic
LEARNING
Dene
aerobic
respiration
we
the
word
State
that
is
respiration
catalysing
cell
in
State
the
uses
human
Investigate
oxygen
energy
by
of
energy
reactions
in
body
is
living
in
the
released
the
uptake
respiring
of
tnemelppuS
State
the
that
living
petrol,
gives
off
oxygen
a
lot
of
is
used
light
up
and
and
carbon
heat.
organism
cells
is
needs
called
energy.
glucose,
A
but
fuel
unlike
used
to
burning
very
gradually
in
a
series
of
small,
petrol,
enzyme-
cells
In
aerobic
balanced
for
break
to
Respiration
down
release
involves
nutrient
a
number
molecules,
such
of
as
chemical
glucose,
energy.
respiration
oxygen
is
used
in
the
breakdown
of
glucose:
organisms
+
→
oxygen
carbon
dioxide
+
water
+
energy
released
chemical
Cells
equation
reactions.
in
glucose
•
as
cells
the
•
every
energy
controlled
•
such
ame
reactions
the
in
fuel
The
involves
provide
enzymes
a
made.
equation
Every
•
burn
and
dioxide
state
respiration
OUTCOMES
When
•
respiration
also
respire
fats
and
proteins
to
provide
energy,
but
you
only
have
aerobic
to
know
about
the
respiration
of
glucose,
which
is
a
carbohydrate.
respiration
Using
Your
the
energy
body
needs
following
•
muscle
•
cell
•
absorption
•
sending
•
protein
energy
for
many
different
things.
Energy
is
used
in
processes:
contraction
division
of
nutrients
impulses
synthesis
in
along
for
the
gut
by
active
transport
nerves
making
enzymes,
some
hormones
and
antibodies
•
computer
generated
mitochondrion.
made
in
these
Most
cell
image
of
the
of
ATP
structures.
in
Each
cells
is
during
is
new
STUD
Y
keeping
the
no t
a
with
C
H
6
in
proces
s
for
O
12
Most
in
of
lo ts
structures
like
the
nucleus
temperature
constant.
Some
of
the
energy
place
of
in
+
heat.
all
by
Wha
t
living
no t
energy
cells
→
to
all
stay
of
the
alive.
time
The
because
balanced
cells
chemical
is:
6CO
2
+
6H
2
O
+
energy
released
2
of
the
energy
you
breath
e
released
Cells
in
that
aerobic
require
a
respiration
lot
of
is
energy
released
have
For
instance,
insect
ight
muscle
has
many
numerous
each
its
located
between
the
muscle
bre.
The
mitochondria
own
the
energy
for
the
muscles
to
contract
during
ight.
Liver
cells
do
have
you
of
respiration
6O
6
mitochondria.
provide
enzy
me.
supply
aerobic
mitochondria
is
form
of
reactio
ns,
cata
lysed
when
the
takes
mitochondria.
chem
ical
138
cell
Respi
ratio
n
chem
ical
cons
istin
g
out
body
constant
equation
conf
use
breath
ing.
a
is
Respiration
respira
tion
one
and
TIP
need
is
membranes
long.
released
Do
cell
growth
about
•
0.002 mm
making
a
in
and
respira
tion!
cells
a
of
active
high
the
metabolism
small
transport,
and
intestine
so
have
have
absorb
large
many
mitochondria.
glucose
numbers
and
of
other
The
epithelial
molecules
mitochondria.
by
tnemelppuS
A
tnemelppuS
PRACTICAL
PRACTICAL
Investigating
the
uptake
of
oxygen
by
respiring
seeds
Investigating
The
apparatus
how
up
quickly
oxygen
which
is
in
Figure
12.1.1
germinating
during
seeds
aerobic
absorbed
by
is
the
a
respirometer
use
up
respiration
soda
lime.
oxygen.
and
The
and
The
release
it
can
seeds
carbon
decrease
in
measure
respiration
take
and
causes
the
red
liquid
to
move
along
the
capillary
tube.
of
movement
can
be
measured
by
the
scale
–
the
faster
of
rate
of
germinating
apparatus
shown
in
Figure
The
12.1.2
rate
of
effect
the
air
The
pressure
the
on
seeds
dioxide,
volume
temperature
the
is
a
more
accurate
rate
respirometer.
of
respiration,
to
keep
the
the
quicker
apparatus
at
the
a
liquid
will
constant
move.
Why
is
it
important
1
temperature?
Place
into
2
1
eye
2
3
4
5
6
7
Set
soda
Figure
the
germinating
boiling
rest
of
seeds
tube.
the
apparatus
8
protection
up
is
some
the
as
shown.
Be
very
careful
lime
corrosive
12.1.1
A
simple
not
to
it
corrosive.
is
touch
the
soda
lime
as
respirometer.
3
Close
the
much
plastic
clip
the
and
nd
coloured
out
liquid
how
rises
in
capillar y
tubing
the
tube
capillary
tube
in
30
minutes.
clip
eye
is
This
protection
soda
water
lime
at
corrosive
a
investigation
works
on
the
bath
same
known
temperature
one.
principle
It
can
number
germinating
of
the
previous
repeated
at
temperatures
a
by
seeds
changing
wire
be
as
gauze
the
temperature
of
the
coloured
water
and
so
compare
the
rate
of
water
soda
Figure
12.1.2
A
respirometer
for
lime
respiration
investigating
the
effect
of
temperature
of
the
seeds.
on
respiration.
KEY
SUMMARY
1
1
Copy
POINTS
QUESTIONS
and
complete
the
sentences
using
these
In
is
words:
aerobic
broken
energy
aerobic
glucose
oxygen
in
carbon
dioxide
takes
place
in
all
living
.
A
fuel
is
.
It
is
broken
down
to
release
is
water
and
the
waste
gas
.
and
Respiration
When
it
of
These
in
the
reactions
structures
2
a
presence
Write
take
of
place
called
down
we
in
every
call
it
living
equation
for
Energy
Make
is
a
released
list
of
ve
during
aerobic
processes
that
cell,
inside
3
tiny
The
word
aerobic
glucose
respiration.
a
Describe
b
What
how
a
simple
equation
+
the
function
use
respirometer
of
soda
this
4
energy.
The
lime
in
the
apparatus
balanced
H
O
12
+
6
do
the
you
think
will
happen
to
the
rate
of
for
or
chemical
aerobic
is:
6O
→
6CO
+
6H
2
O
2
Respirometers
germinating
ii
increases
seeds
to
if
the
temperature
i
can
be
used
to
respiration
decreases
the
rate
of
respiration
to
under
5 °C
→
water
2
measure
of
+
12.1.1?
5
What
oxygen
in
6
c
aerobic
works.
C
Figure
for
is:
respiration.
respiration
is
catalyse
cells.
dioxide
equation
3
the
to
respiration.
carbon
b
in
respiration
word
involves
takes
.
the
water.
enzymes
reactions
place
of
carbon
Also
action
produced
presence
forming
for
2
respiration
glucose
release
cells
dioxide
Respiration
the
to
mitochondria
oxygen,
energy
respiration,
down
different
conditions.
50 °C?
139
12.2
Anaerobic
Muscles
LEARNING
Dene
anaerobic
for
in
the
muscle
exercise
•
word
anaerobic
State
and
that
exercise
equations
in
carry
vigorous
energy
glucose
much
out
tnemelppuS
the
is
possible
balanced
for
Describe
lactic
in
an
is
the
acid
in
oxygen
release
glucose
strenuous
build-up
muscle
and
during
the
of
to
cause
for
energy
in
is
the
this
from
the
get
enough
happens
glucose
release
absence
exercise,
aerobic
not
of
of
oxygen
your
to
muscles
your
start
to
a
without
little
using
energy
oxygen.
from
each
oxygen.
enough
respiration
how
it
tissue
respires
enzyme-catalysed
without
dioxide
oxygen.
and
to
oxygen
supply
all
may
the
reach
energy
the
the
body
muscles
As
water,
anaerobically
reactions
a
result
but
to
of
the
aerobic
glucose
lactic
to
acid
is
release
energy.
respiration
not
do
broken
Most
not
down
of
happen
to
carbon
instead:
recovery
→
lactic
acid
+
energy
released
exercise
tissues,
respire
the
to
make
an
electron
microscope.
beating
lactic
is
alcohol
and
absent
C
→
H
O
12
if
Some
same
in
not
the
bacteria
way,
heart,
release
for
do
not
enough
also
respire
example
normally
energy
to
keep
anaerobically
those
that
we
use
energy
and
set
is
H
+
OH
in
respire
their
anaerobically
surroundings,
when
to
make
carbon
+
in
dioxide
2CO
+
+
energy
released
energy
released
2
water
released
alcohol
yeast,
anaerobically
to
broken
alcohol
as
supply
5
with
compared
in
such
from
so
the
land
or
of
a
is
no
molecule
respiration.
and
form
little
each
aerobic
down
when
lot
of
ooded
oxygen
of
This
energy
chemical
bond
is
and
glucose
is
soils
available.
in
because
remains
energy.
anaerobic
glucose
stored
Y
ou
in
can
is
lactic
see
alight.
–1
energy
aerobic
respiration
fermentation
anaerobic
Hurdlers
140
build
up
lactic
acid
in
their
muscles.
to
dioxide:
2C
respire
completely
you
muscle
would
short
alcohol
saturated
respiration
acid
the
in
2
roots
less
or
6
become
not
in
carbon
→
Far
this
properly.
acid
glucose
Plant
cardiac
as
microorganisms,
oxygen
6
as
yoghurt.
Other
under
such
anaerobically
heart
make
cells
These
vigorous
respiration
to
Muscle
Other
Yeast
cannot
When
During
respiration.
respiration
of
glucose
from
aerobically.
system.
yeast
debt
removed
respire
chemical
need.
•
to
blood
anaerobic
muscles
respiration
lungs
your
respiration
During
equation
glucose
by
molecule
molecule
State
and
enough.
anaerobic
Anaerobic
•
and
muscles
less
It
aerobic
heart
quickly
Anaerobic
anaerobic
releases
than
oxygen
your
yeast
respiration
per
need
to
your
muscles
respiration
during
brought
tnemelppuS
State
muscles
respiration
are
•
oxygen
OUTCOMES
Your
•
without
respiration
by
(kJ
16.1
yeast
respiration
released
1.2
in
muscle
0.8
/
g
glucose)
this
tnemelppuS
Lactic
Lactic
be
acid
acid
can
removed
and
blood,
Our
oxygen
‘paid
after
After
to
by
the
build
in
up
after
we
carry
to
lactic
lactic
up
acid
acid.
to
blood
in
the
exercise
on
hard,
more
The
of
acid
oxygen
beat
at
a
the
and
fast
in
muscles.
They
has
for
is
in
to
to
be
deeper
aerobic
removed
the
rate
muscles
must
muscles
debt
and
debt
acid
it
the
it
faster
oxygen
lactic
so
in
oxygen
breathing
from
their
cramps,
lactic
causes
respiration
the
cause
of
supply
continues
in
and
build
exercise,
order
down
acid
muscles
The
We
aerobic
heart
lactic
up
away.
break
exercise
Sprinters
builds
exercise
recovery
transport
body.
vigorous
straight
vigorous
during
to
debt
poison
the
during
back’
respiration
slowly
from
liver.
order
the
often
liver.
hold
their
3
breath
of
during
oxygen
after
The
the
100
get
race
in
metres
rid
of
order
enzyme-catalysed
aerobic
respiration
function
glucose
acid
to
a
is
without
is
partly
the
to
in
supply
from
acid.
that
That
of
release
oxygen.
in
end
the
is
oxygen
mitochondria.
down
the
Afterwards
their
reactions
broken
produced
lactic
‘repay
occur
a
race.
they
need
why
they
most
These
breathe
of
the
cell
deeply
this
and
energy
structures
anaerobic
cytoplasm
of
7 dm
debt’.
During
product
about
not
respiration,
alcohol
partial
in
do
or
lactic
breakdown.
This
SUMMARY
1
QUESTIONS
a
Dene
the
b
Give
c
Compare
term
runner
breathing
anaerobic
during
examples
the
of
energy
aerobic
and
anaerobic
Describe
and
explain
released
from
anaerobic
the
in
aerobic
and
her
her
oxygen
debt
by
training.
POINTS
a
molecule
of
glucose
1
respiration.
Anaerobic
chemical
differences
between
the
anaerobic
respiration.
respiration
reaction
break
down
in
is
the
cells
glucose
to
energy
release
released
after
respiration.
that
2
repaying
respiration
KEY
two
is
deeply
(See
the
energy
without
using
table
oxygen.
for
some
gures
to
use
in
your
answer.)
tnemelppuS
2
3
The
table
below
shows
the
units
of
lactic
acid
produced
in
In
anaerobic
glucose
leg
muscles
of
an
athlete
during
a
of
/
minutes
0
10
20
30
40
50
60
70
80
0
1
7
12
9
6
3
1
1
in
units
of
lactic
acid
b
When
a
graph
using
the
the
lactic
Explain
why
the
Suggest
why
acid
muscles
the
tissue,
reach
a
end
of
the
produced
lactic
Explain
why
session
of
we
hard
Far
more
muscles
produced
less
lactic
acid
Explain
how
an
alcohol,
dioxide
in
yeast
energy
each
is
released
molecule
in
aerobic
of
than
in
towards
respiration.
race.
carry
on
breathing
heavily
after
we
nish
a
exercise.
The
oxygen
debt
build
muscles
develops
and
how
it
is
has
up
of
during
produces
that
5
acid
acid.
4
4
or
lactic
maximum?
anaerobic
the
to
absence
plants.
glucose
d
down
the
forming
carbon
from
c
in
data.
3
did
energy
muscle
and
Draw
broken
oxygen,
plus
a
is
race:
release
time
respiration,
the
an
to
lactic
hard
oxygen
be
paid
acid
in
exercise
debt
back
by
repaid.
breathing
in
extra
oxygen.
141
tnemelppuS
opposite
PRACTICE
1
Which
QUESTIONS
process
does
not
require
energy
from
6
The
of
A
equations
change
respiration?
diffusion
of
oxygen
across
the
alveolar
that
contraction
C
passage
D
synthesis
of
muscle
during
(Paper
2
When
nerve
of
to
enzyme-catalysed
show
glucose
as
reactions.
the
a
overall
result
the
role
of
glucose
Which
for
the
term
rst
exercise
enzyme
of
respiration
wall
describes
B
for
occurs
in
respiration?
impulses
protein
A
activator
B
active
C
product
D
substrate
molecules
1)
site
[1]
yeast
respires
without
oxygen,
the
cells
produce:
(Paper
A
alcohol
B
carbon
C
lactic
acid
D
lactic
acid
7
dioxide
and
After
[1]
vigorous
high.
A
carbon
Which
carbon
1)
[1]
B
lactic
During
aerobic
chemical
respiration,
reactions
molecules
to
is
enzymes
breakdown
be
to
glucose
B
produce
lactic
C
produce
oxygen
D
release
student’s
heart
rate
reason
from
for
this?
anaerobic
from
anaerobic
removed
the
respiration
muscles
respiration
from
the
muscles
catalyse
C
nutrient
oxygen
to:
produce
a
removed
from
be
is
required
metabolism
A
not
dioxide
to
acid
needs
3
a
dioxide
needs
(Paper
exercise,
alcohol
is
and
2)
D
waste
of
in
lactic
products
of
the
liver
for
acid
respiration
need
to
be
removed
acid
(Paper
energy
8
The
2)
oxygen
oxygen
(Paper
1)
During
vigorous
without
is
the
exercise,
oxygen.
release
The
carbon
dioxide
B
carbon
dioxide
muscle
D
much
result
of
oxygen
this
additional
the
lungs
volume
after
of
exercise.
energy
and
from
energy
each
molecule
of
A
anaerobic
B
metabolism
C
removal
D
respiration
from
each
molecule
does
respiration
in
muscle
tissue
of
lactic
acid
in
the
liver
of
carbon
of
dioxide
for
muscle
tissue
to
release
contraction
2)
[1]
of
(a)
Write
for
Which
for
glucose
9
1)
required
water
glucose
(Paper
is
respiration
(Paper
out
and
aerobic
complete
the
word
equation
respiration:
[1]
+
5
the
by
respires
energy
little
is
of
A
C
debt
absorbed
[1]
This
4
[1]
not
have
oxygen
→
+
+
mitochondria?
[4]
A
ciliated
B
liver
epithelial
cell
A
to
C
student
muscle
nd
red
the
blood
student
apparatus.
cell
opened
(Paper
2)
the
of
for
took
After
apparatus
respiration
several
each
several
[1]
sealed
142
up
rate
shown
of
opposite
crickets.
cell
The
D
set
cell
again.
readings
reading
minutes
the
before
from
clip
the
was
being
spring
clip
time
/
0
5
10
15
20
25
30
35
0
0
0
31
65
95
130
162
minutes
position
of
liquid
/
droplet
mm
(a)
Explain
why
crickets
wire
soda
lime
carbon
gauze
(i)
a
water
(ii)
the
apparatus
before
The
calculate
the
direction
in
which
the
closing
diameter
0.8 mm.
State
was
used
was
left
the
clip.
for
ten
minutes
absorbs
dioxide
(b)
(b)
bath
Use
of
the
the
the
capillary
results
rate
of
[2]
in
tube
the
oxygen
is
table
to
uptake
coloured
3
in
drop
will
move
apparatus.
as
the
Explain
crickets
your
respire
in
mm
per
hour.
answer.
(c)
[4]
Explain
how
the
investigation
(c)
Explain
why
the
clip
is
opened
after
(d)
readings.
State
one
constant
10
Copy
factor
during
that
the
should
be
(Paper
kept
investigation.
complete
The
rst
(a)
the
row
table
has
with
been
ticks
an
completed.
sisehtnysotohp
negyxo
a
series
of
catalysed
reactions
produces
carbon
noitpmusnoc
✗
/
✓
oxygen
of
graph
athlete
short
shows
who
period
of
enzyme-
all
The
of
after
rest.
0.0
5
10
15
dioxide
time
the
time
20
/
25
30
35
minutes
Describe
the
change
in
oxygen
(night
3)
over
the
35
of
shown
the
apparatus
in
effect
respiration
of
was
question
of
Pinto
put
9
was
temperature
used
on
the
Explain
was
the
clip
minutes
taken.
that
[4]
closed
over
and
time.
the
The
changes
(i)
10
and
(ii)
20
to
in
oxygen
between
20
minutes
[6]
beans.
into
open.
the
consumption
a
water
bath
After
ten
position
results
of
are
minutes
the
as
30
minutes.
[5]
at
(Paper
with
recorded
were
[5]
apparatus
27 °C
clip
minutes
day)
determine
rate
consumption
10
0.5
(c)
to
for
energy
place
(Paper
The
oxygen
[1]
1.0
recordings
11
cells
1.5
consumption
and
the
exercised
animal
respiration.
2.0
(b)
takes
inside
aerobic
2.5
0
releases
structures
out
md
cells
the
carry
3
plant
nim
consists
[4]
1–
produces
in
the
3.0
noitaripser
feature
only
if
and
4)
Name
The
and
a
occurs
differ
17 °C
[1]
3)
crosses.
at
50 °C.
that
and
would
repeated
[2]
12
(Paper
results
was
taking
at
the
[3]
the
4)
the
droplet
follows.
143
13
Excretion
13.1
Excretion
LEARNING
OUTCOMES
Excretion
•
Dene
•
Name
the
term
is
the
metabolism,
and
•
the
Describe
in
excretory
excretory
the
the
removal
from
the
body
of
the
waste
products
of
excretion
The
organs
organs,
products
role
of
assimilation
the
of
waste
toxic
materials
substances
which
are
are
the
and
substances
removed
lungs,
liver
from
and
in
the
excess
body
kidneys
of
by
(see
requirements.
the
excretory
Figure
13.1.1).
liver
amino
Excretory
products
acids
Humans
•
Dene
have
two
main
excretory
products.
deamination
•
Carbon
dioxide
transported
of
•
the
to
blood
page
130).
Urea
is
is
the
into
made
in
made
lungs
the
the
air
liver
in
in
in
body
the
blood
the
from
tissues
plasma.
alveoli
excess
during
and
is
amino
respiration.
Here,
it
diffuses
breathed
acids.
It
is
It
out
is
out
(see
carried
to
lungs
the
excrete
kidneys
the
plasma
where
it
is
ltered
out
and
leaves
the
carbon
body
dioxide
dissolved
Excretion
liver
is
substances
processes
materials
a
in
vital
like
the
form
process
carbon
of
in
urine.
the
dioxide
metabolism
and
urea
of
would
the
be
body.
Without
allowed
to
it,
build
toxic
up
makes
in
in
the
tissues.
These
substances
would
reach
a
toxic
level
and
and
destroy
them
the
tissues.
harmless
Do
kidneys
excrete
not
are
13.1.1
The
excretory
are
egested
canal
with
‘egestion’.
body
cells
in
Substances
metabolism.
that
are
Substances
have
been
without
eaten
being
and
have
digested
passed
and
through
absorbed
into
the
the
organs.
bloodstream.
hepatic
by
salts
alimentary
Figure
‘excretion’
produced
urea
that
and
confuse
excreted
Fibre
is
an
example.
vein
Assimilation
stomach
Assimilation
now
become
means
part
of
that
the
the
cells
food
or
molecules
are
used
by
that
the
have
been
absorbed
cells.
liver
portal
tnemelppuS
hepatic
vein
The
liver
carries
out
a
number
of
important
functions
as
part
of
assimilation:
•
stores
glucose
glycogen.
blood
by
This
(see
removing
helps
page
to
it
from
regulate
the
the
blood
and
concentration
storing
of
it
as
glucose
in
the
166)
large
intestine
•
uses
amino
brinogen,
acids
to
make
involved
with
proteins,
blood
such
as
plasma
proteins,
e.g.
clotting
small
intestine
appendix
anus
rectum
•
breaks
•
converts
body,
Figure
13.1.2
The
position
portal
of
the
fatty
e.g.
excess
acids
under
amino
and
the
acids
glycerol
into
fat
which
skin
hepatic
vein.
•
144
down
produces
cholesterol
from
fats
(see
page
71).
is
stored
around
the
tnemelppuS
Roles
The
see
of
liver
the
carries
from
liver
out
Figure
over
13.1.2,
200
all
different
the
blood
roles
from
in
the
the
body.
digestive
As
you
system
STUD
Y
can
TIP
ows
Deam
inat
ion
to
the
liver
rst
before
going
into
the
rest
of
the
circulation.
breakd
own
amino
acids
produced
in
the
alimentary
canal
by
the
digestion
cannot
is
are
absorbed
store
broken
the
down
into
amino
into
the
acids
two
blood
that
parts.
it
in
the
small
cannot
One
of
use
these
intestine.
and
parts
so
is
Your
each
made
of
of
amin
o
protein
is
The
acid
s
body
amm
onia
.
molecule
into
to
mak
e
Urea
prod
uctio
n
urea.
the
excess
is
a
sepa
rate
proces
s.
Other
it
roles
enters
breaks
and
of
the
the
liver
small
down
harmful
include
intestine,
hormones
that
substances,
making
and
have
such
bile,
emulsies
as
which
fat
circulated
alcohol
in
and
neutralises
(see
the
page
84).
blood
drugs
(see
for
acid
The
a
page
as
liver
while
178).
cells
protein
gut
some
acids
into
digestion
amino
are
built
protein
make
new
to
excess
cells
taken
amino
to
the
changed
acids
liver
into
are
and
urea
urea
KEY
1
POINTS
Excretion
is
the
removal
from
liver
the
amino
Figure
acids
13.1.3
made
This
shows
what
happens
to
amino
acids
in
the
body.
that
acids
are
not
cannot
be
required
stored
for
so
making
the
liver
breaks
proteins.
Each
down
amino
amino
acid
broken
down
into
two
by
the
process
of
is
converted
to
carbohydrate
or
deamination.
fat
and
used
as
carbon
acids
The
other
molecule
is
ammonia
(NH
)
which
chemicals
during
products
dioxide
include
and
urea.
The
lungs,
liver
and
kidneys
One
a
source
excretory
combines
organs.
Carbon
of
dioxide
energy.
tissues
Excretory
are
molecule
waste
molecule
3
is
in
of
metabolism.
2
Amino
body
is
excreted
by
the
lungs.
with
3
to
in
the
dioxide
kidneys
urine
(see
contains
to
in
form
the
page
nitrogen
the
146).
is
excretory
blood
where
The
known
part
as
it
of
the
product
is
ltered
the
urea.
out
amino
amino
acid
group
–
This
and
is
is
carried
molecule
this
is
4
is
called
deamination
because
this
group
is
why
liver
liver
breaks
down
toxins,
for
example
drugs
urea
acids.
excrete
from
The
urea
in
urine.
the
The
liver
breaks
down
toxins
removed.
such
The
makes
amino
kidneys
that
5
process
The
excess
excreted
such
as
alcohol
as
alcohol
and
drugs.
and
6
The
liver
uses
amino
acids
to
paracetamol.
make
proteins
proteins
SUMMARY
QUESTIONS
7
Deamination
of
1
a
Explain
and
i
how
then
tnemelppuS
Distinguish
3
Describe
of
removed
carbon
2
each
what
from
dioxide
between
these
excretory
the
ii
excretion
happens
during
products
body:
are
produced
and
excess
liver
is
to
into
as
plasma
brinogen.
is
the
amino
form
made
such
breakdown
acids
in
ammonia,
the
which
urea.
urea
and
egestion.
deamination.
145
tnemelppuS
carbon
13.2
Kidney
The
LEARNING
Describe
kidneys
OUTCOMES
The
•
the
structure
of
kidneys
•
Describe
the
in
role
of
They
also
Describe
Your
control
kidneys
the
internal
of
the
of
urinary
urea
system.
and
excess
the
units
fat
the
water
at
the
They
that
top
are
and
ion
of
your
content
of
abdominal
protected
surrounds
chemicals
STUD
Y
out
TIP
of
the
a
body
cons
ists
subst
ance
s
water
.
becaus
e
It
one
pigm
ent.
plasm
a
of
is
the
a
in
yello
w
in
If
by
the
been
then
the
of
are
in
blood
urin
e.
At
or
the
it
a
As
to
form
tubule
the
lot
cavity
just
underneath
lower
ribcage
water
day
and
back
you
the
blood
a
ows
water
uid
of
are
ltrate.
are
the
ltering
these
urea,
substances
depends
will
much
water.
have
on
the
water)
exercise,
as
you
of
or
as
units
forced
As
the
(glucose
If
produce
because
you
not
body’s
perhaps
they
can
it
and
water
because
is
so
have
been
very
you
taken
you
hot,
produce
in
sweating,
dilute
of
and
at
each
to
the
intervals,
carries
the
tubule
the
bladder
through
blood
with
a
urine
where
a
shorter
low
is
it
released
is
stored.
tube
a
lot
the
of
kidneys
urine.
and
concentration
of
the
here
into
it
the
leaves
urethra.
waste
The
chemicals
the
renal
away
kidney.
renal
vein
blood
away
kidneys
and
ows
From
called
takes
from
‘cleaned’
the
remove
other
from
the
artery
brings
waste
to
kidneys
the
kidneys
in
the
blood
urea
chemicals
blood
KNOW?
kidney
you
as
and
through
through
and
renal
YOU
blood
network
known
useful
the
kidneys
complex
salts,
(short
conserve
and
a
into
blood.
during
take
is
the
reabsorbed
and
cold
the
glucose,
into
a
will
urine
is
less
end
ureter
from
has
are
a
million
born,
decreases
but
with
tubules
the
age.
ureters
to
the
carry
urethra
out
Figure
of
carries
the
13.2.1
ring
urine
The
of
closed
body
urinary
system.
urine
down
bladder
bladder
146
body.
that
vein
number
the
blood.
backbone,
cells
enters
kidney
dehydrated
sweating
concentrated
reabsorb
the
water
kidneys
as
from
Blood
each
plasma
along
you
diffuse
tubules.
reabsorbed
have
body,
when
the
them.
kidneys.
such
blood
volume
water,
a
water
,
are
urea
Inside
kidney
passes
content.
wast
e
compo
und
and
The
yello
w
Urea is
colou
rless
disso
lves
wast
e
disso
lved
is
subst
ance
s
of
salts)
uid
like
the
molecules,
ltrate
Urin
e is
to
arteries.
called
small
Each
are
from
kidney
renal
DID
They
salts
structure
transported
in
are
diaphragm.
Waste
that
part
excretion
the
and
the
up
the
excretion
the
of
for
system
kidneys
•
make
the
responsible
urinary
structure
stores
urine
muscle
until
you
keeps
the
urinate
bladder
If
you
cut
cortex
and
the
–
the
kidneys
open
a
a
kidney
brown
pelvis
–
lengthways,
outer
a
area,
white
the
you
can
medulla
–
see
a
three
reddish
areas:
inner
the
area,
area.
medulla
cortex
medulla
pelvis
renal
artery
brings
to
the
renal
takes
A
kidney
with
A
kidney
cut
part
of
the
ureter
attached.
vein
blood
away
the
blood
kidney
from
kidney
ureter
one
kidney
collecting
tubule
cortex
duct
Figure
13.2.2
A
vertical
of
Inside
which
each
you
the
kidney
can
see
section
kidney
are
of
(left
a
kidney
hand
thousands
only
with
a
(right
hand
side).
Detailed
view
of
part
side).
of
tiny
tubes
microscope.
called
The
kidney
function
of
tubules
the
medulla,
kidney
tubules
determine
is
how
the
cortex.
the
body
The
in
to
lter
much
water
waste
the
urine
the
blood
is
remove
excreted.
chemicals
which
and
and
ows
The
excess
from
waste
ltering
water
the
is
are
kidneys
chemicals
carried
out
removed
down
the
is
stored
in
the
with
POINTS
The
urinary
kidneys,
structure
of
the
artery
in
the
functions
stores
ureter
in
urinary
the
system
right
in
the
left
column
2
The
internal
kidney
column.
lters
kidney
urea
carries
bladder
carries
renal
carries
and
other
waste
chemicals
out
of
the
blood
3
The
vertical
A
cortex
B
blood
with
a
high
concentration
of
a
Distinguish
b
What
the
is
urine
blood
section
medulla
down
to
with
low
of
C
between
the
kidneys
c
Distinguish
d
Name
the
a
the
concentration
kidney
renal
and
artery
D
of
not
main
and
excretion
nitrogenous
where
between
is
the
substances
found
inner
of
a
outer
medulla.
the
it
and
renal
vein
E
in
in
the
urine
of
a
take
substances
back
into
the
and
the
product
glucose,
quantity
the
urine
the
urine.
of
and
control
water
excrete
The
ureters
bladder
excreted
by
5
The
carry
from
volume
the
lost
in
urea
in
depends
urethra.
blood
plasma
on
and
urine
to
the
kidneys.
and
concentration
the
health
e.g.
the
ureter
produced?
found
materials
label:
egestion.
waste
ureter
lter
blood,
urea
of
the
how
urine
intake
much
of
water
which
has
are
an
bladder
water
two
of
urea
4
3
an
kidneys
of
blood,
vein
a
bladder
structure
consists
and
useful
Sketch
ureters,
of
urine
out
2
consists
urethra.
cortex
renal
system
QUESTIONS
each
one
cortex,
bladder.
and
Match
the
from
the
1
show
ureter
.
ureter
1
SUMMARY
to
and
in
KEY
and
open
pelvis
and
been
lost
in
sweat
during
person.
exercise
and
in
hot
weather.
147
tnemelppuS
tnemelppuS
Inside
13.3
Kidney
tnemelppuS
Structure
LEARNING
Describe
the
structure
of
containing
Inside
Describe
the
role
of
the
in
ltration,
removal
and
excess
water
and
of
reabsorption
of
glucose
Each
of
chemicals
these
capillaries
the
ows
renal
into
artery
the
kidney
branches
in
many
the
renal
times
to
give
arterioles
called
a
supplies
blood
to
a
closely
packed
glomerulus
ltration,
blood
ows
out
of
the
glomerulus
into
another
the
arteriole.
Blood
then
ows
into
capillaries
around
the
rest
of
the
and
tubule,
some
waste
kidney,
of
After
urea
the
kidney
group
tubule
tubule
tubule
arterioles.
•
kidney
a
artery.
kidney
a
OUTCOMES
Blood
•
of
function
which
joins
to
form
the
renal
vein.
The
kidney
tubule
itself
salts
consists
of
the
The
of
a
Bowman’s
tubule
being
glomerulus
Figure
13.3.1
is
capsule
pushed
found
shows
in
like
inside
that
the
at
one
the
the
end.
This
nger
of
Bowman’s
tubule
forms
a
is
a
formed
rubber
by
the
end
glove.
capsule.
loop
which
goes
deeper
Bowman’s
into
the
medulla
and
back
to
the
cortex
(see
page
147).
The
end
of
capsule
branch
renal
of
the
kidney
tubule
the
medulla
drains
into
a
collecting
duct
which
goes
through
vein
and
empties
urine
in
the
pelvis
and
then
ows
into
the
ureter.
DID
YOU
KNOW?
collecting
People
on
taught
to
survival
courses
are
duct
assess
dehydration
blood
capillaries
wrapped
colour
of
yellow
the
by
their
their
looking
urine.
urine,
dehydrated
level
the
the
at
The
of
the
darker
more
person.
round
tubule
Figure
blood
Kidney
tubule.
glomerulus
with
waste
e.g.
13.3.1
Filtration
Look
filter
reabsorption
Filtration
urea
small
and
chemicals,
at
Figure
13.3.2
showing
how
a
kidney
tubule
works.
molecules
through
The
kidneys
renal
are
close
artery
is
high.
glomerulus
is
wider
to
You
the
heart
can
see
so
the
blood
pressure
that
the
blood
vessel
in
the
entering
the
Bowman’s
capsule
blood
entering
pressure
to
situation).
useful
the
than
is
this
one
glomerulus
increase
It
the
inside
the
pressure
leaving
than
it.
there
glomerulus
that
causes
is
So
leaving
(it’s
the
there
must
it.
rather
blood
to
be
This
like
be
a
more
causes
bottleneck
ltered.
substances
reabsorbed
into
The
lining
of
the
capillaries
is
like
a
net
with
tiny
holes
in
it.
Blood
blood
cells
and
through
filtrate
(urea,
some
like
large
the
urea,
molecules,
capillary
glucose,
like
lining
salts
blood
and
and
so
water,
proteins,
stay
pass
in
are
the
out
too
blood.
of
the
big
to
Small
pass
molecules,
glomerulus
and
‘cleaned’
salts
and
water)
blood
Figure
148
13.3.2
Filtration
and
reabsorption.
into
the
Bowman’s
capsule.
It
is
in
this
space
that
the
ltrate
collects.
microvilli
All
of
the
the
body.
tubule.
If
you
will
•
glucose,
They
This
look
see
some
are
salts
reabsorbed
reabsorption
at
the
of
a
back
large
of
into
active
the
associated
provide
much
involves
structure
adaptations
microvilli
and
cells
with
surface
the
the
water
blood
transport
in
the
active
area
wall
are
needed
from
(see
of
the
page
the
mitochondrion
by
kidney
35).
tubule,
you
transport:
for
Figure
absorption.
13.3.3
An
epithelial
lining
•
numerous
After
the
dissolved
water
enters
and
the
The
process
in
may
the
then
mitochondria
be
reabsorption,
As
bladder.
the
leaving
of
uid
if
ducts
ureter
From
concentration
this
reabsorbed
collecting
to
blood
of
water.
provide
and
here
the
it
waste
is
It
in
the
for
active
left
is
low
in
Urine
through
renal
and
the
water.
down
vein
The
the
a
uid
that
and
is
at
much
duct
stored
STUD
Y
TIP
in
Reabs
orptio
n
intervals.
and
lower
salts
diffus
chemicals.
ion
and
to
diagram
of
the
kidney
tubule
and
by
a
glomerulus
branch
2
Describe
3
The
of
b
the
what
table
body
activ
e
is
osmos
is.
explai
n
Bowman’s
renal
happens
shows
the
capsule
vein
in
e
c
branch
kidney
collecting
of
the
tubules
concentrations
of
to
ve
in
label:
kidn
ey
d
by
Wat
er
reabso
rptio
n
a
gluc
ose
QUESTIONS
Expe
ct
Sketch
of
occu
rs
reabso
rbed
1
the
tubule.
salts
tran
sport.
SUMMARY
from
kidney
some
collecting
urethra
has
excess
tubule,
collects
the
cell
the
transport.
urea
through
ows
bladder.
expelled
kidney
is
on
body
urine.
the
is
what
ows
the
is
energy
of
duct
renal
form
to
artery
these
page
s
by
the
referr
ing
proces
ses
30
and
(see
34).
urine.
substances
in
three
uids.
–3
concentration
substance
blood
in
renal
ltrate
/
g
dm
in
urine
artery
kidney
tubule
urea
0.2
0.2
20.0
glucose
0.9
0.9
0.0
amino
0.05
0.05
0.0
KEY
1
acids
POINTS
Blood
is
ltered
through
salts
8.0
8.0
removing
16.5
and
protein
82
0
a
the
information
state
the
kidney
in
the
substances
table
that
to:
pass
The
explain
the
blood
into
of
the
the
into
tubule,
kidney
c
state
the
d
how
substances
you
have
named
pass
into
3
substances
kidney
tubule
the
that
and
results
are
reabsorbed
explain
for
why
passes
salts,
glucose
they
into
are
the
blood
reabsorbed,
materials
some
water
the
are
blood
the
salts
such
and
as
most
reabsorbed
capillaries
tubule.
the
tubule,
the
explain
the
urea,
useful
along
b
it
water.
glucose,
from
as
glomerulus
0
2
Use
the
from
Urine,
some
out
consisting
salts
of
the
and
of
kidneys,
ureters,
to
bladder
until
be
urea,
water
passes
along
stored
in
the
the
protein.
urination.
149
tnemelppuS
Reabsorption
13.4
Kidney
kidney
tnemelppuS
The
LEARNING
Describe
the
process
and
person
explain
how
the
concentration
machine
urea
and
can
salt
in
or
survive
on
damaged,
one
it
kidney.
can
be
However,
fatal
unless
a
if
both
kidneys
medical
become
procedure
as
kidney
dialysis
is
available.
A
common
indicator
that
of
the
glucose,
dialysis
it
known
controls
transplants
of
diseased
dialysis
and
OUTCOMES
A
•
kidney
dialysis
kidney
is
damaged
is
the
presence
of
protein
in
the
urine.
This
the
happens
when
the
glomeruli
are
damaged
so
that
large
molecules
of
blood
protein
•
Describe
how
machine
works
a
kidney
pass
out
of
blood
plasma
into
the
ltrate.
dialysis
‘clean’
blood
passes
from
the
arter y
machine
•
Describe
and
the
to
a
vein
advantages
disadvantages
of
vein
kidney
dialysis
transplants
compared
with
dialysis
fluid
blood
carr ying
fluid
blood
in
wastes
dialysis
dialysis
fluid
dissolved
useful
salt
Dialysis
This
machine.
cleaner
blood
fresh
back
body
fluid
to
is
what
•
A
tube
•
The
•
Inside
is
vein
has
a
in
the
sugar
machine
and
salts
it
the
diffuses
Renal
like
sugar
dialysis
thin
fluid
membrane
out
partially
blood
and
permeable
separating
from
dialysis
fluid
blood
into
dialysis
fluid
dialysis.
happens
when
connected
to
someone
one
of
the
has
dialysis
patient’s
treatment.
veins.
dialysis
flowing
dialysis
over
blood
ows
along
the
tube
and
into
the
machine.
membrane
•
•
the
machine
dialysis
membrane,
dialysis
uid.
Urea
into
The
no
diffuses
the
out
dialysis
dialysis
overall
the
urea
13.4.1
to
from
substances
stay
waste
Figure
in
passes
blood
which
of
the
is
pumped
separates
blood,
the
across
over
the
patient’s
the
surface
blood
dialysis
of
and
a
the
membrane
and
uid.
uid
loss
the
of
already
has
glucose
glucose
and
salts
and
from
salts
the
in
it,
blood
so
by
there
will
diffusion
be
into
uid.
urea
•
Urea
and
other
waste
chemicals
leave
the
machine
in
the
dialysis
uid.
•
dissolved
The
patient’s
‘cleaner’
blood
passes
back
into
the
vein.
protein
The
blood
flow
dialysis
patient
times
from
body
has
to
use
the
dialysis
machine
for
several
hours,
two
or
three
fluid
(dialysate)
a
week.
This
may
involve
attending
a
special
ward
in
hospital
or
it
to
can
be
done
at
home.
Between
visits
to
the
dialysis
ward
of
the
hospital,
waste
patients
eat
a
restricted
diet
without
too
much
protein
and
salt.
If
they
dialysis
membrane
Figure
150
13.4.2
Dialysis.
eat
too
toxic
much
and
protein,
would
mean
they
will
more
produce
frequent
too
much
dialysis
urea
which
treatment.
becomes
tnemelppuS
Dialysis
KEY
Dialysis
involves
the
separation
of
two
solutions
by
a
partially
1
membrane.
This
dialysis
membrane
has
tiny
pores
in
it
POINTS
permeable
which
A
dialysis
small
water
and
small
solutes
to
diffuse
through,
but
not
larger
molecules
proteins.
In
the
case
of
kidney
dialysis
the
blood
is
pumped
over
molecules
of
a
dialysis
membrane
which
contains
a
uid
(the
pores
water
has
the
normal
potential
as
concentrations
normal
of
salts
and
glucose
and
is
the
molecules
dialysis,
solute
molecules
2
such
as
salts
and
During
glucose
the
membrane.
As
the
dialysis
uid
has
the
as
normal
blood
plasma,
the
same
concentrations
of
into
as
blood
proteins,
reach
equilibrium
and
are
the
the
Excess
dialysis
salts,
membrane
Kidney
uid,
urea
into
so
and
the
they
other
diffuse
toxic
out
of
restored
chemicals
are
the
and
blood
person
not
is
no
net
since
failed
3
may
have
a
kidney
transplant.
This
the
diseased
kidney
with
a
healthy
one
from
a
donor
.
the
Kidney
be
Before
type
a
a
of
close
relative
kidney
donor
or
friend
transplant
and
is
recipient
or
someone
carried
(the
out,
person
who
the
has
just
blood
receiving
typing
Blood
reduces
typing
the
is
the
chances
same
that
as
the
for
blood
attack
the
new
kidney
and
recipient’s
reject
it.
To
A
and
kidney)
immune
the
occuring,
drugs
are
given
to
the
patient
transplants
be
there
may
nding
a
there
suppress
means
those
they
the
immune
are
more
infections
for
system.
likely
to
They
catch
remain
certain
on
these
infections
the
problems
suitable
is
always
donor
the
risk
of
rejection.
must
be
QUESTIONS
Tissue
system
Explain
the
why
for
and
the
presence
of
protein
in
the
urine
may
operation
indicate
to
avoid
dialysis,
donor
chances
after
uid.
but
of
rejection
same
blood
tissue
transfusion.
reduce
of
involves
1
will
the
died.
type
the
dialysis
SUMMARY
matched.
in
the
of
tissue
may
in
inconvenience
and
replacing
is
the
dialysate.
kidneys
diffusion
it
present
across
transplants
with
the
to
in
A
of
uid.
solutes,
and
in
urea
out
dialysis
concentration
normal.
pass
water
glucose,
such
dialysis,
salts
diffuse
There
potential
kidney
some
blood
through
from
through.
same
plasma.
and
During
pass
prevents
dialysate)
diffusing
which
to
but
the
large
surface
allows
such
through
as
membrane
allow
life,
to
kidney
damage.
which
2
have
Figure
13.4.3
version
longer.
of
a
shows
kidney
a
simple
dialysis
machine.
After
recovering
normal
dialysis
life,
including
treatment
functions
of
a
continuously
They
in
a
also
bone
a
marrow.
match
a
a
operation
normal
not
urea
and
there
to
have
that
it
is
at
is
patient
and
does
home.
some
from
However,
the
diet,
or
just
hormone
people
kidney
the
hospital
remove
wealthy
donate
in
kidney,
make
suitable
Some
from
the
of
them
blood
always
resorted
to
the
to
able
not
as
with
rather
red
nd
danger
paying
to
at
cell
healthy,
all
The
uid
production
a
is
rejection.
poor
people
by
blood
from
a
the
partially
Name
the
which
urea
the
to
permeable
blood
process
by
passes
into
from
the
dialysis
them.
Explain
how
concentrations
dialysis
fluid
and
Make
the
salts
returned
normal
while
on
a
table
to
advantages
show
and
fluid
disadvantages
dialysis
fluid
partially
waste
of
are
dialysis.
fluid
3
dialysis
glucose
in
to
dialysis
and
kept
uid.
b
dialysis
is
dialysis
membrane.
intervals.
that
patient’s
separate
the
Kidneys
kidney
tissue
a
have
dialysis.
donor
of
lead
replace
than
blood
a
to
need
Transplants
stimulates
difcult
is
and
of
kidney
kidney
permeable
out
transplants.
membrane
Figure
13.4.3
Simple
version
of
a
kidney
dialysis
machine.
151
PRACTICE
1
Which
QUESTIONS
substances
healthy
are
found
in
the
urine
of
a
7
person?
The
conversion
proteins,
occurs
A
glucose
and
proteins
B
glucose
and
water
C
proteins
D
salts
(Paper
and
and
The
water
C
B
kidneys
D
(Paper
[1]
part
A
of
it
system
from
the
liver
lungs
8
As
part
makes
urine,
stores
it
the
urinary
body.
Which
organ
[1]
of
an
investigation,
collected
from
a
samples
person
of
urine
throughout
a
and
is
hour
period.
The
urine
sample
collected
not
early
in
the
than
the
morning
was
more
concentrated
system?
kidney
C
liver
D
ureter
(Paper
1)
samples
Which
is
the
collected
used
to
make
less
urea
B
less
water
C
the
the
amino
was
later
in
the
blood
day.
B
excess
fatty
C
excess
glucose
the
D
excess
hormones
9
The
is
from
day
the
urine
night
concentration
decreased
day
concentration
at
of
the
blood
plasma
night
2)
[1]
diagram
blood
Which
the
this?
acids
(Paper
1)
at
for
acids
increased
(Paper
during
reabsorbed
tubules
glucose
the
explanation
produced
was
renal
likely
urea?
D
excess
most
A
in
[1]
is
during
shows
the
urinary
system
and
its
supply.
[1]
(a)
4
plasma
brinogen,
bladder
B
A
to
and
2)
Which
3
acids
organ?
heart
24
removes
which
amino
albumen
salts
1)
urinary
in
of
as
A
were
2
such
the
blood
concentration
of
A
aorta
B
renal
artery
C
renal
vein
C
vena
vessel
with
the
lowest
(i)
(ii)
urea?
Name
State
A
to
parts
the
A
to
D.
functions
[4]
of
structures
D.
[4]
B
5
A
cava
(Paper
1)
[1]
Which
process
ltrate
in
the
A
active
B
cohesion
C
diffusion
D
osmosis
reabsorbs
renal
glucose
from
the
C
tubules?
transport
D
(b)
(Paper
2)
(i)
The
of
6
Which
is
following
is
a
list
of
components
[1]
not
an
A
breakdown
B
deamination
excretory
of
function
of
the
liver?
the
found
alcohol
blood
blood.
in
the
Identify
urine
proteins,
platelets,
red
of
those
that
healthy
urea,
blood
are
people.
glucose,
cells,
salts,
water
C
production
D
protein
of
(ii)
State
three
2)
[1]
(Paper
152
factors
that
affect
the
synthesis
volume
(Paper
[1]
urea
2)
and
concentration
of
urine.
[3]
10
Ammonia
waste
is
produced
product
of
by
their
all
animals
as
11
a
A
man
shows
(a)
Ammonia
produced
by
humans
to
urea.
Explain
why
how
this
blood
table
in
shows
the
The
concentration
of
regular
graph
over
the
17
urea
days
in
of
and
for
10
days
his
afterwards.
the
renal
composition
artery,
of
ltrate
in
blood
3.0
Bowman’s
/
g
dm
urine
capsule
artery
aeru
renal
Bowman’s
in
eht
plasma
doolb
in
/
ltrate
blood
substance
2.0
g
−3
concentration
2.5
md
noitartnecnoc
urine.
3–
and
received
days.
[3]
ni
capsule
17
is
necessary.
plasma
the
failure
for
changed
treatment
The
kidney
treatment
is
his
converted
with
dialysis
metabolism.
1.5
1.0
0.5
urea
0.2
0.2
20.0
glucose
0.9
0.9
0.0
amino
0.05
0.05
0.0
8.0
8.0
0.0
0
5
10
15
time
acids
mineral
ions
82
0.0
0.0
State
Explain
four
of
table
the
are
protein
(ii)
glucose
present
(iii)
the
substances
present
is
is
shown
the
in
ltrate,
the
amino
the
higher
acids
are
not
the
in
of
the
blood
(i)
[2]
urea
urine
and
than
in
the
in
the
renal
concentration
in
how
the
renal
ltrate
is
artery
of
has
urea
(ii)
times
the
give
support
person
the
your
received
evidence
from
answer.
[2]
vein.
formed
a
(d)
the
of
decrease
urea
dialysis
in
until
in
the
day
the
concentration
blood
27.
from
Show
the
your
[2]
Describe
the
the
concentration
urea
in
Explain
Kidney
organ
[2]
in
the
man’s
changes
the
the
that
in
occur
the
in
blood
graph.
changes
[4]
that
you
have
described.
than
of
(e)
[3]
transplants
transplants.
having
with
kidney.
[4]
a
kidney
continuing
Before
living
(Paper
to
shown
mineral
[3]
blood
higher
Explain
days
working.
(c)
urine
the
start
[2]
ltrate
(c)
many
treatment;
graph
Calculate
of
but
not
and
in
in
concentration
ions
(iv)
30
why
(b)
(i)
how
dialysis
the
(b)
25
16.5
(a)
protein
/
20
a
kidney
donor,
it
are
is
most
Describe
the
transplant
with
is
the
dialysis
advantages
compared
treatment.
transplanted
important
common
from
that
the
[3]
a
donor
4)
and
the
types.
is
If
used
the
a
kidney
then
recipient
why
(Paper
recipient
these
it
is
as
have
from
also
compatible
a
deceased
tissue
closely
procedures
as
are
typed
blood
person
to
possible.
match
Explain
necessary.
[3]
4)
153
14
Coordination
14.1
All
LEARNING
Describe
living
impulses
signals
nerve
that
as
pass
of
Describe
your
the
structure
of
that
nervous
tnemelppuS
Distinguish
are
sensitive
to
cells
are
changes
in
their
temperature,
called
that
detect
glands
speed,
environment;
stimuli
detect
the
chemicals
and
in
muscles,
movement,
the
(singular:
stimuli;
your
that
for
food.
bring
availability
stimulus).
example,
Effectors
about
cells
are
the
responses.
secrete
useful
substances
and
muscles
contract
to
bring
about
system
between
involuntary
the
as
wind
detect
buds
such
The
actions
they
take
as
a
result
are
called
responses.
voluntary
Animals
and
they
taste
movement.
•
are
daylight,
the
Glands
human
in
Receptors
in
cells
food
organs,
•
organisms
OUTCOMES
nerve
electrical
control
humans
changes
along
response
Nervous
in
•
and
have
nervous
systems
which
at
their
simplest
are
networks
of
actions
specialised
complex,
human
for
nerve
they
brain.
detecting
cells,
as
in
are
organs
T
wo
organ
changes
in
jellysh
with
systems
our
and
sea
powerful
are
anemones.
processing
involved
environment
–
and
the
the
At
skills,
their
such
sensory
nervous
most
as
the
system
system
for
cranial
coordinating
brain
ner ves
central
our
responses
and
initiating
actions.
Here
we
discuss
the
peripheral
nervous
system.
The
nervous
system
is
involved
in
the
coordination
ner vous
ner vous
spinal
and
spinal
regulation
sensory
system
Human
The
functions.
Topic
14.4.
The
the
spinal
by
You
will
nd
information
about
the
nerves
brain
and
to
spinal
main
parts
nervous
of
the
system.
Each
by
a
but
also
the
nerve
is
you
need
information
STUD
Y
in
up
passing
Voluntary
actions
along
link
the
and
a
nerve
see
nerve
two
by
to
system
organs:
the
skull
different
side
(PNS).
the
and
legs.
cells
the
with
brain
the
impulses
all
or
of
the
Cranial
brain
the
Spinal
Spinal
the
visible
neurones.
parts
system.
of
brain
are
central
column.
between
Nerves
to
of
of
only
abdomen.
and
the
nervous
nervous
either
spaces
lots
microscopes
electricity
on
abdomen
of
parts:
protected
connected
thorax
tube.
form
is
of
vertebral
nerves
the
two
up
peripheral
through
brous
the
is
pairs
thorax,
made
in
the
of
peripheral
made
brain
the
in
the
is
by
Cranial
pairs
protective
up
are
some
arms,
in
The
system
make
nerves
consists
and
system
cord.
nervous
that
cord
system
protected
respectively.
head
human
is
spinal
cord
The
spinal
system
(CNS)
nervous
cord
central
and
14.1.1
nervous
system
central
and
The
nervous
human
nervous
and
nerves
spinal
organs
nerves
nerves
body
in
the
link
leave
the
the
vertebrae.
neurones
to
the
Neurones
which
are
surrounded
naked
eye,
transmit
like
pulses
of
wire.
TIP
Rem
embe
r:
trans
mit
ner ve
cells
impu
lses,
‘messa
ges’.
not
decision
or
a
she
making.
kicks
voluntary
the
154
body
in
ner ves
cord
Figure
of
system
system
brain.
a
are
A
ball.
action.
under
conscious
footballer
T
urning
These
carries
over
the
actions
control
out
a
pages
are
and
involve
voluntary
of
under
a
the
book
the
action
is
an
conscious
brain
when
he
example
control
in
of
of
We
make
having
two
to
types
think
unconsciously
.
heart
are
time,
but
the
four
we
ileum
other
the
When
does
This
can
person
it,
not
is
to
stimulus
The
effectors
to
is
to
a
you
have
them
very
of
on
breathing
are
and
in
the
in
sharp
the
that
are
our
(see
we
most
we
us
occur
of
of
of
page
can’t
those
that
beating
of
Movement
ureter
studied
without
actions
conscious
occasionally
.
occur
a
not
actions
quick,
automatically
involuntary
the
the
food
146)
control
choose
in
are
by
to
make
brains.
object
automatic
such
as
a
response
pin
that
without
the
person
about.
a
simple
pin
the
happen
urine
Voluntary
think
the
are
we
control
of
actions
are
blinking,
down
is
Some
These
that
and
make
sits
example
The
82)
actions
there
need
an
choose
them.
decisions
a
actions
page
about
realising
action.
them.
Swallowing,
such
(see
voluntary
of
about
involuntary
thinking
and
and
and
reex
the
muscles
which
receptors
in
the
legs
is
are
an
involuntary
pain
that
sensors
cause
the
in
action.
the
person
skin.
to
get
Front
up
view
of
the
top
part
of
the
nervous
system.
quickly.
The
sequence
of
events
is:
STUD
Y
stimulus
The
→
coordinator
about
the
central
body
and
Some
for
from
page
→
the
to
brain
pain
part
the
system
the
reexes
(see
is
stimulus
nervous
neurones
eye
receptor
coordinator
of
effector.
to
allow
to
be
the
body
This
of
connect
brain
as
we
effector
that
will
other
Inside
neurones
see
in
the
inside
parts
the
to
Y
ou
the
the
the
of
spinal
section
TIP
response
information
happens
with
stimuli.
with
→
connects
always
connections
aware
receptors
involve
the
→
cont
ro l
the
cord,
on
muscles.
on
can
see
157
.
throug
h
SUMMARY
QUESTIONS
1
complete
and
cranial
the
sentences
peripheral
using
spinal
these
brain
neurones
and
nerves
spinal
of
the
cord
body
make
up
make
the
up
nervous
the
are
connected
to
the
brain
the
connected
to
the
spinal
cord.
The
and
nervous
The
human
of
many
specialised
cells
known
made
up
a
Put
the
following
coordinator
words
into
stimulus
the
system
as
correct
effector
tnemelppuS
3
Dene
a
Explain
each
the
voluntary
of
the
above
difference
system
spinal
receptor
(cranial
involuntary
Neurones
action
and
a
3
Some
(not
Give
two
examples
of
involuntary
c
Give
two
examples
of
voluntary
spinal
or
nerve
nerve
actions
under
control).
b
and
nervous
and
transmit
an
(brain
cord)
the
system
nerves).
response
words.
between
system
central
.
sequence:
action.
the
is
2
b
of
nerves
peripheral
2
nervous
system.
and
composed
CNS
.
POINTS
nervous
are
All
coordi
nated
system.
nervous
is
nerves
are
CNS
.
central
1
the
the
words:
KEY
All
arcs
perip
hera
l
and
respon
ses
The
are
reex
160).
ner ve
s
Copy
reex
es
T
hey
into
invo
lving
abou
t
that
simpl
e
page
arra
nged
the
more
neur
ones
cells
impulses.
are
involuntary
conscious
Other
actions
actions.
are
voluntary
and
involve
actions.
conscious
control
by
the
brain.
155
tnemelppuS
tnemelppuS
Involuntary
14.2
Neurones
and
reex
arcs
Neurones
LEARNING
OUTCOMES
Neurones
• Describe
and
transmit
between
the
three
types
found
in
a
reex
these
the
specialised
cells.
Their
structure
allows
them
to
functioning
neurones
in
a
information
contains
the
as
nerve
nucleus
impulses
and
almost
over
all
of
long
the
distances.
cytoplasm,
The
but
cell
there
arc
are
• Describe
highly
of
body
neurone
are
distinguish
thin
long
of
extensions
way
through
of
cytoplasm
the
that
may
be
quite
short
or
extend
a
body.
reex
Sensory
neurones
transmit
impulses
from
sense
organs
to
the
brain
action
and
spinal
cord.
cytoplasm
nucleus
cell
direction
ner ve
a
ending
sense
of
ner ve
body
impulse
in
organ
axon
myelin
ner ve
ending
in
central
the
sheath
ner vous
system
(insulation)
Figure
14.2.1
Motor
cord
A
sensory
neurones
to
effector
neurone.
transmit
organs
–
impulses
muscles
away
and
from
the
brain
and
spinal
glands.
dendrites
This
neurone
has
a
long
axon.
direction
cell
body
central
in
of
nerve
impulse
myelin
the
nervous
axon
sheath
(insulation)
system
neurone
effector
(as
Figure
The
by
diagrams
insulation.
that
Relay
neurones
bodies
with
in
their
the
brain.
Notice
the
cell
nuclei.
used
The
and
a
YOU
axons
KNOW?
of
motor
metre
neurones
whales!
neurones
long.
in
Think
giraffes
neurones
When
may
There
be
about
or
the
over
the
great
of
and
travel
reaches
a
synapse
impulse
rst
in
one
on
by
is
brain
one
side
through
acting
the
at
It
meet,
or
a
an
a
muscle
gland
the
layer
at
100
sensory
in
do
not
across
Since
synapse,
surrounded
by
fat.
separate
This
neurones,
metres
per
which
to
are
second.
neurone.
neurones
cells
insulation
These
motor
cord.
a
the
the
it
touch
synapse
ensures
is
and
an
released
impulses
drugs
other
.
impulse
triggers
transmitter
that
Many
159).
each
When
substance
chemical
system.
page
actually
synapse.
transmitter
(see
rich
myelinated
called
nervous
neurones
formed
(connector)
from
diffuses
synapses
a
Some
they
motor
myelin,
impulses
them
the
form
spinal
neurone.
of
and
as
relay
and
chemical
second
to
quickly
.
between
a
known
impulses
neurone.
the
direction
effects
gap
sensory
is
transmit
neurones
tiny
the
on
the
a
from
very
neurone
pass
two
the
neurones
reexes,
inside
any
show
the
here)
in
either
neurone.
insulation
is
produced
156
above
This
fast
type
short
motor
around
our
neurones
sensory
A
impulses
in
third
are
DID
grow
makes
A
14.2.2
ends
–
is
an
only
travel
produce
in
their
Reex
ner ve
pain
arcs
impulse
from
white
sensor
matter
sensor y
(axons
neurone
extend
of
myelinated
the
length
of
neurones
the
grey
that
spinal
matter
(neurone
cord)
cell
bodies)
spinal
sensor y
cell
cord
neurone
body
pain
sensor
motor
neurone
synapse
inside
forms
muscle
motor
Figure
If
you
and
example
about
of
the
a
hot
object,
you
automatically
a
simple
pain
but
reex.
not
remove
without
Y
our
until
brain
you
your
hand
thinking.
This
receives
have
already
very
is
stimulated
an
The
impulses
hand.
If
you
relied
on
the
brain
to
make
sensory
would
travel
be
to
burnt
the
in
brain
the
and
time
it
took
for
at
the
diagram
impulse
along
above
the
the
the
grey
across
pathway
is
called
stimulus
receptor
is
in
the
the
and
trace
the
pathway
a
reex
sensor
SUMMARY
QUESTIONS
1
complete
the
synapse
a
the
the
hot
ame.
skin.
sentences
grey
reex
cord
The
When
using
arc
it
the
to
a
spinal
relay
cord
the
impulse
(connector)
relay
to
neurone
a
motor
passes
the
impulse
across
a
neurone
in
neurone
impulses
neurones.
the
arm.
transmits
The
the
muscle
is
impulse
the
to
a
effector
This
Inside
to
action
remove
is
the
the
hand
from
the
hot
and
it
object.
response
is
these
reexes
so
are
you
do
protective;
not
harm
words:
relay
effectors
nerve
by
of
synapse
arc
is
in
sensory
In
The
motor
quickly,
and
a
of
Many
Copy
impulse.
along
neurones.
example
heat
matter
a
synapse
contracts
The
an
cord
impulses
muscle
This
generates
spinal
back.
The
the
the
decision
second
Look
sensor
to
neurone
neurone.
to
heat
travels
moved
a
passes
you
the
impulse
Inside
your
neurone
14.2.3
touch
quickly
relay
neurone
muscle
they
happen
very
yourself.
A
B
C
motor
transmitter
are
transmitted
the
to
matter
the
of
spinal
the
D
spinal
The
go
cord
the
impulses
to
leave
.
where
the
impulse
impulses
the
There
is
are
passed
spinal
a
gap
cord
the
next
to
neurones.
along
between
chemical
to
on
neurones
two
substances
neurones
are
to
called
released
to
a
pass
KEY
1
2
Look
a
at
the
Name
diagram
the
parts
of
the
motor
labelled
A
neurone
to
to
the
right:
A
Give
the
functions
of
parts
B,
arc
and
relay
a
Dene
each
of
the
sensory
and
ii
chemical
iii
myelin
Explain
Make
a
of
neurone,
and
an
a
motor
effector
.
Reex
actions
are
rapid,
synapse
transmitter
iv
substance
relay
a
the
function
drawing
of
a
of
relay
i
–
and
neurone
iv
in
the
(connector)
nervous
and
protective.
often
They
coordinate
responses
4
of
following:
automatic
b
up
types
D
2
i
a
made
three
neurone
neurone
3
is
and
neurone:
D
C
reex
receptor
,
a
b
POINTS
neurone.
by
interpret
stimuli
with
effectors.
system.
neurone.
157
14.3
Synapses
tnemelppuS
LEARNING
Dene
the
term
The
neurotransmitter
Describe
•
Describe
nerve
how
an
how
impulse
many
transmission
passes
drugs,
at
across
e.g.
a
heroin,
synapse
and
a
affect
but
synapses
is
a
junction
between
two
the
The
binding
in
two
neurones
meet,
they
do
a
small
The
gap
that
gap
is
carries
the
presynaptic
the
between
called
impulse
the
them,
not
about
synaptic
impulse
to
neurone.
away
across
the
touch.
from
the
The
the
20 nm
gap.
The
synapse
neurone
synapse
is
only
the
These
to
the
receptor
on
sites
the
have
neurotransmitter,
temporary.
neurotransmitter
postsynaptic
triggers
neurone.
Once
is
the
neurotransmitter
is
broken
enzyme
in
the
synaptic
an
this
has
down
by
gap.
wide.
5
called
The
mitochondria
provide
energy
to
reform
the
neurotransmitter.
the
carries
called
the
axon
postsynaptic
synaptic
sites
There
neurone
that
is
of
the
shape
receptor
neurones.
an
is
specic
membrane.
binding
happened
Where
to
complementary
impulse
synapse
attaches
postsynaptic
4
A
diffuses
synapse
gap
•
drugs
OUTCOMES
3
•
and
of
presynaptic
neurone
neurone
How
does
from
one
a
nerve
impulse
neurone
to
the
transfer
next?
across
the
Chemicals
synapse
known
impulse
as
end
neurotransmitters
are
released
by
the
of
axon
presynaptic
myelin
neurone
an
and
impulse
diffuse
in
the
across
the
postsynaptic
synaptic
gap
to
sheath
trigger
neurone.
mitochondrion
synaptic
Structure
of
the
synapse
vesicle
The
axons
of
neurones
end
in
swellings
synaptic
called
containing
bulb
neuro-
synaptic
bulbs.
The
surface
of
the
synaptic
bulb
is
transmitter
called
the
the
presynaptic
synaptic
gap
from
membrane.
the
It
is
postsynaptic
separated
by
substance
membrane
synaptic
of
the
cell
body
or
axon
of
the
next
gap
presynaptic
neurone.
membrane
If
you
the
look
at
synaptic
Figure
bulb
neurotransmitter
14.3.1
has
you
many
will
vesicles
molecules.
It
also
see
that
dendrite
containing
contains
protein
many
mitochondria
which
suggests
that
energy
is
postsynaptic
receptor
membrane
required
in
synaptic
transmission.
The
postsynaptic
postsynaptic
neurone
membrane
on
its
has
surface
a
which
neurotransmitter
Synaptic
1
When
bulb
it
an
number
act
of
as
large
protein
receptor
sites
molecules
for
Figure
the
14.3.1
The
structure
of
a
synapse.
substance.
transmission
impulse
causes
arrives
vesicles
at
the
synaptic
containing
the
neuro-
neurotransmitter
to
move
towards
neuro-
the
transmitter
transmitter
presynaptic
binds
membrane.
released
2
The
vesicles
fuse
with
the
presynaptic
protein
synaptic
membrane,
into
the
releasing
synaptic
the
neurotransmitter
gap
gap.
Figure
158
to
receptor
14.3.2
Action
of
a
neurotransmitter
at
a
synapse.
a
reex
direction
happens
arc
i.e.
synapses
from
because
presynaptic
bulb
ensure
presynaptic
vesicles
and
the
of
that
nerve
neurone
impulses
to
are
only
postsynaptic
neurotransmitter
receptors
can
only
are
only
found
on
travel
neurone.
present
the
in
in
tnemelppuS
In
one
This
the
postsynaptic
membrane.
The
effect
Most
drugs
synapses.
by
of
that
These
inuencing
with
drugs
affect
drugs
the
receptors
of
of
the
synaptic
the
by
are
a
nervous
neurotransmitters
nervous
inuence
release
either
Amphetamines
activity
on
of
system
the
of
system.
the
have
them
or
excitatory
so
of
or
by
effects
interacting
that
brain
them.
increases
stimulate
increasing
at
impulses
by
inhibiting
drug
Amphetamines
brain,
their
transmission
neurotransmitters
stimulating
type
in
transmission
the
the
release
activity
In
and
is
making
a
person
more
alert.
They
also
have
the
effect
of
this
image
coloured
The
Heroin
between
and
the
beta-blockers
effects
of
are
examples
neurotransmitters.
of
inhibitory
Heroin
acts
on
drugs
and
to
reduce
sensation
of
the
pain.
neurotransmitters
heart
You
release
of
neurotransmitters
Beta-blockers
and
are
taken
by
are
drugs
people
to
that
and
block
reduce
can
this
reduces
receptors
blood
at
presynaptic
neurone.
the
neurone
What
is
meant
by
b
the
each
of
these
terms?
neurotransmitter
function
with
a
synaptic
c
protein
c
receptor
of
an
of
each
impulse
of
the
vesicles
receptor
b
across
of
vesicles
left
of
clustered
the
presynaptic
following
is
meant
excitatory
in
reach
inhibitory
in
an
is
effect
for
of
research
d
b
the
number
far
of
greater:
(0.15
×
10
).
mitochondria
the
following
POINTS
terms?
A
synapse
of
each
different
type
of
is
a
two
junction
neurones.
An
impulse
i
heroin
nerve
and
ii
amphetamines
impulses
across
the
into
the
effects
that
the
have
on
of
c
a
the
neurotransmitter,
the
diffuses
across
the
synapse?
following
receptor
drugs
gap
to
bind
molecules
postsynaptic
transmission:
ecstasy
triggers
drug.
trigger
caffeine
each
drug
do
synaptic
the
As
15
synaptic
on
human
synapses
neurones,
quadrillion
which
some
many
of
drug
example
transmission
adult
billion.
therefore
release
What
number
the
2
Give
the
86
has
between
ii
the
neurotransmitter
molecules
by
for
synapses:
1
i
a
(below).
between
molecules
KEY
What
have
space
KNOW?
other
0.15
transmission
Do
lots
bottom
YOU
brain
QUESTIONS
synapse
Explain
c
neurone
for
these
b
tiny
pressure
estimate
a
the
(×14 000).
neurone
a
is
see
the
neurones
4
neurones
rate.
SUMMARY
3
a
postsynaptic
gap
Estimates
2
the
shows
that
DID
1
of
image
presynaptic
together
neurones
a
synaptic
them.
reduce
and
The
appetite.
(above)
the
cytoplasm
suppressing
synapse
the
the
orange.
an
with
on
the
the
membrane
and
impulse.
cocaine
3
In
a
reex
ensure
only
4
one
Many
arc,
that
travel
in
direction.
drugs,
their
effects
with
the
at
synapses
impulses
e.g.
by
heroin,
have
interacting
receptor
molecules
synapses.
159
14.4
Sense
We
LEARNING
are
Dene
of
sense
receptor
particular
•
organs
cells
as
groups
responding
to
the
function
of
Explain
structure
the
impulses
the
of
and
Some
eye
The
pupil
reex
to
and
also
light
intensity
light
central
are
the
have
as
receptor
stimulated
the
receptors
eye
and
have
other
and
and
use
that
our
sense
organs
These
impulses
concentrated
to
specialised
cells
travel
to
to
detect
generate
along
nerve
sensory
system.
receptors
tissues
are
chemicals.
these
nervous
found
ear
cells
in
groups
arranged
modify
the
in
in
certain
special
organs.
tissues.
information
from
the
in
before
it
reaches
the
receptors.
In
the
eye
there
are
and
structures
pupil
surroundings
have
such
when
environment
terms
our
We
stimuli,
neurones
stimuli
Describe
stimuli.
certain
They
•
of
OUTCOMES
detect
•
aware
organs
for
focusing
light
rays;
in
the
ear
there
are
structures
for
diameter
amplifying
Sense
sound.
organs
are
groups
of
receptor
cells
that
respond
to
specic
stimuli.
•
The
eyes
respond
•
The
nose
to
responds
light
to
rays
and
chemicals
in
give
the
us
air
our
sense
and
gives
food
and
of
us
sight.
our
sense
of
smell.
•
The
us
•
tongue
our
The
ears
use
a
variety
of
their
senses
of
The
to
chemicals
in
our
drink
and
gives
taste.
respond
hearing.
Musicians
responds
sense
ear
to
sound
also
vibrations
detects
and
movement
give
and
us
our
sense
position
of
of
the
body,
when
so
provides
information
about
our
balance.
performing.
•
The
It
socket
tear
also
responds
detects
to
pain
pressure
and
and
gives
temperature
us
(see
our
sense
page
of
touch.
168).
gland
Eye
tear
skin
structure
ducts
Your
cornea
pupil
eye
three
sits
pairs
inside
of
eye
a
socket
muscles
in
as
the
you
skull
can
and
see
is
in
moved
Figure
about
14.4.1.
by
The
eye
iris
is
a
complex
brous
to
eye
brain
a
function
14.4.1
The
eye
in
its
socket.
At
the
the
front
the
chan
ges
and
our
fo r
in
blood
the
also
inside
de tect
ing
thin
gs
tempe
ratu
re
tens
ion
mus
cles.
info rm
ation
hom
eostas
is.
160
syst
em
recept
ors
body
like
is
composed
tissue,
with
the
sensory
of
different
tissue
detection
of
and
light.
tissues,
blood.
Figure
such
Each
14.4.2
as
tissue
has
shows
in
of
the
eye.
of
the
eye
Light
the
eye
is
and
the
then
their
transparent
passes
pigmented
functions.
cornea,
through
iris,
the
through
through
pupil,
the
lens
which
which
to
the
is
a
light
hole
retina
at
in
the
TIP
sens
ory
has
the
centre
back
T
he
help
structures
enters
STUD
Y
to
which
muscle
muscle
the
Figure
organ
tissue,
in
T
his
helps
At
of
the
tears
eye.
very
provides
front
wash
lysozyme,
In
humans,
opposed
views
the
an
the
to
your
shutting
The
of
retina
the
protection.
that
called
with
the
at
your
eyes
the
same
is
visual
is
set
moist
side
a
light-sensitive
transparent
the
time
tear
you
layer,
glands
blink.
receptor
which
that
Tears
cells.
make
also
the
contain
bacteria.
by
eyes
side
at
What
are
from
to
by
every
rabbit.
but
alternately
with
delicate,
kills
the
eld
tissue
a
clean
like
As
the
kept
that
are
side,
eld.
eyes
eye
eye
enzyme
visual
your
It
is
a
a
the
front
you
few
of
in
the
front
centimetres
slightly
experience
see
different
this.
The
head
of
apart,
angle.
two
as
you
Just
elds
is
each
of
eye
try
view
overlap
to
distances
give
accurately.
tree-dwelling
tigers,
The
it
in
off.
lets
which
a
When
you
simple
judge
and
you
light
into
such
as
which
vision
is
monkeys,
distances
gives
an
and
us
the
ability
essential
to
judge
adaptation
predators,
accurately
to
such
as
for
lions
and
survive.
reex
mirror
When
less
light
must
vision
Stereoscopic
animals,
pupil
Look
stereoscopic
into
turn
the
the
your
the
eyes
reex.
shine
turn
eyes
light
so
bright
on
and
off,
you
Receptor
a
light
cells
see
in
near
pupils
the
retina
eyes
decrease
retina
increase
clearly.
the
your
pupils
protects
your
can
light
your
This
is
send
and
in
from
in
size
impulses
turn
This
damage.
to
another
then
size.
let
more
example
along
of
a
sensory
When
neurones
pass
in
the
impulses
optic
to
the
nerve.
These
muscles
in
connect
the
iris
to
motor
stimulate
ciliary
neurones
them
to
that
contract.
pupil
a
bright
light
constricts
to
is
shone
protect
into
the
the
retina
eye
the
from
damage.
muscle
changes
lens
with
thickness
when
of
the
focusing
retina
inner
rod
light-sensitive
cells
that
work
layer
in
which
dim
light,
contains
and
cornea
cone
refracts
cells
that
detect
colour
and
details
light
yellow
most
spot
or
sensitive
fovea
part
of
the
retina
pupil
blind
spot
lens
point
can
change
its
shape
to
focus
light
onto
the
where
the
optic
nerve
attaches
to
the
eye;
no
light-sensitive
cells
here
retina
iris
controls
light
the
intensity
entering
of
through
optic
the
nerve
pupil
carries
suspensory
away
hold
Figure
14.4.2
A
the
horizontal
lens
in
section
of
the
Sense
organs
are
groups
of
QUESTIONS
specic
the
impulses
brain
POINTS
receptor
Give
the
eye.
1
1
to
place
KEY
SUMMARY
nerve
ligaments
name
in
each
case
for
the
part
of
the
eye
is
sensitive
b
controls
c
holds
d
refracts
to
that
stimuli:
respond
light,
to
sound,
that:
touch,
a
cells
temperature
and
light
chemicals.
the
intensity
of
light
entering
the
eye
2
the
lens
in
place
within
the
The
cornea,
retina,
the
light
after
it
has
entered
the
transmits
nerve
impulses
f
controls
the
shape
g
secretes
the
enzyme
h
allows
light
to
of
pass
the
to
the
brain
lysozyme
3
In
Describe
and
explain
the
changes
in
iris
pupil
the
diameter
of
the
the
surrounding
light
intensity
of
and
the
blind
eye
that
described
in
light,
the
diameter
decreases.
intensity
When
decreases
of
the
the
pupils
diameter
when
lens,
14.4.2.
bright
the
light
2
nerve
parts
functions
Figure
the
optic
are
have
lens
through
pupil,
eye
spot
e
iris,
eye
of
the
pupil
widens
changes.
to
let
in
more
controlled
by
light.
a
This
simple
is
reex.
161
14.5
The
eye
tnemelppuS
Control
LEARNING
The
•
Explain
the
pupil
reex
of
light
size
intensity
the
antagonistic
action
Explain
on
in
the
how
near
the
and
State
are
that
light
the
The
pupil
is
controlled
circular
muscles
by
a
are
pair
of
antagonistic
arranged
around
muscles
the
pupil.
The
muscles
muscles
run
are
outwards
described
from
as
the
pupil
antagonistic
like
the
because
spokes
they
in
have
a
wheel.
opposite
iris
far
eye
focuses
while
rods
the
the
circular
radial
muscles
muscles
contract
contract
to
to
reduce
increase
the
the
size
size
of
of
the
the
pupils
pupils.
objects
The
•
reex
of
effects:
•
pupil
and
These
muscles
of
iris.
radial
the
the
in
in
terms
of
OUTCOMES
and
sensitive
cones
cells
in
the
diagrams
intensity
is
potential
show
low
to
and
what
in
damage
happens
bright
the
light
in
dim
when
light
it
is
when
much
the
light
higher
and
has
the
retina.
retina
In
dim
light
In
bright
light
circular
•
•
Describe
the
distribution
rods
and
they
function
State
the
cones
and
position
the
of
of
circular muscles relax,
circular
radial muscles contract,
radial
pupil dilates
pupil
muscles
muscles
contract,
muscles
relax,
way
constricts
the
fovea
radial
muscles
STUD
Y
Here
is
a
way
remem
ber
Cs:
Figure
TIP
cons
tr
the
three
cont
ract,
Figure
14.5.2
through
on
(upside
top
control
the
diameter
of
the
pupil.
how
light
the
transparent
is
focused
retina.
Notice
because
bottom
of
Information
cornea,
in
the
of
the
object
about
this
that
way
passes
the
eye.
the
image
the
enter
light
the
inverted
through
Light
eye
on
rays
and
image
the
the
enters
lens
retina
reected
cross
goes
to
the
be
inverted
from
over
the
is
to
the
behind
brain
the
where
TIP
it
Unit
T
he
shows
the
down)
and
lens.
STUD
Y
and
muscles
aint
.
focused
cells
,
iris
Focusing
eye
In
The
to
this:
circul
ar
,
14.5.1
2
we
dealt
tissu
es,
is
few
interpreted
months
eye
is
right
way
up.
We
learn
how
to
do
this
in
the
rst
with
syst
ems.
a
the
life.
orga
ns
light
orga
n
of
very
from
rays
reflected
object
good
retina
exam
ple
wher
e
you
tissu
es
tissu
e)
rod
eye
an
can
(e.g.
and
and
is
of
syst
em :
cells
of
the
iden
tify
mus
cle
cone
part
orga
n
(e.g.
cells
).
an
T
he
Figure
14.5.2
This
shows
light
rays
refracted
by
the
cornea
and
the
lens.
orga
n
sens
ory
Rods
and
cones
syst
em .
Rods
Rod
and
cells
when
night
162
it
cones
are
is
dark,
vision.
are
the
sensitive
for
Cone
light-sensitive
to
light
example
cells
are
of
at
low
night.
only
receptor
intensity
They
sensitive
are
to
cells
and
in
the
send
responsible
light
of
retina.
impulses
high
for
only
our
intensity.
are
three
wavelengths
cells
to
give
contains
brain
so
This
The
light.
The
our
cones
image.
area
gives
horizontal
of
as
in
the
eye
enters
the
image
clearly.
the
eye
cornea
it
in
blind
is
the
when
must
About
and
Each
our
retina
has
spot.
the
its
which
The
of
own
is
in
from
of
cone
the
neurone
gives
rods
us
and
not
the
fovea
different
centre
eld
contains
centre
to
impulses
in
visual
vision
the
the
fovea
cone
of
the
is
sensitive
as
retina
your
a
retina
to
the
very
few
cones.
detailed.
on
right
the
same
eye
is
to
the
spot.
Accommodation
occur
The
peripheral
fovea
the
blind
of
each
interprets
vision.
middle
rest
our
cell,
brain
rods.
the
The
the
level
your
no
in
us
of
cone
colour
and
area
position
right
of
of
us
this
detailed
types
tnemelppuS
There
term
used
focusing
be
on
refracted
60%
of
the
rest
is
which
can
be
the
done
to
far
describe
and
(bent)
so
refraction
by
the
the
near
that
of
lens.
changes
objects.
we
the
The
can
light
lens
As
see
rays
is
that
light
the
is
the
done
surrounded
by
and
ring
the
of
tissue
lens
controlled
is
If
you
•
the
•
the
(or
are
looking
ciliary
are
retina.
If
you
•
the
so
at
a
distant
the
lens
is
as
distant
looking
ciliary
and
can
recoil.
The
shape
of
the
at
muscles
suspensory
14.5.3
tissue
spherical
when
eye
pulls
pulled
they
the
into
pass
is
a
object:
near
in
suspensory
an
elliptical
through
object
contract
ligaments
around
(fatter).
looking
at
the
ligaments
(thin)
A
distant
lens
and
focused
on
the
focus.
to
counteract
the
pressure
inside
the
ring
the
are
Light
the
lens
not
pulled
recoils
rays
distant
are
so
and
the
become
refracted
object.
The
lens
slack
becomes
so
more
near
than
object
the
in
ciliary
lens
muscle
becomes
When
the
14.5.4
A
near
KEY
POINTS
The
pupil
reex
the
eye
views
a
distant
object,
explain
what
happens
ciliary
muscles
ii
the
suspensory
circular
the
Explain
shape
what
of
the
views
a
lens
happens
near
to
to
the
each
of
these
a
State
what
muscles
control
structures
when
entering
the
the
muscles
size
of
to
each
of
the
following
in
bright
The
the
light:
of
the
iris
ii
radial
muscles
of
the
State
what
the
ciliary
muscles,
lens
ligaments
are
all
involved
to
c
Explain
d
Suggest
why
each
of
the
above
in
dim
In
the
pupil
they
unconscious.
reex
is
retina,
doctors
shine
a
Describe
the
distribution
of
light
in
people’s
eyes
when
of
low
and
cones
in
the
retina
their
cells
are
the
respond
to
detect
high
Cone
light
colour
.
to
light
cells
intensity
The
fovea
is
and
made
explain
and
intensity.
respond
rods
rod
around
controlled.
and
3
in
light.
periphery
are
in
(focusing)
eye.
distributed
the
and
pupil
happens
how
of
through
iris
3
b
eye
the
the
iii
the
object.
happens
circular
in
intensity
the
accommodation
i
the
muscles
pupil.
suspensory
2
radial
ligaments
2
eye
of
to:
light
b
involves
QUESTIONS
the
iii
object.
were
focus.
iris
i
contracts
rounder
more
they
is
of
eye,
and
a
object.
Light
coordination
1
shape
tight
shape.
1
SUMMARY
thin
object:
Figure
elastic
a
muscles
and
•
relaxes
into
the
the
ciliary
muscle
pulled
relax,
inside
the
refracted
The
are
the
muscles
pressure
taut)
rays
by
stretched
is
by
Figure
elastic
ciliary
lens
entirely
of
cones.
functions.
163
14.6
Hormones
The
LEARNING
A
•
endocrine
Identify
on
adrenal
glands,
a
diagram
hormone
•
testes
State
by
the
each
and
the
the
these
Describe
the
adrenaline
released
four
the
and
than
a
glands
into
certain
it.
duct.
organs
These
produced
by
an
endocrine
in
that
the
are
blood.
Endocrine
secreted
into
the
means
that
the
bloodstream
gland
rather
are
of
Hormones
or
tissues
referred
its
target
to
travel
throughout
recognise
as
target
each
the
hormone
organs.
Each
body
and
but
only
respond
hormone
to
alters
the
organs.
of
heart,
lungs
coordinate
the
activities
of
the
body
but
in
a
different
way
pupils
to
tnemelppuS
•
transported
hormones
Hormones
and
substance
ovaries
effects
on
chemical
produces
activity
•
a
pancreas,
hormone
of
is
the
gland
the
system
OUTCOMES
Explain
that
increases
and
oxygen
that
adrenaline
supply
to
of
the
nervous
they
system.
secrete
and
The
the
main
actions
endocrine
are
show
glands,
in
the
Figure
hormones
14.6.1.
glucose
muscles
during
activity
Pituitary
It
•
Compare
the
endocrine
makes
a
gland
at
the
hormones
base
and
of
the
controls
brain.
things
and
like
nervous
is
many
growth,
and
sperm
and
egg
production.
systems
stomach
lungs
STUD
Y
TIP
heart
T
he
term
Pancreas
‘secr
e tion’
blood
means
a
that
cells
subs
tanc
e
mak
e
Adrenal
glands
adrenaline
that
makes
glucagon.
make
glucose
Glucagon
insulin
Insulin
lowers
and
the
concentration.
increases
it.
when you
is
are frightened or angry
.
usef
ul
relea
se
fo r
it
the
into
body
and
Adrenaline helps your
body cope with an
the
blood
emergency
or
some
body
,
o ther
e.g.
conf
use
the
part
gut.
secre
tion
‘excr
e tion’
,
of
whic
h
the
Do
no t
with
Testes
This
is
make
wast
e
of
(see
me ta
bo
page
development
in
males.
of
Ovaries
make
females.
These
oestrogen
control
the
and
progesterone
menstrual
cycle
in
and
the
secondar y
remov
al
testosterone
stimulates
features
during
puberty.
stimulate
lic
during
144).
Figure
14.6.1
The
organs
of
the
development
of
secondar y
sexual
features
puberty.
endocrine
system.
Adrenaline
Adrenaline
are
will
The
are
Adrenaline
is
excitement,
164
released
fear
or
during
stress.
times
of
in
a
is
secreted
situation
immediately
responses
that
by
puts
become
necessary
coordinated
by
the
you
much
to
increasing
the
breathing
•
increasing
the
heart
•
widening
pupils
risk
more
in
which
glands.
of
If
you
injury,
aware
these
gets
or
and
‘ght
you
realise
even
ready
or
that
for
rate
more
light
enters
the
take
ight’
ready
that
death,
to
rate
(pulse)
so
at
survive
adrenaline,
•
the
adrenal
eyes.
you
you
action.
situations
action
by:
levels
of
stimulates
within
activity,
the
an
body.
To
adrenaline
increase
provide
in
the
rate
enough
stimulates
cells
of
chemical
energy
in
the
for
liver
STUD
Y
increased
to
convert
T
he
glycogen
to
glucose,
which
diffuses
into
the
blood.
This
increases
table
of
glucose
in
the
blood,
so
that
there
is
more
the
for
muscles
sudden
as
a
source
of
energy
for
muscle
contractions
needed
action.
coordinates
the
increased
uptake
of
oxygen
and
the
distribution
of
blood
so
that
oxygen
and
glucose
Setti
ng
this
way
•
The
more
that
air
air
oxygen
need
them
passages
into
that
the
can
for
reach
be
in
bronchi
the
and
lungs.
bronchioles)
This
increases
widen
the
to
The
breathing
carbon
the
Arterioles
more
in
rate
increases
dioxide
glucose
the
and
Arterioles
to
divert
in
the
blood
to
at
a
to
increase
faster
the
uptake
of
oxygen
and
Hormones
are
brain
and
oxygen
muscles
for
gut
the
and
dilate
respiration
other
too
much
in
(become
these
wider)
to
deliver
by
organs.
organs
constrict
(become
is
in
as
a
result
of
the
of
anxiety,
constant
high
blood
pressure
prolonged
and
heart
They
Beta-blockers
also
act
adrenaline
blood
on
and
pressure
endocrine
coordinate
the
drugs
surface
reduce
and
Comparing
The
cell
so
are
effects.
the
and
activities
the
of
at
the
synapses
to
block
disease
rate
and
nervous
(see
(see
the
Beta-blockers
heart
endocrine
system
act
membranes
its
decrease
the
that
Topic
nervous
system
act
to
Topic
to
nervous
structures
nerves
forms
for
3
reduce
14.3).
pulse
control
of
and
the
ight’
oxygen
stimulates
pupils
in
situations.
increases
and
supply
glucose
during
SUMMARY
and
system
endocrine
system
cells
in
impulses
hormones
neurones
in
the
What
glands
to
activity.
QUESTIONS
meant
by
the
terms?
a
endocrine
b
hormone
c
target
system
(chemicals)
organ
blood
State
each
fast
is
following
of
information
rates
breathing
systems
2
speed
or
muscles
of
along
organs.
increases
Adrenaline
of
information
pathways
the
body.
secretory
electrical
alter
may
1
feature
and
to
14.3).
receptors
help
secreted
stress
‘ght
result.
blood
target
Adrenaline
widening
and/or
are
glands
narrower)
2
released,
that
endocrine
travel
muscles.
adrenaline
chemical
rate.
and
If
system
s.
POINTS
activity
•
two
of
substances
•
you
absorbed.
1
excrete
tables
allow
volume
KEY
•
system
s
out
compa
rison
s
the
respiration.
(trachea,
alveoli
the
ner vo
us
ensu
res
direc
t
betw
een
muscles
the
changes
mak
e
in
which
horm
onal
work
.
in
Adrenaline
in
available
and
to
compa
res
the
ways
concentration
TIP
tnemelppuS
reactions
also
the
of
gland
the
which
secretes
following:
slow
a
testosterone
c
oestrogen
b
insulin
transfer
short-lived,
longevity
e.g.
of
usually
muscle
contracts
slow
and
longer
3
lasting
a
short
Suggest
four
in
which
the
only
the
area
at
whole
of
a
tissue
or
organ
4
neurone
Explain
how
prepares
e.g.
muscle
of
contraction
response
conversion
by
of
glucose
adrenaline
the
body
for
action.
to
or
glycogen,
secretion
increases.
the
area
end
secretion
time
adrenaline
target
situations
for
action
protein
synthesis,
5
State
four
ways
in
which
the
glands
rate
of
respiration
endocrine
the
system
nervous
differs
from
system.
165
tnemelppuS
tnemelppuS
Adrenaline
14.7
Controlling
in
the
Controlling
LEARNING
the
term
tnemelppuS
Explain
the
metabolism,
concept
cells,
some
Describe
glucose
down,
the
control
of
work
see
concentration
how
STUD
Y
The
maint
aini
ng
cond
ition
s
is
do
In
the
chan
ge
to
It
say
hom
eostas
is
the
and
body.
some
are
Enzymes
are
and
the
such
kept
pH
control
these
temperature,
suitable
inuence
conditions
working.
as
reactions
in
and
in
the
constant.
enzyme
the
body,
so
is
and
See
Unit
5
to
activity.
body
Homeostasis
pH
can
the
that
slow
down
maintenance
enzymes
or
of
control
overall
is
control
an
of
our
example
body
of
processes.
The
control
of
homeostasis.
humans,
the
normal
temperature
of
the
blood
is
37 °C.
When
body
,
reaching
the
brain
is
warmer
than
this
temperature
it
sends
sligh
tly
is
more
our
along
sweat
nerves
glands
to
the
produce
skin
sweat
to
promote
and
this
heat
helps
us
loss.
to
For
cool
example,
down,
that
body
temperature
to
normal.
maint
ains
When
we
brain
or
keep
s
feel
cold
our
blood
temperature
falls
below
37 °C.
Then
the
will
se t
stimulate
and
by
production
increasing
the
of
rate
more
of
heat
in
respiration
the
in
muscles
the
liver.
It
by
also
limits
.
stimulates
sweat
by
The
This
gets
control
is
falls
acts
the
to
body
to
conserve
heat
by
decreasing
the
production
of
glands.
feedback
of
body
same
temperature
temperature
thermostat
the
sweat
Negative
hot
the
them
shivering
too
inside
proteins,
cons
tant
cond
ition
s
oven
occur
as
efciently.
has
returning
with
in
glycogen.
conditions
temperature
impulses
near
ly
such
cons
tant
in
time.
in
from
internal
brain
body
blood
the
reactions
up,
say
hom
eostas
is
precis
e
built
conditions,
water,
change
metabolism
we
of
enzymes
constant
TIP
Alth
ough
all
as
when
temperature
slight
stop
they
such
best
concentration
blood
Any
that
chemical
are
feedback
and
•
molecules
of
broken
negative
many
homeostasis
In
•
conditions
temperature
sort
of
constant
ensure
that
control
at
the
the
is
an
system
pre-set
actual
example
as
in
an
of
oven
temperature.
temperature
is
negative
as
to
keep
Negative
close
to
the
feedback
the
feedback
pre-set
switches
temperature
heater
possible.
In
our
body
,
if
the
temperature
increases
above
off
or
required
as
required
oven
oven
temperature
temperature
below
bring
be
it
close
glucose
oxygen
thermostat
the
back
to
normal
to
it,
37 °C,
normal.
within
set
concentration,
and
carbon
It
then
may
limits.
the
dioxide
it
responds
not
be
There
water
by
exactly
are
also
content
of
concentrations
taking
37 °C
control
the
of
actions
all
the
systems
blood,
the
that
time,
for
blood
will
but
will
blood
pH
and
the
blood.
switches
oven
gets
temperature
heater
too
Figure
on
cold
14.7.1
rises
Controlling
the
Controlling
an
oven
is
an
example
need
glucose
the
energy
and
therefore
need
a
constant
supply
blood.
feedback.
When
you
eat
concentration
stay
high
insulin
a
high
can
because
concentration
166
for
of
from
negative
glucose
temperature
Cells
of
blood
into
in
the
carbohydrate
increase
cells
the
in
the
blood.
blood.
by
a
meal
factor
pancreas
These
Insulin
cells
your
of
20.
blood
detect
secrete
stimulates
glucose
However,
liver
the
the
cells
it
high
does
hormone
to
not
glucose
convert
called
glucose
tnemelppuS
Dene
body
OUTCOMES
During
•
conditions
tnemelppuS
glucose
concentration
glucose
increases
concentration
STUD
Y
TIP
insulin causes
(food
decreases
intake)
Insu
lin
glucose in the liver to
change to glycogen
normal
blood
glucose
normal
level
blood
glucose
and
gluc
agon
are
horm
ones.
not
enzy
mes.
say
that
T
hey
So
insu
lin
are
alwa
ys
and
level
gluc
agon
chan
ges
stim
ulate th
e
to
gluc
ose.
Do
glucagon causes
say
that
‘insu
lin
glycogen in the liver
glucose
gluc
ose
glucose
to change to glucose
concentration
concentration
decreases
to
enzy
mes
such
as
14.7.2
mus
cle
the
the
storage
liver
cells
When
you
muscles
you
a
race
up
Y
our
the
cells
blood
Blood
lots
so
blood
glucose
the
instruct
of
and
out
glucose
cells
the
cells
to
from
to
other
the
the
so
of
•
liver
is
an
makes
makes
blood.
this
by
the
and
it
into
the
normal.
pancreas,
releases
molecules
not
and
stimulates
diffuses
to
does
decrease
Glucagon
which
increases
controlled
but
energy
which
hormones
from
the
blood
or
example
insulin
to
of
negative
stimulate
a
feedback
decrease
because
in
blood
the
tissue
in
the
centre
secretes
make
photo
of
the
glucagon
sure
the
decrease
too
to
stimulate
an
increase
in
blood
1
glucose
POINTS
Homeostasis
concentration
stays
within
limits
and
does
not
much
(see
treatment
of
T
ype
1
diabetes
in
T
opic
as
10.3).
Homeostasis
It
involves
operates
constant
negative
to
conditions
of
QUESTIONS
and
Dene
the
term
Explain
why
is
it
water
,
oxygen
in
important
that
conditions
in
cells
are
its
tnemelppuS
the
as
3
term
an
The
pancreas
negative
feedback
using
controlling
example.
blood
in
the
the
blood
controls
the
roles
of
the
pancreas
and
the
liver
of
by
hormones
glucagon
Explain
as
well
pH.
concentration
glucose
dioxide
blood
kept
constant.
Explain
carbon
the
homeostasis
as
b
such
temperature.
glucose,
a
constant
increase
maintain
b
the
of
conditions,
feedback.
a
is
maintenance
2
SUMMARY
glucagon.
glucose
body
2
this
and
or
internal
1
of
insulin
pancreas:
concentration,
or
and
your
the
KEY
to
cells
cells.
more.
concentration,
•
by
cells,
the
pancreas
This
inside
stimulates
exercise,
provide
decreases,
glucose,
glucose
to
detect
concentration
remove
This
blood
type
blood
concentration
is
the
38).
The
add
T
he
normal.
pancreas
into
glycogen
glucose
page
concentration
in
concentration
liver
(see
to
some
from
glucagon
glucose
blood
glucose
returns
carry
down
blood
glycogen
glucose
Other
break
the
lots
or
of
hormone
to
monitors
to
absorb
decreases
decreasing.
secrete
liver
run
take
need.
keep
compound
to
concentration
done
the
glucose
producing
insulin
which
and
stimulate
the
in
liver.
maintaining
a
constant
blood
glucose
concentration.
167
tnemelppuS
into
is
increases
(exercise)
Figure
conv
erts
glyc
ogen
’.
conv
ersion
not
14.8
Controlling
body
temperature
Birds
LEARNING
and
mammals
successful
•
Identify
on
•
a
different
diagram
Describe
of
how
temperature
ones
structures
the
and
ways
skin
to
animals
be
as
active
adjust
they
a
at
the
can
constant
night
body
as
live
in
body
well
cold
temperature.
as
temperature
environments
during
in
the
day
.
different
as
They
The
well
skin
as
are
very
hot
provides
conditions.
body
is
kept
The
constant
The
STUD
Y
maintain
OUTCOMES
skin
skin
is
the
largest
the
body
organ
in
the
body
and
has
several
important
TIP
functions:
We
produ
ce
respi
ratio
n
shiveri
ng;
to
our
e.g.
we
and
we
by
lose
heat
evapor
ation
swea
t;
e.g.
bene
ath
•
protects
from
damage
•
stops
•
prevents
•
detects
changes
in
•
detects
pressure
(touch)
•
loses
in
surrou
ndin
gs,
by
heat,
heat
when
pathogens
too
from
much
entering
water
loss
temperature
and
pain
we cons
er ve
by
the
havin
g
heat
by
conduction,
convection,
radiation
and
evaporation.
fat
skin
.
oil
gland
hair
erector
muscle
hair
sweat
sense
–
receptors
detect
pore
blood
sweat
capillar y
gland
pain,
pressure,
cold
arteriole
and
heat
sensor y
neurones
Figure
Polar
to
bears
conserve
have
their
a
thick
body
layer
of
insulating
fat
heat.
Many
fat
14.8.1
of
the
structure
structures
temperature.
by
The
radiation.
We
We
lose
use
of
in
the
and
our
human
skin.
diagram
absorb
skin
for
layer
help
heat
heat
in
controlling
through
loss
our
when
skin
we
are
body
–
mostly
hot
and
to
hot
conserve
weather
hairs
lie
heat
Mammals
is
hair
when
we
are
cold.
flat
a
poor
have
fur
or
conductor
hair
,
of
which
heat.
So
traps
air
a
layer
pockets
in
of
air
the
close
fur
or
to
hair
the
skin.
reduce
Air
the
muscles
loss
of
heat
to
the
atmosphere
by
keeping
convection
currents
of
air
away
relax
from
the
contract
warm
so
that
surface
hairs
of
the
stand
skin.
erect
When
to
trap
it
a
is
cold,
thick
hair
layer
of
erector
air
so
muscles
reducing
cold
heat
hairs
weather
stand
loss.
up
When
is
hair
muscles
it
is
trapped
currents
hot,
hair
close
ow
to
erector
the
closer
skin
to
the
muscles
relax
so
so
heat
can
more
surface
of
the
that
be
hairs
lost
lie
as
at.
Less
air
convection
skin.
contract
Mammals
Figure
14.8.2
Hairs
are
involved
maintaining
body
temperature.
168
also
have
a
layer
of
fatty
tissue
beneath
their
skin,
which
is
in
a
good
in
cold
insulator
as
it
environments
does
have
not
very
conduct
thick
heat
layers
well.
of
fat.
Mammals
that
live
Controlling
body
temperature
blood
gets
blood
temperature
brain
too
hot
falls
switches
No
matter
what
the
weather
is
like,
your
body
temperature
stays
on
very
close
to
37 °C
unless
you
have
a
fever.
There
are
receptors
in
cooling
the
mechanisms
brain
that
detect
changes
in
the
temperature
of
the
blood.
When
the
normal
brain
detects
action
of
any
change
effectors
to
in
the
restore
blood
the
temperature,
blood
it
temperature
coordinates
to
the
body
normal
temperature
body
temperature
normal.
brain
switches
In
the
heat,
the
brain
detects
an
increase
in
the
blood
temperature.
on
blood
The
brain
sends
impulses
to
the
skin
to
increase
the
rate
of
warming
gets
blood
temperature
sweating
mechanisms
too
so
that
more
heat
is
lost
by
evaporation
from
the
skin
cold
Figure
In
the
The
cold,
sweat
the
brain
glands
stop
detects
a
decrease
producing
sweat
in
the
and
blood
the
rises
surface.
hair
14.8.3
temperature.
erector
sweat
muscles
contract
to
raise
the
hairs.
The
body
starts
to
shiver
as
evaporating
hot
some
of
the
body
muscles
contract
spontaneously
and
release
cools
heat
heat
weather
from
by
tnemelppuS
A
respiration.
this
very
much
the
Blood
ows
through
the
muscles
and
is
lost
skin
by
radiation
warmed
heat.
effective
blood
skin.
way
ows
to
regulate
through
Arterioles
supply
the
body
temperature
capillaries
these
near
capillaries
to
with
is
to
the
change
surface
blood.
The
change
the
how
of
muscle
arterioles
sweat
around
the
arterioles
can
contract
and
relax
to
blood
dilate
gland
ow.
The
To
lose
vessels
heat,
widen
these
and
muscles
there
is
in
an
the
walls
increase
in
of
the
blood
arterioles
ow
relax.
through
the
Figure
capillaries.
the
In
This
is
surroundings
the
cold,
the
known
by
as
vasodilation.
convection
muscles
in
the
and
More
heat
is
now
lost
14.8.4
to
radiation.
walls
of
the
arterioles
contract
so
the
cold
little
weather
vessels
become
narrower.
This
reduces
the
blood
ow
through
lost
the
heat
by
sweating
radiation
capillaries
the
The
skin.
and
This
control
the
is
of
blood
known
body
is
as
diverted
to
stay
beneath
the
fat
layer
stops
in
vasoconstriction
temperature
is
by
negative
feedback
as
shown
arterioles
sweat
in
Figure
14.8.3.
The
brain
coordinates
the
responses
by
effector
constrict
gland
to
lose,
temperature
conserve
that
stays
or
gain
within
heat
set
in
order
to
maintain
a
body
limits.
Figure
SUMMARY
QUESTIONS
KEY
1
Explain
2
Describe
14.8.5
how
the
brain
controls
body
temperature.
1
what
happens
a
to
lose
heat
b
to
conserve
when
heat
in
we
the
are
when
skin:
are
The
brain
cold.
2
How
do
we
produce
heat
in
the
body
if
we
are
Explain
how
fur
and
control
fat
in
tissue
cold
beneath
the
skin
Insulation
conserves
loses
tnemelppuS
Explain
how
maintaining
vasodilation
body
many
skin.
heat
help
generates
heat,
and
heat.
in
Vasoconstriction
and
environments.
vasodilation
5
the
the
cold?
3
temperature
body
using
in
shivering
4
by
structures
sweating
3
controls
temperature
hot,
we
POINTS
and
vasoconstriction
temperature.
are
involved
in
heat
the
is
lost
control
from
the
how
much
blood
in
skin.
169
tnemelppuS
organs
14.9
Tropic
responses
Tropisms
LEARNING
OUTCOMES
Plants
•
Dene
the
terms
the
and
respond
plant
the
chemical
such
as
towards
light
or
and
away
gravity.
from
the
Different
different
parts
stimuli.
of
These
plant
Explain
plant
growth
the
by
effect
hormones
responses
are
much
slower
than
the
responses
coordinated
by
control
the
•
stimuli
grow
nervous
systems
in
animals.
They
are
called
tropisms
auxins
of
synthetic
used
Gravitropism
as
Whichever
way
a
seed
is
planted,
the
root
always
grows
downwards
weedkillers
in
the
the
shoot
grows
A
direction
direction
growth
of
of
gravity.
The
shoot
always
grows
upwards
against
gravity.
response
to
gravity
is
called
a
gravitropism.
upwards
Roots
are
direction
to
absorb
Shoots,
root
positively
as
the
water
on
the
gravitropic
stimulus,
and
gravity.
mineral
other
hand,
because
They
they
grow
grow
in
the
downwards
same
into
the
soil
ions.
are
negatively
gravitropic.
They
will
grows
always
grow
in
the
opposite
direction
to
the
direction
of
gravity.
This
downwards
ensures
Figure
14.9.1
Which
way
is
that
shoots
grow
upwards
getting
the
leaves
into
sunlight.
up?
Auxin
STUD
Y
TIP
A
A
seed
plant
stimulates
germ
inat
es.
roo t
and
then
Gravi
tro pi
c
ensu
re
the
seedlin
g
itself
o ther
a
Whi
ch
in
If
is
a
of
growth
seedling
the
side
of
causing
the
cells
this
to
growth.
elongate,
Auxin
but
in
in
shoots
by
slowing
down
cell
roots
auxin
elongation.
shoot
is
put
and
and
on
its
root.
side
stimulates
In
the
the
the
auxin
cells
shoot
builds
there
the
to
auxin
up
on
builds
the
elongate
and
up
lower
on
the
side
therefore
lower
to
grow
the
more
on
the
lower
side.
This
causes
the
shoot
to
bend
upwards.
establ
ishes
compe
tition
plan
ts
by
controls
up?
respon
ses
it
growth
auxin
shoo
t
way
sur vi
val
as
called
A
inhibits
appe
ar
.
hormone
with
In
the
down
near
by.
on
root
the
side
upper
so
auxin
the
growth
the
made
auxin
in
side
root
by
a
root
also
root
of
the
bends
builds
by
up
on
inhibiting
root
the
cell
elongate
lower
side.
elongation.
more
than
But
As
a
those
auxin
slows
result,
on
the
cells
lower
downwards.
tip
auxin
builds
lower
up
on
auxin
side
causes
elongate
gravity
lower
less
cells
to
on
side
gravity
Figure
14.9.2
Auxin
controls
the
positive
gravitropism
of
roots.
Phototropism
The
cress
time
These
the
cress
light.
170
seedlings
have
grown
towards
This
and
sort
shoots
seedlings
their
of
growth
grow
in
shoots
the
photo
have
response
towards
the
have
grown
is
light
been
towards
called
they
a
are
put
the
in
a
window
for
some
light.
phototropism.
positively
Because
phototropic.
tnemelppuS
tnemelppuS
Explain
of
either
phototropism
growth
•
to
gravitropism
advantage
maximum
efciently
of
this
surface
for
tropic
area
to
response
the
is
that
tnemelppuS
light.
They
auxin
made
the
can
leaves
then
expose
absorb
the
light
more
STUDY
Cells
This
TIP
photosynthesis.
response
is
controlled
by
in
the
shoot
tip.
become
moves
away
from
the
shoot
tip
down
the
stem.
When
a
light
only
from
one
side
the
auxin
is
unequally
distributed
cells
in
is
on
found
the
direct
towards
on
the
shaded
light.
the
The
light.
shaded
side
to
shoot
side
the
elongate
grows
Roots
of
are
more
more
not
stem.
on
than
the
sensitive
The
to
auxin
the
cells
shaded
made
shoot
by
on
side
the
cells
and
pressure
bends
which
osmosis.
the
turgor
inside
causes
stretch.
the
the
cell
cell
Auxins
wall
work
makes
by
elongate
more
on
shaded
auxin
by
swells,
increasing
side
light.
auxin
tip
water
vacuole
stimulates
to
auxin
they
so
T
he
most
when
shoot
absorb
receives
or
The
elongate,
auxin
longer
,
tnemelppuS
The
making
the
walls
to
it
easier
for
stretch.
side
passes
down
shaded
side
shoot
bends
towards
14.9.3
Synthetic
Synthetic
Auxin
plant
auxins
Important
controls
are
cereal
them
for
water
,
Herbicides
leaves
of
like
the
crops
effective
like
2,4-D
wheat
whereas
nutrients
cereal
positive
phototropism
of
shoots.
hormones
very
(monocotyledonous)
the
light
are
and
selective
and
most
light
sprayed
plants
as
the
are
on
because
barley
of
are
the
narrow
weeds
broad
they
weedkillers.
leaved
crop
are
that
but
thin
with
(dicotyledonous).
tend
and
leaved
compete
to
run
point
off
the
upwards.
The
This
weedkillers
are
more
likely
to
be
absorbed
by
the
broad-leaved
weeds.
plant
weedkiller
fashion,
The
auxins
increasing
food
from
increase
the
rate
the
of
growth
cell
rate
division.
photosynthesis
to
of
The
the
affected
weeds
maintain
this
weeds,
cannot
rate
of
possibly
provide
growth
Dene
of
the
it
soon
die.
KEY
a
tropic
A
b
to
c
State
what
growth
response
will
happen
in
each
of
the
Some
seedlings
are
placed
in
a
window,
in
sunlight
for
6
A
Some
horizontally
for
a
seeds
few
are
placed
with
their
roots
tnemelppuS
the
observed
Auxins
the
growth
responses
in
question
2
in
action
of
Explain
how
growth
of
positively
shoots
are
is
the
a
growth
the
stimulus
are
and
of
positively
grow
light.
are
plant
hormones
growth.
Synthetic
terms
are
used
as
weedkillers
auxin.
by
4
to
control
auxins
of
twisted
hours.
that
Explain
a
gravitropic.
Shoots
towards
lying
3
3
are
and
phototropic
germinating
a
stimulus
phototropism
light.
hours.
b
hormone
in
following.
response
a
a
gravitropism
2
2
is
the
Roots
gravitropic
phototropism
with
grow
die.
gravitropism
response
following:
response
to
it
POINTS
negatively
a
sprayed
made
enough
and
QUESTIONS
each
has
causing
gravity.
1
been
that
by
1
SUMMARY
has
synthetic
auxins
are
able
to
act
as
weedkillers.
making
too
the
weeds
grow
fast.
171
tnemelppuS
Figure
the
PRACTICE
1
In
QUESTIONS
which
spinal
A
pathway
do
nerve
impulses
travel
in
a
6
reex?
effector
diagram
shoot
→
neurone
The
sensory
→
neurone
sensory
cell
→
→
to
shows
receiving
the
light
response
from
of
one
a
plant
side
only.
relay
light
motor
light
neurone
B
motor
C
neurone
→
sensory
neurone
sensory
cell
effector
→
→
relay
→
sensory
relay
neurone
→
effector
neurone
neurone
→
→
motor
neurone
D
sensory
relay
cell
→
neurone
sensory
→
neurone
motor
→
neurone
→
effector
(Paper
1)
[1]
Which
2
Where
are
relay
neurones
statement
explains
how
this
response
is
situated?
controlled?
A
effector
C
B
spinal
D
(Paper
3
A
cord
spinal
nerve
1)
Auxins
stimulate
a
gravitropic
impulse
cord
metres.
in
The
travels
0.02 s.
speed
from
This
of
the
is
a
a
ngertip
distance
impulse
B
Auxins
stimulate
a
phototropic
to
C
Auxins
stimulate
cells
of
the
1.4
C
light
the
opposite
Auxins
from
70 m s
on
−1
7 m s
D
to
grow
on
faster
the
than
side
the
closest
cells
to
on
side.
stimulate
(Paper
1)
Which
shows
the
the
light
cells
to
on
opposite
grow
the
faster
side
away
than
the
cells
side.
170 m s
(Paper
2)
[1]
Which
are
[1]
7
4
the
−1
0.7 m s
−1
B
response.
is:
D
−1
A
response.
[1]
nerve
spinal
A
receptor
hormone
the
and
A
adrenaline
B
insulin
–
its
–
correct
match
between
effect?
decrease
increase
in
in
heart
blood
symptoms
of
Type
1
diabetes?
the
rate
glucose
A
bleeding
gums
B
constant
alertness
C
thirst
D
tiredness
and
and
poor
and
wound
healing
insomnia
unexplained
weight
loss
concentration
C
oestrogen
–
decrease
in
the
volume
and
unexplained
weight
gain.
of
(Paper
2)
[1]
urine
8
D
testosterone
–
stimulates
development
A
man
injures
his
arm
in
an
accident.
of
Afterwards,
he
can
feel
objects
touching
his
sperm
hand,
(Paper
1)
Which
occur
when
in
a
hot
A
environment?
them.
all
in
sweat
hair
skin
glands
muscles
are
A
constrict
active
relax
B
constrict
not
contract
C
dilate
active
relax
D
dilate
active
contract
C
172
his
hand
away
active
cause
of
between
this
could
his
hand
his
spinal
be
and
that:
the
spinal
damaged
all
nerves
effectors
2)
move
erector
B
(Paper
cannot
The
nerves
cord
arterioles
the
he
[1]
from
5
but
all
nerves
hand
D
all
(Paper
[1]
between
in
and
the
2)
his
arm
between
his
are
the
spinal
receptors
in
receptors
cord
his
cord
and
the
cut
are
hand
in
his
cut
are
damaged
[1]
9
The
the
diagram
shows
a
horizontal
section
of
11
eye.
A
scientist
and
investigated
cones
shown
in
across
the
distribution
the
diagram.
of
cones
the
distribution
retina
The
in
the
of
a
of
mammal
graph
shows
rods
as
the
retina.
D
C
B
B
A
E
X
Y
X
Y
A
sllec
the
(b)
Explain
(c)
A
parts
labelled
A
to
E.
[5]
fo
Name
enoc
(a)
person
brightly
(i)
the
walks
lit
eye
is
from
a
a
sense
dark
organ.
room
into
rebmuN
why
[2]
a
place.
Describe
the
change
that
you
would
A
see
happening
to
the
person’s
B
pupils.
[1]
(a)
(ii)
Suggest
the
advantage
of
the
Name
Give
you
described
in
(i).
parts
reasons
(a)
the
retina
X
and
Y
.
for
your
answers.
[4]
Copy
the
graph
and
show
on
it
the
3)
distribution
10
of
[1]
(b)
(Paper
the
change
Copy
that
and
complete
shows
part
concentration
of
of
the
the
ow
chart
control
glucose
in
of
the
(c)
(i)
the
State
the
of
an
rods
involuntary
blood
glucose
retina.
action
[3]
involving
eye.
[1]
Explain
how
involuntary
in
the
blood.
(ii)
increase
in
the
control
action
of
differs
an
from
the
concentration
control
of
a
voluntary
action.
[3]
↓
(d)
Explain
having
detected
by
the
two
advantages
to
coordination
an
animal
systems:
of
the
…
nervous
system
and
the
endocrine
system.
[3]
↓
insulin
secreted
(Paper
↓
12
(a)
4)
Describe
when
liver
cells
respond
by
[2]
(b)
sensory
There
spinal
Write
out
a
similar
ow
chart
to
show
response
glucose
to
a
decrease
in
Explain
using
concentration.
as
(Paper
an
the
the
principle
control
example.
of
of
that
impulse
occur
arrives
at
at
a
synapse
the
end
are
neurone.
of
huge
cord
and
[4]
numbers
the
of
brain.
synapses
Explain
in
why
the
this
so.
[3]
blood
[3]
(Paper
(c)
events
the
is
body’s
the
nerve
…
a
(b)
a
negative
glucose
in
4)
feedback,
the
blood
[5]
4)
173
15
Drugs
15.1
Drugs
What
LEARNING
A
•
Dene
•
Describe
are
the
term
drug
is
any
the
use
of
antibiotics
treatment
of
bacterial
There
the
substance
that
is
taken
into
the
body
that
alters
or
drug
inuences
in
drugs?
OUTCOMES
are
chemical
several
ingredients
of
reactions
different
medicines
in
types
and
the
of
are
body.
drug.
used
Some
to
treat
are
the
and
active
cure
people
of
infection
disease.
•
State
that
some
bacteria
makes
to
antibiotics
them
less
State
that
paracetamol,
designed
to
antibiotics
but
do
which
alter
sensory
perception.
suppress
morphine
muscular
pain
pain,
and
antibiotics
counteract
the
are
medical
symptoms
of
drugs
‘u’,
soothe
useful
are
not
or
kill
socially
pathogenic
acceptable
bacteria.
drugs
Alcohol,
that
people
nicotine
take
for
and
their
kill
pleasurable
bacteria
mood-enhancing
which
caffeine
•
are
are
Aspirin,
resistant
Others
effects,
to
help
them
relax
or
concentrate.
affect
viruses
Drugs
tnemelppuS
are
•
Explain
the
strategies
that
be
used
to
reduce
of
Explain
why
Acid
user.
Diethylamide
Stimulants,
mood-enhancing
antibiotics
well-being
of
their
drugs.
more
severe
effects
Hallucinogens,
or
LSD,
cause
psychedelic
like
visions
like
cocaine,
ecstasy
and
for
amphetamines
the
are
but
do
not
and
drugs
energy.
which
Heroin,
give
the
user
although
it
a
short-lived
affects
the
feeling
body
in
a
kill
different
bacteria
because
bacteria
of
•
illegal
recreational
antibiotic-
all
resistant
be
the
drug
development
to
called
that
Lysergic
can
tend
sometimes
way,
also
gives
a
feeling
of
well-being.
affect
Drugs
act
upon
the
human
body
in
various
ways.
Some
drugs,
such
viruses
as
nicotine
system
and
works
heroin,
and
mood-enhancing
STUD
Y
TIP
in
the
nervous
impulses.
T
here
are
den
e
the
term
ways
to
cell
the
top
of
this
the
liver
page
,
types
can
we
write
describ
e,
it
the
abused
heroin
change
the
combining
way
by
and
way
with
that
the
people.
Many
nicotine,
in
which
protein
nervous
act
of
at
the
synapses
neurones
molecules
send
on
the
neurones.
from
is
are
the
site
broken
of
the
down
breakdown
in
the
body
of
by
alcohol
and
enzymes
other
and
the
toxins.
products
which
excreted.
The
breakdown
products
can
be
detected
in
the
urine,
of
and
drug
s
of
by
as
the
at
are
all
this
often
such
and
with
‘drug
’.
den
ition
Drugs
covers
are
drugs,
do
membranes
The
Lear
n
the
man
y
these
system
They
interfere
so
you
this
taking
mem
ory.
who
have
Many
rely
it
drugs
why
the
in
have
drug,
regularly.
are
urine
tests
Athletes
been
drugs
on
take
is
drugs.
illegal
accidents
the
a
In
are
taking
many
and
are
potential
person
carried
part
can
in
out
routinely
to
be
possession
or
see
tested
addictive.
become
countries
to
if
competitions
addicted
some
or
dealing
all
in
of
people
and
for
If
the
them
been
drivers
drugs.
the
and
have
car
body
feel
comes
the
need
to
to
non-medicinal
results
in
severe
punishment.
The
body’s
produce
to
Many
in
an
on
medical
drugs
uncontrolled
prescription
174
are
way
from
a
dangerous
and
are
doctor.
if
taken
available
only
metabolism
more
increase
to
may
enzymes
have
the
to
become
break
effect
it
that
used
down
the
to
so
user
the
that
rst
drug.
the
The
dose
liver
of
experienced.
may
the
drug
has
Antibiotics
(bacteria
growth.
cure
are
and
a
group
fungi)
Antibiotics
human
Antibiotics
and
can
antibiotics
has
be
to
was
the
Penicillin
acts
on
a
breakdown
Some
are
be
over
the
stop
by
cell
made
to
kill
by
be
by
and
and
the
wall
cell
to
and
their
treat
and
fungi.
Usually
of
a
course
of
time.
and
mass-produced.
formation,
leakage
crossing
stop
vets
mouth.
period
cell
or
bacteria
discovered
inhibiting
wall
by
certain
substances
microorganisms
doctors
taken
to
by
pathogens
caused
a
antibiotic
bacteria
of
or
taken
rst
used
diseases
injected
be
antibiotics
chemicals
are
prescribed
animal
Penicillin
to
of
that
of
cell
leading
contents.
membranes
and
others
MRSA
prevent
enzymes
proteins.
taking
A
big
Antibiotics
antibiotics
problem
resistant
to
to
tnemelppuS
Viruses
are
rely
viruses
for
viral
but
be
have
no
treat
viral
on
and
than
They
the
that
is
such
there
are
is
that
viruses.
many
vets
not
of
use
not
differently
on
such
There
as
is
making
no
point
are
in
and
being
antibacterial
need
bacteria
to
have
know
resistance
carry
their
host.
antibiotics
possible.
diseases
as
to
out
AZT
their
This
that
This
antibiotics
the
development
MRSA.
This
has
of
in
which
is
by
why
viruses.
used
There
that
our
to
are
such
has
hospitals.
deaths
as
number
recent
only
years
when
of
as
cases
a
of
result
in
those
necessary
MRSA
of
and
are
antibiotic
bacterial
treatment
been
caused
Overuse
resistance.
See
anti-viral
was
by
overuse
responsible
prescribing,
test
patients
have
had
with
organ
in
the
USA
and
strategies.
ensuring
that
UK
taking
more
all
on
their
pills
use
aureus
or
suppressed
has
decreased
antibiotic
a
to
against
patient.
contain
nd
the
The
out
white
the
for
a
hospital
discs
on
would
be
has
this
agar
Here,
effective
to
infected
plate
four
ways
resistance
bacteria,
whereas
because
two
they
would
have
not.
their
courses
to
on
POINTS
control
page
239.
A
drug
is
the
a
substance
body,
which
chemical
taken
alters
or
reactions
QUESTIONS
a
Dene
b
Name
two
drugs
c
Name
two
mood-enhancing
the
term
drug
d
Name
two
drugs
that
2
are
used
as
body.
Antibiotics
by
medicines.
the
can
cell
pathogens
wall
inhibiting
protein
drugs.
synthesis
that
destroy
disrupting
formation,
be
harmful,
but
are
not
illegal
and
metabolism
in
in
the
pathogen
cell.
countries.
3
Explain
a
in
in
2
ask
in
antibiotic
that
antibiotics.
inuences
many
may
out
which
pathogen
different
into
1
doctor
carried
antibiotics
complete
are
a
be
transplants.
Prescribing
people
to
of
for
1
SUMMARY
of
using.
HIV/AIDS,
fewer
Staphylococcus
hospital
who
specic
by
is
anti-
KEY
of
doctor
control
killed
The
this
bacteria
use
antibiotics
There
treat
far
to
Before
methicillin-resistant
caused
systems,
which
by
own
antibiotics
immune
hospitals
metabolism,
means
inhibit
explains
caused
antibiotics.
own
antibiotics.
to
especially
gels
in
antibiotic
laboratory
antibiotics,
antibiotic-resistant
become
which
sensitivity
Bacterial
other
controlled
disease.
cells
to
reactions,
diseases.
and
do
control
available,
work
doctors
have
to
effect
antibiotics
so
cells.
used
important
particular
would
drugs
they
drugs
a
not
metabolism
cannot
with
entirely
we
to
them,
prescribe
but
catalysing
how
antibiotics
act
to
kill
pathogens
like
bacteria
Antibiotics
cannot
kill
viruses
and
since
they
have
no
cell
fungi.
tnemelppuS
wall
host
3
Explain
why
antibiotics
can
kill
bacteria
but
not
but
rather
cells,
live
taking
inside
over
their
viruses.
metabolic
processes.
175
tnemelppuS
Antibiotics
15.2
Heroin
LEARNING
Describe
of
heroin
the
effects
of
Morphine
and
codeine
poppies
abuse
of
and
State
that
injecting
heroin
•
infections
Describe
the
addiction
such
as
problems
to
withdrawal
heroin,
is
Heroin
has
as
a
a
tnemelppuS
how
nervous
effect
a
opium
compound
so
is
Heroin
rarely
has
only
limited
medical
uses
as
it
is
used.
depressant
structure
that
that
slows
is
down
similar
to
the
nervous
endorphins,
system.
a
that
are
found
in
the
brain.
Endorphins
are
made
group
naturally
the
brain
and
provide
relief
when
the
body
experiences
pain
or
stress.
and
heroin
work
by
ooding
system,
on
the
limited
function
transmitting
relief.
affects
to
of
When
a
the
synapses
in
the
brain
and
preventing
neurons
blocking
nerve
for
and
alcoho
l
depres
sant
s.
shou
ld
when
use
this
writi
ng
effect
s
more
rst
and
on
time
This
mimics
synapses
they
intense
post-synaptic
in
usually
the
T
opic
feel
happiness.
a
This
so
producing
molecules
bind
membrane
function
14.3).
warm
state
When
rush
is
of
of
pain
to
the
the
synapse,
natural
people
and
known
a
take
feeling
as
of
euphoria
on
the
term
abou
t
their
body
.
shou
ld
apply
be
these
to ler
ance
depend
ence
addict
Addiction
TIP
ideas
and
to
alcoho
l.
injecting
to
heroin
into
a
vein.
heroin
becomes
part
of
the
body’s
metabolism
and
the
body
quickly
able
gets
and
the
heroin
are
Heroin
Y
ou
on
receptors,
the
Y
ou
An
STUD
Y
sites
pain
heroin,
transmission.
(see
the
from
takes
TIP
Heroi
n
bo th
impulses
person
endorphin-receptor
endorphins
synapses
STUD
Y
heroin
used
effect.
to
the
to
to
the
More
take
The
tolerance
People
in
who
dependent
three
the
to
on
weeks
are
of
reduce
the
order
but
This
body
feeling
to
start
experienced,
to
But
heroin
quantities
drug.
painkillers
brain.
painkillers.
a
176
and
chemical
contentment
of
from
is
and
crime
heroin
to
morphine.
powerful
chemicals
from
the
Heroin
infection
Explain
its
extracted
medicine.
severe
symptoms
such
from
addictive
Heroin
They
the
compounds
in
of
in
problems
•
two
painkillers
HIV
of
HIV
as
can
highly
cause
used
heroin
modied
•
are
the
feel
taking
they
needed
does
pain
the
drug,
to
includes
it
heroin
drug.
This
of
misuse
of
produce
This
has
to
or
want
get
can
nerve
prevent
becomes
euphoria
quickly
the
to
not
pain.
and
the
them
more
how
be
the
taken
just
to
of
happen
or
its
and
body
in
the
ever
a
has
its
impulses
own
natural
addicts
have
develops
greater
the
pain.
feelings
addicted
within
it
sending
deaden
repeat
‘hooked’
heroin.
where
unbearable
is
to
cells
as
matter
they
they
of
rst
are
just
two
tnemelppuS
•
Biology
OUTCOMES
is
taken
Injecting
is
highly
surrounding
known
places
The
as
to
by
smoking,
dangerous
injection
gangrene.
inject
danger
it.
page
as
virus
can
die,
it
into
a
collapse
and
tissues
giving
can
the
run
needles
and
is
the
transmission
and
the
virus
that
vein.
condition
out
share
this
(HIV)
to
injecting
addicts
addicts
with
or
veins
start
Long-term
associated
of
suitable
syringes.
of
the
causes
human
hepatitis
211).
Social
problems
Heroin
addiction
often
points
Some
immunodeciency
(see
snifng
is
dominates
a
the
serious
lives
problem
of
addicts
for
and
many
they
countries.
think
only
The
drug
about
how
Heroin
addiction
addiction,
they
can
get
their
next
‘x’.
The
drug
can
be
expensive,
which
at
many
often
people
to
become
turn
to
difcult
crime
to
in
keep
order
a
job,
to
fund
and
their
habit.
addiction
often
It
risk
from
and
breakdown
families,
and
homelessness.
preferring
the
Addicts
company
of
tend
other
to
shun
addicts,
isolated
from
a
nicotine
is
produced
in
and
so
heroin
in
the
and
America
smuggle
the
Afghanistan,
and
It
elsewhere.
drugs
Heroin
which
is
the
largest
is
a
highly
dealers
who
into
sell
in
the
Golden
Triangle
(Laos,
Heroin
is
then
trafcked
Networks
of
developed
illegally
criminal
countries
into
gangs
and
it
on
the
streets.
Most
of
Europe,
help
to
have
harsh
penalty,
to
penalties,
stop
such
trafcking.
A
as
life
user
drugs
their
next
have
resulted
include
happening
A
great
to
go
centre.
which
to
deal
overcome
is
very
unpleasant
sleeplessness
of
addiction.
countries
some
of
the
cramps,
and
stops
and
taking
This
addicts
same
the
from
only
may
are
effects
symptoms.
(imagining
sweating,
support
Often
rehabilitation.
some
gives
withdrawal
hallucinations
muscle
willpower
heroin
into
In
them),
and
way
involve
given
as
to
is
These
the
hepatitis
and
and
needed
staying
in
a
drug,
who
HIV
inject
Heroin
the
interacts
nervous
with
nausea.
to
the
habit
SUMMARY
QUESTIONS
treatment
methadone,
1
Dene
in
heroin.
each
relation
of
to
the
drug
b
dependence
c
addiction
d
rehabilitation
a
Why
a
is
heroin
highly
If
a
heroin
taking
what
Heroin
to
crime,
viral
the
drug
addicts
who
want
to
many
give
up
people
their
becoming
habit
is
involved
available
in
with
crime.
rehabilitation
Support
for
addict
drug,
happens
social
and
how
stops
describe
to
them.
can
and
the
lead
family
spread
of
these
consequences
of
drug?
diseases.
Explain
cause
described
addictive,
addiction
problems
the
use:
tolerance
b
3
following
a
depressant
often
synapses
system.
are
as
are
amongst
heroin.
can
2
Drugs
needles
spread
drug
things
overcome
another
Shared
in
the
the
terrible
vomiting
others
dose.
to
in
experiences
to
for
heroin-producing
imprisonment
who
turn
money
and
3
death
may
obtain
North
process
distribute
the
addicts
Vietnam,
addicts
countries
addictive
drug.
producer
of
drug
lives
society.
world,
Thailand).
and
their
addiction.
POINTS
crime
Burma
of
put
they
2
of
form
people
to
depressant
Heroin
serious
more
friends
1
become
is
far
can
leads
KEY
family
but
drives
society
in
a
can
affect
negative
way.
centres.
177
tnemelppuS
Heroin
15.3
Alcohol
of
drugs
Biology
LEARNING
Describe
the
effects
of
sport
alcohol
a
socially
its
supply
acceptable
and
drug
in
consumption
many
are
countries
very
tightly
in
the
world.
regulated
and
in
consumption
Describe
the
long-term
alcohol
on
the
body
it
is
banned
entirely.
effects
When
of
is
some,
others
•
misuse
excessive
In
alcohol
of
in
the
OUTCOMES
Alcohol
•
and
and
alcohol
is
consumed,
it
is
absorbed
into
the
blood
very
quickly
on
since
it
is
a
small
molecule
that
does
not
need
to
be
digested.
It
is
society
tnemelppuS
also
•
Discuss
in
the
use
of
hormones
sport
soluble
the
wall
the
stomach
Alcohol
type
of
volume
alcohol
of
in
cell
the
membranes,
stomach
slows
gets
and
down
distributed
its
so
it
small
is
absorbed
intestine.
very
The
quickly
presence
through
of
food
in
absorption.
throughout
the
body
in
the
blood.
Some
units
is
lost
through
the
lungs
and
the
kidneys.
It
is
absorbed
by
liver
3
drink
/
cm
by
cells
and
broken
down
by
enzymes
so
that
its
concentration
in
the
volume
blood
/
men
alcopop
extra
decreases
gradually.
This
breakdown
happens
more
quickly
in
%
400
5
500
2
8
4
than
their
and
in
women
enzymes
less
fat
in
concentration
strong
because
tend
to
their
bodies
of
be
alcohol
men
more
active.
than
in
have
the
more
They
women,
blood
to
of
also
which
these
have
more
tends
decrease
enzymes
to
more
and
water
cause
the
quickly.
lager
Like
cider
500
4
2
(glass)
heroin,
down
the
125
40
5
wine
175
12.5
2.2
spirit
35
40
1.4
(vodka)
of
others.
of
is
removing
With
depressant.
of
loss
•
slower
reaction
•
loss
self-control.
nerve
coordination,
It
affects
impulses.
inhibitions
larger
•
of
a
transmission
effect
with
cocktail
the
alcohol
so
quantities
judgment
In
people
this
and
lack
the
brain
small
nd
of
control
by
quantities,
it
easier
to
inhibitions
of
slowing
ne
this
has
socialise
leads
to
movements
times
and
Unlike
heroin,
alcohol
does
not
lead
to
addiction
as
quickly
if
at
mixer
all.
Many
their
The
content
one
extra
strong
cider
drink
throughout
alcohol
8 grams
alcopop
people
of
hour.
lives
alcohol;
The
drink
more
page
200
UK
than
for
alcohol
in
without
of
drinks
this
is
to
advice
4
units
about
moderate
in
day
drinking
units.
broken
recommends
per
quantities
addicted.
measured
quantity
government
3
to
becoming
is
the
small
and
that
in
men
women
during
One
down
2
unit
the
is
liver
should
to
3
(but
in
not
see
pregnancy).
Addiction
lager
Some
people
referred
to
as
metabolise
greater
irritable
and
aggressive
wine
spirit
and
mixer
Figure
178
15.3.1
Some
alcoholic
drinks.
dependent
alcoholics.
alcohol
quantities
Alcoholics
cocktail
become
nd
can
are
of
it
after
alcohol
hard
cause
They
made
to
their
drinking
develop
in
to
the
get
cope
alcohol
a
the
spend
a
They
same
and
lot
of
are
as
effect.
sometimes
more
therefore
everyday
pain
and
tolerance
liver
.
with
families
and
upon
enzymes
need
They
problems
misery.
They
money
on
to
feel
tense
without
can
drink.
that
take
a
and
drink.
become
Social
problems
DID
The
misuse
of
alcohol
is
a
factor
in
crime,
family
disputes,
YOU
KNOW?
marital
Researchers
breakdown,
child
neglect
and
abuse,
absenteeism
from
discovered
vandalism,
assault
and
violent
crime
including
murder.
In
the
damage
done
by
alcohol
is
considerable
and
is
three
for
governments
to
has
and
adverse
making
to
other
effects
them
drink
drugs
feel
alcohol
on
involved
people’s
more
and
are
drive
in
many
road
concentration,
condent.
then
to
four
of
times
the
more
in
people
who
abuse
measure.
alcohol
Alcohol
have
cirrhosis
often
frequent
difcult
Finland
that
some
liver
countries
in
work,
a
In
some
vehicle
accidents.
while
at
countries
or
operate
the
it
is
type
Alcohol
same
against
machinery.
of
and
time
defence
the
that
In
law
most
who
protein
system.
some
have
in
the
This
people
susceptible
to
a
specic
cells
of
their
suggests
are
genetically
cirrhosis
if
they
3
Europe
There
are
the
Long-term
Drinking
serious
and
large
builds
liver
on
is
The
of
the
blood
with
alcohol
It
can
liver
more
is
condition
is
the
to
is
50
than
part
a
mg
the
in
the
of
the
per
100
legal
so
fatty
by
of
cm
.
abuse
that
liver.
brous
If
fat
is
this
scar
have
disease
breaks
quantities
that
can
heart
of
alcohol
stored
and
continues
the
tissue.
Alcohol
the
If
heavy
is
drinking
able
the
continues
to
This
condition
then
carry
out
condition
drinking.
with
in
tnemelppuS
misuse
Anabolic
increased
of
They
hormone.
of
The
strength
as
the
liver
becomes
alcohol
drugs
are
and
by
result
is
the
is
The
full
and
in
liver
toxins
fatal
consumption
of
also
the
the
less
to
reaction
respond
use
of
a
number
anabolic
increased
of
similar
mimicking
the
to
the
male
sex
male
the
features,
facial
In
of
and
protein-building
growth,
which
gives
effects
the
to
times
stimuli,
Armstrong
side-effects
men,
use
of
resulting
these
baldness,
drugs
kidney
from
can
and
the
breasts.
body
In
hair
women,
and
there
irregular
is
a
life
for
was
banned
doping
from
offences
competitive
in
2012.
development
POINTS
of
periods.
Alcohol
is
if
in
taken
a
depressant
excess,
it
reaction
and
can
times
and
QUESTIONS
a
Describe
b
What
how
effects
Explain
alcohol
does
reaches
alcohol
the
have
brain
on
the
after
it
is
about
why
a
person
who
has
drunk
2
brain?
alcohol
should
a
What
are
the
b
Summarise
long-term
effects
of
alcohol
on
the
not
effects
of
alcohol
on
society
and
Long-term
of
its
use
of
lack
effects
include
and
discuss
of
self-
of
alcohol
cirrhosis
brain
of
the
damage.
Performance
enhancing
drugs
the
anabolic
steroids
can
have
use.
serious
the
a
person.
body?
like
banning
a
drive.
3
the
in
drunk.
liver
Discuss
to
lights.
and
abuse
3
longer
trafc
about
damage
control
2
takes
as
excessive
bring
liver
for
bring
c
it
of
lengthen
1
so
such
athlete
1
SUMMARY
be
endurance.
impotence,
development
to
Alcohol
hormone
KEY
even
thought
sport
muscle
harmful
steroids.
aggression,
are
accidents.
damage,
cycling
are
road
stops
brain
Lance
There
drugs
many
blood.
person
leads
other
nodules.
becomes
from
unless
of
behaviour.
substances
work
and
cirrhosis.
removing
reversible
personality
steroids
testosterone.
this
job
not
Long-term
changes
The
its
is
known
and
cause
slows
This
alcohol.
limit.
years
ulcers,
body
large
liver
as
replaced
number
stomach
Drinking
known
and
over
lead
toxins.
metabolism
damaged
in
driving
alcohol
other
the
This
tissue
of
alcohol
for
health.
and
with
up.
of
quantities
damage.
alcohol
interferes
limit
penalties
effects
effects
brain
down
legal
severe
hormones
to
improve
performance
in
side
effects.
sports.
179
tnemelppuS
of
15.4
Smoking
Tobacco
LEARNING
plants
It
is
structure
the
Describe
gas
the
effects
exchange
carbon
and
tar
system
monoxide,
in
on
State
can
that
cause
lung
chronic
tnemelppuS
•
link
and
the
lung
obstructive
at
of
for
smoking
the
T
ar
and
is
It
the
the
smok
e
have
hear
t
syst
em
gas
Y
ou
this
effect
s
and
as
in
be
as
in
on
to
are
the
as
abou
t
it
for
a
a
against
smoke
smaller
and
It
–
Bogart
by
have
nervous
died
smoking.
at
57
from
more
stop
bacteria
insect
a
molecular
system
and
so
ts
particularly
to
the
the
which
enter
the
nerve
cells
depressant.
arterioles,
stickiness
more
as
move
of
these
lining
mucus.
help
to
are
smoke
the
narrowing
There
Some
lungs
irritates
normally
in
material
tar.
a
the
the
T
ar
produce
cough’.
gas.
volume
an
added
in
and
is
to
of
the
about
can
This
remove
the
back
of
4000
cause
cancer
with
hot
there
is
less
supply
may
not
Due
sometimes
heart
can
that
At
a
heart
be
to
may
by
the
the
If
it
blood
a
oxygen
baby
(see
by
already
when
muscle.
enough
this,
with
carry
time
delivered
premature
it
disease
tobacco
the
they
are
keep
but
means
in
may
page
not
where
the
on
the
lungs
the
mucus
removed
This
to
on
is
the
200).
clean.
the
stimulates
the
particles
the
places
settle
to
Tobacco
the
dust,
air
dirt
lungs.
the
of
is
cells
lining
where
out
given
and
airways
cells
and
from
term
bronchitis
Mucus-secreting
cilia
that
multiply.
(COPD)
chronic
smoke
airways.
phagocytes
bronchi
to
the
permanently
blood
nicotine.
there
properly.
response,
bacteria
send
to
including
which
of
This
to
on
that
smoking
diseases
lining
combines
strain
arteries
develop
of
It
oxygen
response
pulmonary
in
of
respiration,
by
stick
and
in
resulting
this
not
increases
to
with
clotting.
to
cilia
in
pregnancy
to
effect
mucus
system
the
alveoli
narrows
collects
them
make
the
its
beating.
that
and
bloodstream.
coronary
lung
the
the
interacts
stimulant,
also
poisonous
weight
efciency
accumulates
immune
for
the
caused
The
It
that
the
faster
obstructive
the
passages
a
fetus
of
to
a
‘smoker’s
puts
and
birth
irritates
produce
on
to
carcinogenic.
during
the
collection
reduce
Humphrey
our
that
blood
smoking,
to
is
This
is
faster
compounds
as
oxygen
for
by
cough
through
smokes
blood
into
because
rise
harder
emphysema.
180
protect
happens
through
drug
it
material
reduces
10%.
more
ows
woman
hum
ans.
as
a
beat
stimulates
monoxide
so
is
promote
pass
and
giving
beating
needs
as
on
sticky
not
chemical
Chronic
brought
with
quickly
it
pressure.
that
described
much
be
blood
Smokers
Diseases
actor
to
smoke
heroin
heart
damaged
haemoglobin
have
cancer
way
drug.
very
unlike
accumulate
throat
and
the
The
interact
heroin,
the
black
are
Carbon
syst
em .
aske
d
ques
tions
tran
sport
on
circul
atory
well
exchan
ge
may
tobacc
o
But
airways
different
in
Like
does
airways.
the
to
term
absorbed
platelets
the
mucus
TIP
is
increases
cools.
of
chem
icals
the
it
tobacco
makes
blood
tends
T
he
of
synapses.
which
coronary
cancer
STUD
Y
of
bloodstream.
Nicotine
(COPD),
evidence
between
allows
denition
Biology
disease
Discuss
a
Nicotine
of
smoking
disease
cancer
heart
as
pesticide.
smoke
tobacco
pulmonary
natural
the
nicotine
tobacco
a
that
Nicotine
•
nicotine
health
OUTCOMES
attack.
•
make
and
body’s
this
the
happens
air.
Large
amounts
bacteria
and
of
phlegm
white
blood
(a
mixture
cells)
are
of
200
mucus,
produced,
which
175
attempt
their
Chronic
nd
lungs
as
it
means
difcult
the
up.
to
bronchi
This
long
term.
move
are
condition
air
partly
is
chronic
People
into
and
with
out
this
of
000
condition
cough
blocked.
001
bacteria
the
Eventually
much
the
lining
this
that
of
cells
the
weakens
they
surface
blood
break
area
for
reach
alveoli
the
alveoli.
digest
a
to
walls
down
gas
the
and
pathway
reach
of
the
burst,
exchange.
100
of
them.
alveoli
the
lung
bronchitis
50
lung
so
cancer
25
reducing
This
tuberculosis
75
shtaed
through
white
tar
/
Phagocytic
and
125
rep
Particles,
150
rep
bronchitis.
to
raey
people
condition
0
is
emphysema,
which
leaves
people
gasping
for
1920
breath
as
remove
lung
have
the
control.
form
this
a
is
area
of
discovered,
the
still,
lung
a
and
part
of
cells
is
block
in
of
out
eventually
a
occupy
Deaths
from
lung
tnemelppuS
From
that
to
the
other
a
smoking
and
twentieth
low,
but
lung
these
cigarette
In
contrast,
you
deaths
increased
smoking
deaths
tuberculosis
In
see
the
the
from
blood
break
the
link
early
lung
more
other
falling,
a
and
small
sort
of
care
and
better
cancerous
smoke
deposit
part
of
as
the
were
the
habit
diseases,
result
of
such
improved
showing
in
the
increases
the
wa lls
chan ce
the
of
ch ance s
arteries.
tha t
disease
the
(see
of
heart
As
1
risk
page
oxygen
in
X-ray
the
on
right
page
lung.
128.
th a t
blood
will
of
developing
108) .
to
th e
B lo cked
h eart
c lo t,
Dene
a rter ies
th is
the
following
words:
there
cor o na r y
and
QUESTIONS
nicotine
b
tar
c
carbon
monoxide
hear t
r edu c e
the
2
da ma g es
Explain
how
increased
cigarette
risk
of
smoking
is
linked
to
an
developing:
muscle.
a
lung
cancer
a
What
b
Describe
is
the
b
bronchitis
function
of
the
c
heart
alveolus
disease
(air
sac)?
POINTS
T
obacco
smoke
monoxide
and
consists
smoke
of
nicotine,
tar
,
alveolus
carbon
particles.
c
Smoking
is
bronchitis,
lung
associated
with
emphysema,
cancer.
diseases
heart
such
disease
two
is
Describe
who
2
cancer
the
nicotin e
3
KEY
with
fat
a
increased
supply
a
housing.
1
increases
an
in
data
SUMMARY
is
alveoli
disease
Tobacco
will
between
between
Compare
Heart
tumour
lungs.
X-ray
medical
1920–60.
widespread.
lung
as
Wales
vessels.
off
cancer
dramatically
became
from
were
can
establish
and
If
the
cancer.
century,
of
as
above,
scientists
England
large
organs.
graph
helped
in
of
A
spread
diseases
may
tumour.
and
may
1960
cells
divide
to
airways
tumour
1950
cause
as
grow
1940
These
DNA
but
1930
or
long-term
The
tar.
and
known
may
the
Many
the
slow
cells
it
in
grow
very
oxygen
conditions.
carcinogens
The
group
enough
efciently.
these
changes
growth
small
of
the
airways.
not
Worse
is
of
promote
This
absorb
dioxide
both
cancer
substances
lining
cannot
carbon
smokers
of
they
ways
adapted
what
develop
in
to
which
carry
happens
to
a
healthy
out
its
alveoli
function.
in
people
emphysema.
as
and
d
Explain
how
functioning
emphysema
of
the
affects
the
lungs.
181
PRACTICE
QUESTIONS
1
denition
The
A
best
any
substance
inuences
of
the
taken
chemical
substance
that
term
into
drug
the
body
reactions
B
any
affects
C
substances
that
are
D
substances
that
may
the
in
6
is:
Which
statement
on
nervous
the
(Paper
to
body
nervous
treat
become
system
A
blocks
B
combines
The
effect
of
heroin
the
activity
with
of
all
sensory
receptors
information
on
about
neurones
nerves
that
pain
disease
C
prevents
the
D
stimulates
release
of
neurotransmitters
addictive
1)
neurones
to
send
impulses
[1]
about
2
the
that
the
transmit
taken
describes
system?
drug
in
tobacco
smoke
is:
(Paper
A
carbon
dioxide
B
carbon
monoxide
7
Why
and
C
nicotine
D
tar
pain
A
2)
is
it
[1]
necessary
develop
all
new
viruses
for
drug
types
have
of
companies
to
nd
antibiotics?
become
resistant
to
antibiotics
3
(Paper
1)
Which
statement
of
A
[1]
is
not
related
to
the
taking
B
antibiotics
have
become
C
antibiotics
have
been
60
heroin?
The
drug
is
a
D
stimulant.
in
drugs
use
of
for
misuse
over
years
many
bacteria
are
resistant
to
some
antibiotics
B
The
drug
is
C
Not
taking
addictive.
the
drug
may
withdrawal
symptoms.
The
a
lead
to
(Paper
severe
8
D
drug
is
depressant.
Tobacco
What
the
(Paper
1)
Which
component
is
[1]
smoke
the
contains
effect
of
carbon
carbon
monoxide.
monoxide
on
body?
[1]
A
4
2)
in
tobacco
smoke
is
causes
mutations
in
the
epithelium
of
the
the
bronchi
cause
of
lung
cancer?
B
A
carbon
dioxide
B
carbon
monoxide
C
nicotine
D
tar
reduces
the
oxygen-carrying
capacity
of
haemoglobin
C
5
1)
Which
drug
muscle
goblet
[1]
increases
protein
synthesis
in
adrenaline
B
antibiotics
C
insulin
stops
(Paper
9
tissue?
A
Drugs
the
movement
make
more
of
cilia
may
[1]
be
classied
as
useful
and
harmful
drugs.
(a)
Explain
(i)
(b)
(i)
why
drugs,
antibiotics
and
Name
(ii)
one
are
useful
drug
classied
as
drugs.
that
is
[4]
classied
drug.
as
a
[1]
testosterone
(ii)
(Paper
2)
Explain
briey
named
is
why
the
drug
you
have
[1]
(Paper
182
to
2)
harmful
D
cells
mucus
D
(Paper
stimulates
3)
classied
as
a
harmful
drug.
[2]
10
The
graph
the
UK
in
between
shown
and
1991
as
per
shows
which
the
number
alcohol
and
number
100 000
was
2006.
of
of
deaths
the
The
deaths
major
death
per
in
12
cause
rates
100 000
The
graph
smoked
are
1910
men
to
number
women.
over
shows
by
men
1980.
of
the
the
The
deaths
same
number
each
year
in
dotted
of
men
of
the
line
cigarettes
UK
from
shows
from
lung
the
cancer
period.
deaths
per
year
20
from
lung
cancer
noitalupop
18
16
males
14
000 001
4000
12
number
10
of
cigarettes
20 000
females
smoked
8
rep
3000
6
shtaed
4
2000
2
deaths
from
0
per
lung
year
10 000
cancer
5
3
1
9
7
5
3
1
1000
0
0
0
9
9
9
9
9
0
0
0
9
9
9
9
9
2
2
2
1
1
1
1
1
year
Source:
is
Ofce
of
reproduced
National
with
the
Statistics.
permission
Crown
of
Public
(a)
Use
the
deaths
graph
in
to
which
describe
alcohol
the
Copyright
Controller,
Sector
the
was
material
Ofce
Information
trends
the
Calculate
rates
(c)
for
Cirrhosis
the
of
cirrhosis
among
between
the
consumption
of
percentage
men
liver
of
has
young
is
increase
1991
often
alcohol.
(a)
cause.
State
(i)
people.
in
by
number
the
Explain
UK,
how
(ii)
[2]
heavy
of
the
the
year
of
nd
out
if
the
cases
of
cirrhosis
increase
in
alcohol
increase
is
likely
to
in
the
Explain
why
inuence
(Paper
11
In
(a)
countries
prescription
Explain
these
to
(b)
alcohol
car
is
under
1980
which
there
was:
highest
number
of
cigarettes,
(b)
Describe
of
deaths
from
cancer.
what
[2]
happened
to:
(i)
cigarette
(ii)
deaths
consumption,
and
from
lung
cancer
over
the
you
shown
by
the
graph.
[5]
number
due
to
(c)
an
[2]
Discuss
whether
evidence
to
lung
the
support
cancer.
graph
the
provides
idea
that
any
smoking
[3]
the
dangerous.
[3]
(Paper
4)
3)
many
on
of
a
1970
cases
consumption.
driving
in
consumption
lung
causes
(d)
1960
especially
the
be
1950
highest
period
would
1940
and
death
2006.
caused
The
increased
in
and
1930
year
[3]
(b)
1920
(OPSI)
in
major
1910
of
antibiotics
from
why
a
antibiotics
countries
are
available
rather
are
prescribed
than
freely
buy.
Explain
only
doctor.
in
available
[2]
why
antibiotics
do
not
kill
viruses.
[3]
(c)
Discuss
the
antibiotics.
(Paper
dangers
of
overusing
[4]
4)
183
16
Reproduction
16.1
Asexual
and
sexual
reproduction
Reproduction
LEARNING
plants
•
Dene
means
producing
new
living
organisms.
Animals
and
OUTCOMES
asexual
and
are
sexual
reproduce
two
types
of
to
make
new
reproduction:
individuals
asexual
of
the
and
same
sexual
species.
There
reproduction
reproduction
Asexual
•
Identify
asexual
In
from
descriptions,
asexual
tnemelppuS
•
reproduction
there
is
only
one
parent.
All
the
offspring
diagrams
are
and
reproduction
reproduction
identical
to
the
parent
as
they
inherit
exactly
the
same
genetic
photographs
Discuss
the
advantages
disadvantages
sexual
of
information.
They
means
there
is
due
the
are
genetically
identical
to
the
parent,
which
and
asexual
little
variation
amongst
the
offspring.
Any
variation
is
and
to
effect
of
the
environment,
for
example
the
availability
of
reproduction
nutrients
fungi
Bacteria
not
and
and
are
have
a
asexually
water
plants
determine
reproduce
microscopic
nucleus,
the
DNA
but
loop
how
organisms
a
loop
is
well
organisms
grow.
Bacteria,
asexually.
of
copied
made
DNA.
so
up
of
When
that
one
cell.
bacteria
there
is
They
do
reproduce
some
for
each
new
cell
cell.
membrane
You
can
nd
some
information
about
how
DNA
is
copied
on
DNA
page
cell
218.
wall.
parent
This
because
cell
duplication
of
the
mould
is
reproduces
specks
a
of
the
of
damp
cell
asexual
parent
cell
a
fungus
asexually
dust,
and
surface,
hypha,
grows
called
produce
divides
into
reproduction
splits
it
which
by
into
two
is
by
making
called
a
binary
new
cell
ssion
two.
grows
making
they
splits
of
over
a
spore
hundreds
oat
open
on
bread
spores.
through
and
a
(see
These
the
air
.
thread
pages
are
When
grows
6
small
a
and
and
spore
out.
This
7).
It
light,
like
lands
on
the
surface
mycelium.
cases
new
or
of
bread
Eventually
,
sporangia
spores
are
at
formed
forming
short
their
a
dense
thread
or
network
hyphae
of
tips.
asexually
grow
Inside
by
upwards
each
division
of
and
sporangium
the
nuclei.
into
Each
two
of
growth
cell
threads
division
bacterial
type
DNA
Pin
continued
The
wall
nucleus
gains
a
small
quantity
of
cytoplasm
and
a
protective
daughter
spore
cells
case.
When
ready
,
the
sporangia
break
open
and
the
spores
are
dispersed.
Potatoes
Figure
Each
16.1.1
new
identical
Binary
bacterial
to
each
cell
other
ssion
is
in
bacteria.
genetically
and
to
the
are
reproduce
swollen
Sucrose
is
asexually
underground
transported
in
by
stems
the
means
that
of
stem
grow
phloem
from
tubers,
from
the
the
which
parent
leaves
into
plant.
these
parent
underground
stems
that
swell
as
they
convert
the
sucrose
into
cell.
starch.
leaving
The
the
However,
‘seed’
from
one
the
farmers
sexual
organs.
184
to
parent
new
potato
Sexual
In
tubers
potatoes
regrowing,
of
parent
plant
in
dig
plant
the
are
shoots
as
at
the
ground
them
plant
known
dies
the
up
and
next
end
to
sell
year.
genetically
and
roots
of
survive
the
them.
All
growing
over
the
Some
from
are
kept
as
produced
When
the
season
winter.
tubers
identical.
emerge
the
they
start
growing
points
‘eyes’.
reproduction
reproduction
The
sex
there
organs
are
make
two
sex
parents.
cells
or
The
parents
gametes.
In
have
animals
sex
the
male
gametes
are
nuclei
are
egg
inside
cells.
structures
fuse
At
an
contain
one
which
half
comes
the
from
set
of
In
grains.
During
may
animals
the
The
A
the
female
into
a
egg
new
comes
The
zygote
or
are
the
from
a
inside
zygote
the
in
gametes
gametes
individual
nuclei
has
male
gametes
gametes
reproduction
gamete.
chromosomes.
the
fertilised
material
female
plants
female
sexual
grow
genetic
the
owering
In
plants
fertilisation.
embryo
half
cells.
owering
ovules.
at
fertilisation,
and
sperm
pollen
In
called
together
form
are
nucleus
to
plant.
male
the
divides
gamete
gametes
that
underground
stem
contains
developing
two
sets
of
chromosomes
–
one
from
each
gamete.
tuber
Unlike
asexual
genetically
reproduction,
identical
to
the
the
offspring
parents.
Each
produced
zygote
are
‘eyes’
not
receives
half
its
genes
young
old
from
its
male
parent
and
half
from
its
female
parent.
This
means
tuber
tuber
that
swelling
sexual
reproduction
brings
about
variation
in
the
with
offspring.
stored
Advantages
and
reproduction
An
advantage
can
plants
If
left
grow.
in
place
Plants
There
in
may
is
very
little,
reproduction.
affected
none
by
may
a
more
be
if
of
rapidly
tubers
any,
is
much
for
from
grow
with
asexual
growth
be
a
disease.
resistance
to
into
each
are
so
as
a
Since
Figure
new
than
plants
for
could
spread
which
all
the
potato
plant.
are
of
if
and
the
same
to
new
areas
many
seeds
wasted.
asexual
these
all
in
parent
seeds.
methods
individuals
genetically
they
may
all
are
identical,
very
quickly
through
a
crop
be
killed.
plants
plants
are
genetically
identical.
reproduce
asexually
by
monoculture,
producing
in
The
resources.
However,
are
the
from
Potato
Disease
16.1.2
Organisms
where
dispersed
result
disease
fast.
other
many
they
is
areas
tubers
disadvantage
the
it
competition.
variation
can
that
colonise
reproduction
as
places
This
and
compete
sexual
certain
have
spread
potato
but
not
unsuitable
reproduction
to
grow
parent,
there
in
asexual
ground,
the
disadvantages
plants
rapidly
produced
where
land
the
as
Seeds
of
of
reproduce
in
If
tubers,
as
well
as
sexually
with
environmental
owers.
conditions
features
rise
to
change,
adapted
variation.
adapted
to
adapted
if
species
the
the
are
it
to
In
is
unlikely
the
the
new
wild,
existing
able
to
there
conditions.
many
conditions
environment
better
that
as
and
their
If
be
Sexual
individuals
changes.
survive
will
individuals
reproduction
may
not
parents,
there
is
with
be
but
plenty
as
may
of
gives
SUMMARY
be
well
1
Explain
each
Asexual
Sexual
nuclei
reproduction
offspring
to
form
Binary
in
in
one
involves
zygote,
different
ssion
formation
a
results
from
reproduction
genetically
3
a
gamete
b
fertilisation
c
zygote
d
embryo
Describe
each
the
bacteria,
the
each
spore
are
all
production
of
of
th ese
fusion
of
male
offspring
other
and
of
that
their
production
examples
in
and
female
are
a
binary
b
spore
production
c
tuber
formation
parents.
fungi
asexual
and
asexu a l
reproduction:
genetically
parent.
producing
from
potatoes
in
of
ssion
Asexual
does
reproduction
not
result
in
may
variation
produce
of
many
tuber
3
reproduction.
offspring
as
individuals
in
sexual
in
bacteria
in
fungi
in
potatoes
Make
the
a
table
to
advantages
disadvantages
4
following:
POINTS
identical
2
the
evolve.
examples
1
of
variation,
2
KEY
QUESTIONS
well
rapidly,
but
tnemelppuS
tnemelppuS
starch
compare
and
of
asexual
it
reproduction
and
reproduction
in
sexual
reproduction.
plants.
185
16.2
Flower
Flowering
LEARNING
the
structure
insect-pollinated
of
to
an
the
grains
ower
functions
of
have
carry
part
• State
petals,
is
and
• Describe
and
out
sexual
female
reproduction
gametes
pollination.
and
pollen
to
parts.
the
female
Female
grains
grow
The
parts.
gametes
a
tube
male
by
producing
to
parts
The
are
transfer
deep
reach
make
owers,
inside
them.
pollen
of
the
Each
grains
pollen
female
pollen
tube
the
a
male
gamete
so
it
can
fuse
with
the
female
gamete
to
form
anthers,
a
stigmas
male
male
delivers
sepals,
carry
OUTCOMES
which
• Describe
plants
structure
zygote.
Fusion
of
male
and
female
gametes
is
fertilisation
ovaries
the
structure
of
a
petals
wind-pollinated
• Compare
the
ower
adaptations
of
anther
stamen
different
types
of
pollen
grain
filament
stigma
sepal
carpel
style
ovar y
ovule
nectar y
Figure
16.2.1
Flowers
vary
A
in
half
ower
structure
Insect-pollinated
The
spiky
pollen
pollinated
from
grains
owers
and
wind-pollinated
are
the
from
smooth
grains
are
Flower
parts
swollen
owers.
•
Sepals
•
Petals
•
stalk
in
ies
a
smell
jump
in,
of
rotting
slide
esh
down
the
of
covered
the
out
to
186
plant
visit
in
pollen;
change,
another
after
a
to
attract
sticky
few
allowing
ower
of
days
the
the
upon
their
ower.
method
of
pollination.
owers
sepals
rings
form
attached
the
outer
to
ring
the
end
and
the
of
a
carpels
that
coloured
and
on
the
full
the
style
are
sugary
protect
the
scented.
nectar.
ower
Many
Visiting
when
have
a
insects
it
is
a
bud.
nectary
land
on
at
the
nectar.
male
sex
where
the
organs.
the
Each
pollen
anther.
In
is
this
one
is
made,
ower
made
up
of
two
and
the
lament,
there
are
four
a
stamens
ower).
female
and
an
inside
sex
organs.
Each
carpel
is
made
up
of
a
ovary.
the
ovary.
Each
ovule
has
a
female
gamete
–
cell.
pollen
in
The
in
structures
holds
the
arranged
makes
anther,
ovules
grains
the
ies
walls
are
of
insect-pollinated
photograph,
above
left.
owers
They
are
are
often
also
spiky
often
like
sticky.
ies
the
to
same
adapted
to
attach
to
hairs
on
the
surfaces
of
insect
The
bodies.
–
grains
become
dislodged
onto
a
stigma
when
an
insect
enters
and
another
are
depending
insect-pollinated
Indonesia
The
the
are
the
egg
grains
produces
feed
a
those
Sumatra
to
are
The
stalk.
brightly
stigma,
The
from
an
ring.
which
Carpels
the
arum
are
in
often
leaf-like
which
(eight
•
are
Stamens
parts:
•
inner
base,
petals
are
ower
the
the
Titan
of
insect-
form
The
drawing
ower
of
the
same
species.
The
ower
in
Figure
16.2.1
has
walls
climb
species.
stigma
its
way
in
the
centre
towards
the
of
the
ower
nectary.
which
an
insect
will
push
past
on
a
Wind-pollinated
owers
STUD
Y
inflorescence
inside
spikelet
(group
a
single
T
here
single
of
TIP
flower
flower
are
type
s
of
feather y
flowers)
some
stigma
long
man
y
ow
er
.
with
a
differ
ent
Look
hand
filament
and
mak
e
sure
anther
you
can
stamen
iden
tify
filament
style
anther
parts
ovar y
hinge
desc
ribed
differ
ent
16.2.2
Grasses
and
perenne,
The
are
so
anthers
that
chances
on
a
small,
the
are
hang
The
feathery
positioned
They
large
act
like
a
surface
pollen
grains
that
get
wind.
that
the
Rye
grass,
wind-pollinated
inconspicuous
no
wind-pollinated
scent
are
wind.
small,
These
no
Lolium
ower.
compared
and
ower.
with
nectar.
smooth
owers
and
light
make
huge
The
ower
the
are
ower
.
providing
for
the
a
a
catching
blown
into
T
wo
them.
Wind-pollination
can
owers
lot
of
pollen,
anthers
which
produce
so
is
why
that
and
cereals
another
plants
much.
such
grow
means
be
close
that
likely
to
were
separated
as
by
and
showing
feathery
large,
loosely
stigmas.
But
the
POINTS
grasses
to
one
pollen
transferred
Bromus,
anthers
the
KEY
fact
of
waste
attached
a
in
the
stigmas
area
a
of
here
ow
ers.
away
outside
net,
on
example
by
of
main
landing
the
blow
an
have
grains
as
small.
outside
can
and
They
carried
grains
very
is
typical
green
grains
grass
pollinated
pollen
easily
pollen
wind
pollen.
also
of
are
rye
all
owers.
pollen
stigma
anthers
so
of
of
features
produce
they
numbers
are
many
insect-pollinated
The
species
cereals
has
owers
This
four
with
mobile
Figure
the
at
lens
is
than
large
1
more
if
Insect-pollinated
have
they
sepals
ower
distances.
Long
anthers
hanging
out
of
rye
grass
petals
in
to
to
the
owers
protect
bud
attract
and
the
bright
insects.
The
owers.
stamens
SUMMARY
consist
laments.
up
1
Copy
use
and
some
of
complete
more
the
than
sentences
using
these
words
(you
of
a
Each
stigma,
carpel
style
2
once):
carpels
pollen
Wind-pollinated
ovary
parts
of
a
ower
are
called
the
.
Each
is
of
an
and
a
lament.
the
.
The
female
The
parts
grains
are
Each
is
made
up
of
Make
a
owers
table
and
of
a
to
compare
the
wind-pollinated
,
pollen
a
ower
are
called
Compare
the
structure
of
an
style
and
of
that
insect-pollinated
large
carried
owers
quantities
pollen
with
on
the
Insect-pollinated
produce
ower
ower.
that
of
is
.
owers.
insect-pollinated
the
smooth
smaller
and
spiky
wind.
owers
quantities
pollen
of
that
a
attach
wind-pollinated
are
feathery
the
sticky
3
anthers
Wind-pollinated
easily
2
owers
with
made
light,
.
and
outside
produce
inside
ovary.
made
3
up
and
stamens
hang
male
and
made
stigma
stigmas
anther
is
may
inconspicuous,
The
anthers
QUESTIONS
to
insects.
ower.
187
16.3
Pollination
Pollination
LEARNING
• Dene
the
the
term
pollination
agents
transfer
Pollination
owers
are
different
adaptations
insect-pollinated
pollinated
adapted
agents
When
the
structural
may
of
of
to
be
pollen
carried
grains
one
pollination;
of
out
these
there
are
by
from
the
insects
methods.
others
or
anther
by
Insects
such
as
the
to
a
wind,
and
birds
wind
and
and
are
bats.
of
pollination
• Compare
the
stigma.
two
• Name
is
OUTCOMES
and
of
wind-
an
its
pollen
to
bring
gamete
anther
so
that
the
so
is
it
splits
pollination
male
that
ripe,
gamete
open
can
occur.
(inside
fertilisation
along
a
can
its
length
Pollination
pollen
grain)
is
and
releases
needed
near
to
the
in
order
female
occur.
owers
tnemelppuS
• Distinguish
between
self-
pollination
and
cross-
pollination
and
discuss
Insect
Look
at
pollination
the
diagram
of
the
ower
below.
It
has
a
number
of
their
adaptations
for
insect
pollination.
signicance
The
ower
tongues
is
and
pollinated
are
able
anthers
brushing
–
by
to
ripe
onto
bees,
reach
with
the
which
the
land
nectaries
on
at
petals.
base
of
Bees
the
have
long
petals.
stigma
pollen
insect’s
the
the
back
insect’s
back
stigma
and
closed
style
ring
of
hairs
stop
anthers
ovar y
small
ovule
the
insects
reaching
petals
nectar
form
landing
–
dead
pad
nectar y
Figure
Honey
bee
with
pollen
on
its
legs.
The
16.3.1
bees
anthers
brush
STUD
Y
of
TIP
Whe
n
you
po lli
nated
a
hand
how
to
insect
s.
able
you
do
at
owe
rs
lens,
their
them
look
shou
ld
for
no t
bee’s
When
against
such
back
the
the
sugary
in
bee
ripe
pollination
Look
the
at
one
nectar
a
as
way
it
to
made
that
pushes
enters
stigma
ower
in
the
sticky
its
another
and
another
of
from
down
ower,
pollination
same
nectaries.
pollen
head
the
it
is
to
species.
The
them
the
brushes
will
base
some
of
achieved.
a
of
outside
wind
the
pollination
ower
so
that
on
the
they
next
release
page.
their
The
pollen
by
owe
r
seen
diagram
hang
the
wind
blows
them.
be
The
stigmas
they
act
as
are
a
feathery
net
to
and
catch
are
pollen
also
found
grains
in
outside
the
air.
the
ower,
where
Wind-pollinated
before
.
owers
by
the
grains
the
188
the
from
helps
po lli
nated
this
the
Wind
when
have
upon
pollen
iden
tify
anthers
Y
ou
transfers
positioned
petals.
pollen
bee
insect
-
with
struct
ure
be
feed
are
against
the
the
A
have
wind
so
same
light,
to
that
smooth
another
some,
species.
by
Most
pollen
ower.
chance,
of
the
grains
The
which
anthers
will
land
pollen
can
easily
produce
on
the
produced
stigma
will
be
many
be
of
carried
pollen
a
lost.
ower
of
The
structural
features
of
insect-
and
wind-pollinated
owers
are
pollen
compared
in
the
feature
caught
table.
insect-pollinated
owers
wind-pollinated
owers
pollen
present
–
colourful
and
absent
or
very
small
and
carried
petals
scented
present
nectaries
which
food
to
–
is
make
a
for
attract
insects
difcult
to
by
see
nectar
sugary
liquid
pollinating
absent
insects
lots
present
–
usually
with
long
laments
so
of
pollen
stamens
laments;
attached
rmly
laments;
for
to
hang
to
inside
insects
small
anthers
quantities
anthers
the
rub
outside
ower
the
against
of
easily
pollen
grains
light
easily
to
blown
attached
so
Wind
pollination.
pollen
to
is
away
quantities
of
smooth,
that
pollen
stick
loosely
16.3.2
ower;
sticky,
large
spiky
the
laments
made
anthers
Figure
short
wind
pollen
that
can
easily
insects’
be
carried
by
the
wind
bodies
sticky,
carpels
small
usually
for
stigmas
inside
insects
to
the
rub
large,
ower
catch
against
air
feathery
pollen
stigmas
grains
in
to
the
tnemelppuS
Hazel
Pollination
and
the
Self-pollination
a
stigma
of
the
catkins
release
pollen
to
be
carried
by
variation
occurs
same
when
ower
pollen
or
to
a
is
transferred
different
from
ower
but
the
on
anther
the
wind.
to
same
KEY
POINTS
plant.
1
occurs
when
pollen
is
transferred
to
a
stigma
Pollination
pollen
another
benet
plant
to
material
a
of
the
species
between
same
of
species.
plant,
different
since
plants
Cross-pollination
it
ensures
and
is
of
exchange
results
in
a
of
which
natural
selection
can
operate
greater
(see
Unit
results
in
much
less
variation,
since
of
the
male
to
the
stigma
exchanged
with
different
is
advantage
plants
but
with
the
part
an
if
there
are
no
plants
growing
in
isolation
from
others
of
genetic
same
material
one.
pollinating
the
of
the
petals,
same
Give
is
b
two
ways
Write
to
down
pollinated
in
the
three
and
pollen
pollen
other
from
from
insect-pollinated
wind-pollinated
differences
wind-pollinated
between
owers
owers.
tnemelppuS
a
What
is
the
difference
between
owers
with
are
feathery
anthers
anthers
same
of
to
the
ower
on
involves
pollen
the
self-pollination
and
of
from
stigma
or
a
hang
the
the
of
the
different
same
Cross-pollination
owers.
that
ower
.
Self-pollination
ower
insect-
and
the
transfer
2
have
nectar
.
species.
3
which
and
and
QUESTIONS
different
owers
scent
However
,
insects,
transfer
a
ower
female
ower.
Insect-pollinated
outside
1
the
the
is
stigmas
SUMMARY
of
anther
variation
inconspicuous
for
of
of
Wind-pollinated
self-pollination
the
18).
bright
not
transfer
from
genetic
2
Self-pollination
the
grains
greater
part
upon
is
of
plant.
involves
pollen
tnemelppuS
Cross-pollination
from
the
the
crossanthers
of
one
ower
to
the
pollination?
stigma
b
State
the
advantages
of
cross-pollination
over
self-pollination.
a
of
another
different
plant
ower
of
the
on
same
species.
189
16.4
Fertilisation
and
seed
formation
LEARNING
OUTCOMES
Fertilisation
State
that
fertilisation
owering
a
pollen
nucleus
plants
occurs
nucleus
in
an
in
fuses
when
with
a
Pollination
the
starts
ovule
to
tnemelppuS
nucleus.
•
Describe
the
events
that
•
complete
part
grow
of
a
a
when
ower.
pollen
Fertilisation
the
If
tube
a
to
pollen
pollen
take
grains
grain
the
land
lands
male
occurs
when
the
male
occurs
inside
the
ovule.
on
on
nucleus
nucleus
the
a
stigma
ripe
to
the
fuses
of
stigma
it
female
with
the
lead
female
to
is
female
nucleus.
This
fertilisation
State
the
requirements
germination
of
Each
for
the
seeds
of
pollen
ovule.
the
style
carries
the
The
the
ovary.
male
grain
As
it
and
carries
male
It
grows
grows,
enters
fertilisation
in
the
a
pollen
ovule
tube
tube
from
nucleus
nucleus
which
pollen
nutrition
gamete
gamete
a
the
with
through
then
zygote
fuses
is
to
take
gains
the
it.
a
tissues
The
formed
male
the
–
egg
fusion
the
style
the
cell
of
nucleus
from
pollen
hole
the
by
of
rst
small
with
the
nutrition
and
tube
reaches
micropyle.
nucleus.
the
to
tissues
two
This
is
nuclei.
germinating
pollen
A
pollen
(left)
grain
with
its
and
a
pollen
germinated
tube
and
pollen
male
grain
pollen
down
gamete
grain
tube
grows
style
nuclei.
ovule
STUD
Y
TIP
Rem
embe
r
male
the
po lle
n
deliv
ered
gam
e te
tube
.
no t
that
gam
e te
the
the
to
and
gamete
fuse
with
nucleus
egg
cell
about
nucleus
is
femal
e
pollen
tube
penetrates
micropyle
po lle
n
po lle
n
male
male
inside
grai
n
to
by
T
he
the
is
the
grai
n
is
Figure
16.4.1
Fertilisation
occurs
within
the
ovule.
gam
e te.
PRACTICAL
Growing
Find
pollen
some
owers
particularly
Cut
some
transfer
sucrose.
anthers
dish
of
Scanning
grains
190
electron
and
pollen
micrograph
tubes
of
lily,
of
pollen
Lilium
sp.
for
small
Use
to
squares
to
a
the
24
forceps,
with
anthers
covered
in
pollen.
Lily
owers
are
suitable.
them
to
tubes
lter
of
paintbrush
squares
48
put
of
hours.
on
a
damp
paper
to
Visking
soaked
in
transfer
dialysis
Remove
microscope
a
(dialysis)
nutrient
some
tubing.
the
pollen
Leave
squares
slide
and
tubing
and
solution
in
grains
a
covered
carefully
observe.
rich
from
with
in
the
Petri
a
pair
tnemelppuS
•
Seed
formation
KEY
After
fertilisation,
the
zygote
divides
and
grows
into
the
embryo.
1
The
ovule
forms
the
seed
with
the
embryo
inside
POINTS
Fertilisation
male
The
of
ovary
the
forms
ower
sepals,
the
are
petals
fruit
not
and
with
needed
stamens
the
seeds
when
wither
inside
it.
fertilisation
and
fall
off.
Many
has
of
the
occured,
They
have
parts
so
gamete
pollen
when
the
fuses
gamete
nucleus
the
with
nucleus
the
from
the
female
inside
an
ovule.
completed
2
their
occurs
it.
A
fertilised
egg
grows
into
functions.
an
ovary
the
embryo
which
becomes
inside
now
an
forms
ovule
the
seed.
fruit
seed
thin
with
The
ovary
forms
the
fruit
testa
containing
3
many
Germinating
seeds.
seeds
require
stone
water,
warm
oxygen
and
a
temperature
suitably
for
growth
skin
and
the
becomes
seed
4
Figure
16.4.2
How
a
plum
ower
grows
into
a
plum
Pollen
that
Each
fertilised
ovule
grows
to
form
a
seed.
Each
seed
is
made
up
the
The
embryo
ovary
forms
Conditions
Three
•
•
the
for
is
energy
store
•
a
seed
coat
or
grows
are
needed
of
some
down
an
ovule
in
SUMMARY
needed
for
seeds
for
to
seeds
swell.
to
Cell
from
seeds.
Cells
expansion
the
absorb
This
swelling
water,
breaks
develop
the
vacuoles
seed.
made
these
a
makes
Water
is
the
also
radicle
needed
(embryonic
to
dissolve
root)
the
Oxygen
is
State
what
happens
by
enzymes
from
the
food
stores.
occurs
when
in
grow
Water
plants.
Describe
the
role
of
the
also
tube.
enzymes.
needed
for
aerobic
respiration
to
provide
the
What
happens
to
each
embryo
of
with
to
soluble
c
•
style
ovary.
seed
pollen
activates
the
and
b
products
the
the
tube
germinate:
owering
out
on
pollen
QUESTIONS
fertilisation
expand.
land
fruit
1
coats
a
testa.
germination
conditions
Water
an
that
produce
of:
reach
•
grains
stigma
fruit.
the
following
after
energy.
fertilisation?
•
A
suitably
warm
temperature
is
needed
so
that
enzymes
can
work
efciently.
i
petals
ii
ovule
iii
ovary
PRACTICAL
Conditions
for
germination
2
a
State
the
three
environmental
Y
ou
can
investigate
the
A
conditions
necessary
B
C
conditions
D
that
germination
germination
Set
up
and
the
leave
checking
with
tubes
them
them
mung
as
for
a
b
to
germination
has
In
each
explain
week,
day
affects
see
damp
if
of
the
seeds.
beans.
shown
every
affect
for
started.
case
how
in
part
the
a,
condition
germination.
cotton








warm
warm
warm
cold
wool
c
Explain
why
the
seeds
in
oxygen
Only
the
seeds
in
A
have
all
tubes
B,
C
and
D
in
the
absorber
the
conditions
germination.
needed
for
temperature
Practical
box
(left)
did
not
germinate.
191
tnemelppuS
ovule
development.
16.5
The
male
reproductive
system
The
LEARNING
or
•
Identify
of
the
on
diagrams
male
system
testes
are
the
male
sex
organs.
They
produce
the
male
gametes
OUTCOMES
and
the
parts
sperm
This
reproductive
state
spermatozoa
cells.
stimulates
during
their
The
–
a
word
testes
also
changes
puberty.
This
that
in
is
make
a
the
boy’s
happens
usually
abbreviated
male
body
between
as
hormone
he
about
to
or
testosterone.
develops
10
sperm
and
into
16
an
years
adult
of
age.
functions
tnemelppuS
The
•
Compare
male
and
female
testes
outside
gametes
sperm
and
are
the
cells
be
need
stored.
cells
which
they
mature.
these
located
body.
uids
sac
the
puberty,
much
to
in
a
keeps
temperature
stored
A
tubules
secrete
a
After
are
inside
This
the
in
urethra.
which
the
tubules
cells
to
outside
the
can
hangs
gland
develop
produce
the
sperm
swim.
which
temperature
37 ˚C
prostate
sperm
scrotum
cooler
constantly
just
called
The
a
than
testes
tube
the
at
cooler
the
small
wider
called
testes
and
The
sperm
testes
duct
as
properly
where
connects
other
glands
prostate
seminal
vesicle
secretes
as
a
mucus
source
together
of
and
other
energy
form
for
semen,
glands
their
also
secrete
sugars
respiration.
known
as
which
Sperm
seminal
cells
sperm
and
cells
the
use
uid
uid.
prostate
gland
The
of
two
the
time.
any
sperm
penis.
A
ring
urine
ducts
Urine
of
join
and
muscle
from
the
with
the
semen
around
bladder
urethra,
never
the
pass
urethra
during
sexual
which
down
runs
the
contracts
down
urethra
to
the
at
centre
the
prevent
the
sperm
and
same
loss
of
intercourse.
urethra
spongy
tissue
Male
and
female
gametes
penis
Gametes
testis
the
are
female
specialised
sex
cells.
gamete
cell
that
is
is
The
male
called
the
adapted
gamete
ovum
for
is
or
called
egg.
swimming
the
The
by
sperm
having
a
cell
is
a
agellum
that
foreskin
lashes
male
from
side
parent
to
to
side.
the
egg
Sperm
of
the
cells
carry
female
genetic
parent.
The
information
nucleus
from
contains
the
the
scrotum
father’s
Figure
16.5.1
Male
reproductive
chromosomes.
provides
front
An
egg
is
much
bigger
than
a
sperm
because
system:
the
food
store
that
supports
the
embryo
after
fertilisation.
view.
bone
rectum
acrosome
middle
the
piece
like
head
the
containing
flagellum
a
whip
sperm
(tail)
and
beats
drives
for ward
enzymes
a
sperm
cell
nucleus
membrane
containing
chromosome
membrane
anus
cytoplasm
sperm
an
egg
tube
jelly
a
coat
sperm
same
this
nucleus
sperm
tubules
in
on
scale
the
as
egg
containing
testis
chromosomes
Figure
16.5.2
Male
reproductive
system:
Figure
side
192
view.
16.5.3
Structure
of
a
human
sperm
(top)
and
an
egg
(bottom).
it
Its
nucleus
half
the
haploid
are
contains
number
cells.
of
Body
described
as
the
mother’s
chromosomes.
chromosomes
cells
have
the
as
body
normal
cells.
Gametes
They
number
of
are
contain
described
chromosomes
as
STUD
Y
Egg
diploid.
cells
An
egg
is
fertilised
by
a
sperm
cell.
The
head
of
the
sperm
to
membrane
The
the
sperm
two
help
of
it
the
reach
sperm
nucleus
nuclei
fertilisation,
cell
moves
fuse
the
the
coat
fuses
to
of
the
with
through
together
jelly
surface
the
form
changes,
the
cell.
egg
zygote
that
no
The
cell
cytoplasm
a
so
egg
cell
func
membrane.
of
the
egg
(fertilised
more
cells
are
egg).
sperm
you
and
can
adap
ted
tions
can
featur
es
After
these
enter.
and
sperm
specia
lised
contains
cells
enzymes
TIP
and
.
fo r
Mak
state
and
adap
t
their
e
sure
their
key
explai
n
them
fo r
how
their
tnemelppuS
func
tions
.
Comparing
male
and
feature
sperm
size
small
female
gametes
cell
egg
cell
much
swims
using
agellum
(or
that
lashes
from
not
store
very
sugar
for
number
move
along
itself
the
–
is
oviduct
and
by
peristalsis
side
has
energy
cell
side
cilia
to
sperm
tail)
moved
(mobility)
than
its
does
movement
larger
little
in
–
uses
seminal
protein
uid
and
cytoplasm
respiration
until
fat
–
in
enough
implantation
to
in
last
uterus
of
23
(haploid
number)
23
(haploid
number)
chromosomes
constantly
produced
produced
puberty)
sperm
swimming
pathway
cell
by
has
the
through
the
The
jelly
SUMMARY
QUESTIONS
1
complete
Copy
and
semen
urethra
sperm
The
male
the
cells
gametes
which
pregnant
releases
contains
surrounding
sentences
testes
penis
are
after
contraceptive
acrosome
coat
month
menopause,
when
life
mitochondria,
tail.
a
until
often
throughout
Each
one
(after
using
energy
called
these
duct
and
taking
a
to
that
power
digest
a
egg.
words:
ejaculation
sperm
or
pill
enzymes
the
puberty
except
are
prostate
Human
made
in
the
organs
the
.
from
to
or
each
tnemelppuS
a
tube
testis.
form
.
and
2
A
which
Give
out
three
called
an
adds
the
erect
differences
within
carries
gland
During
the
contained
the
The
of
are
the
uid
semen
to
a
sac
sperm
the
passes
cells
and
away
sperm
along
1
The
male
consist
cells
sperm
the
egg
cells.
2
The
Explain
how
sperm
cells
and
egg
cells
are
adapted
for
of
fertilising
reproductive
the
ducts,
and
sperm
smaller
b
sperm
an
POINTS
urethra
sperm
and
called
.
between
(top)
male
KEY
sex
sperm
egg.
scrotum
testes,
organs
scrotum,
prostate
gland,
penis.
cells
than
are
the
tnemelppuS
millions
number
much
female
egg
their
cell.
They
are
produced
in
functions.
huge
to
numbers
swim
using
and
a
are
able
tail.
193
16.6
The
female
reproductive
Ovaries
LEARNING
Identify
of
the
on
diagrams
female
system
female
sex
organs
that
produce
the
female
gametes
OUTCOMES
called
•
are
system
and
the
parts
or
oestrogen
between
reproductive
state
ova
eggs.
and
10
The
ovaries
also
progesterone,
and
15
years
of
make
which
age
the
starts
during
female
to
hormones
happen
with
girls
puberty.
their
Oestrogen
stimulates
the
development
of
the
sex
organs
and
functions
secondary
•
State
the
the
parts
functions
of
the
reproductive
of
develop
female
ready
sexual
into
to
an
characteristics
adult.
receive
an
in
a
Progesterone
embryo
in
the
girl’s
body
prepares
case
of
a
as
the
she
starts
uterus
so
to
that
it
is
pregnancy.
system
The
ovaries
kidneys.
oviduct
28
The
ovaries
months.
The
egg
moves
lining
attached
puberty,
days.
openings
uterus
are
After
of
the
slowly
If
sperm
If
the
cells
egg
is
are
not
tend
passes
the
the
egg
to
out
oviduct
down
to
an
in
a
inside
is
release
of
the
present
in
fertilised
it
an
eggs)
into
just
ovary
the
uterus
egg
about
will
a
below
about
on
the
every
alternate
funnel-shaped
ovulation.
the
the
after
an
(or
and
called
oviduct
die
abdomen
from
egg
towards
the
will
the
ovary
process
oviduct
of
released
The
egg
(womb).
be
day.
If
fertilised.
the
egg
is
ovar y
fertilised
uterus
of
will
divide
to
form
an
embryo
it
develops
which
may
attach
itself
to
wall
the
cer vix
it
lining
of
the
uterus
where
into
a
fetus.
(neck
uterus)
vagina
oviduct
uterus
opening
of
Figure
vagina
16.6.1
Female
rectum
reproductive
system:
front
view.
bone
STUD
Y
TIP
urethra
T
he
are
testes
the
and
sex
gona
ds
–
ovar
ies
orga
ns
the
or
orga
ns
clitoris
that
or
fo rm
gam
e tes.
secre
te
–
the
the
T
hey
sex
testos
terone
,
and
that
their
sex
can
also
ho rm
ones
oestro
gen
prog
estero
ne.
you
cells
Be
anus
sure
compa
re
Figure
func
tions
The
It
lower
leads
to
outside
of
the
Above
vagina
birth
194
16.6.2
Female
reproductive
system:
side
view.
.
of
end
a
of
the
body.
urethra
the
is
the
as
tube
is
the
it
is
the
has
a
called
Above
through
urethra
called
canal,
uterus
muscular
the
which
The
through
of
urine
of
from
clitoris.
vagina
here
muscle
vagina
opening
sensitive
vulva.
ring
the
that
is
a
the
the
called
that
vagina
bladder
The
outer
sometimes
baby
the
opens
passes
is
cervix.
to
the
the
opening
passes
opening
known
at
as
birth.
out.
of
the
the
Sexual
During
is
intercourse
sexual
pumped
The
erect
made
by
penis
the
the
vagina.
the
sperm
towards
As
they
are
the
to
the
vagina
movement
move
to
secretions
form
females
in
the
vagina
cells
stimulate
penis
during
lubricates
stimulates
sperm
seminal
and
against
from
semen
uid
at
orgasm.
or
into
and
tissue
the
so
each
that
sexual
penis
the
and
other
.
of
the
around
erect.
Fluid
penis
contractions
tubules
Blood
becomes
intercourse.
movements
from
it
within
begin
the
in
testes
penis.
ow,
an
clitoris
of
males
spongy
placed
walls
ejaculation
called
is
This
the
the
special
ducts
added
move
intercourse
into
or
the
through
this
time
vagina
the
the
Repeated
the
glands
seminal
including
uid.
penis
man
into
the
experiences
movements
walls
may
the
prostate
Contractions
of
also
the
of
vagina.
This
feelings
erect
produce
the
of
penis
gland
urethra
is
an
pleasure
against
orgasms
for
the
the
3
woman.
up
to
Each
500
ejaculation
million
SUMMARY
1
Copy
out
correct
contains
sperm
between
2
to
5 cm
of
semen
with
cells.
QUESTIONS
the
list
function
of
organs
from
ovary
carries
vagina
a
oviduct
receives
cervix
carries
uterus
produces
ring
the
urine
of
list
out
muscle
the
on
on
of
left
the
the
at
penis
the
the
and
match
each
with
its
right.
body
opening
during
sexual
of
the
uterus
intercourse
An
the
egg
eggs
from
and
the
ovary
female
If
egg
the
hormones
cell
sexual
time
of
fertilisation
urethra
2
Look
a
the
at
the
Name
place
where
diagram
the
of
the
a
fetus
female
b
Where
reproductive
system
to
G
A
there
is
ovulation.
at
a
around
chance
that
occur.
POINTS
B
the
do
each
The
female
following
reproductive
of
system
the
at
below:
1
diagram
ovulation
will
ovary
happens
parts
A
on
the
develops
KEY
labelled
leaves
intercourse
consists
of
the
ovaries,
take
oviducts,
uterus,
cervix
and
place?
vagina.
i
the
production
2
G
of
The
ovaries
which
C
ii
fertilisation
iii
development
are
oviducts
F
of
an
3
The
the
released
eggs
at
into
ovulation.
oviduct
is
the
organ
embryo
where
iv
produce
oestrogen
passage
D
The
fertilisation
uterus
is
the
occurs.
organ
in
E
of
the
baby
which
during
Some
women’s
oviducts
can
get
blocked.
Explain
why
with
blocked
oviducts
would
be
unable
to
fetus
have
able
whereas
to
have
a
later
a
woman
with
only
one
blocked
develops.
The
oviduct
cervix
is
a
ring
of
muscle
a
that
baby,
and
a
4
woman
embryo
birth
the
3
the
may
separates
the
uterus
be
from
the
vagina,
birth
canal.
which
is
the
baby.
195
16.7
Fertilisation
and
implantation
Human
LEARNING
There
•
Describe
fertilisation
in
Describe
the
are
millions
an
egg
muscular
of
the
a
ball
of
cells
that
sperm
swim
in
a
man’s
from
the
semen.
vagina
to
If
one
the
of
them
oviduct
–
is
to
the
into
the
tube
that
links
the
ovary
to
the
uterus.
uterus
intercourse,
sperm
cells
swim
through
the
mucus
in
the
cervix
into
is
the
implanted
must
zygote
After
form
it
early
development
to
of
humans
meet
•
fertilisation
OUTCOMES
uterus
and
then
all
the
way
to
the
oviduct.
Many
sperm
cells
do
wall
not
survive
produced
this
–
to
difcult
increase
journey
,
the
which
chance
of
is
why
some
so
of
many
them
a
sperm
reaching
fertilisation
cells
the
are
oviduct.
forms
sperm
head
of
one
penetrates
sperm
egg
membrane
jelly
coat
changes
nucleus
of
other
sperm
stop
fuses
sperm
with
entering
egg
to
successful
the
egg
b
nucleus
at
ovulation
an
egg
into
tail
ovar y
sperm
Figure
16.7.2
STUD
Y
Events
at
16.7.1
If
TIP
the
time
nucle
us
rst
.
T
he
divisi
on
durin
g
T
his
of
divide
nucle
ar
is
there
the
that
the
same
chrom
osom
es
See
page
abou
t
this.
sperm
After
is
an
218
the
in
a
in
fertilisation.
egg
nucleus
contains
readiness
oviduct,
is
46
for
through
has
fuses
with
as
and
it
rst
the
the
egg
division
the
succeed
the
egg
to
sets
start
which
the
in
head
surrounding
father.
these
on
is
left
form
of
the
of
the
membrane
agellum
nucleus
two
the
and
may
coat
with
and
from
cell
acrosome
jelly
contains
one
cell
the
fused
chromosomes
the
sperm
by
cytoplasm
diploid
mother
a
released
membrane
the
which
the
the
pathway
sperm
from
now
the
outside.
zygote
chromosomes
The
zygote
being
occurs
the
egg.
–
nucleus
copied
shortly
after
fertilisation.
This
to
So
stops
fertilise
can
take
if
other
the
sperm
egg.
place.
an
egg
If
cells
there
However,
intercourse
fertilise
196
and
Enzymes
enters
sperm
nucleus
one
egg
it.
digest
nucleus
The
mito
sis.
gene
tical
ly
iden
tical
.
more
divide
s
occu
rs
sure
have
num
ber
for
that
of
grow
th
all
are
cell
mus
t
type
mak
es
cells
and
a
Ovulation
fertilisation.
penetrating
Every
released
oviduct
of
successful
Figure
is
the
if
the
happened
it
is
from
is
no
entering
egg
sperm
just
released
in
can
before
during
so
the
only
stay
alive
ovulation,
this
one
oviduct,
time.
sperm
no
for
the
2
is
able
fertilisation
or
3
sperm
days.
can
Implantation
Fertilisation
zygote
Then
while
to
it
this
a
place
to
continues
divide
After
takes
begins
cycle
while
few
oviduct,
beating
of
to
of
to
give
or
along
ciliated
by
four
slow
embryo
is
a
to
less
this,
form
cells
the
a
and
hollow
the
of
lining
the
at
of
cells
which
cells.
contractions
cells
eight,
Some
rate
ball
fertilised
two-celled
then
regular
.
down
peristaltic
epithelial
After
once
becomes
stop
the
oviduct.
divides
divisions
hours
the
the
It
divide
others
pushed
in
divide.
It
egg
but
after
a
continue
they
moves
the
or
embryo.
divide.
down
oviduct
and
the
the
oviduct.
cell
divisions
form
an
embryo
a
ball
of
cells
forms
zygote
divides
zygote
oviduct
implantation
of
muscular
of
uterus
lining
of
Figure
16.7.3
Implantation
of
the
embryo
wall
developing
ovary
placenta
uterus
embryo.
DID
It
may
The
take
a
embryo
number
embeds
implantation.
contains
oxygen
these
wastes
days
into
the
uterus
numerous
from
chemical
The
of
blood
blood
diffuse
for
the
soft
lining
lining
has
vessels.
vessels
out
in
embryo
the
the
embryo
diffusion.
opposite
reach
the
uterus.
thickened
The
by
of
to
in
This
is
called
preparation
obtains
Carbon
YOU
and
nutrients
dioxide
and
and
Eggs
cell
than
a
to
QUESTIONS
1
complete
and
zygote
sperm
Sperm
cells
The
through
the
one
of
cells
and
these
the
swim
then
words:
implants
fertilisation
the
sperm
using
ovaries
vagina
enter
made
sentences
sexual
cells
intercourse.
the
weeks
female
through
of
the
enter
about
the
every
eggs
ostrich
into
the
present.
oviduct
The
where
which
lining
2
a
of
the
How
fertilised
the
cervix
An
four
passes
down
or
to
and
egg
.
take
were
the
uterus
up
KEY
cells
are
needed
where
to
Why
does
a
membrane
form
around
to
State
the
following
a
an
human
egg
b
a
of
chromosomes
in
it
fertilise
the
the
sperm
cell
c
a
long
equivalent
Fertilisation
of
the
in
the
2
For
an
egg
nuclei
occurs
a
and
of
seven
when
sperm
nucleus
fertilisation
place
egg?
and
must
a
cell
of
to
an
the
fuses
egg
cell.
occur,
have
sperm
reached
the
taken
cell
must
oviduct.
after
of
the
The
a
zygote
ball
of
embryo,
cells:
Aepyornis
bigger
.
an
3
number
60 cm
the
if
form
fertilisation?
3
bird,
of
POINTS
have
b
eggs
even
bigger
weighs
eggs.
ovulation
sperm
times
and
egg
uterus.
many
largest
the
is
The
place
divides
the
were
is
during
oviduct.
may
egg
24
The
elephant
with
are
is
egg
1.36 kg.
nucleus
passes
It
The
today
embryo
1
in
egg.
weighed
uterus
cells.
world
hen’s
maximus,
Its
Copy
single
the
ostrich
up
direction.
are
in
extinct
SUMMARY
KNOW?
uterus.
divides
cells
which
the
oviduct
the
lining
to
called
form
the
passes
and
down
implants
in
zygote
of
the
uterus.
197
16.8
Pregnancy
Pregnancy
LEARNING
OUTCOMES
Pregnancy
•
Outline
the
growth
humans
development
of
the
State
the
functions
of
cord,
sac
the
and
tnemelppuS
Describe
the
placenta
and
embryo
its
functions
of
umbilical
that
some
support
toxins
can
and
cross
affect
The
its
The
so
has
and
orga
ns
the
featur
es
is
know
n
have
embr
yo
that
The
The
the
hum
an,
a
One
is
It
•
are
it
as
the
the
food
area
and
a
a
fetal
there
and
supp
lies
is
why
featu
res
large
are
the
These
site
the
to
lining
gain
projections
cord
of
other
cord
grows
sac
of
the
or
attaches
makes
the
attach
which
of
to
the
and
grow
fetus
surrounds
oxygen
they
fetus
blood
to
amniotic
mechanical
it
oxygen
into
to
the
the
it.
and
diffuse
nutrients
between
fetal
for
blood
to
and
uid
damage,
for
the
placenta
from
to
the
surround
example
and
contains
placenta.
and
when
protect
the
the
mother
movements.
in
the
development
are
after
into
summarised
fertilisation,
tadpole.
where
months
toes
The
Three
are
a
as
human
embryo
a
baby
ready
to
be
born
at
follows.
does
embryo
not
yet
looks
have
a
bit
arms
like
or
a
legs,
sh
but
months
the
the
mother
Seven
the
It
the
is
The
heart
embryo
now
has
has
called
a
a
started
face,
fetus.
and
other
to
beat.
limbs,
Most
ngers
of
the
and
for
carries
fertilisation
the
nerves
and
muscles
fertilisation,
has
perfectly
body
the
hair.
last
after
carbon
wastes
of
the
fetus
rapidly.
after
months
arter y
human.
after
fetus
ngerprints
•
develop.
formed.
months
length,
will
fertilisation
looks
developing
Five
these
after
and
Its
although
formed
only
about
eyebrows,
movements
may
180
from
mm
in
ngernails,
have
been
felt
by
month.
fertilisation
development
is
almost
complete.
dioxide
the
dioxide
and
wastes
fetus
smal
l
diffuse
into
from
the
the
fetal
mother ’s
blood
blood
distan
ce
the
betw
een
blood
blood
maint
ain
grad
ients
vein
from
the
brings
oxygen
placenta
to
and
the
food
fetus
28).
oxygen
direction
of
blood
oxygenated
into
Figure
16.8.1
blood
blood
The
role
the
food
diffuse
mother ’s
blood
mother ’s
blood
deoxygenated
and
flow
from
198
in
period
uterus,
nutrients
continue
to
exchange
wastes;
transport
pregnancy
month
T
wo
the
page
into
tissue
surfa
ce
Sinc
e
good
conc
entra
tion
(see
soft
carbon
the
matern
al
to
•
the
subst
ance
s
short
are tw
o
gas
for
where
and
diffus
ion.
exchan
ges
the
T
his
same
lung
intes
tine:
for
also
absorb
ed.
has
is
surfa
ce
is
the
amniotic
and
to
stages
of
clear
are
fetus.
which
fe tus.
TIP
disso
lved
birth,
gestation
blood.
sudden
organs
placen
ta
the
sac
against
main
and
T
he
and
the
it
•
exchan
ge
is
vessels
amnion
end
it
STUD
Y
lls
dioxide
embryo
as
called
are
•
recogn
isably
it
umbilical
makes
the
implanted
into
umbilical
maternal
fetus
TIP
all
is
fetus
•
Once
has
growth.
An
placenta
blood
fo rm
ed
fertilisation
time
the
the
•
STUD
Y
of
and
and
placenta
between
the
carbon
pathogens
time
period
cord
•
State
of
This
uid
placenta
•
period
projections
placenta.
•
the
months.
placenta,
to
amniotic
9
the
grows
umbilical
is
fetus
After
•
is
and
of
the
placenta.
the
fetal
blood
placenta
dissolved
features
a
short
and
is
food
as
fetus
amino
excreted
an
some
umbilical
placenta
and
Amniotic
similar
sac
into
to
the
should
Young
be
the
HIV
with
can
fetus
returns
from
from
to
and
the
the
has
also
the
surface
are
to
including
water.
where
same
area
between
supplies
and
fetal
maintain
glucose,
The
mother’s
it.
placenta.
blood
oxygenated
ltered
the
have
blood
fetus’
skin
developed
the
The
barrier
a
uid
fetus
blood
The
from
and
are
the
uid
to
has
shed
fetus
to
be
The
fetus
at
26
days.
a
The
fetus
at
8
weeks.
The
fetus
at
5
months.
contains
fetus
the
to
the
fetus.
composition
into
the
carries
lungs.
does
cord
the
blood
the
into
amniotic
and
disease.
that
be
causes
positive
if
management
to
a
child
the
is
The
not
amnion
out
some
fetus
provide
may
during
who
the
This
before
vaccinated
mother
pathogens.
since
cross
is
is
the
carry
a
why
they
urinates
any
is
However,
still
virus
all
can
young
act
with
a
the
mother
the
virus.
even
susceptible
that
become
placenta,
infected
not
by
they
pregnancy
does
fetus
caused
fetus.
rubella
AIDS
the
and
environment,
harm
also
toxins
measles)
against
for
the
to
sterile
(German
should
birth
into
deoxygenated
taking
a
is
placenta
careful
give
as
vaccinated
HIV
mother,
it
is
fetus.
acts
virus
born
why
large
blood
vitamins
diffuses
the
that
drinks
womb
men
its
organs
Rubella
infection
The
be
the
disease.
across
of
for
from
is
a
It
kidneys.
Cells
the
This
fetus.
exchanges
good
food
formed
and
placenta
though
is
two
the
28).
joins
vein
Since
ions,
the
intestine:
page
which
her
movements
uid
nutrients
The
a
when
the
urea
for
absorbed.
small
are
mineral
plasma.
breathing
its
surface
(see
transports
uid
to
and
all
cord
that
there
gradients
fats,
are
the
diffusion.
blood
through
artery
exchange
and
for
obtains
acids,
produces
The
lung
distance
maternal
gas
substances
the
concentration
The
the
can
get
women
pregnant.
as
so
a
a
baby
virus.
who
reservoir
may
However,
is
HIV+
Nicotine
can
SUMMARY
also
pass
across
the
placenta
(see
Topic
1
a
How
to
b
is
the
List
two
in
1
The
fetus
size
and
grows
and
develops
inside
the
uterus.
It
increases
all
the
major
The
umbilical
the
site
of
the
amnion
cord
attaches
exchange
of
the
fetus
substances
amniotic
the
What
is
to
the
between
placenta,
fetus
which
and
is
in
tnemelppuS
The
uid
to
protect
the
fetus
the
has
diffusion
of
mother’s
blood.
What
a
large
surface
area
for
gas
exchange
long
does
it
last
are
the
and
functions
amniotic
of
the
uid?
Describe
nutrients
and
waste
between
fetal
blood
structure
and
pathogens
cross
the
placenta
into
efcient
the
acts
as
a
barrier
to
many
in
the
which
placenta
fetal
diffusion
blood
and
fetus;
mother’s
placenta
ways
of
and
between
toxins
two
and
helps
the
gestation
How
damage.
placenta
Some
pass
direction.
from
the
4
opposite
and
that
mother;
4
3
fetus
humans?
amnion
mechanical
the
that
mother’s
organs.
3
makes
to
the
substances
period?
2
connected
in
2
develops
fetus
substances
from
blood
POINTS
the
placenta?
two
pass
KEY
QUESTIONS
16.9).
blood.
others.
199
tnemelppuS
tnemelppuS
The
16.9
Ante-natal
care
and
birth
Ante-natal
LEARNING
Ante-natal
•
Describe
the
ante-natal
pregnant
Describe
the
while
in
labour
and
tnemelppuS
Describe
the
she
advantages
disadvantages
provides
of
the
is
breast
important
so
iron
the
and
•
calcium,
•
iron,
so
carry
blood
that
right
the
nutrition
mother
obtains
all
Particularly
calcium.
vital
and
has
the
for
also
the
health
needs
protection
a
balanced
nutrients
important
as
the
that
•
to
of
the
make
sure
for
the
fetus
it
diet
needs
during
for
this
growth
are
vitamins
and
and
minerals,
•
her
protein,
new
They
to
preparation
therefore
amnion
at
7
to
8
weeks
that
provide
for
need
body
in
are
the
Her
the
the
the
birth.
will
need
to
ensure
such
that
she
growing
extra
growing
extra
red
iron
blood
pregnant
red
blood
fetus
in
is
the
cells
mother
diet
that
has
cells
also
needed
making
to
make
carries
enough
red
more
oxygen
energy
to
around
amino
mother
making
fetus
make
substance
so
The
the
fetus.
both
the
heavier
tissues.
of
can
the
woman
of:
body
to
carbohydrate,
move
pregnant
bones
her
oxygen
cells.
A
quantities
haemoglobin,
the
the
fetus
adequate
to
inside
is
mother
milk
gets
fetus
birth,
The
milk
as
A
before
womb.
pregnancy.
development.
formula
care
the
and
time
and
or
in
birth
It
•
is
processes
during
involved
it
women
that
•
care,
care
fetus
of
care
OUTCOMES
The
many
acids
makes
fetus
new
that
muscle
is
also
they
tissue
both
in
growing
the
and
need
to
uterus
make
in
developing
and
cells.
of
The
mother
should
not
smoke
since
nicotine
and
carbon
monoxide
pregnancy.
cross
the
babies.
also
placenta
She
crosses
birth
should
the
defects
placenta
so
and
can
drink
no
placenta
and
in
premature
alcohol,
and
mental
some
result
can
or
retardation.
babies
are
very
cause
born
a
small
variety
Drugs,
with
or
an
underweight
quantities,
of
such
effects
as
addiction
heroin,
to
as
alcohol
including
cross
the
heroin.
Birth
A
placenta
the
born
pregnancy
prematurely,
takes
about
perhaps
9
months.
because
there
In
has
some
been
a
cases
babies
problem
are
during
amniotic
cavity
the
normal
pregnancy.
An
early
fetus
most
breaking
of
the
membrane
(amnion)
around
the
fills
uterus
A
is
few
the
weeks
common
before
This
positions
and
the
its
birth,
head
build-up
of
reason.
the
above
fetus
the
pressure
in
usually
cervix.
the
turns
over
Hormones
uterus
inside
released
stimulate
the
by
hormonal
uterus.
the
fetus
changes
in
fetus
(50 cm)
the
mother
.
A
hormone,
oxytocin,
is
released
from
her
pituitary
gland
that
uterus
stimulates
cer vix
small
16.9.1
Position
before
200
of
the
birth.
baby
just
muscles
contractions
These
Figure
the
of
contractions
contractions
breaks,
slowly
allowing
of
the
the
uterus
become
stretch
the
uterus
to
wall.
This
stronger
the
amniotic
contract.
and
opening
uid
is
to
the
The
beginning
more
of
mother
the
escape.
of
frequent.
cervix
starts
and
to
feel
labour
Stronger
the
amnion
The
to
muscles
push
the
the
baby’s
takes
the
and
The
baby
It
umbilical
attaches
navel.
wall.
The
to
After
It
is
a
for
of
is
contract
cervix.
through
As
tied
baby.
few
the
now
soon
that
The
the
as
it
the
very
cervix
widens
vagina.
is
born
baby
strongly
This
the
has
and
or
part
baby
airways
start
dilates
of
the
breathes
clear
of
and
birth
for
mucus
easily.
pushed
process
painful
the
important
cord
the
wall
pushed
quickly.
is
breathe
uterus
towards
is
quite
time.
can
the
head
place
rst
of
and
The
minutes
out
labour
of
the
the
with
mother
.
cut
just
remains
above
the
placenta
vagina
the
She
of
as
help
the
point
heal
comes
the
muscular
can
the
cord
to
away
where
form
from
it
the
the
baby’s
uterus
afterbirth
contractions
process
by
A
of
the
gentle
uterus
newborn
body
before
Pain-killing
may
the
be
drugs
given
space
labour
by
can
an
between
and
also
by
be
epidural.
the
spine
breathing
given
This
and
to
in
ease
involves
the
a
special
the
pain
inserting
spinal
cord.
way
during
during
a
of
impulses
from
pain
receptors
to
The
the
drugs
umbilical
cord.
of
These
(tube)
prevent
1
into
POINTS
During
the
labour
uterus
the
wall
muscles
in
contract.
the
2
transmission
its
labour
.
birth.
catheter
with
is
exercises
KEY
the
baby
At
birth,
the
baby
passes
out
brain.
of
the
breath.
and
The
takes
its
umbilical
cord
Breast-feeding
is
This
is
her
so
Breast
pregnancy
that
milk
soon
the
after
contains
glands
birth
in
she
the
is
mother’s
able
antibodies
which
the
that
to
breasts
produce
pass
to
the
will
enlarge.
detaches
milk.
baby
passes
and
give
immunity
to
diseases
the
mother
has
had
immunity
(see
Topic
10.3)
means
that
the
child
antibodies
in
the
blood,
but
is
unable
to
The
antibodies
remain
in
the
child’s
blood
has
produce
while
it
for
a
short
time
afterwards.
Breast-feeding
also
to
form
between
mother
and
baby
that
is
is
a
research
has
shown
that
breast-feeding
is
to
and
develop
mothers.
certain
Mothers
are
Children
diseases
less
likely
such
to
who
as
are
benecial
breast-fed
childhood
develop
cancers
cancers
of
breast,
are
less
and
iron,
protein
it
women
difcult
Formula
or
milk
convenient,
comes
it
in
needs
with
to
to
may
but
be
water
do
not
be
In
to
breast-feed
They
their
therefore
rely
to
avoid
Breast
milk
likely
not
with
be
the
that
it
contains
Formula
and
that
protect
or
they
it
form
SUMMARY
1
Describe
places
each
able
the
risk
milk
milk
QUESTIONS
of
what
the
birth
happens
following
of
a
to
during
baby:
of
the
muscles
b
in
the
the
uterus
cervix
or
the
amnion
and
amniotic
also
d
the
placenta
whereas
does
not.
sometimes
Make
a
table
simply
to
show
the
Of
and
disadvantages
breast-
of
feeding
from
nd
advantages
course,
baby
infections.
bottle-feeding.
2
milk
the
ovaries.
uid
money,
notably
antibodies
infections
non-sterile
breast
advantages
milk,
to
c
costs
drugs
more
sterile
some
getting
bottles.
smoking,
has
formula
wall
from
She
both
a
babies
diet.
diabetes.
womb
babies
on
her
mixed
under
may
this,
able
since
powdered
conditions.
women
are
embarrassing.
in
alcohol.
common
Some
enough
carbohydrate
both.
over
children
involves
having
close
4
Medical
and
breast-fed
enables
benecial
uterus
afterbirth.
them
and
bond
placenta
the
should
and
the
the
care
mother
and
itself.
as
Ante-natal
calcium,
mother’s
from
out
The
recently.
the
Passive
cut.
it
3
passive
and
tnemelppuS
During
tied
isn’t
breast-feeding
and
bottle-
an
feeding.
option
at
all!
201
tnemelppuS
tnemelppuS
rst
vagina
16.10
Sex
hormones
Puberty
LEARNING
You
•
Describe
the
testosterone
developing
roles
and
oestrogen
secondary
characteristics
are
at
the
only
ovary
testes
start
time
uterus
the
lining
from
the
Whe
n
Paper
you
4
,
mak
e
no te
s
they
10
become
and
14,
the
follicles
your
life
start
is
to
called
develop
in
the
ovaries.
puberty
than
person.
boys.
The
The
actual
changes
that
age
take
of
puberty
place
by
hormones.
At
the
beginning
of
puberty
the
are
all
pituitary
the
base
the
testes
of
the
make
the
sex
which
in
testes
brain
the
starts
to
make
hormones
that
organs
develop
ovaries.
active.
our
The
sex
organs
secondary
sexual
start
to
produce
sex
characteristics.
boys
start
•
the
growth
•
the
testes
•
growth
•
the
•
development
making
of
to
of
the
hair
on
in
of
of
testosterone,
male
make
deepening
ovaries
and
sex
sperm
the
the
which
stimulates:
organs
cells
face
voice
muscles
in
the
body.
girls
start
making
oestrogen,
which
stimulates:
•
the
growth
the
ho rm
ones
T
o pic
to
a
table
ro les
here
16.1
1.
referr
ing
•
the
start
•
growth
of
•
growth
and
•
widening
of
all
and
Keep
your
A
person
nishes
read
and
the
rst
sex
organs
menstrual
cycle
and
the
rst
period
intera
ct
to
men
strual
mood
parts
of
development
the
of
body
breasts
of
the
hips.
becomes
you
can
changes
an
adolescent
stop
be
and
an
growing
emotional
increased
when
at
puberty
about
time.
sexual
18
starts.
years
of
Hormones
Adolescence
age.
can
bring
about
urges.
table
3
how
you
they
cont
ro l
cycl
e
so
the
them
cont
racept
ion
A
cycles
are
complete
hormones
This
to
which
the
changes
receive
an
cycle
lasts
coordinate
coordination
is
for
that
occur
the
important
embryo
so
that
28
activity
so
it
about
in
the
that
can
of
the
start
days
ovary
the
ovary
lining
its
and
of
is
and
the
controlled
and
the
the
by
uterus.
uterus
is
ready
development.
and
Girls
use
on
T
o pics
16.1
unde
rstand
treatin
g
female
hair
Adolescence
uterus.
we
of
when
Menstrual
you
2
of
your
fo r
includ
e
lists
when
start
to
have
periods
between
the
ages
of
about
10
to
15
years
in
and
infert
ility
.
old.
During
and
cells
this
a
period,
pass
happens
menstrual
202
But
about
TIP
revisi
on
fo r
of
adolescents.
STUD
Y
how
and
in
earlier
to
at
The
16.1
sperm
develop
person
stimulate
Puberty
the
organs.
the
The
in
sex
ages
cycle
Puberty
that
of
the
of
hormones
of
make
development
usually
These
group
set
Between
in
gland
A
complete
life.
puberty
during
menstrual
to
of
controlled
the
a
in
sexual
changes
and
with
later
in
varies
the
born
active
Girls
Describe
adolescence
of
This
•
and
OUTCOMES
out
for
cycle.
of
the
the
the
rst
lining
of
vagina.
time,
it
the
This
uterus
is
shows
breaks
called
that
a
down
and
menstruation.
girl
has
had
her
blood
When
rst
Stages
Girls
are
ovaries.
in
the
born
They
potential
menstrual
with
do
egg
is
a
not
very
large
produce
surrounded
cycle
number
any
by
a
of
more
small
potential
during
group
egg
their
of
cells
in
lifetime.
cells
and
their
Each
together
they
ovulation
form
At
a
follicle.
puberty,
involves
some
the
egg
chromosomes
food.
Each
follicle
as
in
by
the
starts
uid
the
to
and
follicle
the
thousands
follicles
by
or
a
develop
moves
bursts,
start
by
in
As
to
by
the
The
the
ovary
This
to
at
the
of
number
lls
with
develop.
gland
it
the
(see
ovary.
is
page
of
the
and
After
cells
of
stored
This
enlarges
follicle
ovary
.
development
beginning
grows
some
each
the
cytoplasm
pituitary
edge
egg,
in
reduces
start
follicle
the
the
follicles
develop.
follicles
the
towards
releasing
these
which
half.
few
released
nishes.
of
meiosis
nucleus
one
hormones
menstruation
with
of
are
dividing
month
stimulated
A
There
2
and
164).
cycle
lls
weeks,
the
uid
uterus
ready
into
the
oviduct.
This
is
called
ovulation.
The
follicle
cells
left
for
behind
implantation
in
the
ovary
weeks.
If
implantation
While
to
If
form
2
the
egg
thicken.
In
vessels
and
form
ball
the
a
the
yellow
implantation
occurs
is
week
glands.
woman
cells
If
not
remains
developing
the
of
it
body
does
in
after
active
the
becomes
it
it
the
has
occurs,
implants
remains
will
during
ovary
ovulation
fertilisation
which
which
occur,
into
the
the
for
then
the
next
decrease
in
size.
pregnancy.
lining
a
of
thick
the
fertilised
thick
uterus
lining
of
egg
uterus
starts
blood
divides
lining
to
and
pregnant.
menstruation
If
fertilisation
vagina
of
the
now
If
a
and
does
the
uterus
begins
not
yellow
breaks
occur,
body
down
the
in
egg
the
and
is
dies
ovary
lost
and
passes
breaks
during
out
down.
of
The
the
thick
menstruation.
The
lining
cycle
again.
pregnancy
does
occur,
the
embryo
releases
a
hormone
that
Figure
stimulates
the
yellow
body
to
remain
active
which
in
turn
16.10.1
During
cycle
the
lining
of
the
uterus
to
continue
to
thicken.
This
supplies
the
with
ensures
that
Between
the
menstrual
food
and
oxygen
menstruation
ages
cycles
of
45
have
will
and
as
it
not
55
stopped.
continues
its
development.
It
also
are
years
This
a
is
woman’s
called
the
Explain
periods
stop
as
her
KEY
role
development
of
and
the
testes
regulation
and
of
the
ovaries
secondary
in
Testosterone
males
the
sexual
males
and
females
at
in
a
List
at
b
the
effects
that
stimulates
the
Oestrogen
testosterone
has
on
the
body
of
a
that
oestrogen
has
on
the
body
of
a
girl
at
puberty.
3
During
follicle
ovary
3
Explain
the
meaning
of
the
following
menstruation
b
ovulation
c
Draw
and
a
in
timeline
the
to
uterus
show
during
the
a
in
stimulates
the
secondary
that
during
a
and
the
in
puberty.
menstrual
develops
sexual
occur
cycle
inside
lining
a
the
thickens.
If
of
the
implantation
implantation
does
4
in
terms:
uterus
a
occur
puberty.
characteristics
boy
females
effects
that
the
sexual
puberty.
puberty.
List
synchronised.
secondary
during
changes
2
the
characteristics
2
in
of
uterus
POINTS
changes
QUESTIONS
the
the
menopause
characteristics
1
and
occur.
1
SUMMARY
menstrual
activities
the
ovaries
embryo
the
stimulates
changes
menstrual
that
occur
cycle.
in
the
ovary
the
not
occur
,
uterus
down.
and
This
is
the
lining
vagina
of
break
menstruation.
203
16.11
tnemelppuS
LEARNING
The
There
OUTCOMES
The
•
Describe
the
production
sites
of
progesterone
cycle
and
in
pituitary
the
Explain
the
hormones
and
gland
at
that
the
control
base
of
the
the
menstrual
brain
cycle.
secretes:
and
•
Follicle
Stimulating
•
Luteinising
Hormone
(FSH)
Hormone
(LH)
pregnancy
role
FSH,
of
the
ovary
secretes:
the
LH,
progesterone
controlling
hormones
menstrual
The
•
four
cycle
of
oestrogen
in
are
menstrual
•
oestrogen
in
oestrogen
Each
menstrual
cycle
cycle
pituitary
it
starts
gland.
stimulates
follicle
there
beginning
FSH
and
progesterone
with
This
the
secretion
hormone
the
development
is
cell
of
a
the
stimulates
that
cycle
other
has
each
cells
is
of
in
one
the
of
into
carried
or
more
cells
follicle
blood
the
potential
these
the
the
in
to
FSH
to
follicles.
grow
starts
to
of
blood
to
into
the
ovary
Inside
grow
secrete
from
the
an
egg.
and
where
each
At
the
divide.
oestrogen
into
the
bloodstream.
Oestrogen
•
In
the
centre
enlarges
in
is
the
a
yellow
second
body
half
of
It
has
stimulates
three
the
main
repair
effects.
and
thickening
of
release
cycle
to
produce
lining
of
the
uterus.
which
the
LH
menstrual
the
released;
and
yellow
progesterone.
body
forms
ovary
relative
concentration
luteinising
in
the
blood
hormones
the
pituitary
hormone
(LH)
of
follicle
from
stimulating
hormone
gland
(FSH)
relative
progesterone
oestrogen
concentration
in
the
blood
hormones
the
of
from
ovary
Lining
shed
Oestrogen
(menstruation)
by
ovary;
uterus
released
lining
starts
Progesterone
yellow
of
uterus
to
body;
released
lining
continues
Lining
by
down
of
to
pregnancy
thicken
does
thicken
lining
breaks
if
not
of
uterus
0
days
7
days
14
days
time
Figure
204
16.11.1
Control
of
the
menstrual
cycle
by
21
/
hormones
days
28
days
days
from
the
pituitary
gland.
occur
It
stops
the
secretion
•
It
stimulates
the
of
FSH
pituitary
from
gland
the
to
pituitary
secrete
DID
gland.
LH.
YOU
Nobody
The
lining
of
the
uterus
thickens
in
preparation
to
receive
an
you
are
can
the
cycle
see
from
important
from
increases
day
in
0
size
the
graphs
hormones
to
day
within
14.
the
in
Figure
during
During
the
this
16.11.1,
rst
half
time
the
FSH
of
and
the
egg
oestrogen
menstrual
develops
and
follicle.
of
of
stimulates
around
day
the
14
follicle
of
the
to
burst
release
its
egg.
This
happens
is
is
certain
about
of
of
In
top
the
part
of
follicle
the
Figure
second
half
of
the
the
shows
yellow
cycle,
that
body
after
which
ovulation
secretes
progesterone
the
by
the
ovary
have
these
stimulate
•
maintain
further
growth
lining
in
its
20%,
has
stop
the
of
secretion
shows
the
eventually
As
the
cycle.
it
of
that
This
stops
for
together
with
the
FSH
the
of
the
lining
state
and
LH
of
and
from
concentration
secreting
the
of
the
the
then
begins.
this
the
gradually
this
role.
the
it
If
secreted
by
They
menstrual
of
it
of
progesterone
of
the
around
may
LH
pituitary
decreases
of
and
the
the
yellow
also
stop
cycle
the
and
middle
in
the
in
the
there
is
second
body
in
early
body
the
part
the
hormone
the
uterus.
This
prevents
occurring
of
the
cycle
and
lining
so
This
and
tests.
use
and
SUMMARY
the
egg
If
pregnancy
there
body
is
excreted
a
that
the
lining
of
occurring
uterus
and
no
in
woman
to
LH
the
the
embryo
continue
stop
from
the
urine
misses
a
secretes
secreting
pituitary
and
this
period
is
she
to
QUESTIONS
Name
four
a
a
pregnancy
testing
kit
to
nd
coordinating
2
cycle
each
Describe
is
The
pituitary
the
hormone
ovary
Oestrogen
the
roles
in
menstrual
cycle.
3
Explain
that
Some
of
why
the
thick
state
of
these
controlling
the
at
it
is
lining
the
important
of
time
the
of
uterus
is
ovulation.
pregnant.
State
what
happens
as
a
out.
of
the
decrease
of
in
oestrogen
and
progesterone
end
of
and
FSH
the
stimulates
secretion
of
the
development
of
a
follicle
5
oestrogen.
stimulates
the
thickening
of
the
that
uterus
inhibits
FSH
production
and
causes
and
the
the
pituitary
towards
from
the
ovulation
remains
of
the
follicle.
formation
The
of
to
yellow
the
body
release
the
which
maintains
the
lining
of
the
why
it
is
important
progesterone
pregnancy
cycle.
is
occurs,
secreted
but
FSH
yellow
not.
LH.
Suggest
why
nd
what
it
difcult
to
proportion
is
of
body
out
secretes
a
progesterone
menstrual
lining,
6
stimulates
the
Explain
is
LH
and
secreted.
hormones
if
3
the
hormone
basis
be
hormones
in
remains
the
gland.
the
a
be
progesterone.
may
as
pregnancy
continue
the
known
is
again.
yellow
as
is
of
so
menstruation
is
POINTS
inside
2
during
happen
occurs.
that
oestrogen
does
concentration
1
of
size.
result
KEY
continues
lining
miscarriage.
4
can
takes
so
less
menstruation
uterine
progesterone
starting
important
pregnancy
She
placenta
Progesterone
gland.
yellow
decreases
decreases
uterus
the
implant
happens,
stimulates
this
oestrogen,
breaking
where
is
yellow
secrete
placenta
maintain
menstrual
This
an
not.
uterus,
prevent
the
stimulation
progesterone
lining
occurs
fertilised,
that
or
the
to
but
involved
During
no
oestrogen
1
intercourse
thick.
is
effects:
thickened
reduces
concentration
stimulation
If
one
and
graph
half
that
whether
pregnancy,
sometimes
The
out
continues
pregnancy.
•
no
there
implanted
menstruation
down,
but
because
and
the
the
estimated
progesterone
to
they
the
group
remains
from
•
in
One
progesterone.
over
secreted
uterus.
nding
During
16.11.1
become
many
implant
at
cycle.
body
The
the
it
way
and
how
not
researchers
embryo
LH
do
embryo.
lining
As
KNOW?
knows
embryos
tnemelppuS
•
woman’s
embryos
never
uterus.
implant
in
the
uterus.
205
16.12
Methods
of
birth
control
Birth
LEARNING
if
•
Describe
the
methods
natural,
control
lets
couples
decide
whether
or
not
to
have
children
and
OUTCOMES
of
how
should
following
birth
so,
many.
To
prevent
pregnancy,
the
method
of
birth
control
either:
control:
chemical,
barrier
•
stop
the
sperm
•
stop
the
eggs
•
stop
from
reaching
the
egg,
and
from
being
made,
or
surgical
the
Barrier
fertilised
egg
from
implanting
and
developing
in
the
uterus.
methods
IUD
The
uterus
cap
cervix
or
diaphragm
before
uterus.
It
is
intercourse.
should
be
used
a
It
rubber
dome.
prevents
with
the
The
man’s
sperm-killing
woman
sperm
cream
or
places
from
it
over
entering
her
the
foam.
strings
The
condom
is
a
thin
rubber
tube.
It
is
rolled
over
the
man’s
erect
penis
vagina
before
It
also
intercourse.
gives
common
Figure
16.12.1
Intra-uterine
It
stops
protection
form
of
the
against
birth
control
sperm
from
sexually
and
is
entering
transmitted
easy
to
the
woman’s
diseases.
It
is
body
.
the
most
use.
device
A
femidom
is
the
female
equivalent
of
a
condom
and
is
inserted
uterus
into
the
vagina.
vagina
Chemical
The
IUD
methods
(Intra-Uterine
wrapped
in
woman’s
copper
uterus
or
and
Device)
contains
it
is
is
a
small
hormones.
thought
to
work
plastic
It
is
by
device
tted
that
inside
preventing
is
the
sperm
rectum
passing
cap
for
Figure
folded
cap
insertion
16.12.2
through
the
uterus.
It
may
also
prevent
an
embryo
from
fitted
over
cer vix
implanting
in
the
uterus
should
conception
occur.
Cap
IUS
is
penis
(Intra-uterine
placed
slowly
and
making
The
in
it
pill’
different
the
causes
unlikely
is
an
types
system)
uterus.
the
is
a
in
sperm
available.
T-shaped
progesterone
the
will
contraceptive
pill
small
contains
mucus
that
oral
of
It
cervix
swim
as
They
it
is
to
plastic
that
is
become
device
that
released
thick
and
sticky,
through.
taken
contain
by
the
mouth.
There
hormones
are
oestrogen
and
condom
progesterone
pills.
by
These
Figure
16.12.3
to
the
be
by
concentrations.
preventing
production
released
by
of
the
the
There
ovary
FSH
by
ovaries
are
releasing
the
and
also
eggs.
pituitary
.)
so
progesterone-only
As
pregnancy
(They
a
do
result,
cannot
this
no
eggs
occur
.
Condom
The
For
woman
many
has
vagina
result
uterus
in
a
heart
In
and
take
the
and
a
a
pill
pill
is
Drawbacks
pregnancy.
depression
effects.
to
couples
contraception.
applicator
varying
work
inhibiting
mature
in
The
painful
very
small
circulation
every
a
day
.
very
are
reliable
that
side
failure
effects
periods
number
–
of
each
are
and
to
sore
pill
has
women,
convenient
take
the
the
pill
breasts,
its
own
pill
weight
set
can
method
regularly
be
of
of
can
gain,
side
the
cause
problems.
spermicide
rectum
A
contraceptive
under
Figure
16.12.4
the
of
implant
the
upper
is
a
small
arm.
It
exible
releases
rod
ovulation
and
works
for
up
to
3
that
is
placed
progesterone
Spermicide
prevents
206
skin
years.
just
which
of
Contraceptive
different
types
Spermicides
cream
or
should
be
they
To
avoid
also
woman
with
contain
between
chemicals
The
that
puts
are
kill
the
not
another
8
progesterone.
and
13
sperm.
cream
very
They
into
such
are
weeks.
effective
method
There
as
are
her
on
sold
vagina
their
the
as
cap
foam,
before
own
or
and
the
condom.
methods
couples
may
work
Spermicides
used
Natural
Some
that
are
jelly.
intercourse.
injections
may
have
not
be
religious
becoming
able
or
to
moral
pregnant
use
the
methods
objections
they
may
to
described
using
abstain
here
or
Figure
16.12.5
from
having
sex
Calendar
for
rhythm
method
contraception.
at
sperm
times
when
rhythm
likely
after
and
is
to
fertilisation
method.
occur
that
then
about
date.
A
This
most
relies
weeks
each
after
especially
in
likely
on
abstaining
woman
predicts
2
method,
and
is
month
having
women
happen.
determining
from
keeps
to
a
sex
record
when
her
in
days
when
ovulation
period.
who
when
the
of
do
This
not
They
may
ovulation
just
she
is
not
a
very
regular
cut
tube
and
ends
tied
most
and
her
occur.
the
is
before
has
should
have
use
just
periods
This
reliable
sperm
periods.
tube
testis
A
better
method
ovulation.
For
is
to
follow
example,
changes
checking
for
in
the
symptoms
increase
associated
in
body
with
temperature
Figure
and
changes
just
before
It
useful
in
cervical
ovulation.
mucus
This
which
becomes
symptoms-based
wetter
method
and
is
less
more
for
people
who
do
not
have
access
to
family
top
and
the
Surgical
other
methods
of
contraception
is
described
end
of
cut
oviduct
planning
and
clinics
Vasectomy
effective.
oviduct
is
16.12.6
sticky
blocked
here.
ovar y
methods
vagina
A
sperm
them
is
tubes
must
a
are
be
duct
also
known
vasectomy
cut
sure
ejaculate
is
but
and
tied.
that
he
there
Sterilisation
is
a
and
The
does
are
no
minor
as
is
a
a
vas
minor
operation
not
deferens.
want
sperm
in
is
operation
not
any
the
operation
The
a
a
man.
reversible,
children.
semen,
for
for
usually
more
operation
just
woman.
The
to
His
so
cut
the
man
uterus
sperm
man
can
still
rectum
uid.
Her
oviducts
are
cut
Figure
and
sure
blocked.
that
she
The
operation
does
not
want
is
not
any
reversible,
more
so
the
woman
must
POINTS
QUESTIONS
1
Barrier
methods
condom,
1
Sterilisation
children.
KEY
SUMMARY
16.12.7
be
a
What
is
b
Under
meant
by
the
term
include
femidom,
IUD
the
and
contraception?
IUS.
what
circumstances
would
a
couple
choose
to
use
2
birth
control
Chemical
methods
contraceptive
2
Explain
how
the
following
birth
control
methods
cap
or
d
vasectomy
diaphragm
b
condom
c
Methods
can
be
rhythm
a
Explain
how
oral
contraceptives
pill,
and
implants,
spermicides.
spermicides
3
3
the
work:
injections
a
include
methods?
(‘the
pill’)
act
to
of
birth
natural
control
(abstinence,
method).
prevent
pregnancy.
4
b
What
birth
are
the
control?
disadvantages
associated
with
this
form
of
Surgical
methods
vasectomy
and
involve
female
sterilisation.
207
16.13
tnemelppuS
LEARNING
Control
Outline
in
the
use
of
contraception
hormones
and
fertility
drugs
Some
had
Describe
vitro
the
process
fertilisation
of
Discuss
of
the
is
regular,
social
implications
and
fertility
the
release
cause
of
to
in
you
n
read
mak
func
tion
a
cannot
sexual
as
because
being
intercourse
for
the
infertile
12
if
months
man
they
or
have
without
pregnant.
infertility
may
be
for
in
due
this
fertility
women
to
a
type
drug
is
lack
of
that
of
FSH
infertility
containing
the
do
production
may
FSH.
ovaries
involve
The
FSH
not
by
the
regular
stimulates
the
eggs.
treatments
involve
Remember
if
the
effect
then
the
pituitary
of
Unfortunately,
of
reasons
tablets
that
that
make
oestrogen
the
inhibits
pituitary
the
insensitive
production
of
to
FSH.
oestrogen
continues
on
to
the
pituitary
release
FSH
is
blocked
and
by
ovulation
the
drug,
occurs.
fertility
that
may
treatment
not
be
easy
does
for
not
always
doctors
to
work
for
discover.
a
On
variety
the
other
how
hand,
it
can
work
too
well;
too
many
eggs
may
be
released,
resulting
cycl
e
in
twins,
triplets,
quadruplets
or
even
more!
and
of
FSH
stim
ulatin
g
the
but
regarded
this
sure
men
strual
deve
lo pm
ent
in
e
unde
rstand
cont
ro lle
d
the
children
are
TIP
So
is
This
release
oestrogen.
the
of
Treatment
injections
Other
you
unprotected
becoming
eggs.
pituitary.
ovaries
Befo
re
have
in
treatments
sectio
to
Couples
(IVF)
contraception
STUD
Y
want
infertile.
woman
Often
•
drugs
couples
woman
the
•
fertility
OUTCOMES
Fertility
•
of
of
Articial
the
fo lli
cles
ovary.
Some
may
couples
be
the
uterus.
If
the
are
man
man
remains
vitro
does
the
placed
is
not
then
a
child’s
It
via
called
is
possible
a
ne
donor
donor
father
is
the
man
sperm
semen
tube
sperm
lead
a
to
for
there
the
this,
or
of
father
be
This
are
collected
woman’s
(AI).
if
the
semen
problems
biological
infertile.
may
into
sample
is
or
insemination
provide
can
not
that
plastic
enough
may
the
enough
articial
produce
by
because
produce
later
who
sperm
for
in
AI.
life
probably
unknown.
fertilisation
fertilisation
‘in
parents
children
not
ejaculation.
and
infertility
means
have
does
insemination
vitro
treat
he
process
defective,
because
In
with
The
Articial
In
cannot
because
problems
from
insemination
glass’.
and
(IVF)
when
Eggs
mixed
is
other
another
technique
methods
and
sperm
together
in
a
have
are
that
been
collected
laboratory
can
be
used
unsuccessful.
from
dish
the
where
to
In
vitro
potential
fertilisation
occurs.
To
increase
FSH
to
eggs
can
body
A
couple
with
treatment.
208
triplets
resulting
from
fertility
be
wall
follicles
that
the
chances
stimulate
the
contains
a
ne
of
success,
development
collected
and
on
the
from
plastic
surface
nutrients
of
her
woman
several
ovaries.
tube
the
and
the
of
A
inserted
ovaries.
oxygen.
The
small
to
is
often
follicles
incision
collect
eggs
so
are
the
kept
injected
that
is
made
eggs
in
a
with
several
in
from
the
the
solution
and
to
is
mixed
the
the
the
A
with
solution
woman’s
is
into
also
inject
it
from
the
and
If
left
to
days
the
(or
that
started
few
uterus.
a
is
used
for
up
from
to
24
fertilisation
divide
and
into
then
procedure
a
is
a
sperm
hours
has
for
fertilisation
occurred
embryos.
doctor
donor)
places
successful,
and
These
the
are
them
kept
into
embryo
will
fetus.
possible
into
a
man
checks
have
for
the
eggs
technician
zygotes
develop
It
collected
occur.
that
in
is
tnemelppuS
Semen
an
to
take
egg.
the
The
nucleus
zygote
is
from
then
a
defective
cultured
for
sperm
several
cell
and
days
so
it
A
grows
into
an
embryo
and
is
then
transferred
into
the
woman
in
technician
with
hope
that
it
The
social
fertility
The
implants
for
the
a
sperm
also
not
had
to
implications
of
couples
It
a
IVF
clinic
also
a
to
safe
plan
gave
great
put
of
contraception
their
and
contraceptive
their
families
pill
and
in
1960
decide
made
when
it
to
been
of
the
of
7
The
women
effect
on
health
infants
ability
at
at
more
control
women’s
risk
by
over
health,
their
giving
pregnancy
and
around
the
is
an
IVF
countries
have
per
plan
to
and
sexually
often
be
a
in
and
has
the
and
time
1970s
of
to
30%
are
to
own
them
birth.
much
fertility.
the
TIP
It
opportunity
Death
birth
have
falling
rates
T
he
use
of
ho rm
ones
in
is
not
can
available
national
receives
in
make
an
treatments
they
may
have
if
the
parts
of
the
world
childless
couples
choices
changed
a
all.
steep
Success
of
service,
and
proves
are
not
how
age.
rates
In
decisions
KEY
POINTS
many
unsuccessful.
Infertile
able
to
afford
A
problem
is
what
to
do
with
‘spare’
embryos
that
implanted.
Some
people
maintain
that
it
is
not
drugs
of
them
or
use
them
for
medical
acceptable
to
to
stimulate
eggs
and
a
QUESTIONS
Explain
how
pregnancy
b
Explain
fertility
in
If
the
of
male
couples
how
drugs
infertile
articial
can
increase
the
chance
of
a
sperm
women.
when
the
insemination
man
is
is
are
can
help
bring
about
Explain
a
nutrients
why
and
eggs
to
oxygen,
be
used
before
and
implanting
b
them
Discuss
that
what
are
possible
not
should
happen
implanted.
in
why
into
future
use
or
to
Should
used
for
for
where
used
to
articial
donor
fertilise
a
eggs.
a
IVF
is
a
IVF
are
kept
embryos
are
in
a
solution
kept
for
a
of
a
the
Petri
technique
in
which
place
inside
few
Oral
contraceptives
allow
uterus.
embryos
they
takes
dish.
women
3
opt
infertile.
4
days
infertile,
fertile
fertilisation
2
the
pregnancy.
may
woman’s
3
pregnancy
release
research.
insemination
1
the
increase
just
2
SUMMARY
take
are
chances
dispose
can
containing
this
of
not
females
In
FSH
treatment.
16.1
2.
parts
fertility
many
T
o pic
16.14).
years
health
rst
is
average
1
repeat
in
control
many
also
with
to
35
treatment
birth
from
has
Topic
under
pills
2013.
promiscuity
(see
in
for
decreased
of
steeply
fallen
1.6
women
women
funded
have
just
infections
and
Methods
Contraception
greater
for
who
pill.
they
that
careers.
procedure
about
the
rates
means
led
publically
of
example,
transmitted
about
made
birth
for
families
education
with
that
woman
expensive
are
introduction
Thailand,
behaviour
in
the
successful
In
to
their
increase
for
so
children
sexual
IVF
since
world.
about
egg
have
desc
ribed
considerably
have
an
and
cont
racept
ive
mothers
injects
uterus.
STUD
Y
children.
an
nucleus.
treatments
introduction
easier
in
at
the
be
from
IVF
destroyed,
treatments
frozen
for
they
to
wish
pregnant
decide
to
or
whether
become
not.
research?
209
16.14
Sexually
transmitted
infections
A
LEARNING
sexually
Dene
sexually
infection
body
uids
gonorrhoea
transmitted
State
•
Describe
that
HIV
is
an
amongst
sexual
(STI)
is
the
contact.
a
disease
major
STIs
that
include
is
infections
that
HIV
,
transmitted
can
be
syphillis
and
transmitted.
the
methods
of
HIV
and
its
spread
(HIV)
human
immunodeciency
virus
(HIV)
is
a
human
pathogen
that
can
rst
identied
in
the
early
1980s.
Like
all
viruses
it
is
composed
of
ways
a
which
virus
of
was
transmission
immunodeciency
STI
The
in
during
(STI)
Human
•
infection
OUTCOMES
via
•
transmitted
(STIs)
few
genes
and
a
protein
coat.
It
enters
human
cells
and
uses
each
be
cell
to
make
more
viruses
which
then
enter
even
more
cells.
The
main
prevented
type
State
lead
that
to
HIV
infection
cell
that
it
infects
tnemelppuS
Describe
how
HIV
HIV
infection
affects
with
virus
who
(TB)
HIV
is
may
lead
is
a
HIV
is
no t
a
negative
and
infection
whic
h
number
of
of
If
Acquired
someone
they
are
described
as
being
HIV
has
positive
been
(HIV+).
the
be
body’s
infected
immune
by
People
other
who
system.
diseases,
do
not
It
is
easier
such
have
HIV
as
for
a
person
tuberculosis
are
described
as
and
destroys
an
important
type
of
lymphocyte
that
the
the
of
Eventually
syst
em .
wo rd
Of te
n
is
T
his
immune
system.
lymphocytes
number
of
T
to
During
produce
lymphocytes
an
infection
antibodies.
decreases
these
T
During
and
so
lymphocytes
an
HIV
fewer
every
time
there
is
another
infection.
By
reducing
antibodies
the
T
lymphocytes,
the
person
HIV
infected
weakens
with
HIV
the
will
body’s
ability
succumb
to
to
ght
any
disease.
number
of
is
infections
because
of
their
weakened
immune
system.
‘synd
rome’
the
term
used
.
a
The
(acquired
a
patient
with
AIDS
weight
of
with
HIV
immune
diseases
virus
(yellow)
deciency
brought
(×5000).
syndrome)
on
by
the
is
the
name
weakening
of
given
the
to
body’s
system.
early
glands
treating
infected
collection
immune
worker
the
the
AIDS
health
to
other
Lymphocyte
in
AIDS.
resu
lt
weak
enin
g
HIV/A
IDS
A
or
(HIV–).
produced
other
what
development
of
are
imm
une
means
.
the
lymphocytes
attacks
stimulate
diseas
e;
co lle
ction
a
lymphocyte.
TIP
diseas
es
from
to
Syndrome
pneumonia.
coordinates
it
HIV
weakens
HIV+
and
HIV
AIDS
of
system
The
STUD
Y
type
the
infected
immune
a
may
AIDS
Immunodeciency
•
is
symptoms
and
a
loss,
high
of
AIDS
are
temperature.
various
types
of
very
much
Later,
cancer
like
u,
symptoms
and
a
with
might
decrease
in
swollen
include
brain
function.
Cambodia.
Not
all
HIV+
without
210
any
people
develop
symptoms
at
all.
AIDS.
Some
people
remain
HIV+,
but
tnemelppuS
•
of
How
HIV
is
is
one
HIV
transmitted?
transmitted
person
to
in
the
another
blood
during
and
semen.
unprotected
The
virus
sexual
can
pass
from
STUD
Y
T
here
Either
partner
may
infect
the
other.
The
virus
can
also
be
passed
are
needles
contaminated
with
infected
blood.
In
this
has
spread
very
quickly
amongst
drug
addicts
who
share
needles.
T
hey
Unborn
babies
are
also
at
risk
from
HIV
.
This
is
because
the
virus
can
the
placenta
to
the
fetus.
Even
more
likely
is
its
passage
from
blood
to
the
baby’s
blood
at
birth
when
the
two
into
for
close
contact.
transfusions
is
HIV
can
another
also
way
be
in
transmitted
which
HIV
in
has
HIV
only
breast
been
milk.
For
not
can
There
are
is
no
trying
that
the
drugs,
HIV/AIDS
cure
to
viruses,
fungal
Since
may
inside
but
that
infection
the
(AZT),
body
with
and
that
damage
the
people
infections
HIV
drugs
zidovudine
multiplying
prevented?
HIV/AIDS
develop
drugs
e.g.
for
be
they
will
by
yet
no
vaccine
inactivate
host
and
cells.
AIDS
as
take
HIV
,
some
of
them
to
these
do
the
There
are
work
the
Scientists
problem
prevent
not
treat
HIV
.
but
lymphocytes.
Antibiotics
for
is
be
cups
of
the
virus.
the
cured,
it
is
important
tracing
is
bacterial
to
of
the
spread
of
HIV
in
the
UK.
person
Any
in
positive
either
as
people
a
are
antibodies
several
is
asked
result
then
in
of
identify
offered
their
weeks
to
sexual
an
blood.
after
the
people
intercourse
HIV
test
has
by
which
However,
person
who
or
diagnosed
these
been
they
may
sharing
reveals
have
the
A
sexually
antibodies
at
be
passed
of
appear
during
2
The
spread
controlled
HIV
condoms,
only
sharing
methods
to
reduce
its
spread
on
via
sexual
infected.
of
by
body
contact.
STIs
the
can
use
be
of
preventing
of
needles,
Other
infection
risk,
These
presence
will
transmitted
with
put
needles.
the
them
.
the
uids
HIV
food,
with
POINTS
can
control
glasse
s
who
and
prevent
important
someo
ne
sharin
g
virus
KEY
Contact
or
or
against
1
transmission
touchi
ng
HIV+
by
insect
s,
anti-viral
have.
cannot
is
HIV
trans
mitt
ed
bloodsuck
ing
How
throug
h
exam
ple,
Blood
transmitted.
AIDS
.
infec
ted
describ
ed
bloodstreams
is
used
becom
e
meth
ods
here.
come
may
AIDS
.
catch
the
the
mother’s
and
cann
ot
myt
hs
pass
with
across
HIV
way,
Peopl
e
HIV
man
y
via
abou
t
hypodermic
TIP
intercourse.
the
hypodermic
and
education
include:
programmes.
the
use
of
condoms
to
provide
a
physical
barrier
to
the
transmission
3
of
the
virus
during
sexual
HIV
in
•
setting
inject
free
drugs;
shared
•
up
this
needles
screening
education
the
exchange
reduces
and
donated
contaminated
•
needle
blood
of
risk
of
for
those
transmission
people
from
the
the
to
HIV
used
antibodies
for
make
HIV
the
a
virus
transmitted
use
or
of
in
a
What
the
known
AIDS.
What
c
Why
a
State
exactly
is
and
aware
how
it
of
can
the
be
methods
of
4
as
The
spread
reduced
prevented.
between
AIDS
and
use
an
the
HIV
ways
infection
not
be
treated
by
State
the
a
is
by
be
sexual
reducing
shared
drug
can
needles
users
of
and
by
donated
in
which
HIV
is
measures
that
can
be
in
transfusions.
HIV
destroys
lymphocytes
transmitted.
taken
to
reduce
the
spread
to
a
weakening
of
the
of
system.
This
makes
infection.
tnemelppuS
Describe
the
effect
of
HIV
on
the
immune
system
and
susceptible
HIV
infection
leads
to
the
development
of
to
many
explain
diseases,
how
to
which
using
during
used
people
3
HIV
men
screening
immune
HIV
lead
antibiotics?
leading
b
time,
HIV?
5
2
With
diseases
of
by
of
between
HIV?
blood
can
is
semen
may
of
intercourse,
difference
the
blood.
infection
careful
b
cells
It
eliminating
QUESTIONS
is
in
collection
the
1
infects
system.
transfusion.
people
virus
and
the
condoms
SUMMARY
that
immune
who
HIV
for
being
programmes
transmission
the
schemes
syringes
blood
is
intercourse
such
as
TB.
AIDS.
211
tnemelppuS
•
PRACTICE
1
The
the
QUESTIONS
drawing
correct
shows
a
half
identication
ower.
of
the
Which
labels
1
row
to
is
3
4?
The
diagram
system.
the
shows
Which
events
row
the
female
identies
reproductive
the
places
where
occur?
1
2
3
2
1
3
4
1
1
2
3
2
3
4
A
anther
stigma
petal
sepal
B
petal
stigma
sepal
anther
C
sepal
petal
anther
stigma
D
stigma
anther
sepal
petal
A
fertilisation
implantation
ovulation
B
implantation
ovulation
fertilisation
C
ovulation
production
fertilisation
of
production
D
fertilisation
of
2
(Paper
1)
Which
row
eggs
implantation
eggs
[1]
shows
the
correct
functions
of
4
insect-pollinated
(Paper
1)
[1]
Which
organ
an
secretes
testosterone?
ower?
A
ovary
B
pituitary
C
placenta
D
testis
sepals
anthers
gland
carpels
provide
A
produce
contain
landing
pollen
grains
ovules
for
sepals
site
insects
anthers
carpels
produce
contain
pollen
ovules
(Paper
B
5
insects
grains
The
stigmas
ovaries
anthers
receive
contain
produce
ovules
pollen
pollen
[1]
following
sexual
C
1)
attract
grains
four
processes
reproduction
1
Pollen
2
The
grains
male
in
lands
gamete
occur
owering
on
the
fuses
during
plants.
stigma.
with
the
female
grains
gamete.
petals
stigmas
protect
D
are
ower
3
anthers
The
male
gamete
travels
down
the
pollen
a
in
site
of
tube.
produce
the
pollination
ovules
4
The
pollen
tube
grows
out
from
the
pollen
bud
grain.
(Paper
1)
[1]
In
which
A
3,
4,
1,
2
B
4,
3,
2,
1
C
1,
4,
3,
2
D
4,
2,
1,
3
(Paper
212
order
2)
do
these
processes
occur?
[1]
6
Which
in
the
hormone
second
is
half
A
follicle
B
luteinising
C
oestrogen
D
progesterone
secreted
of
the
stimulating
by
the
hormone
hormone
yellow
menstrual
body
9
The
diagram
before
cycle?
shows
a
fetus
in
the
womb
just
birth.
(FSH)
A
(LH)
B
C
(Paper
2)
[1]
D
7
The
diagram
occur
to
the
below
uterus
shows
the
changes
that
during
the
menstrual
cycle.
E
day
2
2
lining
of
1
8
2
3
7
4
6
2
(a)
Name
body
(b)
Describe
parts
A
to
E.
[5]
5
uterus
4
2
the
2
7
3
structures
8
22
use
the
changes
to
letters
E
that
during
rather
happen
birth.
than
the
You
to
the
may
names
in
answer.
[5]
0
of
uterus
(Paper
0
2
lining
1
2
9
1
your
A
thicker
3)
1
1
1
9
gets
10
8
1
(a)
Dene
the
(b)
Explain
term
sexual
reproduction.
[3]
1
2
7
1
6
3
1
51
4
1
1
the
following
ovary,
Which
row
events
during
shows
the
times
(in
days)
when
difference
pairs
and
(ii)
of
between
terms:
pollination
(i)
the
ovule
and
and
fertilisation.
the
[4]
the
cycle
occur?
(c)
State
likely
factors
germination
ovulation
is
three
menstruation
uterus
occurs
gets
of
required
for
the
seeds.
[3]
lining
to
(Paper
thicker
3)
occur
11
A
10–27
25–28
Clomiphene
infertility
B
13–15
1–4
6–25
C
22–25
1–4
7–14
D
10–27
13–15
25–28
an
in
increase
pituitary
(a)
2)
in
Explain
Outline
fertility
Potato
and
plants
stem
variation
A
drug
that
It
is
works
used
production
of
by
to
treat
causing
FSH
from
the
how
to
a
be
deciency
in
FSH
causes
infertile.
a
[2]
[1]
(b)
8
a
women.
gland.
woman
(Paper
is
4–10
reproduce
tubers.
among
Which
by
results
offspring
cross-pollinating
means
in
plants
in
of
the
potato
of
the
social
issues
involved
with
treatment.
[4]
owers
least
(c)
plants?
Describe
the
roles
progesterone
in
of
oestrogen
pregnancy.
and
[3]
different
(Paper
4)
varieties
B
cross-pollinating
C
production
D
self-pollination
(Paper
2)
of
plants
stem
of
the
same
variety
tubers
[1]
213
17
Inheritance
17.1
Chromosomes,
and
People
LEARNING
Dene
•
State
who
capabilities
meaning
of
to
the
chromosome,
at
closely;
same
or
traits
such
in
the
family
such
things
case
often
as
as
of
resemble
identical
each
physical
sport
and
twins,
appearance,
music,
often
very
other
–
closely.
personality
run
in
and
families.
the
We
terms
belong
quite
Characteristics
inheritance
the
DNA
OUTCOMES
sometimes
•
genes
gene
say
that
someone
has
inherited
features
from
their
parents.
and
DNA
The
transfer
the
next
genes
Unit
as
16
are
in
zygote
are
we
the
next
its
of
these
inheritance.
like
looked
coded
at
produced.
the
which
individual
transmission
The
features
from
characteristics
instructions.
The
one
are
study
of
generation
controlled
to
by
inheritance
is
genetics
humans
from
or
called
which
known
In
is
contains
from
parent
new
Genes
gametes.
grows
male
how
At
the
the
and
generations
from
one
fertilisation,
genetic
zygote
half
of
generation
the
from
half
its
of
are
gametes
information
–
owering
from
to
both
genetic
female
parent.
and
transmitted
fuse
its
plants
form
to
a
parents.
A
new
information
comes
but
see
Chromosomes
We
cannot
see
genes
chromosomes.
The
to
rst
look
step
at
in
The
cell
There
is
are
called
shapes
and
and
shape.
sorted
into
inherited
DID
YOU
Chromosome
a
lot.
is
numbers
Humans
chromosomes
but
in
chimpanzees
have
body
have
46
cells,
muntjac
deer
can
fruit
held
ies
by
–
have
the
some
the
of
8.
The
adder’s
plants
fern
we
can
information
that
we
inherit
is
that
in
they
the
number.
can
pairs.
the
In
be
each
male
a
microscope
can
into
human
pair,
a
during
human
counted
of
a
one
and
one
pairs
the
and
are
based
male’s
of
cell
blood
analysed.
cell.
This
different
on
their
size
chromosomes
chromosomes
from
division.
white
human
chromosomes
sorted
parent
be
nucleus
The
a
of
the
are
has
been
female.
of
have
in
each
but
two
of
They
not
the
always.
strands
chromosomes
have
of
two
Figure
one
strands
17.1.1
in
the
joined
at
chromosome
the
in
photo
on
together
top
two
of
the
the
left
usually
next
different
at
page
colours.
could
unravel
That
a
thread
is
chromosome,
made
up
of
it
a
would
long
form
chain
an
extremely
molecule
called
long
DNA
stands
for
deoxyribonucleic
acid.
The
DNA
is
wound
around
tongue
of
protein.
During
cell
division
the
DNA
and
protein
are
this
over
each
that
record
very
tightly
together
and
the
chromosomes
are
coiled
up.
1400
At
chromosomes
other
times
cell!
the
214
we
chromosomes.
only
packed
species
containing
chromosomes
photograph,
stranded.
molecules
fern
genetic
through
the
so
They
the
23
microscope,
nuclei
48,
have
which
is
sizes.
see
centre,
shows
thread.
6,
the
chromosomes
from
double
the
If
Indian
visible
shows
diploid
In
light
KNOW?
You
vary
are
prepared
46
the
a
have
chromosomes.
photograph
specially
cells
visualising
these
Chromosomes
through
Most
DNA.
they
are
uncoiled
so
the
cell
can
use
the
information
in
What
Genes
Each
is
a
are
gene?
lengths
of
chromosome
actual
number
chromosomes
large
the
has
many
depends
are
numbers
of
DNA
on
much
that
you
genes
its
along
length.
longer
can
than
see
its
You
in
the
length,
can
others;
see
these
diagram
although
that
some
below.
the
of
our
chromosomes
have
Figure
genes.
17.1.1
A
double-stranded
chromosome.
Each
It
is
gene
a
is
a
unit
chemical
of
code
inheritance
that
the
cell
in
that
it
codes
interprets
as
an
for
a
specic
instruction
protein.
to
make
STUD
Y
a
protein
amylase
molecule.
and
proteins
lipase
and
many
Y
ou
for
know
about
example.
more.
several
There
Humans
is
have
a
proteins
gene
for
between
–
each
20 000
of
to
these
‘Diplo
id’
genes.
The
proteins
produced
by
cells
inuence
means
how
are
two
se ts
works
and
what
it
looks
like.
Some
features
that
genes
inuenced
by
the
environment.
Y
our
height
is
determined
by
inhe
rited
and
you
how
inherit
much
and
your
exercise
environment
you
take.
Other
–
for
example
genes
are
not
by
your
environment.
environment
has
Y
our
no
blood
affect
group
on
this
is
at
determined
by
a
gene
and
diet
affected
inhe
rited
by
A
the
and
se t
the
each
all.
strand
of
cons
ists
The
arrangement
of
DNA
in
a
and
of
and
complete
the
sentences
using
these
pro tei
n.
DNA
genes
genetic
gametes
nuclei
This
in
their
the
(sex
information
called
is
that
threads
are
parents
made
cells)
because
from
contained
are
of
inside
in
of
which
the
the
they
passed
of
and
.
on
use
to
developed.
thread-like
the
proteins
2
in
small
a
Dene
b
Name
the
units
called
terms
gene
cells.
human
Write
the
a
few
and
the
DNA
tight
ly
the
What
b
State
is
1
to
explain
the
relationship
chromosome,
the
diploid
is
pack
ed
cells
can
in
gene
s.
POINTS
Inheritance
genetic
is
the
transfer
information
gene,
to
from
the
diploid
numbers
of
generation.
between
2
by
so
proteins.
sentences
meant
other
inform
ation
A
chromosome
DNA
is
carrying
a
thread
genetic
protein.
information
a
very
At
is
chromosome
following:
nucleus,
pack
ed
.
of
3
cell
and
toge th
er
.
generation
c
is
These
information
of
three
DNA
DNA
structures
most
The
the
KEY
found
mad
e
resemble
less
Offspring
is
information
times
them
Durin
g
are
words:
tight
ly
chromosomes
of
molec
ules
QUESTIONS
pro tei
n
Copy
pro tei
n.
arou
nd
divisi
on,
1
one
chrom
osom
e.
(deoxy
ribon
uclei
c
chromosome.
woun
d
SUMMARY
of
se t
fath
er
.
TIP
DNA
acid)
17.1.2
o ther
the
chrom
osom
e
protein
of
Figure
of
the
DNA
Each
of
the
from
type
STUD
Y
core
one
from
both
mo th
er
genes
–
control
se t
are
of
the
chrom
osom
es
body
that
25 000
there
different
TIP
haemoglobin,
number?
three
non-human
in
the
form
of
genes.
species.
3
A
gene
that
is
a
codes
length
for
a
of
DNA
protein.
215
17.2
Protein
tnemelppuS
Each
LEARNING
chromosome
Explain
bases
that
in
a
the
gene
sequence
code
for
of
order
of
amino
Each
called
genes.
a
length
up
of
A
gene
divided
a
long,
is
a
into
super-coiled
small
thousands
part
of
the
of
molecule
DNA
shorter
of
sections
strand.
to
of
DNA,
make
a
making
up
particular
a
particular
protein.
gene,
Remember
carries
that
the
inside
information
every
cell
protein
there
•
made
is
acids
needed
in
molecule
the
The
correct
is
OUTCOMES
DNA.
•
synthesis
Explain
how
a
protein
is
are
thousands
of
different
chemical
reactions
taking
place.
made
Enzymes
that
all
control
enzymes
determines
which
all
are
which
chemical
these
chemical
proteins.
enzymes
reactions
reactions.
Because
are
take
DNA
produced
place
in
inside
You
codes
each
should
for
cell
remember
proteins,
and
it
therefore
cells.
DNA
gene
1
gene
2
nucleus
Figure
mRNA
The
17.2.1
A
structure
gene
of
is
DNA
a
short
(see
section
Unit
4)
of
DNA.
contains
bases.
The
information
nuclear
is
pore
found
in
the
sequence
of
bases
along
the
length
of
DNA.
nuclear
These
membrane
also
determine
controls
the
the
sequence
production
of
of
amino
other
acids
in
important
the
protein.
proteins,
DNA
including
mRNA
antibodies
+
and
receptors
for
neurotransmitters.
ribosomes
cytoplasm
DNA
carries
information
information
ribosomes
protein
is
Figure
17.2.2
The
vital
role
of
given
the
ribosomes.
code
to
the
a
kind
name
of
build
the
proteins
DNA
to
’messenger
messenger
the
from
site
molecule’.
RNA
amino
of
(mRNA).
acids.
protein
This
The
molecule
role
The
synthesis
of
is
in
RNA
mRNA
is
the
and
to
a
copy
of
the
base
sequence
on
DNA
out
of
the
nucleus
to
the
the
ribosomes
The
are
letters
three
and
A,
of
copies
on
four
T
,
is
the
instance
A
the
the
C
C
different
G.
bases
code
will
will
on
–
bases
Each
on
for
protein
by
G,
this
code
for
a
it
does
G
so
will
replaced
U
on
in
acid
There
different
and
is
found
amino
DNA.
DNA
copy
T
where
synthesis
occurs.
code
coded
base
DNA
cytoplasm
and
these
each
have
in
genetic
There
216
by
to
from
mRNA
carry
carrying
moves
is
are
coded
C.
‘rule
on
of
by
base
to
a
them
DNA.
base
U
by
sequence
different
However
,
another
mRNA.
refer
for
,
20
triplet
the
copy
We
about
base
by
by
DNA.
amino
When
pairing’,
mRNA
does
(uracil).
their
of
acids
mRNA
so
for
not
Therefore,
double
strand
DNA
mRNA
tnemelppuS
DNA
DNA
unwinds
makes
mRNA
amino
methionine
acid
Figure
17.2.3
How
DNA
alanine
base
triplets
code
tyrosine
for
amino
nucleus
arginine
acids.
mRNA
The
coded
information
on
mRNA
is
used
to
assemble
amino
acids
in
ribosome
the
correct
sequence
for
each
protein.
nuclear
pore
•
The
mRNA
arrives
•
The
mRNA
strand
amino
•
The
acid
mRNA
assembles
in
at
the
from
base
the
triplets
nucleus.
for
each
particular
protein.
passes
amino
ribosomes
contains
the
then
the
acids
through
into
the
protein
ribosomes
and
each
ribosome
mRNA
molecules.
ribosome
•
The
amino
•
The
specic
bases
in
acids
bond
order
the
of
mRNA
together
amino
and
forming
acids
each
is
a
long
chain
determined
amino
acid
is
by
joined
–
the
to
the
protein.
sequence
the
next
of
amino
one
acid
passed
by
a
peptide
to
bond.
ribosome
All
a
body
cells
particular
in
an
cell
organism
many
genes
contain
may
not
the
be
same
genes.
expressed
However,
because
the
in
cell
amino
makes
only
the
specic
proteins
it
needs.
acid
added
to
growing
protein
Figure
SUMMARY
17.2.4
How
DNA
controls
protein
QUESTIONS
synthesis.
1
2
What
is
the
function
a
DNA
b
mRNA
c
ribosomes
Look
at
the
part
of
of
a
each
of
the
molecule
of
following
in
messenger
protein
RNA
synthesis?
here:
AUGACGCAUGCAGUCCGA.
a
How
many
b
What
is
base
the
triplets
role
of
are
each
of
shown
these
in
this
base
section
triplets
in
of
mRNA?
protein
KEY
synthesis?
c
Write
down
the
DNA
base
triplets
that
coded
for
this
mRNA.
1
3
Indicate
if
these
statements
are
true
or
The
DNA
is
a
b
DNA
has
sequence
codes
false.
of
a
POINTS
amino
DNA
d
The
the
a
double
contains
acids
2
helix
The
role
four
bases:
A,
G,
C
and
of
code
bases
in
shape
between
of
DNA
is
a
on
DNA
sequence
protein.
base
is
carry
to
it
copy
to
the
the
U
maintained
complementary
mRNA
and
ribosomes
molecular
bonds
of
correct
protein
DNA
c
for
pairs.
by
in
the
cytoplasm.
hydrogen
3
The
ribosomes
acids
into
assemble
protein
amino
molecules.
217
17.3
Mitosis
New
cells
below
•
Dene
its
mitosis
roles
in
•
Dene
role
in
and
of
into
state
growth,
replacement
asexual
As
repair,
cells
In
and
reproduction
meiosis
and
gamete
state
tnemelppuS
State
that
before
are
Outline
what
Describe
the
the
nucleus
cell
cells
into
are
is
a
during
role
of
to
that
is
the
rise
stem
cells
The
a
cell
DNA
of
in
the
The
new
urchin
You
can
has
see
just
that
divided
each
old
ones.
new
is
In
into
two,
wall
nuclei
the
divides,
between
cell
in
the
photograph
is
the
the
the
process
of
nucleus
cytoplasm
two
formed
nuclei
dividing
must
divides.
to
between
divide.
divide
the
nuclei.
divide.
of
nuclear
The
division
daughter
that
cells
occurs
are
during
genetically
growth
and
identical.
organs
to
cells
form
that
gametes.
are
not
It
is
the
genetically
nuclear
division
identical.
divide,
new
copies
chromosomes
exact
is
see
mitosis
copies
divides.
uncoiled
are
of
DNA
of
begins,
thicker.
They
staining
in
is
is
the
This
going
nuclei
coils
visible
up
This
is
the
is
so
a
very
in
this
is
attached
that
the
in
the
each
in
reliable
process
DNA
loosely
when
under
information
copying
on,
very
chromosome
DNA
become
technique
it
genetic
made.
arranged
each
the
the
be
made.
While
and
chromosomes
mitosis
of
must
occurs
the
nucleus.
going
to
on.
the
original
chromosome
microscope
when
a
used.
in
cell
has
During
a
a
cell
division
which
sex
of
can
the
copy
As
suitable
sea
of
urchin
the
occurs
daughter
nucleus
cannot
becomes
a
in
to
which
You
copy.
of
in
type
process
chromosomes
mitosis.
its
plants
ways
sea
mitosis
before
by
In
a
Before
nishing
occurs
gives
process
zygote
cells.
reproduction.
Meiosis
the
two
division
of
constriction
two.
two
Mitosis
Before
A
the
egg
mitosis
happens
chromosomes
•
by
fertilised
daughter
asexual
•
•
produced
the
production
chromosomes
duplicated
two
There
its
left,
animal
the
•
•
are
OUTCOMES
mitosis
the
two
copies
separate
so
each
new
cell
gets
a
copy
nucleus.
of
each
chromosome.
The
diagram
shows
what
happens
to
one
chromosome.
As
a
a
result
of
mitosis,
each
daughter
cell
has
the
same
chromosome
chromosome
number
copied
two
the
a
original
reliable
parent
system,
cell.
they
As
are
the
chromosomes
genetically
identical
have
to
been
each
identical
other
copies
a
as
by
of
and
to
the
parent
cell.
If
they
were
genetically
different
they
the
would
chromosome
be
rejected
by
the
body’s
immune
system.
chromosome
after
is
it
copied
The
nucleus
to
two
starts
copies
of
chromosome
divide
separate
pulled
and
signicance
are
Mitosis
produces
daughter
cells
following
•
•
daughter
chromosome
of
this
cell
has
17.3.1
This
is
each
cells
218
that
the
are
same
an
exact
number
copy
of
of
the
parent
chromosomes
cell.
and
These
are
growth
repair
identical
–
in
in
of
damaged
a
to
the
parent
cell.
Mitosis
is
important
for
the
animals
special
wounds
tissues
this
happens
growing
–
your
and
areas
skin
all
over
such
cells
as
the
the
divide
body,
tips
by
of
in
plants
stems
mitosis
to
it
and
roots
repair
wounds
type
•
Figure
cells
have
processes:
happens
divides–each
mitosis
apart
genetically
cell
of
the
what
happens
chromosome
divide
by
to
when
mitosis.
replacement
which
only
of
live
cells
for
a
that
short
wear
time
out
and
die,
such
as
red
blood
cells
tnemelppuS
LEARNING
reproduction
–
this
occurs
in
fungi
and
in
plants,
but
is
KEY
rare
in
the
animal
reproduction
on
kingdom.
page
There
are
some
examples
of
POINTS
asexual
184.
1
Mitosis
cells
Growth:
As
multicellular
organisms
grow,
the
number
of
produces
that
up
their
tissues
increases.
The
new
cells
must
be
the
existing
ones.
Growth
by
mitosis
takes
place
over
the
in
animals.
In
plants,
group
is
conned
to
certain
areas
2
parent
Stem
cells
and
replacement
of
cells:
Damaged
cells
identical
new
cells.
Your
skin
cells
and
the
cells
must
be
dying
and
being
replaced
by
identical
lining
cells.
your
Red
cells
gut
need
live
to
Asexual
are
only
be
reproduce,
tnemelppuS
Some
a
short
by
to
the
such
as
time
will
wear
away
and
die.
of
the
cells
produce
blood
become
keep
dividing
They
do
cells.
and
Asexual
parent.
yeast
reproduction
Mitosis
and
occurs
potato
results
when
tubers
in
offspring
unicellular
die.
cells.
(see
T
opic
16.1).
that
not
form
by
develop
from
mitosis
into
an
to
any
embryo
type
provide
the
of
remain
as
specialised
unspecialised
body
with
a
cell.
These
These
cells
are
needed
to
replace
cells
constant
that
get
QUESTIONS
cells
supply
a
Which
type
There
is
a
layer
of
stem
cells
just
under
the
These
stem
cells
continually
divide
to
outer
make
toughened
for
protection.
They
get
rubbed
off
constantly
replaced.
When
skin
is
wounded,
cells
and
these
in
as
the
more
bone
cells
to
marrow
repair
to
the
produce
damage.
new
red
There
blood
are
and
cell
division
that
to
the
are
parent
cell?
that
Give
two
examples
of
need
stem
many
cells
cells
layer
mitosis
occurs
i
in
cells
plants
produce
of
worn
when
be
for
that
b
become
to
cells
organisms
identical
skin
daughter
specialised
functions.
produces
of
mitosis.
also
1
out
by
cells
SUMMARY
They
new
unspecialised
cells
cells.
of
are
mitosis.
reproduction:
identical
Stem
for
replaced
as
are
specic
which
same
replaced
that
constantly
the
cell.
produced
They
by
have
chromosomes
called
meristems
Repair
of
whole
the
body
and
identical
number
to
daughter
genetically
cells
identical
making
are
tnemelppuS
asexual
stem
and
ii
in
animals.
cells
phagocytes
2
Describe
the
role
of
stem
cells.
replacements.
Each
time
a
specialised
remains
cells
in
Mitosis
stem
for
cell
some
divides,
specic
unspecialised
meristems
takes
place
in
in
the
to
go
plants
one
daughter
function
through
have
meristem
the
behind
and
the
starts
other
process
same
the
cell
the
root
role
tip.
as
of
to
become
daughter
mitosis
stem
cells
cell
again.
in
Cells
The
animals.
at
various
stages
of
mitosis.
219
tnemelppuS
•
17.4
Meiosis
Meiosis
LEARNING
OUTCOMES
Meiosis
•
Dene
meiosis
as
a
is
a
type
reproduction.
division
in
which
number
resulting
formation
in
is
known
Explain
how
meiosis
variation
by
forming
human
of
of
paternal
essential
the
the
with
haploid
number,
sperm
the
sort
of
This
type
46
which
half
the
normal
number.
is
would
of
after
the
(As
and
results
chromosome
opposed
diploid
cells
both
would
in
to
the
number.
full
number).
had
have
generation
every
father,
nuclear
the
have
in
owering
In
meiosis
different
raw
to
eggs
result
contain
of
the
material
changing
23
23
46
92
chromosomes
chromosomes.
the
number
generation.
in
for
In
a
of
This
This
is
of
If
the
this
chromosomes
does
reduction
not
happen.
selection
humans
are
to
and
in
in
–
the
the
not
the
allows
called
egg
a
different
and
has
23
from
number
of
generation.
ovaries
anthers
gametes.
meiosis
cells
and
the
to
and
and
They
variation
organisms
is
zygote
egg,
identical.
genetic
there
producing
The
generation
occurs
cells
so
reproduction
from
in
in
division
each.
mother,
sexual
contributes
because
involved
chromosomes
the
organs
meiosis
daughter
this
is
constant
sex
46.
life-cycle
chromosomes
from
sperm.
stays
at
the
number
plants
and
in
division
only
the
occurs
In
remains
division
halves
cells
Meiosis
a
egg
double
number
nuclear
chromosomes
as
and
fertilisation
chromosomes,
the
in
are
that
to
testes.
the
ovules.
genetically
provides
evolve
in
the
response
environments.
23
meiosis.
Figure
17.4.2
meiosis.
four
As
cells.
been
shows
you
Each
halved
to
can
of
what
see
these
give
a
happens
there
cells
are
has
haploid
to
one
two
one
pair
of
divisions
chromosomes
of
chromosome,
the
so
cell
the
during
resulting
number
in
has
gamete.
cell
46
46
from
with
in
sexual
chromosomes
sperm
and
cells
at
generation
nuclei
Meiosis
diploid
for
organs
new
Instead,
chromosomes
is
reproductive
maternal
in
sperms
gametes
as
formed
continued
combinations
Human
that
the
produces
zygote
and
in
cells
If
•
division
place
genetically
chromosome
different
cell
takes
is
This
halved,
It
the
the
chromosome
of
reduction
the
one
testis
pair
of
chromosomes
cell
diploid
ovar y
in
cell
testis
first
of
division
the
cell
23
fertilisation
23
haploid
second
division
sperm
haploid
of
the
cell
egg
46
diploid
zygote
Figure
17.4.1
chromosomes
haploid
the
220
in
number.
diploid
The
number
gametes
is
The
number
in
number.
four
of
the
called
a
the
zygote
is
Figure
17.4.2
This
There
one
haploid
shows
are
what
two
cells
which
happens
divisions
chromosome
so
of
the
become
to
the
one
cell
number
sperm
pair
to
of
give
has
cells
chromosomes
four
been
cells.
halved.
during
Each
of
meiosis.
these
has
17.4.2
meiosis.
In
inherited
mother
.
of
each
what
pair
,
one
from
the
father
,
When
the
23
meiosis,
and
shows
the
maternal
produced
in
happens
and
Differences
are
one
of
cells
chromosomes.
meiosis
one
chromosome
pairs
daughter
to
is
is
pair
gain
different
is
genetically
between
one
as
in
it
origin
was
separate
different
in
in
which
from
the
and
the
one
as
it
of
during
was
inherited
combinations
way
mitosis
chromosomes
paternal
maternal
chromosomes
This
of
rst
from
the
division
paternal
haploid
cells
another
.
meiosis
A
The
differences
between
mitosis
and
meiosis
are
summarised
in
the
fertilised
of
and
in
Figure
17.4.3.
One
The
to
sperm
give
division
T
wo
number
the
of
chromosomes
The
same
daughter
cells
number
of
chromosomes
a
are
genetically
The
daughter
cells
from
the
are
cell
STUD
Y
genetically
parent
cells
are
formed
Four
daughter
cells
are
Meiosis
46
the
of
the
chromosomes.
Mitosis
diploid
shou
ld
haploid
haploid
Meiosis
SUMMARY
and
mitosis
diploid
a
compared.
many
pairs
of
body
chromosomes
are
there
in
the
an
iii
a
the
egg
number
POINTS
nucleus
Meiosis
of
chromosomes
cell
in
ii
a
sperm
iv
a
red
these
human
cells:
which
number
to
cell
blood
three
tnemelppuS
b
Explain
ways
in
which
meiosis
are
differs
from
Meiosis
meiosis
produces
the
advantage
of
is
halved
from
resulting
genetically
in
diploid
cells
different.
produces
variation
by
new
combinations
variation.
of
Explain
division
chromosome
mitosis.
forming
how
reduction
cell
2
State
a
the
haploid
that
zygote
a
is
cell?
in
i
spell
co rrec
tly.
QUESTIONS
human
State
to
you
haploid
1
of
how
diploid
KEY
How
learn
are
and
diploid
haploid
17.4.3
T
hey
conf
used
duplication
diploid
haploid
you
mito
sis
diploid
DNA
haploid
when
wo rd
s
meio
sis.
them
c
nuleus
TIP
carefu
l
easily
2
The
nucleus
formed
and
b
with
the
cells
write
a
zygote.
is
Be
1
or
with
divisions
different
daughter
Figure
egg
fusing
halved
identical
T
wo
is
Meiosis
remains
The
the
egg
Mitosis
human
table
genetic
variation
among
gametes.
maternal
and
paternal
chromosomes.
221
tnemelppuS
tnemelppuS
Figure
17.5
Inheritance
Cat
LEARNING
breeders
Use
to
pedigree
show
cats
diagrams
how
features
the
are
terminology
hair,
bred
all
the
if
they
kittens
features
kittens
together
short-haired
haired
the
Use
long
some
are
inherited
•
that
breed
genes
together
two
cats
which
both
OUTCOMES
have
•
know
and
at
kittens
all.
that
then
have
there
in
the
Breeders
appear
will
within
may
litter,
can
long
be
or
make
a
hair.
some
there
If
short-haired
long-haired
may
pedigree
family
two
be
no
long-
diagrams
of
cats
as
in
looks
very
like
and
to
Figure
show
17.5.1.
of
You
will
see
that
a
pedigree
diagram
a
family
tree,
but
inheritance
symbols
•
Distinguish
and
between
are
used
to
indicate
the
gender
of
individuals.
genes
alleles
I
1
Symbols
2
for
II
pedigree
square
=
diagrams:
male;
circle
=
female
III
shaded
circle
individual
or
with
square
the
=
condition
shading
=
long
hair
no
shading
=
short
1
hair
studied
Figure
17.5.1
A
pedigree
family
unshaded
individual
circle
not
or
square
showing
of
diagram
showing
the
inheritance
of
hair
length
in
a
cats.
=
the
Genes
and
alleles
condition
A
individuals
may
be
identied
gene
is
a
molecule.
generation
and
I
–
2,
II
–
5
Each
of
gene
DNA
is
that
always
is
the
and
III
–
the
chromosomes.
genes
from
vary
versions
of
of
a
gene
In
Figure
the
Each
same
between
each
(see
species
gene
17.5.2,
you
You
species
individuals
are
below),
chromosomes.
has
known
but
can
can
has
from
as
usually
see
also
of
Nancy
the
gene
the
three
see
the
father
for
Mary
all
disease,
a
Soto
disease
in
who
these
the
early
from
1800s.
descendants
Maracaibo
in
different
be
two
more.
pair
are
of
and
d/d
different,
heterozygous
The
dominant
expressed
in
the
allele
phenotype.
two
alleles
individual
is
are
the
same,
homozygous
d
These
live
two
alleles
individual
is
are
the
same,
homozygous
of
recessive
and
d
expressed
the
recessive
allele
the
will
be
in
the
phenotype.
Many
from
around
of
mother
Venezuela.
Figure
222
gene.
be
is
may
B/B
alleles
However,
The
serious
by
egg
Lake
one
every
dominant.
chromosome
of
one
A/a
two
this
will
the
descendants
died
many
individual
These
of
for
disorder
,
the
on
B
B
Wexler
position
There
on
alleles
the
studying
protein
and
genes.
species.
are
genes
the
a
d
neurological
a
place
genes
same
alleles.
A
responsible
Huntington’s
making
same
own
each
there
KNOW?
discovered
its
These
sperm
A
Professor
for
the
the
within
chromosome
YOU
in
1.
individual
DID
code
located
number,
of
e.g.
length
by
17.5.2
This
shows
three
genes
that
are
on
the
same
chromosome.
alleles
Sometimes
is
only
one
an
organism
type
metabolism.
of
But
gains
instruction
many
two
to
copies
use
organisms
of
during
contain
the
same
growth:
two
allele
so
there
development
different
alleles.
If
STUD
Y
or
an
Notic
e
is
expressed
and
affects
the
appearance
of
the
individual,
it
is
said
to
dominant
allele.
If
it
is
not,
then
it
is
said
to
be
a
recessive
the
the
1850s,
Gregor
Mendel
investigated
inheritance
in
pea
noticed
that
amongst
garden
pea
plants
one
variety
grew
to
while
another
remained
short,
or
dwarf.
He
used
pea
plants
bred
true
–
from
generation
to
generation
they
were
a
plants
or
dwarf
capita
l
recess
ive
smal
l
letter
.
differ
ent
letter
allel
e
allel
es
of
the
plants.
Never
letter
s
either
the
tall
the
that
use
always
a
be
as
tall
as
alwa
ys
plants.
and
He
we
dom
inan
t
allele
allel
e
In
that
be
show
a
TIP
allele
for
sam
e
gene
.
When
tall.
he
plants
of
been
tall
give
Using
T
these
were
plants
on
about
letters
This
A
for
it
and
has
the
had
allele
the
is
all
when
He
he
there
he
a
the
a
generation
generation
next
that
his
gene
that
pea
consisted
dwarfness
He
did
knowledge
‘factors’
were
of
generation
generation.
used
called
is
next
new
reasoned
‘skipped’
but
the
this
seeds,
dwarf.
what
two
letter
But
DNA,
terminology
capital
letter
some
represent
gene
varieties,
produced
although
represent
dwarf.
and
two
dwarf.
and
genes
to
modern
plants.
case
them
passed
anything
Let
of
self-pollinated
many
to
cross-bred
None
that
had
not
of
controlled
controls
know
algebra
height
height.
in
pea
alleles.
for
tall,
used
recessive
and
for
the
let
t
represent
dominant
the
allele
allele
and
a
for
lower
allele.
Mendel
The
a
genotype
pea
tt,
plant
the
(TT)
or
they
The
of
an
could
plant
is
be
organism
TT,
two
or
alleles
phenotype
is
the
are
way
If
They
recessive
that
the
tt.
homozygous.
homozygous
have
Tt
is
alleles
the
alleles
be
has.
alleles
for
are
So
the
are
genotype
the
homozygous
Individuals
different,
the
two
can
(tt).
it
are
example
expressed
same,
of
TT
refers
to
all
the
aspects
of
an
organism’s
biology
shape
the
of
will
apply
the
term
to
one
feature
of
an
organism,
for
round
of
seven
including
and
the
wrinkled.
POINTS
individual.
its
Pedigree
diagrams
show
genes.
how
We
–
plants
if
KEY
an
seeds
pea
dominant
heterozygous
in
inheritance
in
or
Tt
except
the
features
1
It
studied
different
features
are
inherited
in
example
families.
height
in
pea
plants.
The
genotypes
TT
and
Tt
result
in
plants
with
2
the
tall
phenotype,
whereas
the
genotype
tt
results
in
dwarf
An
allele
is
a
Most
3
The
genes
of
of
an
is
an
phenotype
QUESTIONS
have
genotype
makeup
SUMMARY
version
of
a
gene.
plants.
is
many
the
alleles.
genetic
organism;
all
organism
the
the
features
other
than
its
genotype.
1
Chromosomes
occur
in
pairs
in
all
cells
except
the
gametes.
4
Explain
why
they
are
not
in
pairs
in
A
dominant
expressed
2
a
What
are
b
Explain
5
3
Explain
is
meant
by
the
terms
dominant
allele
and
of
the
following
genetic
terms:
a
homozygous
b
heterozygous
c
genotype
d
phenotype
A
recessive
only
allele
each
6
seed
how
shape
you
is
would
dominant
nd
or
out
whether
is
always
phenotype.
allele
for
wrinkled
allele
no
homozygous
identical
a
is
expressed
dominant
A
two
the
when
present.
has
Explain
the
is
and
4
in
alleles?
what
recessive
allele
gametes.
individual
alleles
heterozygous
two
allele
different
of
a
has
gene
individual
alleles
of
a
gene.
recessive.
223
17.6
Monohybrid
inheritance
Monohybrid
LEARNING
inheritance
characteristic,
•
Dene
•
Explain
concerns
the
inheritance
of
a
single
OUTCOMES
monohybrid
inheritance
It
involves
the
such
as
plant
inheritance
height
of
or
ower
the
parental
examples
alleles
of
of
one
gene.
We
will
colour
tall
×
dwar f
use
phenotype
monohybrid
the
crosses
example
of
Mendel’s
peas.
parental
There
pea
is
one
plants.
gene
The
for
height
gene
for
in
TT
tt
T
t
genotype
plant
genotypes
height
has
two
alleles:
tall,
T,
of
and
dwarf,
gametes
t.
gametes
There
are
three
genotypes
for
t
possible
plant
height:
T
TT
=
homozygous
Tt
tall
F
generation:
genotype
–
all
heterozygous
(Tt)
1
Tt
tt
=
=
The
STUD
Y
The
TIP
tall
Whe
n
you
gene
tic
the
on
them
this
simpl
e
hom
ozyg
ous
only
one
mak
e
write
this
As
–
so
once
parental
result
plants
of
phenotype
dwarf.
Figure
a
above
shows
homozygous
plants
that
a
all
tall
plants
17.6.1
cross
dwarf
Mendel
used
between
plant,
in
his
tt.
a
homozygous
These
crosses.
represent
This
is
the
called
cross.
of
meiosis,
allele,
all
T,
recessive
the
and
allele,
t.
receive
one
dominant
and
all
because
the
have
allele,
T,
gametes
all
heterozygous
tall,
–
cross
and
dominant
the
tall
diagram
T T,
breeding
contain
only
in
parental
genetic
a
the
orga
nism
s
gam
e tes
geno
type
the
like
page
,
homozygous
plant,
pure
out
diag
ram
s
ones
mak
e
write
heterozygous
the
When
allele
the
is
from
gametes
the
tall
from
fertilisation
and
one
genotype,
dominant
to
plant
the
occurs,
recessive
Tt.
Their
the
contain
dwarf
the
allele
plant
new
so
phenotype
recessive
allele,
will
be
will
be
t
the
diag
ram
.
The
rst
generation
is
known
as
the
F
generation,
and
in
this
particular
1
genetic
cross,
all
the
plants
in
the
F
generation
are
heterozygous
tall
(Tt).
1
Crossing
F
tall
×
the
F
tall
generation
(3:1
ratio)
1
1
phenotype
The
F
plants
are
allowed
to
self-pollinate
(see
genetic
diagram,
1
F
Tt
left).
Tt
1
When
meiosis
occurs,
half
of
the
gametes
of
each
plant
will
genotype
have
genotypes
t
T
T
allele,
T,
and
half
will
have
the
recessive
allele,
t
time
when
fertilisation
occurs,
there
are
three
possible
gametes
combinations
gametes
T
t
TT
the
F
,
or
second
generation:
(homozygous
tall)
(heterozygous
tall)
Tt
tt
genotypes
in
2
Tt
generation:
alleles
tt
Tt
T
of
t
TT
F
dominant
t
This
of
the
(homozygous
dwarf).
phenotypes
2
Amongst
25%
homozygous
dominant
75%
50%
heterozygous
tall
homozygous
generation
¼
(or
25%)
will
be
homozygous
½
recessive
(tt)
25%
(or
50%)
be
will
be
heterozygous
homozygous
dwarf.
and
Since
the
therefore
tall;
phenotypes
are
the
same,
¾
of
the
F
plants
will
be
tall
and
2
224
17.6.2
75%
:
25%
is
a
3:1
ratio.
of
¼
(or
TT
25%)
and
dwarf
Tt
Figure
tall;
(Tt)
will
25%
this
(TT)
dwarf.
This
can
also
be
written
as
3
tall :
1
dwarf.
¼
will
be
tnemelppuS
A
If
test
you
allele
cross
look
is
at
not
the
last
two
expressed
in
crosses,
the
F
you
will
generation
see
but
that
is
the
recessive
expressed
in
the
F
1
generation.
plant
have
just
the
plant
This
by
means
looking
same
because
that
at
it
can
only
do
because
phenotype.
it
We
be
STUD
Y
2
we
not
know
plants
do
know
the
with
the
genotype
genotypes
genotype
of
of
TT
a
a
and
G en
e tic
Tt
shou
ld
dwarf
test
cross
whether
If
our
plant
it
tall
is
is
used
gives
heterozygous
half
tall
determine
homozygous
plant
(tt)
to
is
tall
plants
then
(Tt)
and
the
genotype
heterozygous
homozygous
all
(Tt),
plants
or
(T T),
(Tt).
crossing
half
If,
it
(see
then
an
individual
genetic
crossing
however,
with
dwarf
of
a
plants
our
dwarf
(tt)
in
it
diagrams
with
tall
a
the
unknown
tall
phenotype
plant
is
(tt)
ratio
of
nd
out
the
below).
squa
re
possib
le
be tw
een
includ
e
the
to
a
show
fusi
ons
gam
e tes.
is
will
give
1:1.
the
unknown
tall
plant
is
heterozygous:
homozygous:
×
tall
phenotype
tall
‘unknown’
Tt
dwarf
×
dwarf
tt
genotype
TT
‘unknown’
alwa
ys
dwarf
plant
plant
a
to
if
if
diag
ram
s
Punn
e tt
tt
all
A
TIP
tall
tt
genotype
genotypes
T
of
genotypes
t
t
gametes
T
t
of
gametes
t
gametes
t
gametes
T
Tt
genotypes
test
cross
Figure
offspring:
17.6.3
100%
diagrams
SUMMARY
QUESTIONS
1
Complete
these
inside
brackets.
the
(Tt)
like
100%
these
by
test
tall
show
the
ratios
expected
cross
in
the
offspring:
offspring,
50%
heterozygous
50%
homozygous
not
the
actual
choosing
the
correct
word
from
1
A
pea
plant
with
a
tall
(genotype/phenotype)
TT
or
could
A
tall
pea
plant
with
genotype
A
tall
pea
tall
50%
dwarf
offspring.
the
inheritance
inheritance
characteristic
height
TT
is
of
such
a
as
or
ower
colour.
Crossing
a
homozygous
tall
(homozygous/
with
a
homozygous
dominant.
dwarf
c
50%
have
plant
heterozygous)
( tt)
Tt.
2
b
of
Monohybrid
involves
(genotype/phenotype)
(Tt)
recessive
POINTS
plant
the
phenotypes
numbers
single
a
Tt
genotypes
KEY
sentences
tt
T
phenotypes
heterozygous
Genetic
t
plant
with
genotype
Tt
is
plant
produces
all
(homozygous/
heterozygous
tall
plants.
heterozygous).
3
d
A
dwarf
pea
plant
heterozygous)
2
Fruit
a
ies
have
Using
the
a
with
genotype
tt
is
gene
that
symbols
State
for
the
this
Give
W
determines
=
long
the
wing
length
and
w
=
of
their
short
wings.
gives
tall
plants
to
(3:1
genotype
of
a
fruit
y
which
is
genotypes
heterozygous
Crossing
plant
its
tall
A
fruit
which
to
y
is
heterozygous
homozygous
predict
the
ratio
of
3
for
for
wing
short
proportions
of
plant
a
heterozygous
with
a
plant
plant
tall
homozygous
gives
to
1
a
ratio
dwarf
of
plant
gametes.
(1:1
b
a
dwarf
ratio).
dwarf
of
1
wing:
characteristic.
the
heterozygous
plants
1
ii
two
tall
recessive.
4
i
Crossing
(homozygous/
length
wing.
each
is
Use
wing
mated
a
with
genetic
type
in
ratio).
one
diagram
their
offspring.
225
17.7
Codominance
tnemelppuS
Codominance
LEARNING
OUTCOMES
Up
•
Explain
the
term
to
either
•
Describe
the
now
the
inheritance
dominant
blood
or
we
have
recessive.
looked
The
at
recessive
involve
allele
is
alleles
not
that
are
expressed
in
the
of
phenotype
ABO
examples
codominance
of
individuals
with
the
heterozygous
genotype.
Sometimes,
groups
however
,
both
So
alleles
the
are
expressed
phenotype
is
a
and
neither
mixture
of
the
is
dominant.
effects
of
each
allele.
×
parental
This
condition
is
known
as
codominance
and
the
alleles
phenotype
are
called
can
R
parental
C
R
W
C
C
have
codominant
red
owers
alleles.
or
The
white
four
owers.
o’clock
Flower
plant
colour
is
W
C
determined
by
one
gene.
However,
if
you
cross
homozygous
genotype
red-owered
F
plants
with
homozygous
white-owered
phenotype
1
×
all
pink
plants,
the
offspring
are
all
pink.
The
two
parents
produce
flowers
heterozygous
offspring
(the
F
generation)
in
which
both
1
alleles
R
F
genotype
C
1
W
R
C
C
are
R
W
pink
–
an
intermediate
colour.
can
see
are
in
Figure
pollinated
17.7.1
what
amongst
happens
themselves.
when
There
the
are
pink
red-,
W
C
C
give
W
plants
R
to
C
You
C
expressed
C
pink-
and
white-owered
plants
in
the
F
generation
in
a
2
ratio
the
the
Notice
R
W
C
:
50%
phenotypes
when
C
C
C
25%
is
:
25%
the
or
same
1:2:1.
as
the
Notice
ratio
W
W
C
C
of
alleles
also
that
are
R
C
R
R
C
C
genotypes
generation:
of
genotypes
each
allele
is
represented
as
a
capital
letter,
W
red
ower
neither
W
=
allele
is
C
W
and
white
recessive
and
ower
that
=
they
C
.
This
both
shows
exert
an
that
equal
C
effect
F
ratio
codominant.
R
C
the
the
C
so
R
that
W
R
gametes
of
on
the
phenotype.
phenotypes
2
R
25%
homozygous
C
R
C
R
50%
heterozygous
25%
homozygous
C
W
C
25%
red
50%
pink
25%
white
W
C
Multiple
So
Figure
alleles
W
C
far,
we
have
looked
at
examples
where
a
gene
has
only
17.7.1
two
alternative
may
The
four
have
groups
of
alleles.
three
the
or
There
more
are
examples
where
blood
group
determined
human
by
system
one
gene,
I,
A
different
alleles:
I
B
I
O
and
I
I
A
O
I
B
A
I
A
B
I
B
I
B
O
I
B
A
A
The
alleles
I
B
and
I
I
are
B
I
O
I
codominant
slightly
and
different
code
group
A
I
A
three
Blood
are
I
with
gene
alleles.
Genotype
ABO
a
AB
O
I
O
for
molecules
on
O
the
surface
A
I
and
the
four
different
groups
I
at
group.
of
and
anti-sera
anti-sera
clump
the
A
226
A
A
together
or
B
(blue),
and
if
B
the
molecules
anti-sera
(white).
anti-sera
on
their
B
Red
blood
reacts
cells
with
surfaces.
blood
does
table.
Remember
tested
(yellow)
and
the
diploid.
with
red
cells.
The
allele
I
is
recessive
to
both
B
Look
Blood
of
not
You
any
code
can
for
see
person
one
the
can
of
these
possible
only
molecules.
genotypes
have
two
for
alleles
each
as
we
blood
are
all
phenotype:
parental
genotype:
blood
A
I
group
blood
group
O
B
I
I
A
gametes
×
AB
parental
phenotype:
parental
genotype:
A
O
I
blood
O
I
B
I
O
I
group
blood
×
O
I
O
I
B
I
A
Figure
Look
and
at
O.
B
O
O
I
A
I
I
phenotype
O
1
blood
group
A
1
blood
group
B
O
I
A
I
I
B
I
ratio:
O
I
I
B
O
I
A
I
I
phenotype
the
genetic
The
the
diagrams.
children
same
parents
all
will
have
T
wo
parents
blood
have
groups
A
blood
or
B.
groups
None
of
STUD
Y
AB
them
blood
have
four
group
blood
blood
as
their
A
1
blood
group
B
1
blood
group
AB
1
blood
group
O
TIP
ABO
parents.
groups
A
and
B.
They
could
have
blood
is
an
groups
–
A,
B,
AB
and
grou
p
exam
ple
children
and
O.
Y
ou
SUMMARY
can
QUESTIONS
aske
d
in
There
are
varieties
results
in
group
will
discon
tinuo
us
1
blood
O
I
codo
min
ance
with
ratio:
1
17.7.2
syst
em
T
wo
O
I
A
I
T
he
have
O
I
I
B
I
O
I
I
B
I
B
I
O
gametes
group
B
I
A
gametes
I
A
tnemelppuS
parental
the
red-owered,
of
of
the
a
four
o’clock
number
table.
white-owered
of
Explain
plant
crosses
the
of
of
the
each
plants
pink-owered
photo
between
results
number
(see
and
on
right).
varieties
the
expect
abou
t
sam
e
of
also
of
varia
tion.
to
bo th
be
to pics
ques
tion.
The
are
shown
cross.
of
each
colour
crosses
red
×
pink
white
red
×
pink
2
Use
of
a
The
of
126
131
pink
39
and
diagram
as
coat
If
white
a
83
work
the
mother
of
codominance.
known
to
where
the
inheritance
homozygous
88
115
offspring
A
white
92
pink
genetic
the
pink
white
×
group
3
×
red
out
father
is
blood
colour
in
all
the
possible
blood
heterozygous
group
some
homozygous
bull,
the
is
43
red
calves
for
groups
blood
O.
cattle
cow
have
is
is
an
example
crossed
coats
with
with
a
allele
causes
Flowers
R
W
causes
white
hairs.
red
hairs
to
be
Heterozygous
produced
cattle
have
and
the
coats
allele
the
that
are
KEY
of
of
red
genetic
the
o’clock
plant.
and
white
hairs
giving
POINTS
a
Codominance
diagrams
offspring
in
to
the
show
the
following
a
a
roan
bull
and
a
roan
cow
b
a
roan
bull
and
a
red
c
a
roan
bull
and
a
white
cow
occurs
when
roan.
both
Use
four
R
1
mixture
of
‘roan’.
R
The
a
colour
genotypes
and
the
phenotypes
alleles
2
The
over
as
neither
the
other.
inheritance
groups
A
I
expressed
phenotype,
dominant
crosses:
are
involves
B
I
of
ABO
three
in
is
blood
alleles:
o
and
I
cow
227
17.8
Sex
Sex
LEARNING
Describe
how
sex
is
inherited
in
chromosomes
46
chromosomes
Dene
a
and
which
these
sex
occur
in
you
23
are.
In
pairs.
humans
In
there
females
all
46
humans
chromosomes
•
determine
determined
are
and
determination
OUTCOMES
Y
our
•
linkage
can
be
matched
together
into
pairs.
This
is
done
by
taking
sex-linked
images
of
the
chromosomes
and
matching
them
for
size
and
shape.
characteristic
In
•
Describe
an
•
colour
example
Use
of
genetic
blindness
sex
the
the
results
of
and
have
sex
X
Figure
the
the
you
sex
egg
an
X
can
of
and
a
are
have
Y
not
two
alike.
X
These
are
chromosomes
known
and
chromosome.
see
how
individuals.
sex
chromosomes
Remember
that
in
the
the
gametes
number
of
cells
contain
fertilisation,
of
and
Sex
As
XX
the
diploid
in
meiosis
so
each
gamete
can
have
only
one
egg
is
chromosome.
of
may
with
there
child
X
half
fuse
with
the
an
being
the
X
a
with
Y
Half
sperm
female
either
chance
or
the
a
of
sperm
Y
contain
chromosome.
with
Since
and
the
a
sperm
chromosome.
chromosome
equal
of
contain
sperm
zygote
an
there
X
are
with
equal
the
inheriting
Y
XX
or
male.
inheritance
you
can
see
is
in
the
very
electron
small
micrograph
and
much
opposite,
smaller
than
the
the
X.
Y
Therefore
cell
the
testis
in
sperm
sperm
chromosome
cell
a
an
and
the
or
chromosome,
XY
halved
chromosomes.
chromosome
numbers
XY
is
sex
chromosome
Y
chromosome
has
far
fewer
genes
than
the
other
chromosomes
ovar y
and
the
has
X
chromosome
17.8.1
two
All
At
Gametes:
that
Females
linkage
of
in
chromosomes
crosses
chromosomes
diploid
two
chromosomes.
an
determine
involving
are
Y
to
In
predict
there
X
males
linkage
diagrams
males
as
as
far
fewer
than
development
mutated)
the
of
then
X.
One
testes
the
in
body
gene
the
on
the
embryo.
that
Y
If
develops
chromosome
it
is
is
not
stimulates
present
(or
if
it
female.
Y
Sex
all
X
eggs
have
of
an
chromosome,
X
50%
sperm
have
a
linkage
an
chromosome
The
50%
tnemelppuS
X
genes
that
are
located
on
the
X
chromosome
are
described
as
have
Y
sex-linked
even
gender
controlling
or
though
they
have
sexual
nothing
to
characteristics.
do
with
Among
determining
the
genes
on
the
X
X
chromosome
are
genes
involved
with
controlling
vision
and
blood
clotting.
X
50%
XX
female
Males
if
any
only
of
have
them
one
are
copy
of
recessive,
the
then
genes
the
that
effect
are
on
will
be
X
chromosomes,
seen.
Because
Y
women
50%
XY
male
linked
have
common
Figure
17.8.1
The
diagram
shows
X
and
Y
.
only
Do
not
of
the
forget
sex
(egg
and
that
sperm)
each
of
contain
to
give
the
228
than
in
this
girls.
is
they
why
T
wo
are
less
affected
sex-linked
examples
are
by
sex-
conditions
discussed
are
more
here.
blindness
haploid
of
the
genes
on
the
X
chromosome
controls
the
ability
to
see
known
as
cones,
red
other
number
green
colours.
The
gene
works
in
the
receptors,
of
in
23.
boys
and
the
22
and
chromosomes
chromosomes
chromosomes,
One
gametes
in
X
alleles
the
Colour
inheritance
two
recessive
the
retina
of
the
eye.
There
is
an
allele
of
this
gene
which
does
not
tnemelppuS
produce
so
any
protein
girl
vision.
the
a
or
woman
Males
allele
r
necessary
only
they
who
have
will
is
one
be
for
colour
vision.
heterozygous,
X
Rr,
chromosome
colour
The
so
allele
has
if
is
recessive,
normal
they
have
colour
inherited
blind.
colour-blind
normal-sighted
×
parents
male
female
r
R
X
R
X
X
Y
meiosis
meiosis
r
R
gametes
X
X
Y
Figure
r
gametes
17.8.2
What
can
cannot
see
familiar
r
R
R
X
X
you
Figure
1
female
carrier
:
1
If
you
something
then
you
may
have
R
X
X
Y
red-green
ratio:
see?
Y
X
normal-sighted
colour
blindness.
male
17.8.3
carrier
normal-sighted
parents
×
female
male
r
R
X
R
X
X
Y
meiosis
meiosis
r
R
gametes
X
R
X
X
Y
R
gametes
Y
X
r
X
X
X
X
R
R
X
r
r
R
X
Y
R
R
Y
X
X
An
F
X
chromosome
on
the
left
and
a
Y
ratio:
1
chromosome
normal-sighted
female
:
1
carrier
female
:
1
normal-sighted
male
:
1
colour-blind
electron
17.8.3
shows
what
to
expect
if
the
mother
is
and
the
father
is
colour
blind.
Notice
POINTS
that
none
of
Sex
is
determined
children
can
expect
to
be
colour
blind,
but
the
girls
will
inherit
colour
have
this
blindness
allele,
but
on
it
the
does
X
chromosome
not
affect
their
from
their
who
are
heterozygous
are
carriers
of
phenotype.
colour
XY
and
females
17.8.4
shows
what
to
expect
if
the
mother
has
normal
colour
vision.
In
this
case,
there
sex
Males
XX.
Any
A
sex-linked
is
one
in
characteristic
which
is
a
carrier
is
a
1
and
is
in
4
the
gene
located
on
a
sex
the
chromosome,
father
Y
.
blindness.
responsible
Figure
the
and
father.
2
females
X
the
are
for
by
the
chromosomes,
They
in
microscope.
homozygous
1
dominant
allele
photographed
17.8.4
KEY
Figure
right,
male
an
Figure
the
usually
the
X
chance
chromosome.
that
1
in
one
2
of
the
chance
children
that
any
will
boy
be
will
colour
be
blind.
colour
Note
that
there
is
a
blind.
3
Males
have
only
chromosome
SUMMARY
QUESTIONS
are
in
tnemelppuS
1
Explain
how
2
Explain
the
sex
is
determined
in
a
sex
linkage
b
terms:
carrier
males
Females
linked
c
likely
than
to
in
X
re-issue
be
alleles
expressed
females.
humans.
4
following
more
one
so
colour
blindness
green
are
carriers
disorders,
colour
of
such
sex-
as
red-
blindness.
229
tnemelppuS
1
on
PRACTICE
1
Which
QUESTIONS
explains
occurring
in
a
the
life
advantage
of
6
meiosis
The
of
cycle?
cell
A
meiosis
allows
sexual
reproduction
Indian
6.
How
and
muntjac
many
in
a
deer
has
a
diploid
chromosomes
sperm
cell
of
this
are
number
there
species
of
in
a
skin
deer?
to
occur
skin
B
meiosis
as
four
times
C
meiosis
produces
haploid
D
meiosis
produces
sperm
A
many
A
6
6
B
12
6
and
C
6
3
D
3
6
eggs
discover
that
they
albinism
in
are
both
which
skin
carriers
of
not
made.
What
is
the
probability
(Paper
2)
child
will
A
0%
B
25%
C
50%
D
100%
(Paper
have
this
that
Which
feature
inuenced
controlled
by
the
only
by
a
gene
and
environment?
condition?
1)
A
blood
group
B
concentration
C
heart
D
lung
of
glucose
in
the
blood
disease
cancer
(Paper
2)
[1]
Which
describes
[1]
recessive
causes
the
genetic
code?
allele:
A
A
is
their
8
A
[1]
pigment
not
3
cell
[1]
condition
rst
sperm
gametes
7
is
cell
cells
1)
couple
the
as
mitosis
(Paper
2
produces
a
harmful
the
four
different
bases
that
are
found
in
feature
DNA
B
is
never
C
is
not
expressed
in
the
phenotype
B
expressed
when
in
a
genotype
the
in
a
D
dominant
produces
mRNA
a
cell
that
is
that
making
leave
the
nucleus
proteins
allele
the
homozygous
same
as
phenotype
when
C
the
sequence
D
the
triplet
of
bases
in
a
gene
when
of
bases
in
DNA
and
RNA
that
heterozygous
code
(Paper
molecules
with
1)
for
the
different
amino
acids
in
[1]
proteins
4
Which
is
meiosis
involved
with?
(Paper
A
asexual
reproduction
B
growth
of
C
production
9
stems
of
and
egg
2)
(a)
Dene
(b)
Explain
[1]
the
repair
(Paper
5
A
man
not
sons
normal
colour
blind.
will
be
A
25%
B
50%
C
75%
D
100%
(Paper
230
[1]
has
2)
[2]
the
difference
pairs
of
between
the
terms:
tissues
1)
have
colour
of
inheritance.
cells
following
D
term
roots
colour
vision.
blindness
What
colour
is
the
but
His
her
wife
father
probability
that
does
is
their
blind?
[1]
(i)
genotype
and
(ii)
gene
allele
(Paper
3)
and
phenotype
[2]
[2]
10
Brachydactyly
is
which
with
people
ngers
drawn
and
for
a
toes.
this
rare
genetic
the
A
rare
condition
condition
pedigree
have
diagram
in
(a)
short
Use
genetic
was
patterns
condition:
(i)
without
female
with
the
condition
(ii)
the
in
following
Key
female
diagrams
proportions
of
cats
the
to
predict
with
next
the
different
generation
coat
in
the
crosses:
homozygous
dominant
homozygous
recessive,
heterozygous
×
×
[4]
homozygous
condition
recessive.
male
without
male
with
the
(b)
the
[4]
condition
condition
Explain
why
genotype
(c)
stripes,
but
Explain
why
with
Use
is
a
not
with
the
possible
tabby
one
male
blotched
kitten
(d)
it
of
cat
with
and
stripes
parallel
example
to
state
with
parallel
female
cannot
the
blotched
stripes. [3]
tabby
cats
produce
a
stripes.
of
[2]
inheritance
in
this
3
question
to
explain
the
terms
gene
and
allele.
11
12
13
14
(Paper
15
12
(a)
(i)
State
whether
brachydactyly
is
(a)
a
dominant
or
a
recessive
3)
Explain
allele.
nd
Give
evidence
from
the
family
the
you
would
genotype
use
of
an
a
test
cross
organism
that
[1]
could
(ii)
how
caused
to
by
[3]
either
be
homozygous
dominant
or
tree
heterozygous.
that
supports
your
answer
to
part
The
Refer
to
the
people
shown
in
the
four
numbers.
red-owered
What
are
the
chances
of
parents
3
and
another
child
with
this
a
genetic
diagram
to
explain
When
these
have
(i)
pink
Explain
(ii)
[3]
Show,
the
In
is
has
are
cross-bred
the
owers.
why
by
this
is
so.
[3]
means
result
of
of
cross
a
genetic
breeding
diagram,
the
pink-
3)
owered
11
jalapa,
white-owered
your
answer.
(Paper
a
condition?
(b)
Draw
Mirabilis
and
4
offspring
having
plant,
variety
[3]
variety.
(b)
o’clock
tree
a
by
[3]
(i).
tabby
cats
controlled
stripes
(T)
blotched
is
the
by
pattern
a
gene.
dominant
of
The
to
stripes
allele
the
in
for
allele
the
coat
parallel
(t)
pattern.
for
a
(c)
Plants
plants
with
64
of
(i)
(ii)
genetic
why
owered
(Paper
parallel
of
the
were
The
When
pink
crossed
seeds
they
[5]
with
were
owered,
variety
and
diagram
to
78
explain
results.
Explain
in
owers
owers.
themselves.
variety.
a
these
among
grown.
were
red
Use
red
and
plants
the
pink
with
collected
plants
this
there
plants
cross.
[5]
were
among
no
white-
the
offspring
[3]
4)
blotched
231
18
Variation
18.1
and
Variation
T
ypes
LEARNING
Distinguish
between
variation
humans
and
have
many
features
in
common
as
we
are
all
members
of
the
genetic
same
variation
of
OUTCOMES
All
•
selection
species.
Now
think
about
the
similarities
and
differences
between
phenotypic
ourselves
and
monkeys
and
apes.
We
have
many
features
in
common,
variation
but
•
State
the
differences
there
and
signicant
differences
species.
Biology,
which
we
use
to
categorise
animals
between
into
continuous
are
different
In
the
term
variation
means:
discontinuous
•
differences
between
•
differences
It
is
species
–
we
use
these
when
constructing
keys
variation
•
Identify
of
and
explain
variation
differences
tnemelppuS
Although
•
State
that
a
species.
we
within
all
a
belong
species
to
the
that
we
same
are
concerned
species,
there
are
with
in
many
this
unit.
differences
discontinuous
between
variation
within
examples
is
caused
by
us
–
even
between
identical
twins.
Some
people
are
taller
genes
or
heavier
,
others
have
different
coloured
hair
,
skin
and
eyes.
There
is
alone
considerable
Variation
that
the
we
occurs
cannot
different
examples
As
we
of
have
Individuals
alleles
the
of
all
one
we
show
a
lot
of
variation,
we
seen
have
these
but
of
in
two
that
continuous
•
discontinuous
of
of
we
the
can
same
see,
equipment
that
people
species.
but
to
also
in
detect,
have.
features
such
These
are
as
all
variation.
17,
variation
genotypes
they
between
•
that
specialist
haemoglobin
Unit
types
individuals
features
use
different
genes
the
have
also
–
exists
different
inherited.
genotypes
phenotypic
of
at
the
genetic
combinations
Genetic
level.
of
variation
is
individuals.
variation
within
a
species:
variation
variation.
are
species.
Continuous
If
you
nd
)slaudividni
divide
mean
the
of
the
fo
.on(
This
ycneuqerf
is
into
heights
of
of
heights
groups
a
2
0
0
–
2
0
9
9
9
1
9
0
–
1
8
9
1
8
0
–
1
1
7
0
–
1
7
9
6
9
1
6
0
–
1
1
5
0
–
1
5
9
9
1
4
0
–
1
4
3
9
1
3
0
–
1
2
9
1
2
0
–
1
of
16
year
olds
/
their
all
the
from
pupils
the
(170 cm
to
in
your
shortest
179 cm,
to
year
the
etc.)
group
tallest.
you
can
If
you
you
plot
to
histograms
present
continuous
of
is
range
take
your
to
called
of
the
and
the
mean
group
called
a
from
your
quality
of
your
different
the
normal
shortest
the
and
you
this
in
a
the
middle
number
of
distribution.
to
Also
be
largest
because
tallest.
height.
food
height.
will
variation
overall
ages
height
with
continuous
to
inuence
at
is
heights
contribute
spurts
from
that
distribution
quantity
growth
get
likely
correspond
that
you
is
But
eat
will
There
other
and
people
there
the
go
are
factors
amount
through
inuence
the
results
class.
cm
data
variation.
features
that
you
can
measure
also
show
this
type
of
variation.
are
T
ry
drawn
the
It
variation
genes
as
Other
Frequency
type
of
exercise
you
and
continuous
such
of
histogram.
This
type
many
18.1.1
the
range
class
range
people.
Figure
a
height
frequency
height
variation
measured
would
232
between
phenotypic
the
are
in
see
types
differences
There
Although
variation
measuring
the
length
of
your
index
nger
or
your
hand
span.
Y
ou
on
collect
data
from
the
whole
class
and
plot
as
frequency
histograms.
can
Continuous
lengths
of
clear
stems
extremes
divisions
with
you
many
between
the
plants.
will
You
get
can
the
measure
same
intermediates
in
results
the
–
between.
a
35
range
There
30
intermediates.
variation
eht
Discontinuous
and
in
egatnecerP
no
two
or
occurs
fo
are
leaves
also
noitalupop
between
variation
25
20
15
10
5
Some
people
have
attached
ear
lobes.
Other
people’s
ear
lobes
are
free
0
and
In
not
this
(e.g.
If
attached.
type
of
collect
is
variation
attached
you
This
and
data
not
an
example
there
is
usually
attached
about
a
of
ear
feature
discontinuous
variation.
a
of
small
lobes)
number
and
showing
no
this
A
intermediates.
type
of
Figure
plot
it
as
a
bar
chart
(see
question
11
on
page
18.1.2
percentage
variation,
groups
you
B
(A,
of
B,
This
bar
people
AB
and
O
AB
Blood
phenotypes
group
chart
with
O)
the
in
shows
four
the
blood
Maharashtra,
243).
tnemelppuS
India.
Discontinuous
environment
example.
O.
There
owers
variation
has
Everyone
are
of
no
twins
identical.
will
have
womb
an
ABO
they
about
have
been
are
up
often
show
alone
blood
blood
Some
the
–
it
owering
This
and
group
group
same
different
they
exposed
separated
genes
colours.
because
twins
by
ABO
is
the
system
is
either
plant
is
another
A,
B,
species
another
AB
or
have
example.
environment
from
Identical
apart
The
different
versus
However
,
and
caused
intermediates.
develop
come
is
effect.
has
distinctly
Inheritance
Identical
no
at
to
birth,
striking
embryo
in
many
or
genetically
These
slightly
afterwards,
These
are
differences
differently
environmental
shortly
similarities.
are
ways.
developed
different
and
and
often
in
the
inuences.
to
These
plantlets
Mexican
hat
grow
plant.
The
The
effect
It
shows
You
under
the
environmental
shows
reproduces
leaves.
them
of
of
photograph
plant.
its
which
can
the
factors
plant
asexually
detach
different
environmental
inuence
to
these
that
can
be
and
lots
grow
Any
have
on
investigated
sometimes
make
conditions.
genes
called
of
tiny
them
variation
the
do
with
shown
all
and
will
Whe
n
plants.
the
identical.
TIP
hat
are
around
used
you
keep
be
the
word
s
‘distin
guis
h
in
need
factors.
thin
gs.
to
POINTS
to
the
ques
tion,
give
the
be tw
een
Here
aske
d
be tw
een
be tw
een’
a
differ
ence
s
because
be
KEY
of
with
Mexican
pots
leaves
genetically
us.
plantlets
in
the
are
brought
STUD
Y
personality,
on
They
you
two
could
distin
guis
h
two
type
s
of
varia
tion.
1
Variation
is
the
difference
between
individuals
of
the
same
species.
2
Genetic
variation
individuals;
and
is
the
phenotypic
internal
differences
in
variation
the
is
the
genotypes
differences
of
in
external
SUMMARY
appearance.
1
3
Continuous
resulting
in
variation
a
range
is
of
inuenced
by
phenotypes,
genes
e.g.
and
height
the
in
Distinguish
between
continuous
and
environment
Discontinuous
phenotypes
variation
with
no
results
in
a
small
number
tnemelppuS
Discontinuous
blood
groups.
and
examples
of
of
give
three
each.
intermediates.
2
5
discontinuous
humans.
variation
4
QUESTIONS
variation
is
cause
by
genes
alone,
e.g.
human
Describe
how
investigate
you
the
environmental
growth
share
of
the
would
effect
factor
plants
same
that
of
an
on
the
all
genotype.
233
18.2
Mutations
A
mutation
change
•
Dene
•
State
the
term
the
mutation
in
base
a
way
in
mutation
which
new
is
Describe
alleles
Gene
the
possible
effects
the
and
certain
rate
of
are
tnemelppuS
Describe
an
•
that
condition
gives
of
the
of
cell
anaemia
as
of
the
of
heterozygous
sickle
to
cell
to
a
rst
trait
malaria
A
similar
the
skin,
eyes
is
They
to
versus
white
the
Often
and
red,
chromosome
A
this
some
gene
that
mutation
change
have
studied
but
a
red
may
no
can
effect
be
at
is
a
cause
change
a
harmful,
but
in
some
all.
was
in
mutant
the
fruit
form
y.
with
The
white
normal
eyes
eye
was
of
colour
the
gene
had
no
changed.
longer
This
coded
was
for
due
the
albinos.
It
is
The
a
cell
gene
gene
anaemia
is
and
are
an
the
production
protects
mutate
allele
mutations
controls
which
can
recessive
Gene
Sickle
A
melanin,
to
a
the
form
skin
that
homozygous
cause
of
of
and
does
recessive
many
human
example.
mutations
are
by
the
the
before
rate
radiation
gamma
only
damage
occurs
but
and
in
light.
albino.
caused
that
eye
that
pigment
melanin.
are
so
pigment.
eye
ultra-violet
ionising
X-rays
controlling
DNA
occurs
and
mutations
are
random,
colour
the
diseases.
process
eye
of
produce
Gene
gene
example
Causes
at
in
nuclear
or
by
occur
most
alleles
failure
They
is
chemicals.
the
new
a
division.
they
some
are
which
DNA
which
and
rays
way
to
in
are
the
occur
increased
The
naturally
by
Ultra-violet
damaging.
formed.
copying
at
exposure
radiation,
greater
the
(mutant).
dose
of
radiation,
cigarette
If
smoke
mutations
example
bombs
were
station
at
that
can
are
be
The
for
may
cell
is
at
cells
are
top
a
in
the
SCA
rate
like
which
can
or
than
if
long
–
may
as
it
fatal
This
Benzpyrene
is
the
in
(A
for
cells.
sickle
the
the
1986.
these
red
red
The
a
It
is
only
themselves,
mutations
the
have
blood
blood
at
the
red
tool
abnormal
cells
cells
sickle
anaemia.
blood
blood
These
C -shaped
cells
abnormal
causing
of
(SCA).
is
These
distorted
so
power
gametes
disease
anaemia
cereals.)
in
For
atomic
variation.
blood
destroys
cells,
or
cell
sickle.
the
nuclear
because
of
individual.
after
red
difcult
if
spleen
a
the
cells,
inherited
and
the
exploded
forms
sickle
of
grasses
blood
term.
affect
and
Union
normal
with
shape
mutation.
happened
1945
new
an
shows
the
in
Soviet
makes
red
they
gamete-forming
the
of
mutations.
cells
provide
prove
chance
cancers,
the
in
the
Japan
person
plants
vessels,
greater
in
to
in
in
and
the
from
of
body
anaemia
haemoglobin
blood
in
lead
occur
important
greater
cause
dropped
that
cutting
oxygen.
a
Chernobyl
blood
bottom
blood
is
inherited
Sickle
the
occur
they
mutations
234
DNA.
mutations
ies
in
hair
from
genetic
(normal)
A
change
individuals
Red
of
benecial
fruit
production
mutation
resistance
18.2.1
a
chemicals
not
Figure
or
mutations
sickle
example
State
gene
mutations
discovered.
•
a
of
colour
on
in
characteristic.
are
One
radiation
change
the
formed
•
a
phenotypic
sequence
mutations
that
is
OUTCOMES
to
carry
block
cells
at
a
tnemelppuS
LEARNING
is
a
genetic
disease
A
allele,
Hb
allele,
Hb
(or
H
S
two
from
a
gene
mutation.
The
normal
),
codes
for
normal
haemoglobin
and
the
SUMMARY
QUESTIONS
mutant
S
(or
alleles
have
resulting
A
H
are
both
),
codes
for
codominant
forms
of
an
so
abnormal
that
haemoglobin
form
people
in
their
of
who
red
haemoglobin.
are
The
1
a
Explain
a
heterozygous
blood
cells.
b
gene
Explain
what
how
mutation
Heterozygotes
of
the
SCA
the
disease
alleles
carry
called
puts
abnormal
oxygen
who
a
sickle
person
form
which
one
of
causes
SCA
cell
at
a
allele
trait.
great
a
Clearly,
selective
haemoglobin
severe
have
is
not
problems.
much
the
good
at
inherited
of
c
two
in
West,
Central
and
East
List
since
by
transporting
SCA
allele
common.
normal
is
This
and
common
is
because
abnormal
among
people
forms
of
problem
with
transport
of
disease
is
malaria
as
the
parasite
people
who
from
are
areas
where
heterozygous
haemoglobin
oxygen.
that
a
What
cells.
Figure
and
do
malaria
have
not
both
usually
is
b
18.2.2
that
of
alleles
them
The
are
are
link
have
But
causes
shows
of
one
shown
as
expressed
between
example
a
SCA
natural
in
that
four
for
in
they
this
do
have
disease
children
chance
of
codominance
the
red
body
There
is
a
strong
a
for
is
the
of
Explain
of
parents
blood
heterozygotes
(see
cells
enter
who
and
from
page
of
226),
to
is
a
selection
sickle
strong
normal
most
are
of
areas
pressure
against
cell
anaemia,
people
So
selection
allele,
where
for
badly
the
the
on
the
anaemia.
allele
is
commonly
people
who
in
live
certain
parts
of
Africa.
Note
since
both
people.
malaria
is
STUD
Y
an
TIP
who
are
in
allel
e
the
for
rst
SCA
place
S
H
H
,
because
they
could
arose
by
die
H
pressure
against
people
homozygous
for
gives
the
but
has
H
,
because
they
could
die
from
malaria
is
common,
there
from
sickle
malaria
is
heterozygous
cell
an
anaemia
allele
individuals,
and
remains
important
they
in
are
the
selective
H
is
a
now
strong
kille
r
selective
,
since
protected
population
they
from
in
do
diseas
e
×
areas
where
POINTS
normal
S
A
H
S
Mutation
is
H
gene
caused
base
Ionising
radiation
S
S
H
H
A
3
Sickle
A
A
H
H
50%
H
Figure
the
rate.
cell
anaemia
caused
by
is
a
an
genetic
allele
of
S
phenotypes
normal
H
4
gene
for
Individuals
haemoglobin.
haemoglobin,
no
resistance
to
malaria
with
heterozygous
SCA
in
condition
the
have
S
H
S
H
increase
some
A
A
25%
and
H
the
H
DNA.
S
H
disease
H
of
in
S
A
A
a
H
mutation
H
in
change
sequence
chemicals
H
a
S
A
S
change
by
H
H
H
a
S
H
A
H
gametes
25%
a
malar
ia.
malaria.
2
genotypes
–
not
the
A
of
agent
H
A
H
agai
nst
S
H
1
A
H
it
malaria.
KEY
normal
becaus
e
adva
ntag
e
A
A
advantage
suffer
cell
both
pro tec
tion
in
effects
selection.
A
But,
sickle
anaemia.
There
the
of
their
SCA.
heterozygous
resistance
the
why
increa
sed
•
cause
sickle
mut
ation,
from
caused
resistance
cannot
suffering
S
homozygous
genetic
are
have
T
he
•
human
that
Describe
the
in
heterozygous
increased.
anaemia?
groups
red
be
of
most
found
to
rate
Africa.
c
a
by
mutation.
cell
The
the
can
some
diseases
2
common
meant
form
possession
disadvantage,
very
This
milder
is
mutation
tnemelppuS
SCA
mixed
normal
and
abnormal
haemoglobin,
to
malaria
resistance
S
H
resistant
abnormal
haemoglobin,
sickle
cell
to
malaria.
anaemia
18.2.2
235
tnemelppuS
tnemelppuS
•
18.3
Adaptive
An
to
•
Dene
adaptive
the
term
survive
below
adaptive
on
feature
its
Interpret
images
or
seeds
about
a
species
its
adaptive
tnemelppuS
Explain
the
of
the
of
plants
adaptive
leaves,
to
stems
pond
The
examples
so
to
the
Arctic
fox
feathery
dispersed
by
they
grows
behavioural
as
and
and
together
to
that
are
features.
carried
has
a
by
the
The
helps
The
thistle
wind
attened,
three
an
organism
to
photographs
has
tufts
disperse
streamlined
them
body
of
rocks
so
it
is
not
washed
away.
and
In
winter,
white
fur
as
a
camouage.
Adaptive
features
keep
well
as
structural;
for
example,
penguins
huddle
Adaptive
features
warm.
roots
desert
an
individual’s
like
those
tness
in
which
reproducing
the
photographs
refers
and
to
its
having
are
chances
of
offspring.
likely
to
increase
surviving
These
in
its
offspring
are
tness
likely
The
feature
environment.
adaptive
nymph
underside
environment,
Dene
that
mayy
of
its
features
environments
•
inherited
in
features
are
•
an
to
the
describe
is
reproduce
other
clings
information
and
show
widely.
•
feature
OUTCOMES
tufts
the
of
thistle
seeds
are
A
mayy
does
wind.
not
to
show
larva
get
has
a
the
same
attened
washed
away
in
features.
body
so
The
it
Arctic
fox
has
to
endure
extreme
cold.
fast-owing
streams.
Pond
plants
Hydrophytes
in
water
.
Buoyed
plants
roots
The
for
it
Water
lilies,
Nymphaea
alba.
up
if
by
to
is
water
water
absorb
no
plants
energy
and
problem
are
to
through
respiration)
leaves
buoyancy
oxygen
to
and
air.
since
it
have
through
both
with
they
for
an
keep
is
ions,
that
or
since
there
partially
transport,
xylem
there
are
submerged
benets.
no
little
carbon
water
for
soluble
system
diffuse
plants
dioxide.
its
water
little
have
applies
very
gases
for
and
through
extensive
the
carbon
need
and
or
no
or
is
tissue.
no
root
no
oating
need
for
the
hairs.
cuticle,
since
water.
same
not
which
costs
produce
mineral
diffuses
is
its
hydrophytes
conserve
The
no
submerged
anchorage
or
of
grow
hydrophytes
photosynthesis,
does
has
since
water
for
that
and
stems
need
hydrophytes
236
in
present,
leaves
there
The
Living
save
Roots,
are
close
in
of
oxygen
water.
air
quickly.
to
the
dioxide,
much
Therefore
spaces
in
air
and
is
for
their
a
than
plant
many
stems
spaces
are
needed
slowly
(needed
These
light
which
more
and
provide
reservoir
of
tnemelppuS
LEARNING
features
tnemelppuS
Desert
All
adaptations
plants
have
important
Very
high
enough
water
is
desert
•
•
A
to
are
water
maintain
prevent
plants
Cacti
can
that
kill
are
water
in
a
water
their
plant
loss.
cells,
if
it
or
It
is
they
cannot
will
wilt.
absorb
wilting.
able
xerophytes
reduce
with
turgor
long-term
are
are
uptake
the
transpiration
Cacti
regions.
Their
the
of
scarce.
following
balance
they
rates
Xerophytes
water
to
that
to
that
loss
exist
in
conditions
survive
in
hot,
and
conserve
dry
water
where
(arid)
in
the
ways:
leaves
leaf
are
over
thick,
reduced
which
waxy
to
water
cuticle
spines.
can
covers
be
the
This
reduces
the
surface
area
of
Cacti
store
water
in
their
swollen
stems.
lost.
plant’s
surfaces
and
reduces
transpiration.
•
They
have
swollen
•
They
have
a
•
Many
area
from
cacti
so
•
They
•
Their
shallow,
rain
have
is
open
a
their
overnight
round,
less
shiny
stomata
spreading
and
have
there
stomata
at
root
to
to
tissue.
quickly
which
which
reect
during
night
system
shape
through
which
closed
water-storage
absorb
any
condensation.
compact
surface
surfaces
are
containing
the
heat
day
absorb
reduces
water
to
the
and
can
be
their
surface
lost.
light.
reduce
carbon
water
loss.
dioxide
They
which
Spines
they
store
for
use
in
photosynthesis
during
the
day.
from
occurs
in
the
outer
layers
of
cells
in
their
provide
Research
a
b
an
how
the
following
animals
are
adapted
to
extreme
POINTS
camel
to
desert
Arctic
fox
to
An
adaptive
and
helps
feature
an
survive
and
Fitness
is
tnemelppuS
a
list
of
four
arctic
conditions.
an
the
organism
ways
in
which
desert
plants
are
able
water
loss
and
conserve
probability
surviving
Explain
each
of
the
following
statements
about
pond
They
need
little
xylem
in
Pond
their
stems
and
Their
c
They
roots
have
stems
and
do
an
not
have
extensive
plants
root
hairs.
system
of
They
air
Freshwater
spaces
inside
to
their
are
higher
stems
water
and
plants
potential
are
than
surrounded
the
cell
sap
in
store
by
a
the
solution
cells
of
of
carbon
in
how
4
their
Desert
have
this
is
an
advantage
to
the
maintenance
in
the
plants
What
Ions
prevents
in
the
these
water
mechanism
dioxide
diffuse
spaces
and
very
such
as
cuticles,
to
spines,
cacti
leaves
swollen
to
store
water
and
cells.
cells
from
by
are
which
at
a
very
these
root
systems.
Often
bursting?
their
c
water.
air
of
extensive
b
since
in
water.
thick
stems
turgor
up
a
leaves.
Explain
need
tissue
extensive
which
reduced
a
not
buoyed
have
oxygen
roots.
aquatic
do
transport
slowly
4
and
offspring.
leaves.
they
b
its
reproducing
plants.
much
a
in
of
water.
3
3
to
to
having
reduce
inherited
reproduce.
environment,
Make
is
organism
conditions
2
2
protection
QUESTIONS
conditions:
a
and
stems.
1
1
shade
herbivores.
KEY
SUMMARY
some
Photosynthesis
low
ions
concentration.
are
taken
up
by
State
plants.
the
the
stomata
day
dioxide
and
at
close
absorb
during
carbon
night.
237
tnemelppuS
water
stems
18.4
Natural
Natural
LEARNING
selection
tnemelppuS
•
Describe
natural
•
Describe
evolution
pass
selection
well
•
adaptive
Dene
the
as
features
process
the
over
of
on
to
their
Variation
the
in
a
which
An
to
term
give
example
two
alleles
a
organisms
greater
that
generation
be
chance
than
summarised
to
are
well
those
as
breed
that
and
are
less
follows.
to
of
describe
organisms.
new
genetic
advantage
having
good
is
to
all
the
Gene
differences
mutation
material
the
is
produced
to
by
that
the
produced.
individual
camouage
also
is
that
avoid
sexual
only
Some
expresses
being
seen
reproduction
individuals.
the
from
alleles
in
the
the
two
Gene
between
of
different
gametes.
different
in
are
‘shufed’
fertilisation,
individuals
mutation,
individuals
genes
At
meiosis
every
are
and
when
to
the
combined
fertilisation
give
gametes
within
give
rise
generation.
man.
Over-population
of
These
return
sockeye
same
in
15 000
eggs
fairly
salmon
Colombia
produce
where
millions
other
seeds
and
a
(see
eggs
hatch
starvation.
may
land
from
the
places
the
of
spite
of
Pacic
in
a
of
are
poppy
this
animal
Ocean
order
which
example
in
to
rivers
breed.
fertilised.
plant
huge
and
to
The
We
releases
in
females
see
over-production
plant
species
the
over
of
remain
254).
stable
are
because,
eaten
eggs.
Similarly,
in
Yet,
from
hatched
many
for
page
remain
the
they
populations
most
of
offspring
eggs,
year.
seeds,
stable
of
species,
Populations
that
the
young
poppy
they
in
predators
Many
many
where
by
seeds
cannot
case
as
of
are
salmon
may
grow
sockeye
many
be
as
die
of
from
eaten
there
by
is
salmon,
the
young
disease
birds;
no
soil
and
others
or
salmon.
water
.
Production
enough
offspring
population
from
Among
the
and
gnu.
a
hyaena
compete
for
food
from
large
for
and
nutrients.
and
mates.
for
numbers
into
of
eggs
early
and
stages
seeds
of
life
ensures
to
that
maintain
the
year
.
that
resources.
is
the
resources
Animals
This
or
it
to
organisms
competition
existence’
of
make
year
Competition
238
may
variation
nucleus.
variation
an
is
But
meiosis,
same
British
dead
next
used
completely
may
combinations
fuse,
a
which
populations
populations
predator.
new
the
is
within
During
young
the
process
within
between
a
The
to
Variation
by
Vultures
by
have
adaptation
them.
as
alleles
adapted.
mutations
Sockeye
process
environment
time
way
Darwin
their
change
exist
Charles
the
OUTCOMES
adapted
in
is
selection
survive
Plants
compete
referred
‘struggle
to
for
by
the
early
compete
for
food,
biologists
survival’
stages
for
water,
as
(see
of
space,
the
page
life
there
light,
space
(territories)
‘struggle
255).
is
water
for
Competition
have
the
ercest
same
between
adaptive
individuals
features
to
of
the
obtain
same
their
species
resources
KEY
as
from
1
the
environment.
Individuals
of
different
species
also
POINTS
compete,
There
is
variation
individuals
often
feed
the
at
competition
night
different
and
foods
the
in
is
not
other
their
as
erce.
during
For
the
example,
day,
or
one
they
species
have
individuals
slightly
2
diets.
3
with
features
that
adapt
them
to
the
conditions
There
is
environment
are
those
most
likely
to
survive
and
that
competition
to
are
for
reproduce
not
so
well
resources.
or,
if
they
adapted
individuals
the
generation.
They
do
have
adapted
may
die
reproduce,
a
greater
are
likely
before
have
chance
out
have
a
offspring.
pass
on
and
disease.
individuals
than
others
and
in
tnemelppuS
the
environment
already
of
does
not
organisms
well
are
their
their
better
new
adapted
unlikely
to
individuals
conditions
that
are
now
pass
on
their
alleles
Explain
over
the
a
an
are
change,
so
to
they
their
survive
with
at
better
do
then
not
natural
change
environment.
to
breed.
an
features
that
advantage
adapted,
alleles.
time.
idea
process
their
of
terms
natural
variation,
over-
selection
much,
Any
as
that
maintains
not
When
the
struggle
survival,
help
over
compete
them
others.
Natural
selection
bring
Thus
selection
is
the
rst
proposed
by
to
survive
These
Darwin
of
adaptation
whereby
populations
environment
over
environment.
a
Antibiotics
are
prescribed
in
bacterial
by
in
diseases.
the
Explain
why
to
all
people
are
told
individuals
survive,
about
mechanism
Charles
to
well
environment
successfully,
will
for
adaptation
many
are
competition,
breed
take
a
change
which
1859.
become
the
antibiotics
and
to
they
are
given
rather
a
stopping
when
they
evolution
better
.
Evolution
more
Why
do
drug
companies
suited
invest
to
alleles
production,
b
is
following
context
feel
–
to
their
QUESTIONS
the
than
occurs
on
to
that
species
pass
offspring.
SUMMARY
for
changes,
adapted
survive
chance
The
2
adapted
better
will
selection
populations
are
survival’
predation
the
selection:
If
for
competition,
Only
in
Natural
species.
in
1
next
same
reproduce.
lose
they
few
to
to
the
‘struggle
to
to
Individuals
a
due
breed
their
of
may
Reproduction
The
between
but
in
nding
new
generations.
antibiotics?
tnemelppuS
Antibiotic
resistance
Key
bacteria
Antibiotics
Soon
are
after
developed
the
a
chemicals
that
introduction
resistance
to
kill
of
bacteria
antibiotics
their
or
in
inhibit
the
their
1940s,
growth.
some
to
bacteria
not
bacteria
with
mutation
effects.
giving
antibiotic
When
bacteria
are
exposed
to
an
antibiotic,
such
as
penicillin,
killed.
However,
there
may
be
some
individual
bacteria
that
mutation
giving
them
resistance
to
the
antibiotic.
The
used
to
bacteria
for
the
first
able
to
produce
an
enzyme
that
breaks
down
the
antibiotic.
bacteria
survive
and
now
have
more
resources
bacteria
reproduce
available
non-resistant
as
all
their
competitors
–
the
non-resistant
bacteria
–
have
died.
bacteria
survive
to
reproduce
and
pass
on
the
gene
to
their
offspring.
This
is
an
example
of
natural
example
aureus
that
of
is
this
is
the
resistant
to
strain
the
of
the
bacterium
antibiotic
are
by
have
been
introducing
responsible
antibiotics,
but
for
we
the
have
not
for
new
which
are
antibiotics
resistant
as
to
bacteria
antibiotics.
in
the
to
environment
consciously
develop
There
be
used
(MRSA).
chosen
bacteria
the
is
resistance
a
to
constant
existing
now
resistant
antibiotic
the
selection
bacteria
to
Staphylococcus
methicillin
change
killed
continues
all
Humans
stop
reproducing
selection.
antibiotic
An
and
for
or
resistance
bacteria
The
growing
resistant
grow
These
and
individual
time
may
resistant
be
treat
have
disease
a
resistance
most
antibiotic
are
resistant
antibiotic
search
antibiotic
has
occurred
for
resistance
ones.
Figure
18.4.1
Selection
for
antibiotic
resistance.
239
tnemelppuS
they
is
18.5
Selective
Selective
LEARNING
Describe
the
role
of
in
of
Over
animals
and
crops
time
and
they
kept
have
animals
kept
seed
for
at
from
least
one
ten
year
thousand
to
another
have
increased
bred
their
livestock.
Domesticated
plants
and
animals
have
plants
changed
with
grown
that
producing
and
varieties
have
selective
years.
breeding
breeding
OUTCOMES
People
•
breeding
considerably
over
that
time
due
to
this
articial
selection.
economic
These
changes
have
happened
in
this
way:
importance
1
•
Describe
examples
of
Humans
choose
a
desirable
feature
or
features
of
an
animal
or
plant
articial
to
improve,
e.g.
fast
growth,
short
stems
(so
less
straw),
docile
(not
selection
tnemelppuS
erce)
•
Outline
how
is
carried
State
the
Animals
differences
and
or
natural
The
4
plants
offspring
This
animals.
are
cereal
in
beef
This
is
to
The
such
as
shortages
of
and
to
Zebu
are
conditions
water.
drought.
features
are
bred
to
produce
the
to
nd
those
that
show
an
such
the
Plant
as
rice,
yield
increase
breeders
wheat
dairy
dogs
to
the
features.
have
and
cattle,
and
as
as
it
improve
yields
of
and
it
is
These
many
their
are
kept
for
meat
of
crops
the
such
who
of
breeders
quantity
natural
and
yield
and
ornamental
humans
which
generations.
importance
Animal
features,
with
and
of
increased
growers
is
for
economic
maize.
non-economic
as
to
grain
have
quality
plants
are
appearance.
are
the
selection.
individuals
selective
Humans
survive
to
genes.
been
selectively
successful
from
or
continues
features
selection
their
have
of
in
of
other
on
particularly
danger
to
improve
feature
Zealand
breeding
environment
pass
feature
since
bred
being
for
their
wool.
introduced
to
They
have
Australia
and
Europe.
selective
breeding
is
that
there
may
be
too
much
breeds
in
Africa
inbreeding
recessive
e.g.
(a)
of
These
sheep
ram
a
are
who
thick
between
alleles
of
ewes
have
also
from
a
hip
of
joint
flock
wool.
with
related
passed
breeds
the
thick
mated
closely
being
Many
failure
They
this
on
dog
to
(b)
–
individuals.
to
the
suffer
develop
to
give
some
thick
of
offspring
whom
wool
has
may
have
and
effects
of
leading
(c)
result
but
thicker
a
to
Articial
selection
in
sheep.
harmful
lameness.
these
wool
selected
in
reduction
inbreeding,
to
generation
sheep.
18.5.1
the
properly
these
This
descendants
from
coat
Figure
240
these
desired
want
to
prots.
sheep
variation.
Merino
to
generation.
articial
which
and
the
selective
improve
decide
New
(top)
checked
Breeders
not
been
of
milk
called
Merino
adapted
the
agent,
breed
well
their
cattle.
looking
in
want
crops
increased
longhorn
showing
next
farmers
They
maximise
in
the
process
Commercial
cattle
resistance
selection
breeding
of
resistance,
generation.
improvement
Ankole
disease
between
3
articial
yield,
out
next
•
high
selective
2
breeding
nature,
sheep
and
breed
have
are
the
next
in
tnemelppuS
Differences
and
natural
Some
(the
between
selection
between
evolutionary
process)
articial
are
selection
shown
selection
Selection
due
to
very
in
the
breeding)
human
and
natural
selection
table.
Natural
selection
Selection
inuences
Produces
(selective
selection
differences
Articial
articial
due
to
environmental
factors
varieties
different
of
from
organisms
native
Produces
greater
biodiversity
May
to
species
generations
Does
not
result
Inbreeding
A
loss
of
is
species
common,
vigour
relatively
new
fast
Proportion
of
individuals
in
in
the
leading
to
A
heterozygous
population
new
Outbreeding
offspring
process
the
lead
is
reduced
hybrid
slow
is
process,
Proportion
of
individuals
in
remains
common,
leading
vigour
taking
many
years
heterozygous
the
population
high
Hybrid
There
are
two
main
Outbreeding
This
may
be
individuals,
another
with
both
results
called
in
involves
used
for
crop
a
to
the
high
that
yield
tougher
of
carrying
breeding
combine
example
plant
hybrid
methods
the
crossing
is
a
is
to
with
a
breeding:
animals
characteristics
plant
with
disease,
resistant
individuals
selective
unrelated
crop
resistant
and
of
good
out
to
can
disease.
better
of
high
or
plants.
produce
of
survival.
often
This
Selective
more
offspring
is
vigour
It
involves
breeding
close
relatives
in
an
attempt
to
breeding
for
combines
such
as
high
yield
a
result
characteristics.
of
inbreeding.
population
There
is
weakened
also
a
greater
However,
These
by
a
can
lack
there
can
include
of
gene
susceptibility
to
a
be
loss
harmful
of
diversity
disease
and
as
a
with
reduced
that
the
fertility.
KEY
b
sheep
that
are
improved
by
Selective
breeders
from
wild
breeding
in:
cereal
tnemelppuS
3
a
milk
List
features,
and
the
Selective
crops,
e.g.
wheat,
rice
or
with
(articial
humans
with
crossing
selecting
next
the
best
generation.
breeding
the
procedure
yield
four
of
a
herd
differences
that
of
a
farmer
would
take
to
natural
selection
and
animals
with
improve
cows.
between
new
has
varieties
maize
of
Describe
the
involves
organisms
produced
2
varieties
relatives.
horses
2
c
and
crossing
POINTS
desirable
features
by
result.
QUESTIONS
useful
race
features,
as
them
a
to
resistance
come
or
variety
desirable
commercial
nding
State
many
years
breeders
disease
selection)
1
takes
10
the
1
SUMMARY
vigour.
retain
effects
vigour,
hybrid
commercial
low-yielding
desirable
take
plant
a
existing
Inbreeding
display
KNOW?
may
develop
that
plants
YOU
years.
with
Outbreeding
chance
DID
separate
yield,
maize
and
increased
plants
economic
importance,
e.g.
crops,
that
cattle
high-yielding
produce
more
articial
milk
or
that
produce
better
meat
and
sheep
selection.
b
What
is
meant
by
i
outbreeding
c
What
is
meant
by
the
and
ii
hybrid
wool.
inbreeding?
3
term
more
vigour?
Differences
and
between
natural
summarised
selection
in
the
articial
are
table.
241
tnemelppuS
to
in
PRACTICE
1
Merino
wild
QUESTIONS
sheep
sheep.
have
much
Merino
A
mutation
of
B
natural
C
phenotypic
D
selective
a
thicker
sheep
are
wool
the
6
than
result
Which
row
correctly
continuous
of:
and
identies
the
discontinuous
causes
of
variation?
gene
discontinuous
continuous
selection
variation
variation
variation
environmental
factors
A
(Paper
breeding
1)
[1]
genes
environmental
Which
is
an
variation
in
example
only
genes
only
and
B
2
genes
only
of
factors
discontinuous
environmental
humans?
C
genes
factors
only
only
A
blood
B
body
group
genes
mass
D
genes
and
only
environmental
C
foot
D
hand
span
(Paper
(Paper
1)
On
very
appear
have
2)
[1]
[1]
7
3
factors
length
rare
in
a
occasions
wild
brown
a
white
population
hair.
This
is
the
of
mouse
mice
result
that
Sickle
is
may
all
of:
cell
most
at
risk
of
this
anaemia
common
from
is
in
malaria.
similarity
in
a
genetic
areas
disease
where
Which
is
an
distribution
that
people
are
explanation
of
the
two
diseases?
A
adaptation
B
articial
A
both
diseases
are
associated
with
tropical
selection
climates
C
competition
D
mutation
(Paper
1)
B
malaria
C
people
An
island
that
was
preyed
butteries,
invaded
on
by
a
butteries.
only
those
species
In
the
of
bird
population
individuals
that
protection
against
D
of
toxic
substance
predation
as
survived.
A
articial
B
a
This
is
an
example
to
people
with
cell
allele
of:
8
selection
Biologists
use
to
term
ability
C
immunity
C
the
possession
of
D
natural
D
the
probability
that
selection
ability
the
the
1)
of
burrowing
beetle
to
a
species
almost
colour
reason
Beetles
as
for
are
predators
B
for
Beetles
achieve
to
in
leave
the
tness
great
very
an
of
range
black.
the
this
well
colour
to
a
mean:
feats
many
of
endurance
offspring
attractive
phenotype
individuals
in
likely
which
to
see
(Paper
2)
survive
and
Match
each
[1]
from
pale
have
they
9
the
correct
of
the
denition
following
on
the
C
Beetles
D
Dark
are
beetles
with
the
live.
mutation
outward
variation
genetic
selection
range
phenotype
change
appearance
of
an
organism
be:
so
constitution
of
an
organism
that
of
forms
found
in
a
species
them.
colour
subject
terms
right:
to
match
in
DNA
their
best
adapted
to
their
genotype
environment
242
have
sand-
beetles
camouaged
cannot
change
in
The
sand
is
ightless
surroundings.
2)
cell
environment
organisms
(Paper
sickle
[1]
Individuals
A
more
[1]
B
The
are
2)
competition
same
anaemia
produced
the
brown
anaemia
malaria
A
(Paper
cell
malaria
the
to
reproduce
5
sickle
catch
resistance
(Paper
a
with
sickle
[1]
likely
4
causes
to
absorb
articial
more
survive
and
breed
selection.
heat.
(Paper
[1]
3)
[5]
10
The
distance
and
little
students
is
between
nger
is
the
measured
shown
in
the
the
outstretched
handspan.
their
A
handspans.
(c)
thumb
group
The
A
couple
child
of
data
is
blood
blood
diagram
to
Before
kidney
group
group
explain
how
B.
They
O.
Use
this
is
have
a
a
genetic
possible.
be
handspan
number
/
students
of
a
carried
/
160–69
7
4.7
170–79
12
8.0
180–89
25
16.7
(Paper
12
and
200–09
34
210–19
19
blood
recipient
why
operation
groups
of
may
the
it
is
must
be
important
checked.
to
do
this.
[3]
3)
Xerophytes
They
45
transplant
the
%
Explain
190–99
out,
frequency
donor
have
are
plants
many
that
adaptive
grow
in
dry
places.
features.
30.0
(a)
Dene
(b)
Describe
12.7
that
the
are
term
three
adaptive
features
adaptations
feature.
of
for
[2]
xerophytes
growing
in
dry
habitats.
220–29
8
5.3
150
100.0
(c)
Total
An
area
climate
(a)
(i)
Calculate
who
the
had
between
a
percentage
handspan
200
and
of
students
plant
measurement
209 mm.
State
the
range
in
the
frequency
in
the
Gonorrhoea
histogram
of
the
(i)
State
table.
the
type
of
variation
shown
your
a
taken
ensure
answer
to
part
(i).
(b)
were
carried
of
become
change.
[6]
disease.
carried
out
Antibiotic
on
samples
from
people
with
of
gonorrhoea
that
they
are
treated
with
an
antibiotic.
Describe
how
out
in
Pakistan
bacteria
become
resistant
[2]
3)
Surveys
species
to
environmental
bacterial
are
antibiotics.
Explain
how
transmitted
11
a
of
[1]
to
(Paper
how
time
result
in
graph.
Explain
a
[5]
(a)
(ii)
is
tests
appropriate
your
this
over
as
results
to
(c)
Explain
change
to
dry
[1]
bacteria
shown
very
4)
sensitivity
a
change.
may
adapted
13
Draw
becomes
handspan
measurements.
(b)
[3]
[2]
(Paper
(ii)
[3]
antibiotic
from
one
resistance
bacterial
is
cell
to
and
others.
New
Zealand
to
nd
the
percentage
of
in
the
different
blood
groups
Explain
ABO
blood
group
why
antibiotic
results
are
shown
in
the
sample
in
of
people
each
blood
in
B
Explain
be
the
AB
O
Pakistan
31.0
36.2
7.7
25.1
New
35.5
8.8
2.6
53.1
(b)
Draw
(i)
a
bar
What
the
(ii)
chart
type
to
of
show
the
variation
is
data.
shown
data?
Explain
your
a
why
used
to
Antibiotic
problem
which
(a)
to
tests
carry
before
course
of
antibiotics.
[2]
antibiotics
treat
viral
should
not
diseases.
[3]
group
(e)
A
Zealand
important
table.
(d)
percentage
country
is
sensitivity
system.
prescribing
The
it
of
out
the
[2]
the
(c)
population
[5]
table.
(d)
mm
are
who
(Paper
resistance
worldwide.
this
problem
is
a
serious
Suggest
may
be
medical
ways
in
overcome.
[3]
4)
[5]
by
[1]
answer
to
part
(i).
[2]
243
19
Organisms
19.1
this
State
that
main
source
the
Sun
is
of
energy
State
the
•
that
a
food
of
organism
Dene
the
chain
energy
to
and
shows
from
another
terms
consumers
the
Construct
is
at
the
ow
of
energy
through
living
organisms
of
nutrients
to
organisms
in
biological
systems.
important
difference
between
these
two
processes.
is
a
principal
energy
to
other
when
source
‘lost’.
that
food
trophic
absorbed
organisms
animals
Eventually
producers,
decomposers
simple
all
is
feed
the
make
up
animals
on
energy
Nutrients
on
of
energy
input
photosynthetic
chemical
plants
is
the
living
and
as
by
into
biological
and
energy
.
when
transferred
other
organisms.
eventually
to
hand,
Energy
animals
the
are
back
and
systems.
of
feed
the
taken
into
on
as
by
animals.
heat
and
is
elements
plants,
biological
available
occurs
other
chemical
up
made
transfer
environment
consist
They
recycled
organisms
passed
systems.
on
This
is
chains
as
nutrient
cycling,
since
they
are
constantly
reused.
level
Communities
Living
organisms
However,
more
useful
Living
own
when
to
and
Producers
be
group
organisms
food
can
placed
looking
make
a
them
can
those
at
be
groups
according
divided
that
their
into
community
up
of
to
into
based
living
the
way
those
on
similar
things,
that
that
it
is
they
can
features.
often
feed.
make
their
cannot.
own
organic
nutrients
from
simple
raw
producer
materials,
a
source
such
of
as
energy
photosynthesis.
photosynthetic
Some
from
of
carbon
the
to
or
reactions
make
Some
their
are
in
water
.
from
also
energy
involved
involving
and
sugars
bacteria
obtain
bacteria
dioxide
carbon
from
of
plants
dioxide
producers
recycling
compounds
Green
and
simple
and
they
obtain
(see
light
water
are
chemical
nitrogen
nitrogen
use
either
reactions.
their
page
as
by
energy
253).
primar y
Producers
make
energy
available
for
all
the
other
members
of
the
consumer
community
in
the
carbohydrates,
energy
for
form
fats
almost
of
and
all
energy-rich
proteins.
food
carbon
Sunlight
chains.
The
is
compounds,
the
major
ultimate
exceptions
such
as
source
are
the
of
vent
secondar y
communities
in
the
deep
ocean
that
rely
on
chemical
energy
rather
consumer
than
Figure
19.1.1
A
food
light
energy.
chain.
Consumers
plants
make
or
their
primary
own
eat
and
other
Sunlight
things
244
in
is
the
this
source
of
ecosystem.
energy
for
all
food,
as
they
energy
both.
so
are
organic
material
eat
Each
of
these
from
a
feeding
word
by
they
have
eat
and
and
pages
6
groups
meaning
eating
animals
the
to
are
is
a
‘to
other
7
eat
(consume)
T
ertiary
that
for
it.
called
gain
their
of
can
top
(The
put
are
are
they
word
each
carnivores
from
into
a
trophic
level
as
you
will
see
in
these
trophic
organism
food
waste
feed).
living
ecosystem
are
secondary
carnivores.
energy
how
either
cannot
Herbivores
Carnivores
level.
Y
ou
They
consumers
details
trophic
feed’.)
organisms,
consumers.
sometimes
bacteria
and
are
producers.
herbivores.
fungi
(see
All
they
carnivores,
Decomposers
Greek
their
or
consumers
consumers
that
obtain
animals
chains.
comes
in
an
tnemelppuS
tnemelppuS
Dene
an
Sun
known
•
recycling
Light
to
•
looking
systems
transfer
one
are
for
The
•
we
ow
the
There
biological
unit
environment
OUTCOMES
and
•
their
Energy
In
LEARNING
and
Food
Food
They
next.
chains
chains
show
show
the
Look
at
ecosystem.
ow
the
The
the
ingests
the
This
can
food
one
living
food
in
show
and
always
energy
Figure
the
organism
grass
chain
organisms
and
chain
arrows
from
that
of
food
transferred
gazelle
what
feed
from
19.1.2
direction
to
that
the
the
begins
in
next.
lion
with
on
a
in
one
an
which
to
food
tells
gazelle.
often
a
the
African
in
chain
the
producer
,
East
energy
food
ingests
community.
organism
from
This
a
us
is
that
Notice
green
KEY
plant.
1
include
parts
of
a
plant,
such
as
seeds,
fruits
or
even
POINTS
Sunlight
energy
leaves.
the
Food
ow
energy
of
chains
not
energy.
chain
only
show
Producers
would
look
like
the
gain
ow
their
of
food,
energy
they
from
the
is
also
for
→
producers
→
Sun,
so
an
2
this:
primary
A
food
chain
transfer
consumers
→
secondary
we
Food
do
not
chains
include
start
the
with
Sun
in
food
chains,
as
it
is
not
a
‘food’.
food
simple
ows
food
to
decomposers,
but
they
are
rarely
included
in
these
of
in
chains.
the
from
another.
one
Food
show
interconnecting
chains.
the
provide
form
of
compounds
energy
carbon
for
consumers
decomposers.
webs
4
In
shows
energy
to
Producers
and
Food
of
systems.
producers.
3
Energy
source
consumers
webs
But
main
biological
show
organism
Sun
the
dead
most
communities,
animals
will
eat
more
than
one
type
of
Energy
is
animals
organism.
A
food
web
gives
a
more
complete
picture
of
the
transferred
to
living
when
they
ingest
feeding
food.
in
an
ecosystem.
5
grey
kestrel
lizard
praying
A
trophic
level
of
organisms
or
a
food
is
in
the
a
position
food
chain
web.
tnemelppuS
relationships
mantis
SUMMARY
QUESTIONS
spider
1
Look
at
the
woodland
moth
a
grasshopper
grasses
Christmas
Give
food
web
ecosystem
one
example
the
food
web
of
the
following:
for
from
each
i
a
producer
ii
a
primary
iii
a
secondary
the
here:
of
consumer
bush
consumer
b
Name
the
19.1.2
A
food
web
for
a
West
African
forest
Draw
four
over-harvesting
manner
e.g.
can
result
overshing.
of
in
food
a
Also,
species
decrease
the
in
by
humans
their
introduction
in
numbers
of
foreign
an
the
unsustainable
and
native
organisms
due
to
predation
and
(alien)
species
competition
e.g
food.
Both
of
these
result
in
disruption
of
webs,
due
to
the
removal
of
a
species
or
a
decrease
food
in
chain
organisms.
with
Indicate
levels
on
the
chain.
can
Dene
the
term
explain
trophic
how
energy
level
is
chains
transferred
and
food
for
and
resources,
a
trophic
food
extinction,
2
displace
in
ecosystem.
c
The
carnivores
web.
between
trophic
their
levels.
numbers.
245
tnemelppuS
Figure
the
food
19.2
Pyramids
and
describe
and
pyramids
of
numbers
pyramids
of
biomass
chains
plants
pyramids
food
they
webs
do
show
not
feeding
show
how
relationships
many
living
in
a
organisms
are
For
and
instance,
many
grasshoppers
grasshoppers
and
feed
on
lizards
many
are
grasses
eaten
by
and
grey
other
kestrels.
of
Food
and
and
but
and
involved.
numbers
numbers
interpret
community,
• Compare
of
OUTCOMES
Food
• Draw,
numbers
biomass
Pyramids
LEARNING
of
pyramids
chains
and
food
webs
do
not
show
this.
of
Look
at
Figure
19.2.1.
There
are
far
more
plants
than
caterpillars
biomass
because
fewer
Look
one
This
The
at
caterpillar
than
the
600
shrews
numbers
→
of
in
eats
can
each
this
be
box
organisms
in
there
leaves
because
are
owl
→
in
a
plants.
eats
each
mice
many
10
pyramid
pyramid
at
many
There
are
far
shrews.
chain:
100
shown
the
from
each
food
caterpillars
information
area
living
ten
owls
plants
owl
each
shows
trophic
→
of
owl
1
numbers.
roughly
how
many
level.
shrews
hundreds
of
caterpillars
The
producers
and
are
carnivores
consumers
than
than
primary
primary
the
are
rst
the
level,
third.
producers.
consumers.
consumers
as
There
But
they
herbivores
Notice
that
are
also
secondary
have
to
eat
tertiary
1
are
there
the
are
fewer
second
fewer
level
primary
secondary
consumers
are
consumers
bigger
than
them!
consumers
thousands
secondary
90 000
of
primary
200 000
Figure
19.2.1
This
shows
the
and
consumers
consumers
leaves
consumers
producers
producers
1 500 000
an
owl
for
that
several
support
days.
number of
Figure
A
19.2.2
problem
Pyramid
with
of
numbers
pyramids
of
for
a
grassland
numbers
is
community
that
they
do
in
0.1
not
hectare.
take
into
tertiar y
individuals
account
consumers
the
size
of
organisms
at
each
trophic
level.
decreases
secondar y
consumers
buzzard
primar y
consumers
size of
blackbirds
individuals
producers
decreases
Figure
19.2.3
Pyramids
of
numbers
caterpillars
and
mahogany
biomass
show
these
tree
trends.
Figure
19.2.4
A
pyramid
of
numbers
for
the
organisms
living
in
a
mahogany
tree.
parasites
For
instance,
a
mahogany
tree
and
a
grass
plant
each
count
as
one
ladybirds
organism.
greenfly
than
one
unusual
rose
19.2.5
An
inverted
numbers.
246
one
grass
mahogany
plant.
As
a
tree
result
can
some
support
many
pyramids
of
more
herbivores
numbers
can
have
shapes.
bush
In
Figure
But
pyramid
Figure
19.2.5
the
tertiary
consumers
are
parasites.
Many
of
them
feed
of
on
a
single
ladybird
so
this
pyramid
is
inverted
and
it
looks
top
heavy
.
way
instead
biomass
each
to
of
biomass
overcome
numbers.
pyramid
trophic
the
problem
Biomass
shows
the
is
of
the
actual
size
mass
is
of
weight
to
measure
living
or
mass
of
STUD
Y
biomass
material.
So
living
things
Prod
ucer
s
at
plan
ts)
level.
the
To
A
draw
a
sample
weighed.
mass
is
dry
it
mass
this
much
and
The
is
does
fats
as
constant
for
the
rst
each
the
needs
trophic
sample
estimated
is
to
be
level
is
calculated.
number
of
not
food
for
in
for
the
mass.
change
as
it
It
plant
is
the
recorded
is
is
in
in
at
by
beca
use
and
The
inpu
t
their
as
to
body
Dry
it
mass
mass
tells
carbohydrates,
community.
in
an
estimate
instance,
do
not
grass
take
often
into
such
as
The
is
time
will
be
grows
This
us
over
a
period
into
the
the
how
proteins
data
is
instant
at
a
how
fast
fast
in
rate,
an
time.
Biomass
but
organism
because
it
grows.
and
cattle,
its
biomass
at
is
grazed
any
POINTS
For
by
Pyramids
means
it
is
better
to
calculate
the
of
time,
e.g.
over
a
year
or
a
of
numbers
show
instant
many
individuals
there
are
biomass
at
produced
provid
e
metre.
one
account
grasshoppers
low.
and
energy
water
how
in
level
abso
rb
oven
1
animals,
tro ph
ic
green
on
the
KEY
pyramids
of
as
alwa
ys
they
sunl
igh t
average
organisms
drying
possible
plants.
the
square
taken
of
present
organisms
per
matter
usually
65%
does
material
grams
rst
collected.
taken
(suc
h
are
ecosys
tem .
approximately
biological
mass
by
data
from
mass
determined
a
expressed
dry
the
community.
animals:
useful
usually
organisms
multiplied
the
of
pyramid,
average
reaches
mass
and
The
in
dry
until
the
then
present
The
biomass
of
TIP
a
growing
each
trophic
level
but
give
no
season.
indication
2
of
their
size.
Pyramids
of
biomass
the
of
living
indicate
2
5.8
g
per
m
dog-whelks
mass
each
trophic
material
level,
but
at
give
2
71
g
per
periwinkles
m
no
indication
of
the
rate
of
tnemelppuS
One
of
growth.
algae
2
3987
g
per
on
m
and
Figure
19.2.6
A
Phytoplankton
in
water
–
pyramid
consists
both
of
biomass
of
tiny
freshwater
for
a
rocky
seashore
photosynthetic
(lakes
and
ponds)
growing
seaweeds
the
rocks
community.
organisms
and
in
the
that
sea.
oat
The
SUMMARY
plankton
and
the
grow
sea
is
quickly
warm
at
times
with
of
plenty
the
of
year
light.
when
They
there
live
for
are
only
a
few
days
1
as
they
are
grazed
by
animal
plankton.
So
their
biomass
at
any
Draw
two
is
small.
But
over
say
a
year,
their
biomass
is
huge.
This
records
only
a
few
days’
growth
and
so
is
of
with
different
biomass
shapes.
pyramid
pyramids
one
numbers
time
QUESTIONS
nutrients
Explain
their
shapes.
inverted:
2
Draw
for
a
an
pyramid
of
ecosystem
biomass
and
explain
2
21
g
per
m
its
zooplankton
shape.
you
Make
include
the
measurement
4
g
phytoplankton
your
sure
unit
for
that
of
biomass
on
pyramid.
2
per
m
3
Figure
19.2.7
Biomass
pyramid
for
the
English
What
criticisms
made
about
numbers
Biomass
can
vary
with
the
seasons.
In
have
been
Channel.
temperate
latitudes,
pyramids
and
of
pyramids
of
deciduous
biomass?
trees
than
shed
it
is
their
in
leaves
winter
as
in
winter.
they
will
Their
have
biomass
leaves,
is
greater
owers,
fruits
in
summer
and
seeds.
247
tnemelppuS
tnemelppuS
Pyramids
19.3
Shortening
the
food
chain
tnemelppuS
The
LEARNING
The
• Explain
energy
losses
of
energy
transfer
levels
in
efciency
of
energy
transfer
between
trophic
levels
can
be
seen
between
by
trophic
efciency
OUTCOMES
food
using
energy
pyramids.
These
show
the
energy
transferred
from
chains
one
trophic
level
to
the
next.
The
energy
pyramid
in
Figure
19.3.1
2
• Explain
the
shows
increased
that
87 000 kJ
per
m
per
year
is
passed
to
the
tadpoles
from
2
efciency
green
in
supplying
plants
compared
plants
to
as
to
human
feeding
food
the
plant
plankton.
the
small
sh,
and
The
so
tadpoles
pass
on
to
a
tran
sfer
char
ts
consumers
in
14 000
primar y
87 000
producers
consumers
Ano
ther
water
char
t
o ppos
ite.
the
as
to
T
his
energy
respira
tion
able
tertiar y
energy
ow
decom
posers
.
be
67
weeds
show
n
show
s
to
1600
of
energy
is
year
TIP
ecosys
tem .
way
per
crop
tadpoles
an
m
animals
Pyram
ids
show
per
on.
pike
STUD
Y
14 000 kJ
Figure
19.3.1
An
energy
pyramid
for
a
lake.
Figures
are
in
kJ
per
m
per
year.
and
Y
ou
shou
ld
interp
re t
that
2
losses
2
The
tadpoles
obtain
87 000 kJ
per
m
per
year
from
the
water
plants
2
but
ow
only
pass
on
14 000 kJ
per
m
per
year
of
this
to
the
small
sh.
2
show
energy
ow.
The
remaining
chain.
they
The
will
energy
it
tadpoles
have
that
biomass
–
is
they
a
will
passed
their
swallows
Energy
73 000 kJ
do
per
m
have
out
pass
muscles
per
used
some
on
in
to
and
year
a
lot
of
waste
the
other
has
small
–
been
energy
urine
sh
organs
lost
is
that
in
the
the
swimming
and
the
from
faeces.
energy
sh
and
The
in
eats
food
only
their
every
time
tadpole.
always
‘lost’
in
this
way
as
it
passes
from
one
trophic
level
to
2
STUD
Y
the
TIP
next.
Of
the
87 000 kJ
per
m
per
year
of
energy
in
the
producers
2
only
As
you
will
Phys
ics,
proce
sses
efc
ient.
‘lost’
is
no
as
energy
are
page
per
m
carnivore,
the
pike.
trophic
is
not
heat.
energy
the
by
next
the
of
it
only
an
size
becomes
some
energy
of
the
of
energy
the
in
energy
pyramid
organisms
is
the
is
never
or
how
esh
of
passed
inverted.
many
the
from
of
Its
top
one
shape
them
there
since
it
simply
looks
at
the
energy
that
is
passed
on.
is
Birds
re tain
a
and
this
heat
cons
tant
tempe
rature
(see
Energy
Energy
plants
it
is
losses
ow
through
absorb
leaves.
Much
reected
them,
Plants
or
is
use
only
of
green
As
2
this
from
much
respiration.
248
to
year
Since
Resp
iratio
n
except
ion.
168)
.
level
affected
per
100%
are
maint
ain
body
from
trans
fer
neve
r
Muc
h
mam
mals
to
know
67 kJ
5%
energy
the
light
of
an
ecosystems
to
the
of
is
not
surface
which
energy
energy
is
the
of
they
in
leaves,
cannot
trap
inefcient.
energy
trapped
the
they
transfer
relatively
light
in
process,
that
At
strikes
best,
their
photosynthesis
passes
straight
because
through
absorb.
photosynthesis
respiration
is
in
their
about
own
40%
so
about
60%
of
the
energy
is
lost
tnemelppuS
efcient
as
released
heat
to
the
plant
and
then
to
the
atmosphere.
in
Much
of
the
plant’s
biomass
is
lost
respiration
to
tertiar y
decomposers
in
the
form
of
dead
leaves,
twigs,
consumers
dead
remains,
released
fruits,
etc.
About
10%
of
the
energy
trapped
by
faeces,
in
the
plant
Much
is
of
available
what
they
to
eat
secondary
consumers.
is
edible
not
very
or
etc.
respiration
secondar y
easy
production
digest.
So
primary
consumers
make
dead
available
released
only
about
10%
of
what
they
have
eaten
remains,
faeces,
etc.
to
in
secondary
sresopmoced
consumers
to
respiration
consumers.
primar y
However
,
the
animal
esh
in
primary
for
example
heat
consumers
dead
consumers,
of
grasshoppers
remains,
and
faeces,
etc.
released
gazelles,
is
easier
to
digest
and
carnivores
may
in
obtain
slightly
more
than
10%
of
the
respiration
energy.
producers
At
each
trophic
level,
energy
is
lost
as
heat
to
dead
the
environment
and
consumers
lose
energy
remains,
in
their
faeces
and
urine
to
decomposers
etc.
energy
which
means
trophic
level.
that
there
Food
is
chains
less
on
for
the
land
input
next
rarely
have
sun
more
than
When
four
farmers
trophic
grow
crops,
human
consumption,
grain
available
is
farmers
They
grow
may
to
or
buy
levels.
all
us
buy
as
the
as
such
food
as
rice,
energy
primary
plant
cereals
such
of
for
in
Figure
consumers.
to
feed
barley
19.3.2
Energy
their
Livestock
level,
animals.
or
maize
or
grass,
alfalfa
and
used
i.e.
in
grow
fodder
crops,
such
as
consist
clover
,
for
grazing.
Animals,
such
as
pigs,
cattle
use
up
much
of
the
energy
in
their
that
there
is
not
as
much
energy
food.
vegetarian
diet
can
support
far
more
available
to
cut
down
the
number
of
links
in
people.
the
food
individuals
This
is
at
the
because
end
we
are
of
the
food
cutting
chain
down
the
of
energy
that
occurs
between
in
of
many
food
countries
of
plant
developed
diet
which
poultry,
human
can
provide
tend
origin
to
includes
sh,
lamb,
population
enough
a
and
is
b
Give
to
change
each
and
less
to
one
food
sh.
of
a
meat
pork.
If
farmers
our
diet
are
may
of
that
includes
animal
more
plant
origin.
trophic
POINTS
Energy
losses
occur
between
QUESTIONS
is
the
ultimate
form
of
energy
input
in
a
food
levels
two
ways
in
which
energy
is
‘lost’
from
food
why
food
chains
usually
have
fewer
than
ve
as
and
a
result
in
of
waste
chain?
produced.
chains.
2
Explain
mainly
or
be
materials
2
or
have
proportion
everyone,
respiration,
What
that
meat
people
increasing.
for
trophic
a
diets
some
many
higher
beef
food
1
1
undigested
have
with
countries
KEY
SUMMARY
uneaten,
level.
90%
foods
‘wastage’
is
each
chain
have
fed.
that
at
If
to
more
energy
us.
The
we
ecosystem.
This
from
A
the
respiration
Western
varied
means
an
and
In
chickens,
in
they
People
may
losses
the
More
energy
is
available
in
trophic
foods
for
human
consumption
levels.
if
3
a
Explain
supply
b
Explain
why
it
green
why
inefcient
in
is
efcient,
plants
a
diet
terms
as
rich
of
in
terms
human
in
energy
transfer,
to
products
loss.
feed
secondary
food.
meat
energy
of
we
is
relatively
as
consumers
3
A
more
that
than
as
consumers.
vegetarian
far
primary
rather
diet
people
includes
can
than
meat
support
one
products.
249
19.4
Nutrient
Nutrient
LEARNING
Describe
the
carbon
far
we
Describe
the
role
ow
(fungi
in
recycling
Describe
the
different
the
water
with
food
ecosystems
and
from
energy.
the
There
Sun,
and
is
a
energy
through
the
This
different
topic
trophic
and
the
levels
next
are
and
is
about
then
lost
some
of
to
the
the
elements
comprise
living
organisms
and
how
they
are
cycled
in
nature.
stages
Most
of
into
carbon
that
•
concerned
energy
and
atmosphere.
bacteria)
been
of
of
ows
decomposers
have
cycle
constant
•
cycling
OUTCOMES
So
•
cycles
living
matter
(95%)
is
made
up
of
six
elements:
carbon,
cycle
hydrogen,
have
a
oxygen,
constant
carbohydrates,
a
nite
source
nitrogen,
supply
fats
of
and
phosphorus
these
other
of
these
to
continue,
elements
organic
nutrients.
Life
and
if
sulfur
.
they
are
materials.
has
Living
to
Unlike
existed
on
things
make
energy,
Earth
must
proteins,
for
there
is
millions
faeces
consumers
and
of
urine
years.
become
For
it
locked
up
in
dead
these
elements
bodies
and
life
must
will
be
recycled
become
or
they
will
extinct.
feeding
death
and
Bacteria
decay
feed
producers
decomposers
on
breaking
that
and
the
down
they
water
a
aerobic
Many
warm
are
feed
on
matter
of
dead
of
fats
these
temperature
catalysed
by
and
animals
carbohydrates,
absorb.
and
respiration
nutrients
fungi
waste
and
are
as
decaying
(urine
and
proteins
respired.
the
enzymes.
matter.
into
To
do
processes
They
They
faeces).
also
of
They
small
this
by
molecules
they
digestion
need
also
feed
oxygen
require
and
for
respiration.
in
environment
Decomposers
Figure
19.4.1
The
role
of
decomposers
in
They
also
release
break
carbon
down
as
amino
carbon
acids
dioxide
releasing
when
they
ammonia
respire.
into
their
ecosystems.
surroundings.
the
most
absorbed
These
in
by
this
plants
nutrients
plants.
carbon
In
important
We
say
are
that
way
they
elements
and
recycle
for
converted
then
passed
nutrients
carbon
organisms.
into
on
are
to
and
nitrogen
Simple
complex
animals
–
two
compounds
of
are
compounds.
when
they
eat
the
cycled
dioxide
air
The
carbon
cycle
respiration
photosynthesis
and
decay
Carbon
is
used
important
carbon
in
to
make
biological
carbohydrates,
molecules.
The
proteins,
carbon
fats,
comes
DNA
from
and
other
carbon
compounds
dioxide
animals
and
in
use
the
it
in
compounds
air.
Plants
absorb
photosynthesis
by
eating
to
carbon
make
dioxide
food.
from
Animals
the
get
atmosphere
the
carbon
plants.
feeding
Carbon
•
carbon
in
Plants
and
carbon
plants
•
formed
of
years
dead
ago
animals
fuels:
peat,
dioxide
Decomposers
of
dioxide
the
250
carbon
(as
some
use
well
dead
decaying
Fossil
(plus
fuels
water
like
dioxide
in
of
the
their
following
food
as
water
plants
and
for
ways:
respiration,
releasing
and
energy).
material
for
animals
for
food.
They
respiration,
releasing
oil,
and
also
use
natural
contain
carbon
energy).
is
peat,
one
of
coal,
the
and
gases
gas
released
gas
combustion
The
air
carbon.
oil,
Carbon
19.4.2
use
the
from
vegetation
•
Figure
into
millions
some
coal,
gets
compounds
burning
fossil
dioxide
cycle.
when
these
fuels
are
burnt.
into
the
air
during
STUD
Y
TIP
Durin
g
These
processes
release
carbon
dioxide
into
the
air
and
this
carb
on
the
uptake
by
photosynthesis
so
the
concentration
of
pho to
synt
hesis
balances
carbon
is
suga
rs.
in
the
atmosphere
remains
constant.
Sometimes,
dead
plants
do
not
decompose.
Their
dead
bodies
become
fossilised
coal,
oil
and
gas
–
fossil
The
effects
of
combustion
concentration
Topics
21.2
of
and
carbon
of
fossil
dioxide
fuels
in
the
and
deforestation
atmosphere
are
on
the
discussed
sam
e
in
cycl
e,
The
water
water
cycle
cycle
water
Follow
moves
demonstrates
the
on
how
important
water
is
to
life
arrows
between
on
the
living
diagram
organisms
to
see
and
how
their
the
world’s
from
the
the
nitrog
en
no t
muc
h
than
as
use
carb
on
more
nitrog
en
).
2
gets
More
powers
is
T
he
–
environment.
It
Energy
(N
into
xatio
n
beca
is
reactiv
e
on
–
the
but
dioxid
e
gas
Earth.
in
a
of
compo
und.
idea
occu
rs
21.5.
simpl
e
conv
erted
compl
ex
comm
The
is
fuels.
a
as
means
compo
und
to
carb
on
form
T
his
and
simpl
e
animals
xed
dioxide
colder
water
as
the
air
condenses
rises.
out.
Sun
water
cycle.
The
droplets
heavier
or
condensation
to
form
from
clouds
tiny
of
and
snow.
get
fall
This
is
bigger
as
rain,
and
hail
precipitation.
water
made
water
droplets
animals
water
some
breathe
out
vapour
water
evaporates
from
evaporation
from
the
of
the
soil
and
19.4.3
The
SUMMARY
water
(especially
vapour
through
returns
streams
to
the
and
sea
via
a
Describe
what
and
two
living
c
is
meant
living
by
the
term
cycle,
in
the
context
the
organisms.
substances
six
POINTS
of
that
are
absorbed
and
recycled
by
Carbon
of
elements
that
make
up
95%
of
living
is
cycled
ecosystems
organisms.
Name
water
cycle.
1
State
feeding,
matter.
by
State
the
roles
of
the
following
in
nutrient
3
Look
decomposers
at
the
diagram
b
of
green
the
plants
water
cycle
c
State
three
b
Explain
ways
in
which
water
c
State
the
it
rains
source
of
when
the
clouds
energy
respiration,
decomposition,
and
combustion.
Decomposers,
like
and
important
fungi,
are
bacteria
in
above.
gets
into
the
recycling
of
nutrients.
atmosphere.
3
why
processes
animals
the
a
the
cycles:
2
a
through
photosynthesis,
fossilisation
2
water
QUESTIONS
nutrients
b
lose
rivers
underground
KEY
1
trees)
transpiration
sea
water
Figure
plants
water
Evaporation,
condensation
precipitation
are
and
rise.
that
powers
the
water
cycle.
processes
in
the
important
water
cycle.
251
19.5
The
nitrogen
cycle
tnemelppuS
Nitrogen
LEARNING
OUTCOMES
Nitrogen
•
Describe
the
roles
is
molecules.
microorganisms
an
element
required
for
many
biologically
important
of
in
Amino
acids,
proteins,
DNA
and
chlorophyll
contain
the
nitrogen.
Approximately
inert
very
80%
of
the
air
is
nitrogen
gas
(N
)
but
it
is
2
nitrogen
•
cycle
Describe
the
stages
nitrogen
cycle
in
and
most
the
to
The
as
and
xed
nitrogen
and
below
changes
that
in
cannot
nitrogen
proteins,
diagram
the
organisms
microorganisms
them
acids
few
the
in
as
shows
happen
can
use
the
ions
the
to
make
it
in
form
such
use
this
of
as
Plants,
It
has
compounds
cycle
as
it.
form.
nitrate
nitrogen
nitrogen
of
it
is
and
animals
to
be
such
available
as
amino
ammonium
which
and
ions.
summarises
all
recycled.
air
lightning
animal
protein
fertilisers
plant
animal
proteins
wastes
death
and
decay
nitrogen-fixing
denitrifying
bacteria
in
nitrogen-fixing
bacteria
decay
soil
bacteria
nitrate
act
ions
the
on
dead
plants
and
remains
and
up
of
by
in
bacteria
in
taken
soil
root
nodules
roots
animals
animal
wastes
nitrifying
bacteria
nitrate
Figure
19.5.1
The
nitrogen
in
the
soil
cycle.
Most
STUD
Y
ions
of
nitrate
TIP
the
ions
nitrogen
(NO
).
that
They
plants
use
this
obtain
to
they
make
absorb
amino
in
acids
the
in
form
their
of
leaves.
3
The
Be
carefu
l
‘plan
ts
when
you
abso
rb
Also
do
the
they
eat
plants
Any
the
no t
add
and
so
process
of
used
obtain
amino
acids
to
form
their
are
proteins,
nitrogen
broken
deamination.
in
the
down
Animals
such
by
that
as
form
enzymes.
of
animals
live
on
plant
to
land,
Animals
protein.
ammonia
such
as
by
the
‘plan
ts
cow
in
the
cycle
above,
convert
ammonia
to
urea
and
excrete
it
in
urine.
that
nitrog
en
Decomposers
(bacteria
and
fungi)
break
down
dead
remains
and
+
T
hey
don’
t,
fertili
sers
nitrat
e
animal
wastes
releasing
ammonium
ions
(NH
)
into
the
soil.
Bacteria
4
also
break
down
urea
in
urine
to
ammonium
ions.
This
process
that
is
sometimes
called
ammonication.
Deamination
results
in
the
ions
.
production
urine
252
are
ions
’.
write
add
acids
excess
their
soil
’.
provid
e
writi
ng
nitrog
en’
mean
nitrat
e
‘farm
ers
to
abou
t
abso
rb
amino
(see
of
the
Topic
excretory
13.1).
product
urea,
which
passes
out
in
animal
ions.
These
reaction
If
you
bacteria
instead
are
where
T
wo
bacteria
of
tracing
we
Nitrogen-xing
nitrogen
gas
themselves.
available
The
These
a
can
suitable
all
the
cycle
in
source
light
the
of
or
air
they
are
into
die
energy
feeding
of
help
found
in
the
compounds
and
are
a
by
soil.
this
we
are
back
plants.
nitrogen.
These
nitrogen
decomposed,
nitrate
oxidation
realise
recycle
of
into
decomposer.
will
ions
to
ions
from
as
you
nitrate
microorganisms
the
ammonium
diagram
absorption
bacteria
alfalfa
bacteria
bacteria
plants
their
change
this
can
convert
that
they
xed
use
nitrogen
is
plants.
beans,
trees.
soil
bacteria
from
Nitrogen-xing
peas,
of
When
to
gain
with
groups
the
absorbing
the
started
other
in
tnemelppuS
Nitrifying
and
are
to
that
clover
and
they
amino
for
found
need.
gas
the
In
the
the
legume
trees,
ammonia
(in
of
roots
return
bacteria
Nitrogen
roots
tropical
on
into
acids.
the
in
many
swellings
nitrogen
make
environment
sugars
also
inside
change
use
are
the
that
requires
the
like
ame
nodules.
legume
plants
and
a
as
root
legume
nodules)
xation
such
called
plants
also
lot
of
provide
provide
energy.
The
Denitrifying
bacteria
live
in
water-logged
soil.
They
change
nitrate
top
root
to
nitrogen
gas.
It
is
thought
that
they
balance
the
uptake
of
by
nitrogen-xing
nodules.
the
cells
reveal
bacteria
causes
temperatures.
washed
into
nitrogen
Nitrogen
the
soil
ions
can
washed
be
are
lost
by
and
oxides
rain
from
out
of
oxygen
are
to
formed
where
they
react
in
together
the
form
at
reactions.
nitrate
of
the
the
soil
soil
before
by
plants
rainwater
.
can
This
is
the
some
nitrogen-xing
bottom
a
root
photo
nodule
thousands
that
you
broken
can
open
live
of
nitrogen-xing
inside.
high
These
are
ions.
KEY
Nitrate
the
bacteria.
to
Lightning
shows
In
nitrogen
see
gas
photo
ions
absorb
called
them
as
POINTS
they
1
leaching
Nitrogen
as
a
gas
is
in
(N
)
the
but
atmosphere
is
not
2
Farmers
add
fertilisers
containing
nitrogen,
e.g.
ammonium
nitrate.
available
These
are
manufactured
from
ammonia
made
in
the
Haber
add
replace
Some
extra
the
sources
nitrate
farmers
do
of
nitrate
absorbed
not
use
by
ions
the
inorganic
for
crop
plants
plants.
and
fertilisers,
The
removed
but
most
organisms
process
as
and
to
it
is
not
reactive.
fertilisers
at
instead
harvest.
use
2
Some
(N
natural
)
bacteria
x
converting
nitrogen
it
to
2
fertilisers
nitrogen
such
cycle
as
at
manure.
the
This
point
provides
where
the
dead
material
decomposers
that
enters
ammonia.
the
live
act.
inside
legumes.
Some
root
3
Bacteria
and
QUESTIONS
are
to
List
the
four
substances
element
present
in
living
organisms
that
Describe
the
the
protein
ammonia.
to
convert
nitrate
ions.
nitrogen.
4
2
bacteria.
bacteria
ammonia
contain
of
called
decompose
urea
Nitrifying
1
these
nodules
They
nitrogen-xing
SUMMARY
of
roles
following
of
microorganisms
(bacteria
and
fungi)
Denitrifying
nitrate
in
(N
processes:
bacteria
ions
to
convert
nitrogen
gas
).
2
a
decomposition
b
nitrication
c
nitrogen
d
denitrication
xation
5
Plants
and
acids
3
Explain
how
nitrogen
in
the
protein
of
dead
animals
absorb
convert
which
4
is
Explain
made
how
available
to
available
farmers
crop
to
can
plants.
plants
increase
in
the
the
form
of
quantity
nitrate
of
they
to
use
ions
amino
to
make
and
proteins.
plants
nitrate
them
Animals
obtain
the
ions.
nitrate
amino
acids
eating
and
animal
they
need
digesting
by
plant
or
protein.
253
19.6
Populations,
and
ecosystems
Population
LEARNING
Dene
the
term
population
State
the
factors
affecting
same
of
growth
of
a
Identify
of
growth
growth
•
the
State
different
in
a
phases
interbreed.
that
of
food
disease
are
factors
that
affect
and
population
the
of
the
the
same
species
individuals
in
a
living
in
population
Sometimes
such
or
on
like
This
it
as
a
on
is
is
difcult
easiest
to
tell
an
island,
mountain,
wildebeest
where
the
in
like
the
like
the
geographical
organisms
Komodo
Protea
game
kilimanjaro,
parks
live
dragons
of
East
or
in
on
a
islands
they
are
Africa.
species
into
terms
are
very
separate
widely
distributed
populations.
and
However,
it
is
there
difcult
are
to
usually
divide
barriers
reproduction,
such
as
rivers
and
mountains,
that
divide
them
into
growth
community
so
there
populations.
is
Some
interbreeding
individuals
between
migrate
across
these
barriers,
populations.
ecosystem
The
•
All
Describe
and
different
phases
population
explain
of
growth
table
shows
some
animal
and
plant
examples.
the
the
population
habitat
creole
coral
place
curve
reefs
wrasse
around
Tobago
in
the
reef
Caribbean
wildebeest
grassland
dry
Komodo
Nepenthes
Komodo
rajah
carnivorous
A
community
organisms
Wildebeest
in
East
a
Africa.
–
An
factors,
their
log
(the
such
shrubland
includes
decomposing
component
as
in
Indonesia
Mount
Kinabalu
in
Mount
Kilimanjaro
Malaysia
forest
all
the
ecosystem
and
Island
forest
mountain
plant
kilimanjaro
ecosystem.
Africa
grassland
dragon
and
Protea
East
is
populations
a
unit
environment,
or
a
lake.
community)
light,
water,
An
interacting
ecosystem
and
pH
of
different
containing
the
and
is
abiotic
the
in
Kenya
species
in
community
together,
made
for
up
of
component
an
of
example
the
in
biotic
(physical
temperature).
immigration
Population
+
Figure
19.6.1
population.
population
size
number
of
shows
The
the
factors
number
deaths
of
that
births
decreases
it.
determine
adds
to
the
Individuals
the
size
of
population
may
enter
or
a
and
leave
the
a
size
population
Animals
are
xed
plants
leave
emigration
Figure
19.6.1
Factors
migrate
so
use
one
affect
from
you
seed
so
there
would
the
rate
of
mixing
think
dispersal
population
is
of
populations.
to
that
between
migration
colonise
plants
population
to
new
join
populations.
is
not
areas
another
.
growth
are
and
The
food
Flowering
possible.
in
this
main
supply,
plants
However
,
way
individuals
factors
that
predation
inuencing
population
size.
and
disease.
growth.
An
exponential
predators
254
neighbouring
Figure
19.6.2
organism
and
and
that
stationary
no
disease.
shows
enters
the
a
phases
different
new
if
stages
habitat
there
is
may
plenty
of
population
show
of
the
food,
no
lag,
tnemelppuS
tnemelppuS
Dene
area,
visible,
separate
•
time.
the
to
of
individuals
the
them
rate
of
same
supply,
Some
main
the
population.
Indonesia,
highly
and
a
restricted
in
population
curve
predation
group
at
population
limits
•
a
habitat
the
may
rate
is
population
the
•
growth
OUTCOMES
A
•
communities
Competition
water
and
East
•
nutrients.
and
mates.
factor
for
Plants
Animals
compete
Competition
species
of
compete
for
for
food
herbivores,
for
is
food,
a
such
light,
space,
space
common
as
wildebeest
rebmun
limiting
soil
resources.
fo
(territory)
for
airetcab
tnemelppuS
•
in
Africa.
Predation.
Predators
often
take
young,
sick
individuals
or
less
time
lag
well-adapted
individuals.
Predators
may
limit
the
growth
of
exponential
phase
population
of
prey
animals,
but
it
is
more
often
the
case
that
(log)
of
prey
animals
limit
the
population
size
of
the
death
phase
phase
phase
the
Figure
numbers
stationar y
a
19.6.2
Growth
of
a
bacterial
predator
.
population.
Disease
is
an
important
control
factor
when
KEY
populations
individuals
increase.
more
Pathogens
easily
when
are
transmitted
organisms
live
close
together.
1
A
population
of
The
growth
of
a
population:
POINTS
between
of
growth
a
of
a
population
bacterial
population
changes.
A
small
is
a
good
number
of
way
to
bacteria
show
are
how
placed
the
into
size
habitat
with
a
warm
nutrient
solution
which
is
aerated
so
the
bacteria
aerobically
.
Bacteria
grow
The
and
divide
under
these
of
bacteria
divide
every
20
minutes
if
conditions
conditions.
are
ideal.
the
growth
work
to
out
reach
a
give
two
how
very
cells,
many
large
two
cells
cells
there
divide
will
be
to
give
after
4
four
,
hours
and
and
so
on.
you
One
Y
ou
will
quickly
3
There
and
are
sigmoid
you
look
phases
•
The
the
in
at
the
lag
the
phase,
numbers
make
graph
growth
new
in
of
when
are
so
a
Figure
19.6.2
population
doubling
small.
cytoplasm,
of
Bacteria
DNA
and
you
of
will
see
four
main
The
exponential
rapidly.
The
limiting
growth
a
while,
•
The
rate
factors,
•
The
at
which
of
death
food,
The
such
no
they
are
phase,
the
shortage
curve
lack
which
or
shown
phase
food
phase,
food
so
as
as
the
numbers
take
up
has
little
and
effect
species
resources
algae,
of
grow
them
fairly
show
become
of
food
slows
when
being
when
the
and
down
waste
graph
is
this
and
four
This
are
stable
Most
over
by
by
disease.
in
the
growth
exponential
death
(log),
known
species
species
When
do
not
inuenced
phases.
factors,
such
by
as
food
QUESTIONS
of
But
wastes
that
the
do
of
as
no
in
can
–
b
Give
be
than
rapid
the
because
are
c
State
and
same
of
2
up.
examples
sigmoid
wild.
are
an
lack
products.
growth
When
used
up,
populations
Explain
growth
be
rapidly,
in
of
natural
the
ways
3
like
how
most
may
each
can
of
a
example
act
which
increase
food
b
predation
c
disease
each
and
following
the
limit
the
giving
case:
supply
reference
describe
of
to
population,
in
a
With
in
decrease.
following
being
may
waste
reproduce
their
three
ecosystems.
limit
at
death
toxic
the
population
populations
after
building
of
the
resources
this
Dene
populations
are
dying
growth
a
increasing
are
phase
dying
may
Causes
build-up
population
available,
exponentially.
die.
by
phases
and
are
SUMMARY
stops.
cells
are
of
is
there
growth.
products
cells
and
build-up
and
declines.
a
population
During
produced.
or
the
population
bacterial
more
oxygen
this
food,
as
nutrients,
curve
Some
of
availability.
water
doubling
water.
limit
population
in
or
when
by
to
because
of
size
enzymes.
increases
factors
such
growth,
stationary
produced,
of
are
factors
shortage
log)
population
there
population
(or
of
population
lag,
limiting
bacteria.
1
•
nal
inuenced
growth
These
If
is
cell
number
.
bacterial
same
time.
can
stationary
in
and
availability
curve:
Phases
same
Some
predation
divides
the
living
at
population
the
species
in
same
may
a
respire
group
the
a
2
ask
a
of
bacteria
species,
The
is
individuals
tnemelppuS
Disease.
to
Figure
explain
19.6.2,
each
of
the
phases:
remain
a
lag
b
c
stationary
exponential
(log)
time.
d
death
255
tnemelppuS
•
19.7
Human
Human
LEARNING
Describe
and
explain
in
the
population
present,
and
its
of
social
the
world.
in
the
human
were
and
of
TIP
your
self
world
cur ve
was
a
a
estimated
years
Lack
of
that
Look
cont
ro l
snoillib
of
not
food
live
and
the
to
make
crops
remain
shelter
meant
population
by
an
and
human
impact
together
that
was
with
mortality
about
in
from
the
communities
activities.
on
keeping
food
so
scattered
their
the
case
wild,
of
the
and
0.2
the
rates
billion
However,
much
They
by
relied
although
shing
of
people
environment
livestock.
clearing
less
these
on
were
still
industry.
3.0
1950
0
2
0
0
0
2
2
1
1
7
9
0
1
1
5
0
0
0
9
0
0
0
0
that
AD
19.7.1
Notice
the
long
lag
phase
and
short
exponential
phase
of
no
sign
of
a
stationary
phase.
species
.
human
for
population
the
Improved
following
has
agriculture
nutrition
those
increased
exponentially
over
the
past
300
reasons:
means
means
they
caused
by
that
are
most
better
people
are
defended
better
against
fed.
diseases,
malnutrition.
TIP
•
Public
health
drainage
a
good
the
place
section
to
on
be
page
on
awar
e
contro
l
ts
Y
ou
popu
lation
s.
of
of
to
care
antibiotics;
how
in
Medical
diseases,
improved.
and
There
sewage
waterborne
are
clean
treatment.
diseases
such
as
water
This
supplies,
has
decreased
cholera.
has
improved.
people
such
as
are
also
Since
the
1940s
vaccinated
diphtheria
and
doctors
against
many
have
used
infectious
polio.
the
The
sujec
t
has
waste
birth
206.
of
of
epidemics
•
effects
of
these
improvements
have
been:
hum
an
•
decrease
•
decrease
•
increase
In
is
in
in
in
Europe
for
256
and
wars
4.0
especially
broade
r
people
increase
5.0
be
Better
birth
slow
cont
ro l
•
shou
ld
billion
a
0.4
years
revis
e
7
1.0
The
contro
l
be
only
long.
world’s
small,
collecting
and
Figure
is
an
6.0
with
T
his
at
po pu
latio
ns
from
STUD
Y
to
was
0
hum
an
anim
al
growing
2.0
how
have
may
in
0
0
5
the
and
decide
these
Y
ou
how
differ
s
there
and
year
of
is
7.0
long
fo
chan
ged.
planet
8.0
shor
t
phas
e.
and
effect
s
aske
d
has
predat
ion
–
the
the
compe
tition
food,
diseas
e
the
–
did
unaffected
growing
elpoep
fo r
why
and
factor
s
species
were
of
diseases
ago
lived
beginning
po pu
latio
n
phas
e
the
people
years
People
hunting
expone
ntia
l
at
there
thousands
population.
and
important
lag
2011,
malnutrition,
high
forests,
grow
th
In
For
thousand
were
Ask
on
growth
the
hum
an
people
human
people.
STUD
Y
of
and
Six
population
number
impact
graphs
diagrams
rate.
in
effects
Interpret
the
human
environmental
•
growth
the
alarming
increase
population
OUTCOMES
At
•
populations
men
68
the
death
life
and
and
years.
infant
and
rates
from
expectancy
North
80
child
–
starvation
people
America
years
for
mortality
the
women.
are
and
now
average
In
rates,
malnutrition,
living
life
India,
much
longer.
expectancy
average
life
is
76
years
expectancy
In
spite
of
housing,
these
water
population
and
life
improvements
and
live
in
health
poverty
expectancies
services.
with
that
there
are
huge
Many
high
half
are
of
infant
those
inequalities
the
and
world’s
child
in
food,
human
mortality
rates,
aforementioned.
KEY
Controlling
There
are
oods,
life.
still
wars,
But
the
estimated
human
controls
on
tsunamis,
overall
that
it
population
earthquakes
trend
could
population
is
a
rapid
double
in
increase.
and
other
increase
the
next
POINTS
growth
in
30
Famines,
epidemics,
disasters
the
lead
world’s
to
1
loss
of
population.
Improved
public
It
is
care
years.
have
Europe
places
and
North
populations
America
continue
the
to
population
grow.
The
is
virtually
Earth
has
stable.
limited
In
space
and
the
population
will
have
to
stabilise
and
resources
even
some
time
in
the
future.
The
most
obvious
way
to
do
this
is
birth
rate.
But
many
groups
of
people
have
strongly
held
to
in
an
the
and
Fewer
children
are
dying
from
decrease
to
and
lack
of
food,
and
reduce
people
the
increase
population.
disease
at
better
medical
other
2
limited
and
contributed
exponential
human
In
agriculture,
health
religious
are
now
living
much
or
longer.
moral
views
on
birth
control
and
family
size.
This
means
they
may
often
3
have
large
families.
China
has
had
a
‘one-child’
policy
since
1979
and
The
increase
population
is
claimed
this
has
restricted
population
growth
in
that
country
.
No
in
has
has
such
a
base
of
the
population
pyramids
below
show
the
percentage
food
below
the
age
of
5
years.
The
oldest
people
appear
at
The
rate
proportion
Increasing
of
of
needs
increase
in
populations
child-bearing
human
women
population
size
in
is
most
the
brings
inuenced
by
of
food,
and
problems
housing,
for
transport
the
how
to
dispose
demands
of
our
and
greater
environment,
energy
rubbish
needs.
(see
–
to
the
demands
such
There
as
is
the
on
also
supply
Unit
the
QUESTIONS
of
problem
Study
the
population
21).
pyramids
Ethiopia
space
rubbish.
population.
1
of
and
our
SUMMARY
resources
as
housing,
the
dispose
top.
supplies,
of
energy
children
such
policy
.
on
The
human
social
other
implications,
country
the
it
on
the
left.
2014
a
State
which
country
has
100+
Male
Female
95–99
the
greater
proportion
90–94
85–89
of
i
young
people,
ii
old
80–84
75–79
people.
70–74
65–69
60–64
b
Suggest
reasons
for
the
55–59
50–54
differences
45–49
between
the
40–44
populations
35–39
of
the
two
30–34
25–29
countries.
20–24
15–19
c
10–14
Suggest
what
you
think
5–9
0–4
9
7.2
5.4
3.6
1.8
0
will
0
1.8
3.6
5.4
7.2
happen
(millions)
Age
group
Population
United
States
–
to
i
the
numbers
(millions)
of
women
of
child-
2014
100+
Male
each
9
country
Population
in
bearing
age
in
10
years’
Female
95–99
90–94
time,
and
in
years’
ii
the
birth
rate
85–89
80–84
75–79
10
time.
70–74
65–69
d
Outline
the
likely
effects
60–64
55–59
that
50–54
your
answers
to
part
45–49
c
40–44
will
have
on
the
two
35–39
30–34
countries
in
the
future.
25–29
20–24
15–19
2
Explain
why
infant
and
10–14
5–9
child
0–4
15
12
Population
9
6
3
0
Age
(millions)
0
3
6
group
9
12
Population
15
19.7.2
Population
pyramids
for
Ethiopia
and
the
USA
and
rates
why
have
people
(millions)
are
Figure
mortality
decreased
living
much
longer.
(2014).
257
PRACTICE
1
The
for
QUESTIONS
diagram
an
shows
ecosystem.
tertiary
a
pyramid
Which
level
of
numbers
indicates
6
the
Some
species
nodules
consumers?
do
of
these
of
bacteria
legumes.
bacteria
A
compounds
B
protection
C
sugars,
D
water
live
Which
provide
of
inside
of
to
the
the
the
root
following
legumes?
nitrogen
A
from
infection
by
fungi
B
C
D
(Paper
(Paper
1)
Fungi
and
carbon
they
and
as
ions
sucrose
from
the
soil
2)
[1]
[1]
7
2
such
bacteria
and
are
nitrogen
important
in
in
ecosystems
recycling
What
is
the
population
best
size
explanation
shown
in
for
the
the
change
in
graph?
because
are:
A
decomposers
B
herbivores
C
parasites
D
producers
population
size
0
(Paper
3
In
the
1)
[1]
carbon
carbon
cycle,
dioxide
to
which
the
A
combustion
and
B
decomposition
C
feeding
D
photosynthesis
and
two
processes
add
atmosphere?
respiration
and
fossilisation
A
birth
B
emigration
C
an
outbreak
rate
and
D
no
limiting
death
of
rate
and
1)
is
a
factors
2)
[1]
The
diagram
shows
a
pyramid
→
simple
food
grasshopper
arrows
→
bird
in
a
food
in
chain
decrease
numbers
B
the
ow
of
C
the
increase
in
complexity
D
the
increase
in
size
between
of
2000
weeds
the
20 000
organisms
Which
energy
400
represent:
the
of
10
fish
tadpoles
A
the
the
of
organisms
the
is
pyramid
organisms
A
a
correct
shown
Biomass
1)
From
the
and
about
the
diagram?
less
between
secondary
producers
and
primary
consumers
primary
than
consumers.
[1]
B
5
statement
in
decreases
consumers
organisms
between
(Paper
biomass.
chain:
water
The
of
[1]
small
grass
same
disease
pike
Here
the
respiration
8
4
are
fossilisation
(Paper
(Paper
time
0
which
A
maize
B
soya
food
→
beef
beans
→
chain
is
cattle
most
→
energy
lost?
The
very
humans
C
The
is
humans
biomass
of
each
of
the
individual
producer
is
large.
biomass
more
than
20%
primary
of
the
consumers
biomass
of
the
producers.
C
grass
→
dairy
cattle
D
phytoplankton
→
humans
D
→
(Paper
small
2)
sh
→
→
mollusc
tuna
→
There
are
humans
(Paper
many
producers.
[1]
9
(a)
2)
Use
[1]
this
Flower
black
that
258
very
larvae
information
beetles
cherry
eat
eat
trees.
ower
to
the
draw
pollen
a
and
Kookaburras
beetles.
food
chain:
nectar
are
of
birds
[2]
(b)
State
the
chain
role
you
of
have
each
organism
in
the
food
drawn.
(a)
[3]
The
plant
energy
absorbs
that
photosynthesis
(c)
Dene
(d)
State
the
term
population.
factors
that
inuence
the
growth
of
a
State
population.
Outline
the
reasons
for
the
human
the
population
two
plants
large
State
over
the
years.
The
Only
dry
three
as
about
shows
square
the
metre
total
of
biomass
grassland
formed
during
in
one
plant
gures
mass
were
and
obtained
not
the
by
fresh
measuring
mass
of
the
State
uses
the
to
living
(ii)
2
organisms
in
are
produced
sugars.
which
adapted
to
[2]
the
trap
leaves
as
much
[3]
of
the
energy
dry
mass
/
g
m
photosynthesis
plants
trapped
by
carnivores
0.1
the
biomass
percentage
between
Show
decrease
green
(c)
Name
(d)
Suggest
in
plants
your
the
plant
available
how
antelopes
[2]
much
each
energy
year.
reaches
Express
your
as
kJ
m
.
Show
your
working.
process
the
advantage
rather
than
of
trophic
mass
as
antelope
faeces
loses
more
compared
of
with
its
the
[2]
This
food
chain
has
three
trophic
levels
it.
Explain
why
there
are
no
more.
[4]
during
4)
levels.
12
The
following
substances
measuring
fresh
the
intake
[1]
[2]
formed
between
why
X.
cheetah.
working.
biomass
decreases
mass
the
not
and
[3]
dry
is
–2
(Paper
Explain
which
that
–1
in
why
year
in
herbivores.
year
(e)
herbivores.
the
ways
energy
Calculate
energy
Explain
to
[3]
0.9
the
passed
480
herbivores
Calculate
is
antelopes.
two
the
answer
green
(c)
that
simple
possible.
like
the
the
(b)
the
ways
are
10%
in
herbivores
material.
(a)
sugars.
year
.
(i)
The
in
3)
table
one
it
[4]
the
10
the
past
(b)
(Paper
compounds
from
plants
light
250
simple
of
uses
increase
of
in
make
1%
and
[3]
(ii)
(e)
about
plant
rate
in
of
to
the
[3]
(i)
three
only
strikes
when
urea,
are
that
ammonia
biologically
contain
(NH
),
the
important
element
amino
acids,
nitrogen:
nitrite
3
investigating
different
biomass
production
in
ions,
ecosystems.
Choose
match
4)
may
11
The
diagram
shows
the
passage
of
a
food
light
chain
energy
in
that
a
grassland
strikes
the
each
year
is
400 000 kJ
m
of
of
each
the
the
one
substances
statements
once,
more
from
(i)
the
to
than
(v).
list
to
Y
ou
once
or
all.
ecosystem.
leaves
of
the
main
nitrogen-containing
the
excretory
2
grass
each
use
at
(i)
The
one
energy
not
along
ions
[3]
(a)
(Paper
nitrate
product
of
animals
.
(ii)
absorbed
by
(iii)
a
(iv)
synthesised
(v)
the
plants
33%
process
radiant
from
X
70%
energy
process
product
of
deamination
X
into
proteins
sun
400 000
kJ
(b)
10%
end
Nitrogen
product
gas
(N
)
in
of
nitrication
the
atmosphere
[5]
is
2
inert.
very
12%
in
10%
in
Unlike
few
carbon
organisms
Describe
how
dioxide
are
nitrogen
able
gas
body
of
body
antelope
(N
)
oxygen,
use
it.
present
in
of
the
faeces
faeces
to
2
20%
55%
and
atmosphere
is
made
available
to
be
cheetah
used
(Paper
by
organisms.
[4]
4)
259
20
Biotechnology
and
genetic
engineering
20.1
Microorganisms
and
biotechnology
The
LEARNING
use
of
microorganisms
Biotechnology
•
State
how
bacteria
are
biotechnology
biotechnology
and
is
the
use
of
microorganisms,
such
as
bacteria
and
useful
fungi,
in
and
OUTCOMES
to
make
useful
products
or
to
carry
out
services
for
us,
such
as
genetic
making
wastes
harmless.
engineering
The
•
Describe
the
role
of
yeast
of
anaerobic
breadmaking
•
Describe
the
respiration
in
production
•
role
yeast
of
in
the
ethanol
use
of
both
bacteria
and
fungi
are
in
various
processes
is
widespread.
in
Bacteria
taken
•
for
Unlike
the
biofuels
or
•
reproduce
for
numbers
animals
nished
quickly
double)
plants,
product
very
with
that
microbes
quickly,
a
is
generation
often
can
i.e.
as
convert
in
time
little
hours
as
raw
(the
30
time
minutes.
materials
rather
than
into
months
weeks.
The
use
of
bacteria
independent
•
or
very
to
Bacteria
can
antibiotics)
harvested.
of
means
that
food
production
can
be
climate.
produce
that
pass
Enzymes
complex
out
into
made
by
proteins
the
(like
enzymes
surrounding
microorganisms
and
medium
are
used
and
in
can
the
be
food
industry.
Examples
food
•
of
enzymes
industry
amylase
that
are
produced
by
bacteria
for
use
in
the
are:
for
breaking
down
starch
in
the
production
of
glucose
syrup
of
the
products
of
pectinase
•
sucrase
•
protease
for
for
extracting
breaking
for
making
juice
down
meat
from
fruit
sucrose
more
in
(see
page
making
263)
confectionery
tender
traditional
biotechnology.
With
the
aid
microbes
of
In
plants
and
addition
with,
since
In
copies
The
of
use
people
have
concerns
about
the
of
and
health
of
chickens
260
the
and
and
contrast,
long
bacteria
the
the
bacterial
the
same
cells
are
alter
new
multiply
gene
can
can
be
rapidly,
(see
varieties
of
concerns
contain
to
be
work
cut
spliced
making
page
manufacture
ethical
also
easy
Plasmids
organism
inserted
in
breeding
Plasmids
quickly.
another
quickly
time.
DNA,
very
fungi
raise
In
can
open
into
many
267).
complex
over
their
the
kept
in
and
growth
as
would
be
the
case
in
the
use
of
other
these
living
conditions.
not
of
from
media
a
scientists
plasmids.
replicate
plasmid
does
take
loop
called
gene
bacteria
manipulation
welfare
a
nutrient
chemicals
Many
can
and
products.
can
single
DNA
they
enzymes
them.
the
of
engineering,
modify
animals
to
circles
genetic
so
and
small
by
of
organisms,
for
example
keeping
chickens
in
battery
farms.
tnemelppuS
Some
•
Biofuels
Many
and
microbes
respire
When
with
or
yeast
breadmaking
can
respire
without
respires
successfully
without
oxygen.
Yeasts
can
oxygen.
without
oxygen
(anaerobically)
it
is
called
fermentation.
Glucose
→
alcohol
+
carbon
dioxide
+
energy
released
Biofuels
Some
Biofuels
are
fuels
made
from
biological
material.
Sugar-rich
products
This
biofuels
biobus
cooking
from
sugar
cane
and
maize
can
be
fermented
anaerobically
own
uses
to
produce
and
have
fermenters
sugar
cane
to
juice
maize
starch
starch
with
ethanol.
developed
is
another
is
and
when
as
fuel
ethanol
dioxide
Car
Oil
a
in
called
good
a
the
engines
seed
raw
burned
need
is
to
a
be
for
raw
oil
supplies
for
material
is
obtained
other
from
waste
made
waste
from
material.
used
of
food
products
from
industry.
their
example,
often
carbohydrates.
This
petrol
that
not
there
As
a
that
because
produce
is
no
result
modied
crop
of
material.
does
atmosphere.
rape
The
lot
no
Brazil,
fuel
used
Glucose
by
is
from
treating
the
enzymes.
substitute
means
a
have
substitute.
ethanol.
contains
carbohydrase
content
countries
biofuel
produce
which
Ethanol
Some
a
and
made
on
with
the
yeast
oil
are
runs
to
overall
this
be
provides
it
fuel
able
oil
has
toxic
high
increase
is
to
that
a
gases.
in
carbon
use
is
pure
energy
Using
carbon
neutral
ethanol.
converted
into
fuel
biodiesel
Bread-making
Yeast
Baking
is
another
Bread
is
made
yeast.
This
the
Bubbles
of
rise.
gas
sugar,
carbon
When
make
the
the
evaporate,
from
mixture
ferment
it
example
dough,
is
kept
at
using
dioxide
bread
is
mixture
a
warm
are
behind
in
a
our,
inside
hot
texture.
the
of
help
dioxide
trapped
in
to
produce
water,
temperature.
carbon
baked
‘light’
yeast
a
producing
bread
leaving
of
gas
the
oven
The
traditional
taste
of
sugar
the
and
starts
produced
bread
their
light
carbon
dough
to
dioxide
rise
and
the
of
the
alcohol
to
bread.
POINTS
Bacteria
are
useful
reproduce
2
a
Write
b
In
ways
in
which
bacteria
are
useful
in
a
word
equation
for
anaerobic
respiration
in
why
is
yeast
mixed
to
our
and
with
sugar
before
it
to
Make
of
a
table
ethanol
as
the
ethanol
summarising
a
fuel
for
make
Yeast
carries
out
anaerobic
in
the
production
water?
made
by
yeast
in
the
cars.
advantages
and
ethanol
for
biofuels.
bread-making?
3
3
and
is
of
happens
rapidly
molecules.
respiration
added
What
genetic
they
yeast.
2
bread-making,
as
biotechnology.
complex
c
in
and
QUESTIONS
engineering
four
loaves
texture.
biotechnology
List
caused
these
make
1
1
which
give
to
KEY
SUMMARY
and
alcohol.
bubbles
causes
food.
yeast
dough
the
heat
salt,
The
and
a
disadvantages
Yeast
carries
respiration
out
anaerobic
during
bread-
making.
261
20.2
Enzymes
and
biotechnology
Enzymes
LEARNING
•
have
Investigate
pectinase
the
in
use
the
of
Biological
production
Investigate
enzymes
washing
tnemelppuS
•
Explain
the
important
in
industry.
washing
powders
washing
powders
may
contain
one
or
more
of
the
juice
following
•
very
of
Biological
fruit
become
OUTCOMES
in
the
use
biological
powders
the
types
of
enzymes:
of
•
proteases
•
lipases
–
–
break
break
down
down
protein
fats
in
stains,
grease
e.g.
stains,
blood,
e.g.
grass
butter,
and
egg
lipstick
and
mayonnaise
use
of
lactase
production
of
lactose-free
in
•
amylases
–
•
cellulases
break
down
starch,
e.g.
food
stains
containing
starch
milk
fabrics
The
the
to
–
enzymes
high
water
listed
down
the
powders.
the
and
are
of
removed
been
alkaline
a
the
bres
attached
have
and
During
products
cellulose
dirt
above
temperatures
washing
stains;
break
remove
to
reactions
the
the
modied
so
conditions
washing
when
on
outside
of
cotton
them
cycle,
the
dissolve
washing
that
they
required
for
enzymes
or
are
withstand
some
break
suspended
machine
empties.
down
in
For
BIOLOGICAL
example,
Washing
proteins
cellulose

Contains

Works

More

Avoid

Do
protease
best
at
effective
using
not
use
low
and
boiling
are
broken
down
into
into
amino
acids
and
starch
and
glucose.
(40°C)
detergent
water
PRACTICAL
silk
Comparing
Figure
broken
down
lipase
temperatures
thanordinary
with
are
Powder
20.2.1
Biological
washing
the
action
of
biological
and
non-biological
powder.
washing
powder
1
what
Decide
soya
2
sauce,
Decide
linen
3
Add
you
what
or
sort
sort
wool.
the
put
of
Also,
same
it
of
stain
mustard,
fabric
the
are
you
decide
amount
into
you
going
to
have,
e.g.
egg,
etc.
of
are
what
stain
beakers
to
going
size
to
of
the
to
use,
fabric
fabric
e.g.
to
and
cotton,
use.
let
it
dry
before
‘wash’.
3
4
Granules
of
biological
washing
Weight
out
water
at
5
Add
piece
6
Decide
a
30 °C
Inside
as
of
the
these
cleansing
granules
granules
are
are
partially
enzymes
each
a
the
powder
dissolve
each
in
500 cm
which
act
7
Decide
you
fabric
are
with
going
the
to
same
stir
the
stain
to
each
‘washing’
beaker
.
over
a
period.
how
to
compare
the
cleanliness
of
each
fabric
after
agents.
8
Repeat
Safety:
into
You
your
Wear
contact
could
tests
to
gloves
with
of
beaker.
same
often
and
opened.
washing.
262
in
of
how
of
powder.
10-minute
Some
5 g
produce
see
and
your
if
do
skin
a
you
not
to
scale
get
let
avoid
of
the
the
a
cleanliness.
same
results.
washing
possible
powders
allergic
come
reaction.
Extracting
Pectinases
molecules
for
fruit
are
that
extracting
juice
enzymes
act
like
fruit
a
apples
that
break
‘glue’
juices
and
in
for
down
plant
pectins,
cell
walls.
softening
which
are
Pectinases
are
used
vegetables.
PRACTICAL
juices
Extracting
juice
from
apples
with
pectinase
Figure
1
Cut
an
apple
in
B
A
20.2.2
Extracting
apple
juice
using
half.
pectinase.
2
Chop
each
half
into
small
pieces
and
put
them
into
separate
the
juice
in
from
a
apple
water
each
of
in
bath
the
in
beaker
beaker
at
of
and
10 cm
of
B.
40 °C
beakers
A
for
20
apple
minutes.
31
30
20
eciuj
Filter
beakers
the
apple
emuloV
5
both
over
the
fo
Place
solution
over
decudorp
4
water
/
3
of
10 cm
pectinase
elppa
Pour
mc
3
3
40
3
beakers.
10
2
pieces.
0
water
•
Explain
the
results
shown
in
the
pectinase
graph.
A
•
How
does
the
pectinase
release
this
juice
from
the
apple
cells?
Figure
20.2.3
Why
was
10 cm
of
water
added
to
beaker
tnemelppuS
SUMMARY
use
Some
people
problems
get
lactase
do
not
digesting
diarrhoea,
milk
be
of
broken
into
enough
lactose,
and
Lactose
down
making
produce
and
wind
products.
in
the
stomach
is
a
sugar
cramps,
complex
simple
lactose-free
lactase
sugars
sugar,
by
the
and
found
if
to
from
extract
the
juice
A?
from
The
results
practical
3
•
B
Sample
milk.
to
enzyme
or
that
Describe
what
following
may
milk
sucrose
1
have
They
consume
similar
QUESTIONS
milk
therefore
in
they
apples.
each
enzymes
a
amylase
c
lipase
b
of
the
do.
protease
can
d
pectinase
lactase.
2
Explain
the
advantages
of
lactase
using
glucose
+
sugar)
(2
simple
can
using
investigate
test
strips
the
test
use
Benedict’s
strips
reducing
the
that
that
test
sugars
detect
are
as
and
effect
used
all
of
the
lactase
in
breaking
concentration
to
detect
glucose
three
sugars
in
give
a
positive
powders.
sugars)
3
You
biological
galactose
washing
(complex
in
the
of
in
down
glucose.
urine.
equation
lactose
These
You
Explain:
by
a
are
water
beaker
cannot
above
why
are
b
result.
the
was
added
to
A,
results
in
the
graph
above,
c
4
a
how
pectinase
juice
from
How
is
releases
apple
tissue.
lactose-free
tnemelppuS
lactose
enzymes
milk
produced?
KEY
POINTS
b
Why
for
1
Biological
wash
washing
powders
temperatures
and
in
contain
alkaline
enzymes
that
work
at
is
there
Pectinase
conditions.
c
Outline
an
in
is
used
the
cell
to
extract
walls
in
fruit
fruits
juice
such
by
as
breaking
down
tnemelppuS
Lactase
breaks
down
lactose
to
is
the
to
best
the
to
produce
apple.
lactose-free
3
milk?
experiment
which
temperature
pectin
demand
low
discover
2
a
lactose-free
produce
lactose-free
milk.
milk.
263
20.3
Fermenters
tnemelppuS
You
LEARNING
may
without
•
Describe
the
Penicillium
of
•
the
role
in
it
of
the
antibiotic
how
fermenters
used
penicillin
refers
useful
production
oxygen
to
any
may
Industrial
production
inoculated
•
Adding
for
Penicillium
Fungi
are
growing
cultured
on
like
whether
they
are
suitable
as
that
carry
uses
out
with
However,
as
or
a
in
meaning
an
respiration
industrial
microorganisms
useful
without
process
to
for
context
produce
us.
The
agar
this
to
organisms
of
in
a
of
such
culture
This
inside
then
the
nutrients,
penicillin
large-scale
antibiotics
a
of
of
industrial
as
a
penicillin.
suitable
proceeds
fermenter.
such
as
fermentation
to
grow
These
sugar
or
The
fungus,
fermenter
in
under
this
the
conditions
starch,
as
is
a
is
case
Penicillium
conditions
should
source
include:
of
Ammonia
or
•
Vitamin
complex
•
Maintaining
a
constant
temperature
•
Maintaining
a
constant
pH
Batch
B
urea
is
added
is
as
added
a
source
for
of
of
nitrogen
to
make
proteins
respiration
about
of
about
30 °C
6.5
culture
sources
takes
about
30
hours
for
penicillin
production
to
start.
of
is
biomass
secreted
into
the
surrounding
liquid
100
of
by
the
10
fungus.
yield
of
penicillin
Penicillium
90
9
–3
–3
/
g
/
dm
80
g
dm
8
penicillin
70
7
60
6
50
5
TIP
40
4
biomass
Ferm
enters
suita
ble
of
carbon
respiration
Penicillin
grow
th
the
nd
antibiotics.
STUD
Y
a
oxygen.
•
It
out
to
use
with
maintained
dish.
fermentation
140).
production
chrysogenum.
fungus
or
respire
important
production
Petri
word
page
are
One
The
the
(see
process
product
involved
penicillin
Explain
in
recognise
OUTCOMES
30
me ta
bo
fo r
lism
micro
orga
nism
s,
3
Penicillium
provid
e
cond
ition
s
and
of
20
2
10
1
such
0
as
If
bacter
ia
the
high
,
fung
i.
tempe
ratu
re
enzy
mes
micro
bes
the
0
and
60
80
in
/
100
120
140
160
hours
too
the
Figure
20.3.1
This
graph
production
and
140
and
shows
of
160
the
growth
penicillin
of
during
a
the
fungus
Penicillium
fermentation
that
and
lasts
the
between
hours.
die.
Look
264
40
time
is
dena
ture
orga
nism
s
20
at
the
graph
production.
This
a
which
substance
is
above.
You
because
is
not
should
penicillin
necessary
see
is
for
a
that
there
is
secondary
the
growth
of
a
delay
in
metabolite,
the
fungus.
production
starts
after
the
exponential
growth
phase
in
motor
response
in
is
the
one
or
fermenter
then
as
to
puried
batch
cleaned
more
is
ltered,
into
culture.
and
limiting
a
the
penicillin
crystalline
After
sterilised
the
ready
6
factors.
salt.
day
for
After
is
This
extracted
type
period,
the
next
about
the
of
6
days,
using
a
is
mixture
solvent
production
fermenter
the
is
and
steam for
foam breaker
sterilisation
reduces
known
emptied,
foaming of
the culture
batch.
culture broth
Industrial
Industrial
fermentation
fermenters
are
large
tanks
(see
right)
that
can
hold
as
much
probes for
monitoring pH,
3
as
500 000 dm
of
fermenting
mixture.
Conditions
inside
these
huge
oxygen and
tanks
are
carefully
controlled.
We
will
use
the
production
of
the
temperature
antibiotic
penicillin
to
show
how
these
fermenters
work.
large stirrer to
•
The
fermentation
with
a
medium
sugars
and
vessel
containing
ammonium
is
made
the
salts.
of
stainless
required
To
this
steel
nutrients.
some
of
the
and
These
fungus
is
lled
mix contents
include
Penicillium
water-cooled
jacket removes
is
added.
excess heat
•
The
fungus
grows
well
in
the
conditions
inside
the
fermenter.
sterile air –
Sugars
provide
energy
for
respiration
and
ammonium
salts
are
used
provides
by
the
fungus
to
make
proteins
and
nucleic
acids
(DNA
and
RNA).
oxygen for
diffuser – sends
After
a
few
days
the
fungus
starts
to
produce
penicillin,
respiration
bubbles of air
which
through the
accumulates
in
the
fermenter.
mixture
har vesting
•
A
stirrer
keeps
the
microorganisms
suspended
so
they
always
have
drain
access
even
•
An
to
temperature
air
supply
fungus.
to
•
A
nutrients
(No
make
at
alcohol.
6.5
to
See
oxygen
page
a
Stirring
the
supplied
jacket
the
adding
Explain
is
give
monitor
by
SUMMARY
1
provides
water-cooled
Probes
oxygen.
throughout
oxygen
fermentation
•
and
for
to
maintain
an
Figure
the
the
aerobic
yeasts
respiration
respire
of
without
20.3.2
Large
industrial
fermenter.
the
oxygen
261.)
removes
the
heat
produced
temperature
temperature
if
helps
fermenter.
as
constant
alkalis
also
and
make
of
by
24°C.
sure
the
pH
is
constant
necessary.
QUESTIONS
the
function
of
each
of
the
following
in
an
industrial
Industrial
fermenters.
fermenter:
a
a
stirrer
b
an
d
temperature
air
supply
c
a
water-cooled
jacket
KEY
and
pH
1
2
Explain
3
State
in
a
the
the
role
of
Penicillium
conditions
POINTS
probes
in
necessary
the
for
production
the
of
production
Microorganisms
reproduce
quickly
conditions
penicillin.
of
found
penicillin
the
fermenters
fermenter.
products
4
Explain
how
and
fermentation
why
these
factors
change
during
ideal
inside
large,
such
temperature
b
2
oxygen
concentration
c
The
What
is
meant
ideal
conditions
batch
for
include
adding
correct
nutrients
and
by:
maintaining
a
useful
penicillin.
pH
the
5
as
a
process:
fermentation
a
industrial
producing
culture
b
secondary
metabolite?
and
a
constant
pH
temperature.
265
tnemelppuS
Penicillin
20.4
Genetic
Genetic
LEARNING
engineering
Dene
the
term
is
genetic
engineering
•
State
can
of
that
be
human
and
tnemelppuS
•
in
Outline
engineering
the
production
medicines,
insect
providing
vitamins
in
how
herbicide
resistant
plants,
species
never
the
of
DNA
changing
the
DNA
achieved
one
of
humans
is
of
by
species
transfer
codes
the
the
genetic
material
of
a
gene
This
selection,
another.
between
totally
from
individual
production
species.
with
and
inserting
the
transfer
articial
bacteria
or
for
another
breed
genes
to
changing
that
engineering
to
be
would
removing,
of
from
is
a
because
specic
the
DNA
an
only
in
species,
A
one
can
rare
for
gene
protein.
of
that
engineering
unrelated
to
a
process
Genetic
bacteria
of
genes.
cases
allows
example
plants.
plants
Examples
genetic
is
by
section
from
additional
crop
engineering
a
Genetic
genetic
used
resistant,
involves
OUTCOMES
organism
•
engineering
used
to
of
genetic
engineering
make
Human
medicines
insulin
Many
•
Discuss
the
advantages
and
disadvantages
of
human
blood
clotting
modied
are
Herbicide
A
a
makes
with
the
the
affected
weeds
insulin,
human
produced
by
appropriate
reduce
the
can
be
sprayed
competition
of
variety
growth
bacteria
hormones
that
human
genes.
have
been
These
the
herbicide
of
to
from
medicines.
so
rape
a
has
soil
herbicide
this
itself.
and
as
oilseed
it
the
rape
crop
used
plants
into
resistant
oilseed
also
the
and
crop
transferred
rape
but
by
are
Insect
soya
is
elds
weeds,
in
modied
gene
to
produced
resistance
oilseed
applied
Herbicide-resistant
mass
genetically
which
to
are
crops
proteins
herbicides
including
agents,
genetically
genetically
modifying
proteins,
and
the
would
GM
continues
developed
This
glufosinate.
herbicide
But
been
bacterium.
to
not
oilseed
grow
When
only
rape
while
in
gene
kill
is
not
only
the
destroyed.
resistance
in
crop
plants
with
from
Maize
and
attacked
weeds
maize
and
cotton
by
are
are
insects
root
cotton
worm
boll
both
which
important
reduce
larvae
weevils
are
and
cash
their
crops,
yields.
The
stem-boring
pests
of
cotton
but
both
major
can
pests
caterpillars.
be
of
Caterpillars
plants.
th
At
the
beginning
produced
for
this
The
a
toxin
toxin
that
pesticides,
people
giving
to
it
available
disease
glasshouse
266
resistance
conditions.
in
GM
rice
under
on
it.
only
genes
make
its
to
people
who
reduce
the
grow
eat
high
has
the
in
crop
A.
on
it.
a
to
In
their
feeding
own
on
was
the
maize
environmental
rice
scale
be
rates
have
a
soil
resultant
Rice™.
will
mortality
caterpillars.
and
The
large
They
bacterium
1990s
and
toxin
crop
that
the
cotton
than
gene
plants.
which
impact
the
found
kills
insect
spraying
plants
are
killed.
plants
of
maize
Golden
soil
produce
less
insects
varieties
from
a
transferred
plants
vitamin
name,
certain
and
This
vitamins
century
kills
isolated
modied
transferring
20
which
because
Genetically
the
modied
feed
Additional
Assessing
was
genetically
larvae
of
If,
it
able
as
a
or
will
to
been
developed
bacterium,
rice
is
when,
pale
this
improve
make
result
of
that
yellow
rice
the
vitamin
poor
by
enables
diets
A.
in
colour
becomes
of
This
immune
the
will
systems.
production
Genetic
engineering
cheaply
on
a
large
makes
scale.
it
The
of
tnemelppuS
Industrial
insulin
possible
human
to
make
gene
insulin
that
codes
quickly
for
the
and
production
enzymes
used
to
cut
bacterium
of
insulin
cut
A
the
is
identied.
human
circular
insulin-making
piece
bacterium.
Restriction
of
The
DNA
same
enzymes
gene
called
a
from
the
plasmid
restriction
enzymes
is
act
as
rest
chemical
of
the
removed
are
then
scissors
to
open
DNA.
from
used
a
to
cut
the
open
is
the
plasmid.
The
two
ends
of
the
DNA
of
the
plasmid
insulin-making
gene
new
put
human
plasmid
into
a
put
new
insulin
into
gene
plasmid
are
bacterium
an
exact
called
match
‘sticky
Another
with
called
insulin-making
gene
now
a
bacteria.
as
The
two
DNA
ends
and
the
plasmid.
These
are
ends.’
enzyme
known
the
ligase
to
the
is
used
sticky
recombinant
bacteria
now
has
to
ends
attach
and
plasmid
the
gene
the
sticky
plasmid.
and
code
is
The
ends
back
insulin.
The
cell
the
plasmid
inserted
for
of
is
into
the
bacteria
each
multiply
very
rapidly
inside
an
industrial
fermenter
and
produce
insulin.
modied
The
•
and
disadvantages
of
bacterium
make
has
Advantages
division
insulin
the
can
now
because
insulin
it
gene
genetically
crops
benets:
Solving
global
hunger
–
genetic
modication
could
feed
more
insulin
people
as
climate
the
crops
conditions
marginal
that
and
are
produced
soils.
Food
are
able
production
to
tolerate
could
be
increased
in
Figure
areas.
20.4.1
Human
by
•
Environmentally
friendly
can
be
insects,
less
use
–
GM
crops,
like
soya,
maize
purified
extreme
and
insulin
genetically
is
made
engineered
rice,
bacteria.
would
resistant
of
pesticides.
mean
less
environmental
Consumer
an
avour
and
require
for
that
benets
improved
produce
Also,
need
threat
weeds
–
genes
improve
fertilisers
so
there
would
nitrogen
and
be
uptake
lessen
the
cause.
crops
better
fewer
diseases
that
chemical
they
GM
and
and
have
already
keeping
been
qualities.
produced
They
are
with
easier
to
additives.
SUMMARY
The
concerns:
1
•
Environmental
become
safety
successful
–
weeds.
there
are
Pollen
concerns
from
GM
that
crops
new
that
GM
are
plants
will
Food
may
safety
–
be
transferred
new
gene
to
other
plants
combinations
may
by
insects
resistant
have
or
effects
the
Explain
what
genetic
unknown.
They
may
result
in
harmful
substances
that
being
Describe
three
in
crops
are
which
Biodiversity
reduce
the
–
increasing
number
of
use
plant
of
herbicides
varieties
and
and
wild
plant
breeding
ways
been
engineered
to
them.
will
3
What
4
List
is
the
meant
by
stages
a
plasmid?
involved
bacteria
human
insulin.
Discuss
the
in
that
make
POINTS
Genetic
engineering
involves
taking
a
gene
from
one
and
putting
it
into
another
and
human
plasmid.
insulin
The
gene
bacteria
can
grow
the
of
GM
concerns
species.
people
The
benets
species
crops
2
have
relatives.
5
1
different
so
producing
KEY
by
produced.
improve
•
meant
wind.
genetically
far
is
engineering
to
2
weedkillers
•
QUESTIONS
be
to
transferred
produce
lots
into
of
a
bacterial
human
have
about
their
safety.
insulin.
267
tnemelppuS
•
to
PRACTICE
1
In
QUESTIONS
order
to
to
transfer
another
it
is
a
feature
necessary
to
A
a
chromosome
C
B
a
gene
D
from
one
species
6
a
a
Which
is
the
best
temperature
transfer:
genotype
nucleus
in
a
reason
1)
Yeast
high
temperatures
enzymes
B
at
high
temperatures
the
is
used
biofuels.
in
the
production
of
too
denature
of
much
at
low
This
is
yeast
cells
yeast
bacteria
reproduce
fast
because:
are
cells
a
good
produce
source
oils
that
of
are
at
low
of
nutrients
temperatures
there
is
no
diffusion
energy
added
into
bacteria
to
(Paper
petrol
temperatures
some
D
B
increases
rate
bacteria?
[1]
too
A
contains
at
C
2
controlling
that
A
fermentation
(Paper
for
fermenter
2)
[1]
(gasoline)
7
C
yeast
cells
respire
D
yeast
cells
to
produce
carbon
The
following
modication
respire
without
oxygen
processes
occur
in
the
genetic
dioxide
of
bacteria
to
produce
a
human
to
protein:
produce
(Paper
3
A
to
alcohol
1)
student
is
planning
compare
powders
1
a
gene
is
at
the
a
laboratory
2
a
plasmid
3
bacteria
divide
4
bacteria
are
effectiveness
removing
controlled
stains.
of
three
a
human
cell
factors
during
the
Which
inuences
washing
is
cut
open
by
restriction
enzymes
the
by
binary
ssion
washing
grown
in
a
fermenter
to
combination
activity
of
human
protein
the
5
enzymes
from
investigation
produce
of
isolated
[1]
recombinant
plasmids
are
taken
up
by
process?
bacteria
A
size
of
container,
frequency
of
stirring,
6
type
of
washing
type
of
fabric,
bacteria
make
recombinant
B
length
of
washing
of
type
of
stain,
appearance
D
washing
pH
4
of
size
of
of
fabric,
plasmids
Which
temperature,
1)
Which
substance
volume
of
water,
[1]
A
carbon
B
ethanol
Which
causes
dioxide
bread
C
dough
lactic
D
to
sequence
used
not
bacteria
5,
7,
6,
3,
4
B
2,
1,
7,
6,
4,
5,
3
C
1,
2,
3,
7,
6,
5,
4
D
1,
2,
7,
5,
6,
3,
4
(Paper
acid
a
in
many
reason
do
their
bacteria
not
An
for
industrial
268
events?
is
of
growing
herbicide-resistant
that:
A
less
herbicide
B
there
have
needs
to
be
sprayed
on
the
crop
processes.
is
less
competition
between
weeds
this?
complex
soya
plants
requirements
have
many
enzymes
so
can
there
is
less
risk
of
disease
attacking
the
sets
of
reactions
to
plants
carry
the
soya
plants
grow
faster
make
reproduce
slowly
under
optimum
conditions
are
fewer
safety
the
genes
of
bacteria
the
genes
of
crop
2)
of
products
bacteria
(Paper
order
[1]
advantage
(Paper
there
correct
environment
complex
useful
D
to
oxygen
D
C
combine
2)
soya
out
the
1,
C
B
genes
plasmids
[1]
are
from
is
2,
and
A
human
rise?
1)
is
and
recombinant
A
soya
Bacteria
plasmid
mixture
8
5
the
nal
fabric
washing
(Paper
(Paper
of
fabric
form
C
copies
time,
7
size
multiple
powder
concerns
with
compared
plants
and
modifying
with
modifying
livestock
[1]
2)
[1]
9
A
student
on
the
were
pulp
investigated
extraction
cut
up
was
and
of
crushed
divided
Sample
A
Sample
B
was
the
apple
into
mixed
effect
juice.
to
two
with
of
pectinase
Several
make
a
pulp.
samples,
A
pectinase
12
apples
growth
growth
and
treatment
The
and
Human
made
B.
used
as
a
for
188
to
reduced
amino
(HGH)
young
promotes
people
growth.
It
is
as
a
a
protein
acids.
(i)
State
how
many
bases
in
DNA
code
control.
for
(a)
hormone
given
powder.
(a)
was
of
is
this
protein.
[1]
your
[2]
Suggest:
(ii)
(i)
what
should
be
added
to
sample
B
Explain
Genetically
it
is
being
used
as
a
control,
three
variables
that
the
student
hormone
and
bacteria
a
similar
make
human
hormone
found
should
in
keep
engineered
[1]
growth
(ii)
answer.
as
constant.
cattle.
HGH
is
used
to
treat
children
who
[3]
do
not
grow
properly.
There
may
be
a
genetic
3
(b)
The
student
obtained
35
cm
of
juice
reason
from
for
this
or
they
may
have
received
3
sample
A
noticed
and
that
appealing
15
cm
juice
than
from
from
the
sample
sample
juice
from
A
B.
looked
sample
radiation
She
a
more
brain
Explain
juice
why
from
there
sample
was
much
Suggest
the
why
juice
the
from
A.
student
sample
A
thought
was
Suggest
in
which
the
effective
of
fruit
the
investigation
to
nd
Many
pectinase
is
at
increasing
such
modied
as
HGH.[5]
advantages
to
of
produce
using
genetic
HGH.
[3]
may
children,
suffer
who
from
do
not
blindness
have
a
caused
a
lack
of
vitamin
A.
Lack
of
this
vitamin
in
the
juice.
diet
also
harms
their
immune
system.
[3]
Explain
the
consequences
of
an
ineffective
3)
organisms
can
be
genetically
that
they
can
be
used
in
but
bacteria
are
[4]
is
the
main
foodstuff
in
many
parts
of
biotechnological
the
processes,
system.
engineered
Rice
so
the
especially
diet
immune
10
genetically
out
(a)
(Paper
are
protein,
4)
People,
their
yield
human
student
by
how
had
[2]
ways
improve
bacteria
a
engineering
that
varied
could
have
more
13
three
how
produce
(Paper
State
or
[3]
appealing.
(c)
leukaemia
tumour.
Outline
to
more
(c)
(ii)
for
B.
(b)
(i)
treatment
one
of
the
world.
Researchers
have
used
genetic
most
engineering
to
produce
a
strain
of
rice
that
has
common.
seeds
(a)
Dene
(b)
State
the
the
term
genetic
advantages
industrial
engineering.
of
using
rich
in
the
State
bacteria
the
human
(b)
Suggest
examples
of
body
selective
genetic
converts
why
(d)
at
265.
Penicillium
rice
and
had
not
State
three
other
crop
the
produce
an
Name
diagram
of
the
fermenter
on
State
is
grown
in
fermenters
the
Discuss
(Paper
antibiotic
by
[2]
reasons
for
genetically
[3]
the
arguments
produced
conditions
the
each
condition,
maintained
inside
from
the
and
against
food.
[3]
4)
by
that
are
maintained
fermenter.
and
Describe
for
[1]
maintained
(Paper
genetically
produced
to
antibiotic.
ve
inside
(d)
be
page
Penicillium.
For
to
simply
plants.
genetically-modied
(c)
A.
3)
Look
(b)
vitamin
breeding.
modifying
(a)
into
[3]
(c)
11
which
[2]
engineering.
(Paper
carotene
in
processes.
three
beta
[2]
engineered
(c)
chemical
how
[5]
describe
explain
the
the
it
is
it
is
must
fermenter.
antibiotic
fermenter.
how
why
be
[5 + 5]
obtained
[2]
4)
269
21
H uman
on
in f l u e n c e s
e co s y s t e m s
21.1
Food
Increased
LEARNING
Describe
ways
in
modern
technology
resulted
in
increased
60
Arable
food
elds.
years
farms
negative
ecosystems
of
monocultures
and
resulted
in
advances
in
agriculture
over
the
improved
food
supplies
in
many
parts
of
the
world.
large
are
and
agricultural
tractors
combine
and
machines
ploughs
harvesters
for
for
to
work
preparing
harvesting
very
land
crops.
large
for
Chemical
impacts
of
the
encourage
crop.
the
Pesticides
growth
intensive
kill
pests
of
crop
like
plants,
insects
increasing
that
feed
on
the
yield
crops.
crop
Herbicides
plants
has
large-
of
scale
use
seeds
fertilisers
on
and
Examples
sowing
the
technology
has
production
Describe
production
which
past
•
food
OUTCOMES
Modern
•
supply
kill
weeds
that
compete
with
crop
plants
for
water,
light
livestock
and
nutrients.
Selective
breeding
has
increased
yield
and
made
production
crops
•
Discuss
the
has
and
implications
of
food
transferred
human
an
Intensive
global
yields
over
of
In
large
many
by
intensive
especially
and
this
gas
Mongolian
surroundings
farmer’s
of
his
farm.
such
waste
sh,
A
as
High
engineering
There
has
to
crop
plants
soya
are
and
even
their
pests
Thailand.
and
some
and
plant
often
high
crop
in
plants
large
restricting
their
and
of
indoors
the
faeces,
the
sea
large
numbers.
environment.
methane
and
in
which
often
where
it
is
a
known
can
cause
have
mean
using
growing
of
and
that
of
of
parasites
and
crop
allowing
specic
effects
on
on
the
such
to
as
large
cages
The
surrounding
pathogens
these
large
in
controlled.
and
to
farmers
crops,
kept
antibiotics
resistance
same
are
carefully
serious
pesticides
the
tilapia,
to
treat
can
the
chemicals.
areas,
year
concentrate
wheat,
after
on
barley,
rice.
that
inside
lots
on
conditions
problems
effects
pesticides
agents,
achieve
livestock
and
reared
Urine
bass
can
sh
quantities
and
sea
advantage
negative
eggs
selective
is
the
to
growing
21.4).
farms
come
keeping
effects
21.5).
growing
of
involves
supply
are
generate
trout,
means
this
food
waterways
and
sh
This
large
Herbicides
in
resistance,
indoors.
negative
Topic
densities
with
This
maize,
farming
food
monoculture
growing
270
Genetic
technology
This
and
animals
Topic
lakes,
modern
their
them
cattle,
(see
from
easily.
and
year.
sh
diseases.
herbicide
densities
have
salmon,
their
food
waters.
high
(see
pollutes
have
spread
Intensive
as
livestock.
systems
Animals,
slurry,
using
and
keeping
methods
Fish,
the
such
supplementing
eutrophication
from
at
Intensive
as
is
plants
areas
greenhouse
pollutes
and
species.
farming
crop
movement
waste
features,
unrelated
numbers,
cows
drought
providing
for
population
The
to
economic
from
increasing
resistant
social,
environmental
sufcient
more
may
pest
of
kill
plant
help
species.
resulting
in
pathogens
monoculture
the
and
insect
crop,
such
Continuous
the
(see
evolution
T
opic
on
18.4).
environment.
species
as
use
of
the
that
parasitic
of
these
resistance
are
harmless
wasps
that
chemicals
among
act
lay
as
weeds,
The
the
large
soil
scale
so
that
organisms
matter,
not
such
the
as
manure,
food
to
in
from
starvation
and
their
or
of
to
food
is
Many
ooding,
most
places
Social,
Food
that
most
often
have
pests
production
of
where
is
the
The
the
structure
biodiversity
addition
good
the
also
but
caused
enough
to
and
soil
of
of
of
soil
organic
structure
ability
of
increased.
every
requires
year
politics,
the
but
is
world’s
There
many
is
enough
people
to
do
may
die
because
of
have
plantations
and
lived
political
land.
for
to
to
to
food
wars
Machinery
like
farmers
grow
sell
to
for
for
food
damage
that
is
pressures
in
labour
increasingly
force
so
rural
mechanised,
there
unemployment
is
or
war.
Often
this
has
meant
forcibly,
from
years.
has
resulted
in
T
opic
21.2.
As
has
not
the
farming
driven
demand
the
of
oil
palm
South-East
cover
Asia.
huge
Here
a
areas
lorry
of
from
a
in
for
movement
a
in
Indonesia
carries
away
the
fruits
has
these
trees
to
be
processed
into
palm
oil.
large
of
people
KEY
to
allows
elds.
at
of
become
large
implications
sometimes
ranching
described
harvester
very
to
plantation
environmental
in
but
those
land
clearance
combine
crops
food
Plantations
Land
this
feed
fail,
to
transporting
displaced,
ancestors
have
crops
economic
areas
been
of
but
food
currency.
supply
problems
and
so,
cause
to
economics,
enough
foreign
failure
are
large
have
land
gain
a
by
produce
diseases
by
there
famine
people
their
has
countries
caused
Often
there
increased,
everyone,
environmental
groups
places
feed
often
starvation.
where
supports
growth.
maintain
food
cash-crops
famine
of
to
has
poorer
Drought,
risk
crop
reduce
malnutrition.
or
non-food
is
helps
enough
and
populations
grow
longer
can
supply
world
poverty.
no
good
population
food
Shortage
it
fertilisers
out.
produce
the
time
supports
carried
world’s
farmers
chemical
POINTS
cities.
Intensive
fossil
who
agriculture
fuels.
own
does
not
It
also
farms
reach
requires
requires
and
local
large
much
inputs
of
investment
plantations,
often
energy
by
taking
from
large
prots
burning
1
that
use
of
breeding
corporations
so
The
and
chemicals
money
increase
people.
2
negative
crop
How
have
the
following
increased
food
Famine
improved
use
of
production?
agricultural
machinery
b
articial
Describe
fertilisers
d
use
of
the
negative
monoculture
tnemelppuS
Describe
on
impacts
of
the
reasons
result
transport,
of
intensive
livestock
the
people.
from
lack
of
and
drought,
an
ever
human
population.
production
Intensive
agriculture
has
crops
social,
3
on
pesticides
4
and
and
selection
increasing
2
livestock
many
problems,
ooding
c
and
impacts
can
political
food
a
an
QUESTIONS
3
1
in
production.
have
environment
SUMMARY
resulted
food
production
selective
agricultural
has
in
Intensive
machinery,
tnemelppuS
tnemelppuS
As
of
over
that
always
World
use
for
food
shortages
in
the
world.
environmental
economic
and
implications.
271
21.2
Habitat
The
LEARNING
pressure
Describe
habitat
the
reasons
natural
for
is
destruction
State
that
humans
have
losses
deliberately
by
altering
food
•
impact
List
food
on
the
chains
on
Reasons
negative
effects
has
the
on
effects
on
on
been
for
a
natural
and
variety
are
has
resulted
continues
of
to
reasons,
ecosystems,
such
many
in
be
but
as
reasons
why
destroyed.
we
have
pollution.
the
Land
many
There
Earth
that
is
unaffected
by
human
is
no
activity.
for
habitat
destruction
that
natural
habitats
of
plants,
animals
and
microorganisms
are
habitats
for
a
number
of
different
reasons:
of
•
deforestation
has
There
and
destroyed
Explain
population
habitats
The
•
world
habitats.
a
webs
deforestation
natural
cleared
effects
ecosystem
negative
increasing
of
environment
indirect
•
an
OUTCOMES
signicant
•
of
destruction
The
clearance
of
land
for
crop
production
(see
Topic
21.1)
and
for
the
the
production
of
biofuels
(see
Topic
20.1).
environment
•
Space
of
•
as
More
build
for
Digging
such
•
to
land
mines
iron
people
The
human
needed
(see
•
Marine
which
wells
Open
of
cast
coal
mining
destroys
large
for
Topic
and
At
high
coral
If
we
or
•
•
•
otters
or
and
latter
of
half
being
have
preyed
less
their
the
upon
prey
to
numbers
20th
by
hunt
killer
but
because
of
in
now
whales
Killing
Killing
to
and
and
this
coal
the
and
is
mineral
ores,
produced.
associated
etc.
huge
of
of
aluminium
shops,
pollutants
cause
algal
industrial
destruction
In
the
been
quantities
waste
and
of
for
waste.
Space
recycling
is
it
of
the
blooms
sea
in
include
the
sea,
fertilisers,
oil
from
oil
chemicals.
by
pollution
Caribbean
destroyed
cleared
them
of
large
they
of
on
areas
by
it
and
of
the
is
are
are
chains
natural
we
coral
reefs
estimated
many
food
pollution,
of
predators
were
large
from
has
species
in
an
–
have
humans
dangerous
herbivores
these
Overshing
that
which
over
considered
and
at
very
of
high
risk.
webs
environment
removed
have
23%
completely
organisms
either
huge
for
food
numbers.
estimated
had
(see
60
signicant
results
in
have
also
–
killed
Topic
there
The
many
were
many
population
million
in
of
these
21.9).
1492
of
to
different
American
750
in
bison
1890.
effects.
that
that
are
further
unbalanced
at
risk
of
food
damage
webs
by
and
other
unbalanced
factors.
the
they
are
Top
predators
control
the
populations
of
primary
consumers.
Their
may
removal
means
so
is
that
populations
of
herbivorous
animals
increases
overshing.
there
The
272
clearance
are
increased
century,
and
indirectly:
ecosystems
protected
housing
storage
inuences
haven’t
Removing
Sea
extraction
which
produces
Major
thought
of
decreased
crab.
production
21.8).
destroyed
species
a
long-term
the
from
industries,
population
have
because
eating
more
roads,
ships,
risk
reefs
directly
otter
for
bauxite
require
biodiversity.
Human
sea
livestock
areas
land.
high
A
intensive
quarries
and
pollution.
are
for
rearing.
and
ore
infrastructure:
•
units
cattle
effect
increased
can
be
competition
overgrazing
for
and
the
plant
habitat
food
that
destruction.
they
eat.
and
The
Pacic
sea
otter,
Enhydra
lutris,
is
a
secondary
consumer
that
KEY
feeds
on
invertebrates,
century
the
change
to
animals
such
were
as
sea
hunted
urchins
for
their
and
fur
crabs.
and
In
there
the
was
a
striking
1
the
whole
of
the
food
web
as
urchins
exploded
POINTS
19th
in
Habitats
by
and
ate
many
of
the
giant
seaweeds
that
provided
a
habitat
have
and
clearance
many
the
other
species.
catastrophic
web,
such
as
loss
many
The
of
loss
many
small
of
one
other
species,
animal
invertebrates,
the
species
sh,
sea
otter,
from
octopus
the
and
of
destroyed
land
for
food
farming,
for
been
numbers
led
extraction
of
to
resources,
such
and
ores,
as
fossil
fuels
food
metal
housing
and
scallops.
industry.
2
Pollution
has
destroyed
many
Deforestation
marine
Humans
food
have
and
been
provide
clearing
land
for
forests
for
settlements
over
and
10
000
provide
years
to
grow
transport
are
now
very
few
forests
in
temperate
regions
that
have
cleared
at
some
time
in
the
past.
Tropical
forests
in
Humans
and
South
America
have
been
cut
down
over
the
of
these
forests
are
rainforests
rich
in
past
100
food
has
resulted
in
a
number
of
the
extinction
of
impacts
removing
chains
and
species
webs.
Deforestation
leads
to
biodiversity.
environmental
of
species,
loss
of
problems:
soil,
•
negative
by
years.
extinction
Deforestation
coral
South-East
4
Many
have
habitats
from
Asia
as
not
on
been
such
links.
3
There
habitats,
reefs.
of
species
ooding
carbon
and
dioxide
increase
in
the
atmosphere.
•
the
•
an
•
the
of
soil
increase
in
increase
in
removed
degraded
Local
of
tropical
formation
the
of
ooding
carbon
rainforests
soil
is
gullies
after
weather
dioxide
all
are
easily
and
the
the
very
of
are
change
and
away
plant
cut
atmosphere.
thin
washed
loss
trees
patterns
in
when
causing
nutrients.
the
soil
The
vegetation
erosion,
land
is
rapidly
SUMMARY
down.
with
more
frequent
and
severe
1
storms.
much
Flooding
quicker
happens
and
is
not
more
frequently
absorbed
by
as
plants
water
and
QUESTIONS
runs
off
transpired
the
into
Outline
some
Forests
act
as
‘stores’
of
water,
their
leaves
slow
the
that
increasing
effects
an
human
the
population
atmosphere.
of
land
has
had
on
the
down
environment.
the
rate
water
of
evaporation
reaches
the
from
the
soil
and
decrease
the
rate
at
which
2
soil.
It
is
estimated
1880
Carbon
dioxide
is
added
to
the
atmosphere
because
vegetation
There
is
increased
decomposition
that
also
releases
that
1980
between
about
40%
is
of
burned.
and
all
tropical
rainforest
was
more
destroyed.
carbon
dioxide
which
is
not
absorbed
by
plants.
a
Rainforests
have
no
effect
on
maintaining
the
correct
balance
Give
three
large-scale
carbon
dioxide
and
oxygen
in
our
atmosphere.
They
produce
much
such
a
carbon
huge
produced
oxygen
that
of
all
of
plants
rainforests
of
other
rainforests
many
be
reserve
by
concentration
the
plenty
dioxide
species.
identied,
of
reasons
There
the
to
are
in
the
photosynthesis
atmosphere
makes
little
atmosphere.
‘lungs’
stop
loss
of
many
and
use
in
Earth
the
the
studied
they
oxygen
on
are
means
as
of
the
cutting
many
species
that
the
difference
There
earth.
down
is
no
There
forests.
habitats
in
and
and
rainforests
to
there
this
Outline
some
of
the
is
effects
that
has
the
deforestation
quantity
the
on
environment.
overall
3
evidence
are
for
deforestation.
about
b
as
reasons
of
however
Explain
the
negative
effects
of
deforestation.
Destruction
the
extinction
that
have
yet
of
to
classied.
273
tnemelppuS
tnemelppuS
Soils
is
loss
21.3
Pollution
Anything
LEARNING
that
•
State
of
the
sources
pollution
of
and
land
tnemelppuS
Discuss
the
effects
of
the
chemical
effects
and
has
material
power
the
biodegradable
plastics
in
environment
in
both
as
and
as
harm
is
as
a
a
result
of
fertilisers,
animal
noise
and
from
pollutant.
human
activity
oil
and
human
Pollutants
carbon
wastes;
industrial
and
are
monoxide;
heat
released
domestic
is
sources.
the
of
substances
aquatic
from
terrestrial
such
such
stations;
cause
the
release
environment,
to
nonPollution
and
into
potential
substances,
biological
water
from
•
released
OUTCOMES
human
activities
ecosystems
that
are
harmful
to
the
environment.
We
expect
natural
ecosystems
and
absorb
breakdown
these
substances.
Topics
we
to
21.3
will
look
examples
of
to
In
21.5
at
some
pollution
We
of
land,
sea
and
throw
away
mountains
places
a
this
visual
rubbish
pollutant
is
as
undesirable
pollutant
of
rubbish
every
day.
In
many
air.
taken
well
to
as
a
effects
rubbish
danger
of
dumps,
to
the
becoming
environment.
pollutant
on
the
sources
environment
carbon
dioxide
burning
cattle;
fossil
paddy
fuels
elds
for
coal
human
sewage
and
and
contains
oil
industrial
–
chemical
includes
a
variety
waste
ammonia,
carbohydrates,
effect
(see
page
278)
enhances
greenhouse
effect
(see
page
278)
extraction
livestock
urea,
greenhouse
growing
methane
rice;
enhances
fats
and
protein,
pathogens
reduces
oxygen
destruction
(see
page
of
concentration
freshwater
in
rivers;
communities
276)
waste
of
toxic
can
be
fatal
to
wildlife
and
humans;
can
factories
substances
mercury
such
and
fertilisers
as
lead,
accumulate
N
and
P)
arable
agriculture
arable
agriculture
eutrophication
spray
for
killing
weeds
the
pesticides
for
killing
pests
and
and
livestock
waste
(non-pest)
(biodegradable
non-biodegradable
buried
domestic
and
industrial
waste
rubbish)
nuclear
(beta
274
gamma
atomic
radiation)
power
bomb;
accidents
stations;
nuclear
at
nuclear
tests
in
rubbish
toxic
fall-out
and
kills
fresh
water
harmless
(rivers,
plants;
lakes)
persist
in
in
food
chains;
kills
harmless
agriculture
diseases
solid
drift
in
environment
accumulates
arable
and
organisms
cyanide
(mostly
herbicides
in
species
ground
tips;
liquids;
death
with
humans;
(landll)
health
release
high
hazard;
of
in
left
on
leakage
of
methane
exposure;
mutations
or
cancers
non-human
in
species
pollution
STUD
Y
Rubbish
is
chemicals
not
that
only
a
leach
visual
from
pollutant,
rubbish
but
dumps
it
contains
into
the
many
ground.
Examples
are
T
he
heavy
metals
that
enter
water
courses
and
the
drinking
water
table
applied
such
as
chemicals,
correctly
DDT
can
and
such
affect
dieldrin
as
areas
have
herbicides
locally
been
and
and
also
detected
in
pesticides,
far
the
away.
body
if
not
you
Insecticides
fat
sum
need
Paper
3.
mammals
and
birds,
many
thousands
of
miles
the
mar
to
If
where
away
used
of
they
would
in
aircraft
disease,
forests,
can
such
have
destroy
drift
onto
as
been
used
mosquitoes.
to
control
the
habitats
areas
of
of
natural
Herbicides,
crop
animals
pests
especially
and
vegetation
when
and
kill
you
Paper
by
materials
are
because
a
we
called
they
problem
into
this
sprayed
from
POINTS
–
throw
these
away
are
are
called
broken
when
a
it
long
time
comes
to
and
in
the
biodegradable.
non-biodegradable.
last
down
do
Plastics
not
disposing
are
decay
of
Some
used
easily.
plastics.
environment
are
for
But
Most
not
1
to
and
landll
sites
or
rubbish
dumps
where
they
take
up
a
is
the
Biodegradable
conventional
plastics
are
designed
non-biodegradable
to
break
plastics
once
down
they
release
of
by
example,
structures
some
which
is
plastics
now
digested
by
have
starch
bacteria
in
incorporated
the
lot
can
recycle
many
thermoplastics
that
we
by
into
Pollutants
affect
them
into
new
shapes.
Burning
plastics
in
they
the
volume
of
waste,
but
many
plastics
them
the
Nuclear
fall-out
testing
and
threats
to
produce
aquatic
and
toxic
gases
are
threatened
jellysh.
discarded
United
try
to
Fish
and
if
they
plastic
Arab
reduce
other
swallow
nets
Emirates
and
aquatic
plastic
other
banned
animals
bags
forms
of
can
life
too.
plastic
Some
plastics
are
In
plastic
others
but
are
some
non-
can
them
entangled
waste.
non-biodegradable
from
Sea
mistaking
get
from
nuclear
as
be
for
of
leakages
biodegradable
turtles
comes
use
reactors.
biodegradable;
pose
rivers,
incinerators
4
plastics
like
sea.
and
burn.
Non-biodegradable
air,
and
their
nuclear
reduces
the
land
ecosystems
and
weapons
remoulding
on
quickly
3
melting
activities.
dumped.
soil.
use
substances
human
of
the
We
done
by
waste
more
are
harm
environment
produced
becomes
plastic
the
the
packaging
this
Pollution
lakes
For
an
rest
plants.
aquatic
than
is
the
unit.
ecosystems
space.
to
and
2
goes
it
plastics
decomposers
these
4
,
recycled.
in
2014,
the
products
to
pollution.
SUMMARY
1
List
of
2
three
the
QUESTIONS
pollutants
of
each
following:
a
the
atmosphere
b
aquatic
c
the
a
State
ecosystems
land
the
main
sources
of
radiation.
b
Describe
effects
3
Explain
to
Most
plastic
bottles
have
a
recycling
symbol
with
a
category
number.
These
bottles
the
the
of
the
problems
environment
be
category
recycled
1
as
to
they
make
are
made
products
of
polyethylene
such
as
terephthalate
packaging
materials
(PET
and
or
PETE)
which
fall-out.
caused
by
non-
are
biodegradable
in
undesirable
nuclear
plastics.
can
carpets.
275
tnemelppuS
tnemelppuS
Some
fo r
are
when
KEY
Waste
what
from
of
vectors
ises
know
introd
uctio
n
places
previo
us
of
taki
ng
Antarctic
on
supply.
page
Agricultural
TIP
harmful
tnemelppuS
Land
21.4
Water
tnemelppuS
Pollution
LEARNING
Describe
water
pollution
and
toxic
Describe
rivers
the
and
sewage
seas
pollution
lakes
and
due
the
and
and
industrial
into
the
pollutants
are
often
discharged
straight
into
sea.
chemicals
Rivers
•
and
by
rivers
sewage
rivers
OUTCOMES
Domestic
•
of
pollution
empty
toxic
wastes
into
the
sea,
resulting
in
the
following:
of
to
over-use
•
of
Fertilisers
and
sewage
encourage
the
growth
of
algae
that
release
toxins.
fertilisers
•
Describe
of
the
female
negative
•
Pesticides
•
Radioactive
hormones
in
water
the
effects
Toxic
and
pesticides
metals,
Sewage
environment
algae
The
As
is
and
of
water
found
the
in
in
higher
is
molluscs
(shellsh).
concentrations
and
and
river
,
not
lead,
are
around
found
in
tissues
know
the
and
farmer
wrong
The
how
result
pollution
enriched
•
sewage
of
is
much
too
e.g.
of
in
can
be
land
to
to
of
that
use
washed
This
of
sh
in
a
organic
and
river
it
matter.
organisms
add.
the
rivers
oxygen
is
as
more
treated
suspended
sewage
is
concentration
so
that
raw
lakes.
We
But
have
particular
Problems
is
seen
farmers
can
soil
occur
added
at
need
and
if
the
rain.
can
cause
means
sequence
soil
may
no
crops.
which
the
If
fertiliser
heavy
is
improves
their
fertilisers
through
The
growth
284).
for
the
eutrophication,
leaching.
the
the
and
yield
if
as
sewage
rivers
or
period
nutrients.
on
bacteria.
page
the
fertiliser
is
killing
dumped
freshwater
recovers
into
fertiliser
these
is
gradually
by
(see
fertiliser
a
oxygen,
feed
many
countries
rivers
the
before
plant
called
of
that
water
increase
of
much
either
with
the
can
type
resulting
Fertiliser
this
best
uses
time,
from
into
of
the
away.
community
many
encourages
sewage
decomposed
In
deposited
drain
using
the
It
lots
that
migrate
are
the
up
bacteria
means
or
increases.
pollutant.
use
downstream,
out
fertilisers
a
raw
die
how
crop
world
copper
untreated
of
oxygen
so
the
water
raw
growth
of
travels
single
which
If
Fertilisers
to
into
ow
of
rivers
into
a
water
that
the
water
is
events:
and
streams
–
lake.
rivers.
•
Once
in
the
Nutrients
water
•
•
in
and
Animals
their
water,
the
so
that
this
stimulates
fertilisers
limit
eat
the
the
are
growth
algae
population
usually
do
of
the
not
in
low
growth
of
algae.
concentration
in
the
algae.
multiply
fast
enough
to
control
growth.
Algae
plants
cover
at
the
the
•
These
plants
•
Algae
also
shaded
276
some
stations.
mercury,
biggest
the
settle
sewage
the
as
bacteria
survive
dumped
of
such
the
shortage
wastes
parts
are
power
invertebrates.
cannot
into
of
organisms.
encourages
many
chemicals
nuclear
marine
small
drains
tissues
on
of
In
the
of
of
herbicides
the
in
courses
•
Describe
concentrated
contraception
coastal
•
are
impact
by
surface
bottom
of
eventually
die
the
as
there
algae
layers
the
die
is
on
of
water,
and
rot
on
competition
the
reducing
the
light
reaching
lake.
surface.
the
for
river
bed.
resources
and
many
are
Decomposers,
•
Bacteria
respire
dissolved
•
The
chain
of
multiply
result
the
The
they
ions
act
added
of
are
as
in
feed
multiply
a
the
oxygen
cannot
events
quickly,
death
problems
These
of
that
Bacteria
in
bacteria,
aerobically,
concentration
same
as
on
dead
rapidly
plants
and
use
and
up
algae.
a
lot
of
oxygen.
invertebrates
The
such
tnemelppuS
•
of
decreases
respire
can
use
happen
up
short
limiting
form
this
kills
sh
and
if
sewage
oxygen
in
gets
into
respiration,
waterways.
which
can
sh.
eutrophication
in
and
properly.
supply
factor
of
are
in
to
the
fertilisers,
caused
most
growth
plant
by
natural
of
nitrate
plants.
growth
and
aquatic
phosphate.
ecosystems,
When
they
so
are
increases.
Fertilisers
Farmers
make
up.
are
sure
encouraged
that
Phosphate
they
are
tends
to
to
reduce
applied
remain
the
at
in
a
fertilisers
time
soils
they
when
and
apply
crops
much
of
will
the
and
take
water
to
water
comes
detergents
has
from
domestic
helped
to
sources.
reduce
this
Removing
in
the
sea
–
nitrate
in
the
type
sea
of
pollution.
causes
growth
which
produce
toxins
and
kill
other
marine
algae,
of
contraceptive
Water
pollutants
women
Topics
16.12
therefore
in
take
and
nds
its
contraceptive
contraceptive
16.13).
way
pills
The
into
is
a
pills
human
containing
is
oestrogen
excreted
sewage.
The
oestrogen
in
urine
If
excess
are
not
broken
down
in
fertilisers
active
known
pass
through
unchanged
to
all
sewage
nutrients
amphibians
respond
to
this
leached
nutrients
for
enter
rivers
treatment
and
oestrogen
in
lakes.
the
they
causing
by
supplying
algae.
EE2.
plants
Female
contraceptive
so
Male
are
water
by
causing
the
sh
feminisation
and
are
lakes
eutrophication
ingredient
as
and
hormones
they
pesticides
metals.
rivers
provide
(see
and
3
Oestrogens
fertilisers,
toxic
hormones
hormone
synthetic
include
life.
into
Many
this
events
2
effects
turn
many
and
The
and
POINTS
sewage,
of
grow
from
Similar
of
to
phosphate
phosphate
1
happen
algae
them
KEY
in
caused
green.
of
aquatic
gaining
organisms.
certain
female
characteristics
‘feminisation’,
testes,
having
protein
found
as
it
is
some
in
also
yolk
a
condition
called,
female
egg
–
involves
reproductive
which
is
known
producing
structures
carried
as
in
their
intersex.
eggs
and
This
inside
making
blood.
In
their
a
addition,
SUMMARY
their
sperm
Drinking
rivers
water
water
works.
the
cells
An
do
is
may
often
be
increase
decrease
in
not
develop
taken
taken
in
from
downstream
oestrogens
sperm
rivers,
counts
in
of
and
the
drinking
recorded
in
in
the
case
efuent
water
men
in
of
from
has
long
been
some
1
a
sewage
parts
linked
over
the
past
20
of
Dene
the
pesticide,
to
terms
insecticide
and
herbicide
the
b
world
QUESTIONS
properly.
Explain
why
they
are
years.
used.
This
in
is
the
the
only
same
from
part
of
the
environment
effects.
agriculture
story
and
These
and
as
many
there
other
chemicals
industry,
are
other
synthetic
are
in
including
the
sources
plastics
food
of
chemicals
oestrogens
that
and
processing
in
c
have
the
can
waste
those
There
no
that
deal
with
implicated.
works
so
easy
EE2
the
is
rest
solutions
removed
could
be
to
of
the
drinking
effective
water
ways
this
from
problem
the
waste
upgraded.
treatment
to
the
a
Explain
the
negative
soya.
The
as
many
water
use
of
chemicals
from
some
charcoal
are
do
this.
works
will
Upgrading
be
sewage
sewage
lters
works
of
female
contaceptive
water
hormones
in
courses.
is
b
one
pesticides
environment.
effects
are
how
damage
plants
2
especially
Explain
What
steps
taken
to
could
be
and
rectify
the
expensive.
problem?
277
21.5
The
greenhouse
Greenhouse
LEARNING
Describe
the
contribution
atmosphere
greenhouse
gases
and
methane
tnemelppuS
change
Explain
how
in
greenhouse
climate
air
pollution
gases
heat
like
the
that
so-called
vapour
•
of
a
blanket
gases
in
surrounding
the
atmosphere
the
act
Earth
like
a
keeping
it
greenhouse
to
otherwise
would
be
radiated
into
space.
These
are
to
the
climate
Some
carbon
keep
dioxide
is
of
warm.
the
gases
OUTCOMES
The
•
effect
and
greenhouse
methane.
Some
(chlorouorocarbons),
by
causes
other
problems.
These
greenhouse
gases
are
which
man-made
greenhouse
are
air
carbon
dioxide,
pollutants,
gases
as
well
such
as
the
water
as
CFCs
cause
of
change
surface.
Some
atmosphere
Some
heat
gases
energy
as
heat,
energy
allow
enters
which
is
escapes
solar
food
energy
chains
radiated
into
to
and
away
pass
is
from
space,
but
gases
keep
through
eventually
the
much
to
lost
Earth’s
is
the
to
Earth’s
the
surface.
reected
back
greenhouse
towards
the
Earth.
Greenhouse
our
atmosphere
at
the
gases
temperatures
It
is
important
process
be
that
and
about
build-up
Power
to
it
the
to
exist.
that
the
average
However,
greenhouse
stations,
life
understand
without
–17 °C.
of
allow
over
greenhouse
temperature
the
last
100
effect
on
years,
the
is
a
natural
Earth
there
has
would
been
a
gases.
factories,
domestic
heating
and
transport
use
fossil
fuels
solar
and
release
huge
amounts
of
carbon
dioxide
into
the
atmosphere.
As
radiation
we
Figure
21.5.1
The
greenhouse
have
seen,
removed.
are
In
burned,
and
other
South
even
There
also
the
has
release
the
oil
huge
reneries
and
quantities
atmosphere
when
of
power
carbon
they
burn
fossil
into
Of
all
the
severa
l
areas
a
due
of
forest
to
the
is
and
into
the
decomposed
farming
being
and
atmosphere.
by
microbes
in
they
Roots
the
soil,
dioxide.
signicant
increase
expansion
released
found
material
oil
are
dioxide
for
in
in
by
of
sites
gas,
are
methane
rice
cattle
ooded
landll
natural
in
(another
cultivation
and
rice
and
also
elds
by
and
rubbish
other
and
bacteria
tips,
sources
of
in
natural
as
well
as
methane.
greenhouse
and
has
gases
CFCs
risen
by
the
cannot
greenhouse
gases
10%
largest
be
in
the
increase
ignored
than
last
as
carbon
30
has
they
years.
been
in
carbon
are
However,
much
more
dioxide.
know
.
table
that
Look
on
you
back
page
your
self
change
air
Human
pollu
tants
need
to
274
of
causing
to
these
.
activities
greenhouse
has
the
the
the
is
are
gases
by
so
the
0.7 °C
an
increase
atmosphere
greenhouse
over
the
past
is
in
the
getting
effect.
century.
concentration
warmer.
The
This
surface
There
are
of
fears
of
is
the
Earth
that
this
0 °C
then
increasing.
temperature
polar
causing
enhanced
warmed
warming
If
278
large
cleared
TIP
are
remin
d
of
carbon
carbon
conditions
which
Climate
the
in
are
fuels.
effective
to
resulted
trees
stations
dioxide
methane
T
here
has
the
parts
Methane
Rotting
extraction
dioxide,
STUD
Y
more
gas)
anaerobic
tree
been
rearing.
wetlands.
the
releases
remaining
producing
cattle
America
which
greenhouse
Factories,
deforestation
effect.
ice
of
would
the
start
Arctic
to
and
melt.
Antarctic
This
would
was
to
cause
a
rise
above
rise
in
sea
level
ooding
would
of
include
many
some
low-lying
of
the
areas,
capital
for
cities
example
of
the
in
Bangladesh.
These
KEY
world.
1
There
could
rainfall
leading
become
as
very
parts
mean
also
of
a
be
to
dry.
the
change
more
Some
USA
massive
a
in
wind
extreme
of
and
these
Asia,
reduction
in
patterns
weather.
are
so
and
Some
important
that
the
crops
the
parts
distribution
are
expected
agricultural
warming
grain
of
of
the
areas,
climate
Central
Asia
of
America.
The
pattern
of
the
world’s
food
The
naturally
greenhouse
to
such
could
blanket
around
prevent
some
escaping
distribution
could
with
economic
and
political
carbon
to
reduce
emissions.
using
energy
cattle
to
the
This
more
effects
may
be
efciently,
of
by
recycling
change
involve
encouraging
and
reducing
public
Air
pollution
changing
the
effect
transport,
diet
to
them
releasing
a
method
combined
domestic
is
to
heat
use
and
fossil
fuels
power
and
more
plant
in
efciently
which
the
as
happens
heat
is
used
in
and
tnemelppuS
The
diagram
in
for
of
in
effect
more
detail
possible
Earth
how
the
greenhouse
effect
cools
heat
down
back
into
in
sea
and
from
the
level,
low-lying
the
some
in
be
changes
climate
crop
and
a
production
areas.
QUESTIONS
radiates
Sun
Copy
and
complete:
and
carbon
radiate
part
energy
into
of
the
dioxide
absorbed
energy
space
atmosphere
space
Solar
passes
the
Space
water
and
absorb
air
radiates
absorbed
infra-red
Earth
carbon
radiation
Earth’s
dioxide
and
through
and
radiate
surface.
heat
the
The
energy
Earth
back
into
CO
O
H
could
ooding
areas,
world’s
warms
the
consequences
space
water
warms
contributing
works.
1
some
radiation
is
change
SUMMARY
the
has
greenhouse
change.
climate
rise
in
shows
carbon
methane
this
climate
The
a
heating.
greenhouse
space.
by
the
reduction
The
and
energy
methane.
of
One
a
of
3
stop
as
Earth
consequences.
climate
done
heat
into
increased
Measures
act
the
be
dioxide
affected
occurring
gases
and
2
North
POINTS
tnemelppuS
and
some
2
2
H
2
CO
of
the
energy
back
O
to
Earth
CO
2
2
CO
This
is
mainly
radiation.
2
CO
2
CO
Some
2
H
the
heat
energy
is
O
H
O
of
2
2
by
the
greenhouse
atmosphere
H
Earth
gases.
O
How
the
to
CO
2
21.5.2
effect
radiation
List
passes
through
the
atmosphere
and
warms
the
the
The
red
Earth
radiates
heat
energy
back
into
space.
This
is
mainly
infra-
as
Some
and
in
each
a
human
source
of
this
causes
vapour
Human
the
the
heat
air
heat
activity
dioxide
and
greater
impact
energy
is
absorbed
by
the
greenhouse
is
give
the
that
acts
gas.
a
Describe
the
likely
gases.
to
warm
energy
is
other
up.
would
causing
a
carbon
pass
large
greenhouse
than
Without
carbon
straight
increase
gases
dioxide
such
(see
in
as
dioxide
back
the
out
and
into
space.
atmosphere
methane,
question
12
of
which
on
page
b
carbon
has
a
291).
the
increases
in
these
gases
in
the
atmosphere
that
Describe
which
for
the
enhanced
greenhouse
the
global
ways
people
governments
the
emission
and
and
can
of
in
their
reduce
greenhouse
attempt
to
are
reduce
responsible
of
warming.
water
gases
It
case
activity
of
consequences
This
contribute
greenhouse
radiation.
3
•
that
surface.
one
•
gases
enhanced
the
effect
Earth’s
the
up.
works.
to
Solar
warm
2
greenhouse
2
•
causes
2
CO
Figure
This
the
effects
of
global
effect.
warming.
279
21.6
Acid
tnemelppuS
Sulfur
LEARNING
rain
dioxide
(SO
)
is
released
when
fossil
fuels
are
burned.
2
OUTCOMES
T
ogether
with
nitrogen
oxides
(NO
)
from
exhaust
fumes,
they
cause
x
• Describe
effects
the
of
causes
acid
acid
and
dioxide.
rain
in
•
State
the
measures
that
taken
to
reduce
acid
Rain
in
the
nitric
when
acidic
sulfur
atmosphere
acids
as
be
as
low
acid
in
clouds
dioxide
and
react
acid
which
lower
the
pH.
and
as
and
dissolves
nitrogen
with
oxygen
carbon
oxides
they
dissolve
produce
In
some
places
the
pH
of
sulfuric
the
rain
3.0.
polluted
by
the
air
wind
nitric
be
water
considerable
and
droplets
become
polluted
acid
distances)
dixoxide
water
produces
(may
sulfur
the
rain
blown
sulfuric
naturally
can
may
oxidation
is
However
,
water
and
be
rain.
nitrogen
(nitric
and
sulfuric
acid)
oxides
wet
deposition
(acid
rain)
dr y
deposition
power
and
stations,
vehicles
into
the
industries
release
gases
trees
atmosphere
rivers
and
affecting
decreasing
the
lakes
water
and
polluted
pH
and
affecting
soils
These
gases
winds
dissolved
both
can
before
of
in
carried
being
the
these
be
21.6.1
over
deposited
rain.
types
The
The
of
term
causes
and
large
as
dry
‘acid
effects
of
distances
particles
rain’
acid
by
to
deposition.
are
acid
rain
falls
on
trees
it
kills
leaves
their
ability
to
resist
disease.
Many
European
forests
have
been
killed
trees
by
sulfur
is
affected
dioxide.
Most
by
high
sensitive
lichens,
Increasing
280
of
sulfur
dioxide
in
aluminum
from
soils
algae
their
Some
grow
can
and
water
species
only
fungi
and
are
where
tolerate
high
living
together.
nutrients
very
the
from
sensitive
air
is
free
of
concentrations.
the
to
sulfur
the
gas
Others
tolerate
useful
intermediate
indicators
the
of
concentrations.
pollution.
By
Lichens
looking
at
the
rain.
of
growing
average
b
concentration
of
c
atmosphere
→
in
an
concentration
which
a
leaches
in
acid
concentrations
are
and
some
species
Vegetation
rain
polluted
life
and
are
central
acid
all
atmosphere.
can
reduces
absorb
dioxide
the
and
composed
They
and
When
polluted
lakes
water
rain.
or
refers
affected
life
rivers
Figure
vegetation
area,
of
you
sulfur
can
deduce
dioxide.
the
acid
because
the
falls
on
and
there
out
of
these
on
is
of
soils
affected
The
•
by
•
ue
station
and
and
chimneys
catalytic
aluminium
water
converters
Acid
little
rain
effect,
When
already
it
acidic
causes
soluble
low
waste
or
pH
plant
and
coal
live
and
the
can
in
pH
increase
Trees
these
aluminium
have
been
in
exhaust
These
fumes
solutions
are
of
but
are
and
sulfur
washing
its
from
with
before
being
the
damage
America
China’s
are
cleaning
rapid
stations
means
b
Name
d
Explain
country
time
the
the
with
a
content,
powdered
can
escape,
nitrogen
introduced
has
when
damage
and
use
of
oxides
gradually
Europe
done
coal
problems
Sulfur
Acid
normal
gases
rainfall
which
sources
the
of
effects
aquatic
in
catalytic
by
in
with
and
acid
its
carbon
they
convert
acid
also
reduces
monoxide
oxides
of
pollutants
and
by
hydrocarbons;
nitrogen
(NOx)
to
North
rain,
many
converter
oxidising
nitrogen.
palladium
when
The
which
vehicles
catalysts
are
are
are
recovered
platinum
and
or
recycled
scrapped.
power
rain.
is
slightly
dissolve
in
the
acidic.
water
in
clouds
to
form
these
of
acid
gases.
rain
on
coniferous
trees,
soils
animals.
what
dioxide
from
rain
also
Acid
can
be
done
to
reduce
the
effects
of
acid
rain.
from
car
dissolves
causes
rain
the
burning
exhausts
useful
the
are
nutrients
release
damages
of
the
leaves
of
fossil
main
out
of
aluminium
and
kills
fuels
causes
the
soil
ions
trees.
and
of
rain.
making
that
Fish
nitrogen
acid
are
and
it
infertile
toxic
to
sh.
invertebrates
A
die
if
lakes
become
ue
gas
power
Measures
taken
to
reduce
acid
rain
include
removing
fuels
and
acidic
gases
from
waste
sulfur
dioxide
plant
station
that
from
which
burns
waste
coal.
gases
The
at
a
product
sulfur
of
from
desulfurisation
acidic.
extracts
4
rain.
POINTS
and
3
the
Explain
oxides
2
of
a
acid
rain.
State
KEY
some
At
expansion
the
why
the
c
e
up
rain.
by
QUESTIONS
Explain
and
1
that
a
acid
acid
industrial
SUMMARY
1
from
killed
power
wet
they
it
sulfur
into
stop
Europe
as:
cars.
expensive,
Central
them.
A
the
in
ions
badly
animals
reducing
reduce
5.5.
lowers
no
such
gases
gases
to
pH,
few
the
tted
that
Norway
Crushing
the
be
a
compounds
acidic
below
rivers
sh
rain
removes
can
is
acid.
is
become
and
very
acid
used.
the
the
concentration
and
have
sulfur
treating
neutralising
there
soil
rain.
to
and
with
Scotland
be
the
the
soluble
streams
combat
could
by
become
some
to
dissolves
acid
invertebrates
Canada,
fuels
neutralises
calcium,
lakes,
tolerate
chalk
infertile.
soils
The
or
granite,
the
and
them
in
of
exists
this
as
neutralise
enters
rain
limestone
such
desulfurisation
limestone,
•
in
acid
that
gas
to
water.
cannot
sulfur
solvent
rocks,
leaving
of
technology
low
alkaline
Species
Lakes
on
potassium
that
bodies
toxic.
soils
compounds
considerably.
are
are
hard
as
water
ecosystems
on
nothing
such
Aluminium
Acidied
falls
soils
soils
nutrients,
wash
rain
tnemelppuS
When
this
process
is
gypsum
(calcium
sulfate)
gases.
which
is
used
in
the
construction
industry.
281
21.7
Sustainable
A
LEARNING
resource
Dene
any
substance,
organism
or
source
of
energy
that
we
OUTCOMES
take
•
is
resources
the
term
from
the
environment.
sustainable
A
sustainable
resource
is
a
resource
which
is
renewed
by
the
resource
activity
•
Explain
the
need
to
organisms
the
environment
State
that
stocks
can
forests
be
that
there
is
always
enough
for
us
to
without
it
running
out.
Examples
of
take
these
resources
sustainable
•
so
conserve
from
non-renewable
of
and
sh
timber
for
or
renewable
building
and
resources,
sh
that
harvested
can
from
be
maintained,
the
sea
and
are
lakes.
managed
Non-renewable
resources
include
energy
sources
such
as
fossil
sustainably
tnemelppuS
fuels
•
Explain
how
forests
and
cannot
sh
stocks
are
minerals,
e.g.
copper,
zinc
and
lead
ores.
gone,
they
are
These
resources
and
be
replaced:
once
they
are
gone
forever.
managed
sustainably
The
•
Dene
the
term
development
that
it
at
and
requires
planning
local,
and
The
explain
management,
is
world’s
supplied
conserve
cooperation
national
international
need
to
conserve
fossil
fuels
sustainable
by
and
by
future
There
•
the
for
sources
various
fossil
fuels
energy
energy
fuels
–
coal,
non-renewable
generations
are
Use
fossil
these
renewable
levels
demand
of
until
we
more
released
so
can
oil
increasing
and
a
time
that
natural
so
by
we
burning
combustion,
have
e.g.
all
fuels
them
most
We
they
supply
fossil
and
gas.
that
that
they
conserve
efciently
on
ever
resources
such
energy
ways
is
be
this
to
used
developed
for
to
need
can
our
combined
of
energy
the
needs.
future:
make
heat
full
and
use
of
power
plants.
•
Reduce
houses
wastage
in
cold
conditioning
that
•
use
Reducing
public
•
Heat
and
Power
plants
like
and
or
in
Berlin,
Germany,
distribute
steam
to
heat
houses
surrounding
in
generate
the
and
form
hot
in
water
from
the
fast
to
is
a
As
soon
an
example
to
quotas
282
has
alternatives
more
for
energy
petrol/gasoline,
encouraging
(see
fuels
nuclear
willow
as
production
of
contributed
the
tree
cover
charcoal
to
the
from
for
removal
the
of
country.
so
trees
of
at
be
by
timber
valuable
products.
forests
all
insulation
to
of
conventional
efcient,
such
as
air
those
Topic
car
e.g.
by
providing
better
pools.
21.8).
as
sources
power,
of
and
energy
burning
are
wind,
rubbish
solar,
and
wood
trees.
area.
tend
almost
and
fossil
and
growing
harvested
cooking
using
are
the
cooling.
materials
hydroelectric
many
the
improving
this
Timber
Haiti,
and
that
demand
Sustainable
In
e.g.
electricity
of
industry
for
the
Alternatives
one
countries
systems
transport
Recycling
energy,
resource
Some
are
felled,
same
softwood,
issuing
they
trees
restocking
the
as
can
they
so
rate
it
not
that
many
in
a
replanted.
the
resource
becoming
trees.
logging
more
in
grown
are
without
to
take
used
be
coniferous
permits
do
production
Some
industries
The
can
than
continue
They
are
regrow.
is
to
These
governments
can
make
way.
replanting
depleted.
companies.
trees
to
sustainable
be
trees
manage
given
tnemelppuS
Combined
ice
of
tnemelppuS
Sustainable
Populations
now
For
example,
Some
so
of
are
steps
•
need
the
sh
to
•
Quotas
too
•
can
•
them
of
of
the
a
other
cod
sea
Many
that
To
of
they
collapsed
creatures
sustainably.
sea
to
are
This
the
‘no
in
in
these
are
the
such
continue
declared
ensures
stock
take’
to
off
that
each
zone
shing
sustainable.
1990s.
as
to
populations
not
crustaceans
do
this
and
various
limits
a
year.
help
for
suitable
The
shing
Cayman
conserve
during
number
a
of
young
Islands
sh
in
known
the
as
to
sh
captivity
in
be
a
red
so
that
boats
cannot
take
be
restocked
them
where
sea
minimum
size
so
that
small
sh
breed.
raise
Japan
including
certain
to
can
and
authorities
season.
survive
of
are
by
each
have
and
stocks
sh
stocks.
taken:
issued
nets
in
sh
overshing
Atlantic
and
season.
sh
Examples
the
as
by
grouper.
escape
Some
sh
has
are
many
Fishing
of
recruited
Nassau
known
depleted
hunted
be
areas
Caribbean
the
of
be
breeding
are
are
stocks
can
Certain
sh
severely
species
molluscs
shing
in
if
is
possible
facilities
shellsh,
bream
it
and
known
prawns
ounder,
and
are
to
as
breed
hatcheries.
several
released
Sustainable
forestry:
ready
felled
as
to
and
into
the
released
into
Sustainable
Sustainable
increasing
Many
Sturgeon
Caspian
Sea
aims
population
signed
up
development
Janeiro,
impact
the
year.
development
countries
de
each
by
to
provide
facilities
in
caviar
are
Brazil.
assessments
to
Agenda
that
arose
Agenda
that
to
provide
without
21
assess
21,
from
a
risk
of
needs
the
global
the
promotes
the
the
harming
action
1992
the
of
trees
have
use
Earth
of
plan
20
years
to
The
grow.
for
Summit
in
environmental
developments
to
the
This
is
one
way
in
which
cooperation
exists
at
national
and
local
factory
ships
like
this
one
have
taken
the
many
sh
from
the
oceans
that
stocks
are
levels.
sustainable
to
and
some
species
are
being
extinction.
POINTS
SUMMARY
A
another
an
driven
1
are
trade.
environment.
not
KEY
trees
timber
Iran.
so
international,
mature
the
reared
Large
environment.
for
development
human
sustainable
Rio
sea
be
young
young
stages
the
species
sustainable
resource
is
one
which
can
be
removed
from
the
1
environment
without
it
running
QUESTIONS
Dene
the
term
sustainable
out.
resource
There
is
a
need
to
conserve
non-renewable
resources,
such
as
2
fossil
fuels,
for
future
Explain
tnemelppuS
stocks
3
Forests
and
sh
stocks
can
quotas
and
restocking.
be
sustained
using
education,
legal
but
3
4
Sustainable
increasing
development
human
provides
for
the
needs
of
an
Cooperation
between
organisations
is
List
may
forests
fossil
ve
fuels
be
and
sh
fuels
ways
can
be
sustainable,
are
in
not.
which
fossil
conserved.
population.
4
5
why
generations.
international,
essential
for
national
sustainable
and
local
development.
Discuss
in
the
role
conserving
of
education
forests
and
sh
stocks.
283
tnemelppuS
2
21.8
Sewage
treatment
and
recycling
Sewage
LEARNING
Raw
•
Outline
how
sewage
is
make
the
water
sewage
that
faeces
safe
environment
to
or
return
for
made
and
up
urine,
of
but
a
number
industrial
of
unpleasant
waste
and
materials,
run-off
from
not
roads
and
it
paths.
contains
is
treated
just
to
treatment
OUTCOMES
to
Not
only
is
it
unpleasant,
but
it
is
also
a
major
health
hazard.
the
human
use
sewage
aeration
settlement
tank
•
State
and
that
metal
paper,
can
glass,
be
plastic
reused
tank
outlet
or
recycled
river
air
pump
pump
screening
for
and
grit
disposal
generator
anaerobic
sludge
tank
processed
Figure
There
•
21.8.1
are
solids
•
Activated
sludge
three
Primary
twigs,
Components
main
means
are
of
allowed
Secondary
a
stages
treatment
by
of
sewage
in
the
involves
lters
to
or
settle
treatment
treatment
removing
out
in
involves
of
large
Then
large
out
plant.
treatment
screens.
sludge
sewage:
solids,
the
grit
like
and
paper
and
organic
tanks.
microbes,
mainly
bacteria,
treatment.
decomposing
material
suspended
in
water.
This
may
happen
in
two
ways.
•
The
activated
sewage
respire
with
in
proteins
Trickle
lters
the
large
rotating
•
T
ertiary
the
any
may
population
which
provide
dumped
Trickle
put
is
a
passes
into
break
The
sea
down
methane
or
for
is
waste
spread
on
the
the
down
microbes.
these
beds
through
settling.
tanks.
out
may
to
go
matter
burned
operating
of
large
it
the
which
carbohydrates,
broken
with
over
secondary
or
is
through
protists
to
the
The
liquid
from
gravel,
the
matter.
settle
the
and
ions.
trickles
period
into
material
back
covered
sprayed
pumped
down
Urea
nitrate
liquid
is
fungi
break
organic
microorganisms
energy
at
the
the
air
as
a
form
anaerobic
an
increase
methane
in
the
soil
from
in
the
stage
water
make
it
to
all
kill
return
leaving
safe.
to
For
the
plant
example
it
microorganisms.
the
environment
will
be
may
Water
or
for
treated
be
in
treated
a
works
may
also
be
conditioner.
variety
with
leaving
the
human
use.
of
chlorine
process
is
in
anaerobic
sewage
Sludge
and
This
to
to
a
sludge.
to
fuel
as
liquid
microbes
stage
machinery.
land
The
Here
lters.
The
284
of
bacteria
conditions.
to
organic
be
to
gravel
involves
process
remaining
sludge
As
down
treatment
secondary
and
dioxide.
treatment
arms.
break
of
which
bacteria,
converted
beds
primary
microbes
carbon
then
are
from
to
in
of
conditions
fats
and
process
community
aerobic
and
ammonia
•
sludge
a
ways
or
now
to
ozone
safe
to
Recycling
Another
of
more
of,
it
and
sites
This
to
than
a
them.
saves
be
to
same
such
the
savings
mass
of
in
which
in
of
metals,
paper
aluminium
tips
animals
and
the
you
raw
extracted
of
useful
less
carefully
can
For
plants
managed
habitats.
all
be
materials
ore,
disposed
materials
recycled
its
production
and
animals,
energy
materials.
from
the
their
plastics
compare
to
and
recyclable
and
is
handled
harm
conserving
from
if
cause
rubbish
quantities,
material
energy
population
properly
and
because
large
is
can
plants
problem
materials
in
make
the
increasing
waste
waste
deprives
Glass,
raw
made
95%
Dumping
to
an
this
pollution
also
solution
of
Unless
cause
ourselves.
recycle
waste
consequence
waste.
may
landll
The
our
is
is
to
recycled.
do
not
used
to
example,
have
recycle
there
aluminium
to
is
the
bauxite.
This
recycling
bin
says
it
all?
What
do
you
recycle?
Paper
is
a
However,
paper
These
Waste
paper
pulp
pulped,
toilet
resource
the
is
are
be
are
and
up
and
it
is
made
recycled.
The
waste
the
converted
paper
and
as
and
required.
removed
other
bundled
supply
collected
is
dried
and
SUMMARY
limited
trees
dyes
paper
paper
can
from
sheets
in
pulp
into
from
This
paper
is
then
wood.
means
is
rolled
newsprint,
that
less
collected,
into
paper
sheets.
towels,
products.
shredded.
This
saves
it
being
otherwise
thrown
into
landll
sites,
like
the
KEY
QUESTIONS
1
1
Outline
what
happens
one
to
raw
sewage
as
it
passes
through
above
right.
POINTS
Sewage
treatment
screening
sewage
treatment
to
remove
a
Make
a
list
of
materials
that
can
be
material,
recycled.
decomposition
b
Describe
on
the
the
effects
that
recycling
of
these
materials
have
and
following:
i
the
raw
ii
the
energy
iii
landll
materials
used
needed
sites
settling
suspended
in
making
and
in
making
rubbish
to
Make
a
list
of
the
different
these
goods
Decomposition
populations
that
dumps
types
of
digest
packaging
that
of
by
protein,
In
and
fats,
cellulose
in
wastes.
shops.
3
b
requires
bacteria
are
human
used
microbes
material.
carbohydrates
a
by
remove
goods
2
3
non-
plant.
biodegradable
2
involves
a
what
ways
does
this
packaging
cause
problems
Recycling
materials,
such
for
as
paper,
saves
money,
raw
society?
materials,
c
Explain
how
the
recycling
of
paper
helps
the
energy
and
reduces
environment.
pollution
by
waste.
285
21.9
Endangered
A
LEARNING
species
becomes
Explain
why
become
and
organisms
endangered
or
extinct
tnemelppuS
Explain
the
risks
to
a
they
time.
far
•
the
size
of
decreases
its
so
in
the
are
we
reducing
variation
in
the
of
becoming
numbers
We
have
already
hunting
(T
asmanian
wolf)
died
and
difcult
becomes
been
to
extinct,
Reserve
there
in
know
but
periglenes,
seen
predation
past
the
last
was
Costa
since
the
when
as
Golden
restricted
Rica
and
the
to
the
has
the
wild.
Extinction
that
past.
are
This
is
captivity
occurs
occurring
as
a
result
all
the
now
are
of
all
the
decrease
most
and
of
are
to
is
to
the
causes
habitat
Others
kill
such
described
a
level
as
of
that
it
is
at
endangered
species
destruction,
becoming
climate
are:
animals
that
are
a
threat
to
livestock
that
humans
have
moved
from
one
part
or
alien
species.
the
ancient
the
ago.
habitats,
here
trees
that
Jurassic
They
but
in
are
occurring
in
cooled
most
ice
is
as
of
sheets.
the
As
warming
heated
North
the
land
result
Climate
and
Europe,
species
a
atmosphere.
world
will
with
equator.
tropical
Plants
outcompete
lower
Brazil
Florida.
over
threatened
grow
have
little
period
are
can
is
of
even
changes
at
was
more,
to
was
different
America
world
that
of
change
and
warmed,
a
the
feature
times.
much
the
ice
of
During
of
Asia
melted
and
exposed.
regions
better
other
able
are
and
plants
to
species.
extending
and
survive
Examples
in
their
animals
ranges
changing
of
this
are
away
from
environments
evident
on
1989.
safe
in
100
Plants
in
adapted
altitudes
there
will
and
be
destruction
have
the
largely
is
not
habitats
been
drained
and
lion
as
cold
in
of
cause
provide
migrating
to
provide
for
down.
tamarin
they
towards
left
covered
cut
only
leisure
conditions
retreating
was
the
for
to
nowhere
been
golden
grounds
development
their
peaks.
If
this
go.
21.2.
The
robbed
Atlantic
many
forests
species,
habitats.
habitat
Many
for
to
has
ecological
birds.
land
Topic
disappearing
mountain
them
This
of
are
loss.
Wetlands
services
wetlands
farming,
for
us
across
housing,
are
and
the
very
also
world
industrial
facilities.
their
botanic
Pollution
reefs
Sea
oil
are
is
occurring
endangered
otters,
like
pollution.
they
286
the
species
survival
the
world
associated
feeding
as
alive
in
another
colonised
important
gardens,
in
overshing.
species
the
of
Deforestation
years
the
extinctions
These
introduced
age
covered
including
natural
left
only
a
of
million
to
by
to
ice
Habitat
since
and
change
continues
are
extinct.
with
world
the
from
changed
considered
sport
mountains.
Cycads
in
alive
Unit.
the
or
•
Now
not
individuals
kept
1936.
sometimes
Monteverde
of
been
species
food,
organisms
Incilius
no
are
in
was
Toad,
a
crops
competition
the
of
for
composition
species
extinct
this
life,
•
Climate
is
in
extinct
pollution
Threats
It
have
describe
risk
of
thylacine
as
number
they
When
human
Zoo
are
species
population
•
Hobart
there
Some
species
change,
last
the
than
endangered
The
world.
described
However,
higher
activities
if
if
OUTCOMES
anywhere
•
extinct
species
ingest
many
Oil
toxic
on
a
global
ecosystems
marine
sticks
to
a
animals,
their
chemicals
scale.
as
fur
that
are
and
cause
As
we
result
at
stops
organ
of
have
seen,
coastal
risk
of
coral
pollution.
extinction
providing
damage
thanks
insulation
(see
T
opic
to
and
21.2).
Many
sea
Exxon
otters
Valdez
Introduced
Sometimes
sport
•
or
half
in
small
1872
by
crop.
They
parts
of
have
done
Alaska
been
this
small
to
become
foxes
Indian
to
of
the
release
in
of
oil
from
the
tanker
1989.
moved
around
deliberately
by
the
globe
introducing
by
humans.
animals
for
pests:
the
have
predation
The
Bay
have
control
Australia
•
the
following
species
we
to
Almost
in
died
medium-sized
extinct
introduced
mongoose
control
rats
proved
due
so
by
was
that
native
eating
to
in
rabbits
Jamaica
much
they
with
and
colonists.
introduced
that
marsupials
competition
European
were
successful
to
of
were
the
from
sugar
introduced
India
cane
to
other
A
the
Caribbean.
However,
as
with
many
such
project
tamarin
the
to
•
mongoose
fed
on
other
prey
as
well
as
the
one
it
was
intended
to
Plant
species
can
become
introduced
species
damage
many
hunted
to
has
for
remove
involved
natural
the
golden
captive
habitat
breeding
in
in
lion
Brazil
many
has
zoos.
food,
and
populations
the
for
sport,
ago
of
15 000
years
moved
southwards
People
have
because
goats,
extinction
for
animals
harvested
many
extinct
especially
of
which
overgrazing
have
done
by
untold
islands.
caused
dangerous
animals
or
plants
these
people
they
of
trade
and
pests.
from
some
migrated
a
the
wild
have
for
Asia
many
of
policy
been
to
hunted
With
increasing
unsustainable.
into
the
have
always
food.
became
from
They
deliberate
Humans
populations
destroyed
as
species.
the
large
About
Americas.
mammal
As
they
species.
Coral
collected
been
hunted
beautiful
trapped
materials
and
became
deliberate
policy
T
asmania,
some
and
shot
animals,
interesting
for
their
available.
as
is
people
the
In
case
hunted
such
plants
fur
in
some
with
the
as
‘big
for
the
show.
days
places,
or
for
before
that
sport
Animals
animals
elephants
thylacine,
cats’
and
by
reef
tnemelppuS
There
is
very
and
With
little
in
no
it
genetic
individuals
are
evolving
because
endangered
few
species
partly
at
alive,
left.
to
believed
variation
species
left
longer
response
was
This
in
to
small
particular
many
of
reduces
changes
in
the
the
are
threatened
change
and
overexploitation.
have
shot
invade
as
a
farmland.
wolf,
to
POINTS
sheep.
populations,
risk
the
climate
man-made
are
T
asmanian
kill
communities
pollution,
KEY
extinction
rare
reintroduce
its
control.
Hunting
In
to
introductions,
of
so
becoming
alleles
of
chances
the
of
environment
makes
1
in
left
that
are
18.4).
become
there
alive
in
captivity.
population
Topic
Organisms
when
extinct.
genes
the
(see
this
are
the
no
extinct
individuals
wild
or
Endangered
those
that
are
at
in
species
risk
of
extinction.
SUMMARY
2
QUESTIONS
An
at
1
Dene
the
following
terms:
a
extinction,
b
endangered
endangered
risk
because
species.
small
2
Explain
a
d
how
these
hunting
habitat
b
threaten
the
overshing
destruction
e
survival
c
of
Use
examples
to
explain
the
of
species
may
climate
population
very
When
a
population
population
survival
of
decreases
decreases.
a
species
What
when
in
are
this
little
is
genetic
species:
variation
that
adapt
changing
to
effects
that
is
needed
to
conditions.
Causes
on
food
webs
of
extinction
size,
the
variation
and
change,
habitat
ecosystems.
within
implications
happens?
are
the
destruction,
4
is
extinct
change
possible
have
its
with
climate
introduction
species
becoming
hunting
3
3
of
for
the
the
pollution
by
hunting,
and
introduced
competition
predation
species
with
or
them.
287
21.10
Conservation
Endangered
LEARNING
by
•
Describe
species
how
can
area
endangered
be
putting
tnemelppuS
Explain
why
important
conserved
species
a
alone.
changes
•
should
to
to
in
No
can
for
National
be
•
and
the
legs
information
of
birds
about
has
how
•
live
and
how
migrate
far
over
they
travel.
thousands
Some
of
in
parks
•
like
this
should
Lanka.
bred
of
rare
plants
be
and
in
for
the
enjoyment
of
conserved
animals,
future
it
had
zoos
and
reintroduced
being
on
in
planet
closely
and
East
them.
East
a
the
so
it
monitor
counting
Africa
Other
duty
which
land
Africa
areas
set
to
this
aside
which
of
Island
animals
to
the
Pacic
are
such
the
as
sea
Marine
and
wild.
use
is
the
ocks
of
aeroplanes
techniques
conserve
is
have
to
ecosystems
done:
for
wildlife
patrolled
Masai
from
by
Mara
damage
Reserve
breeding
Many
islands
ready
was
become
them
but
which
wardens,
in
Kenya
and
in
New
them
in
by
shing
Zealand.
species
of
captivity
Partula
and
snails
during
the
20th
century.
Some
are
which
in
bred
to
in
nearly
released
and
back
into
their
reintroduced
to
habitats.
Oman
extinct.
plants
the
be
zoos
in
botanical
gardens
and
re-
wild.
destruction,
e.g.
deforestation
issuing
and
licences
protecting
for
logging
wetlands
to
in
prevent
drained.
establishing
Preventing
may
of
dry
take
ecosystems
forest
up
in
to
where
land
Guanacaste
300
years
to
has
become
National
Park
degraded,
in
Costa
achieve!
trade
in
Trade
endangered
in
species.
Endangered
CITES,
Species,
the
Convention
imposed
a
of
worldwide
generations.
on
the
ivory
has
into
in
Encouraging
Seed
for
in
1989.
like
sustainable
forests
natural
are
cold
seeds
wild.
Their
from
or
produce
may
to
of
an
increase
in
elephant
conserve
in
the
case
for
products
by
planting
Trees
or
allowing
seeds.
around
useful
ecosystems.
replaced
from
species
be
valuable
be
that
banks
many
genes
led
management
stores
Seed
This
Kenya.
should
replacement
species.
store
to
trade
countries
from
banks
they
crop
such
seeds
world
as
of
endangered
hope
become
to
extinct
improvement
medicinal
collect
in
in
the
drugs.
or
and
the
future
Seeds
been
the
collected
from
plants
in
the
wild
and
are
put
into
long-term
wild,
storage.
Seeds
of
many
species
are
stored
by
dehydration
so
they
successfully.
contain
288
of
in
of
Goat
them
Re-establishment
are
in
tagging
have
and
protect
e.g.
prevent
valuable
sometimes
and
the
as
•
bred
to
habitat
time
Ieucoryx,
parks
we
ways
tracts
endangered
to
removed
Oryx
on
and
•
oryx,
radio
people
captivity
populations
Arabian
by
forests
ban
The
habitat
count
so
some
large
oryx
International
also
are
Reducing
Rica
Areas
•
habitats
–
extinct
Growing
e.g.
Sri
everywhere
Researchers
and
isolation
endangered
Arabian
them
Park,
affect
bird
•
wilderness
simply
leaving
T
anzania.
establishing
the
achieved
and
miles.
•
National
in
returning
where
of
never
elephants.
Here
Parks
Rescuing
The
Plains
is
habitat
long
now
Horton
This
organism’s
labelling,
elephants
game
became
species
of
pollution,
then
they
an
organism’s
animals.
occupied
the
Marine
of
lives
Serengeti
onto
the
involve
forest
habitats.
e.g.
ring
conserved.
activities
manage
herds
species
may
a
be
population.
herds
used
and
•
and
nd
be
scientists
can
around
Human
Monitoring
birds
given
barrier
be
conserved
Putting
species
OUTCOMES
only
5%
water
and
can
thus
survive
being
kept
at
–20 °C.
Removing
that
they
remain
are
water
viable
removed
germinate.
made
if
in
seed
from
This
their
for
banks
takes
to
every
up’
the
affect
and
ve
and
metabolism
seeds
tested
years.
bank
wildlife
their
However,
Some
thawed
knowledge
actions
down
years.
forever.
place
‘top
slows
many
storage,
people’s
conservation
seeds
viable
possible
Increasing
which
from
remain
for
seeds
from
to
see
help
if
to
sample
they
will
continue
to
be
species.
understanding
will
not
each
Collections
each
so
do
of
ensure
the
the
way
in
success
of
programmes.
tnemelppuS
These
Reasons
We
•
should
for
conserve
Ecosystems
providing
provide
•
•
•
for
example
not
are
more
to
support
do
in
useful
help
we
take
with
fuels
habitats
services
and
giving
substances
maintain
the
and
such
us
species
as
treating
areas
such
as
balance
for
Fuels
fully
by
few
from
plants
a
wide
variety
understand,
keeping
foods,
the
smaller
–
apart
wild
in
and
from
large
animals
of
often
pests
quantities,
and
fossil
provide
Drugs
•
Genes
in
Papua
eggs
Guinea
are
turtles.
medicines.
of
life
on
the
planet,
e.g.
organisms
to
diseases
some
sh
quantities.
such
that
as
we
that
continue
Brazil
could
in
But
on
there
that
are
There
utilise
this
in
ways
planet,
check.
species,
nuts.
interact
life
as
we
many
may
food
take
be
that
we
many
sources.
The
fuels
fuels,
will
such
as
not
last
forever.
biomass
fuels
We
(see
still
Topic
need
timber
Svalbard
cut
into
–
drugs
for
treating
cancer
have
been
–
as
a
result
of
selective
breeding
diversity
in
our
three
main
staples
–
rice,
to
conserve
any
locally
is
wheat
adapted
in
wild
relatives
that
have
genes
we
can
be
kept
in
botanic
very
and
varieties
could
gardens
Norway
little
POINTS
Endangered
maize.
that
use
in
and
their
species
can
be
genetic
It
exist
by
the
monitoring
the
is
of
their
populations,
and
habitats,
using
future.
captive
plants
northern
plants.
protecting
any
in
permafrost.
to
sizes
important
bank
Arctic
21.7).
discovered
there
seed
the
conserved
These
New
leatherback
They
1
also
of
waste,
recreation.
KEY
•
the
because:
is
•
wardens
conserving
cycles.
Habitats
directly
us
and
with
Ecosystems
There
ecosystems,
provide
food
us
nutrient
conservation
seeds
in
breeding
programmes
seed
and
putting
seeds
into
long
banks.
term
Prevent
directly
species
by
becoming
human
extinct,
especially
those
storage
2
activities.
Educating
about
the
practices
SUMMARY
Explain
QUESTIONS
the
meaning
of
essential
each
of
the
endangered
species
b
species
captive
There
State
two
country.
importance
of
Explain
species
Describe
the
for
part
a
national
c
botanic
are
that
the
are
endangered
steps
being
in
taken
your
to
region
conserve
or
and
survival
is
of
species.
many
them.
reducing
protecting
reasons
such
extinction,
vulnerable
environments
played
by
each
of
the
following
in
parks
gardens
b
zoos
d
cycling
seed
tnemelppuS
why
it
is
necessary
to
banks
conserve
and
such
and
resources
habitats
and
ecosystem
conservation:
drugs,
Explain
the
conservation,
functions,
4
ages
conservation
maintaining
3
all
breeding
as
2
of
monitoring
for
c
banks.
following:
3
a
seed
people
endangered
1
in
threatened
tnemelppuS
•
nutrient
providing
such
fuel
as
and
as
food,
genes.
ecosystems.
289
PRACTICE
1
QUESTIONS
Competition
for
between
resources
causes
of
is
one
reduced
competition
chemical
B
herbicides
C
pesticides
D
selective
the
yields.
between
A
crop
of
plants
and
biggest
Which
crop
weeds
6
potential
and
stocks
major
reduces
plants
Fish
method
weeds?
fertilisers
The
pest
of
decreasing
B
setting
C
breeding
up
reducing
weevil
shown
plants.
below
What
is
a
notorious
at
should
be
of
the
boll
used
When
the
sh
herbicide
C
insecticide
mesh
exclusion
the
time
quotas
stocks
size
of
zones
nets
and
‘no-take’
that
shing
boats
can
for
can
the
be
maximum
numbers
caught.
2)
[1]
a
population
genetic
D
molluscicide
1)
becomes
variation
This
population
means
there
are
A
alleles
B
chromosomes
C
DNA
D
genes
base
within
that
endangered
the
population
within
the
fewer:
sequences
[1]
ecosystem
is
all
the:
(Paper
A
organisms
in
an
area
B
organisms
in
an
area
factors
that
inuence
and
the
8
physical
them
2)
[1]
Eutrophication
may
fertilisers
bodies
enter
concentration
C
the
that
decreases.
B
An
make
to
7
3
to
many
a
weevil?
fungicide
(Paper
used
in
not
sea
issuing
(Paper
A
be
is
[1]
cotton
control
decline
Which
zones
1)
boll
serious
could
A
D
2
that
in
areas.
sustainable?
stay
(Paper
are
shing
physical
factors
that
inuence
an
in
happen
the
of
when
water.
water
may
sewage
The
or
oxygen
decrease
organism
because:
in
D
an
area
plants
and
animals
interactions
(Paper
4
What
between
an
area
and
is
acid
them
decomposers
B
less
C
more
carbon
D
there
are
the
negative
on
effect
of
the
over-use
respiring
aerobically
oxygen
dissolves
dioxide
in
is
water
from
released
by
the
(Paper
farmland?
bacteria
more
animals
in
the
water
2)
[1]
rain
Human
which
wastes
use
complex
C
global
D
more
enter
sewage
microorganisms
compounds
in
treatment
to
urine
works
breakdown
and
faeces.
warming
(a)
Outline
what
happens
in
the
primary,
photosynthesis
secondary
1)
and
tertiary
stages
of
sewage
[1]
treatment.
5
Which
pair
enhanced
of
gases
contributes
greenhouse
A
carbon
dioxide
B
oxygen
and
to
the
(b)
effect?
and
carbon
State
three
treated
sulfur
dioxide
and
(c)
dioxide
water
water
vapour
and
290
2)
why
safety
of
sewage
humans
should
and
recycle
be
the
[3]
in
sewage
carbon
as
treatment
part
of
the
carbon
vapour
oxygen
(Paper
(Paper
reasons
the
Microorganisms
cycle.
D
for
[6]
environment.
methane
works
C
air
of
eutrophication
(Paper
are
[1]
9
B
A
the
1)
fertilisers
A
in
[1]
3)
Explain
how
they
do
this.
[2]
10
(a)
Dene
the
term
pollution.
[2]
12
The
table
three
When
populations
reach
a
certain
size
they
to
be
State
the
concentrations
increased
between
of
1890
and
It
also
shows
how
effective
they
are
endangered.
as
(b)
how
have
are
1990.
declared
shows
gases
what
is
meant
by
the
greenhouse
gases
compared
with
carbon
term
dioxide.
endangered
(c)
The
tusked
insect
that
Zealand.
species.
weta
used
It
did
is
to
not
[2]
a
large
live
concentration
carnivorous
throughout
survive
the
the
New
certain
introduction
years
/
relative
in
atmosphere
effect
in
as
greenhouse
parts
gas
of
alien
species
breeding
and
and
a
was
rescued
reintroduction
by
per
captive
gas
million
compared
programme.
1890
1990
2030
with
CO
2
Suggest:
carbon
(i)
why
the
tusked
weta
did
not
survive
400–
dioxide
the
introduction
of
alien
species
1
354
500
(CO
New
290
to
Zealand
)
2
[2]
methane
(ii)
how
a
captive
such
an
breeding
programme
0.9
(CH
insect
would
be
carried
2.2–
for
out.
30
1.7
2.5
)
4
[2]
nitrous
(Paper
3)
0.33–
oxide
0.28
160
0.3
0.35
11
The
Asian
elephant,
Elephas
maximus,
is
a
(N
O)
2
large
herbivorous
International
as
an
Union
endangered
researchers
the
in
the
for
in
the
centre
It
of
is
classied
Conservation
animal.
published
population
Park
animal.
the
In
January
rst
T
aman
of
Peninsular
the
Nature
(a)
2009,
estimate
Negara
by
of
atmosphere
Show
counted
piles
of
dung
to
your
population.
Their
estimate
was
The
main
Suggest
why
the
researchers
could
the
of
elephants,
dung
but
had
to
Suggest
why
it
is
the
population
why
Explain
have
reliable
sizes
of
been
(i)
List
if
estimated
can
there
four
limit
the
that
T
aman
Explain
large
Asian
the
concentrations
and
(ii)
of
methane
the
twentieth
century.
[4]
the
gases
global
shown
in
the
table
warming.
[5]
why
it
effects
is
of
important
these
to
gases
know
as
the
shown
are
no
a
a
rate
limiting
that
population
in
at
are
in
why
it
of
is
Asian
the
population
likely
to
of
Park
important
animals,
elephant,
too
4)
2%
Asian
such
as
[4]
herbivorous
the
[3]
factors.
growth
National
table.
elephant
Negara.
increase
(Paper
increase
factors
elephants
(ii)
in
how
Suggest
(Paper
year
are
[3]
populations
per
oxide
endangered
the
has
nitrous
fertilisers.
estimates
species.
It
of
and
dioxide,
cause
relative
(c)
[2]
for
(d)
of
1990.
[3]
important
to
sources
carbon
may
conservationists
and
the
the
count
instead.
(c)
(b)
1890
in
in
not
increased
piles
between
increase
dioxide
631.
(i)
count
carbon
working.
vehicles
Explain
(a)
of
estimate
motor
the
percentage
The
(b)
researchers
the
concentration
National
Malaysia.
Calculate
in
a
much.
but
to
conserve
such
not
as
allow
National
Park
to
[5]
4)
291
Alternative
to
practical
paper
Experimental
1
Use
a
2
4
techniques,
sequence
Make
3
and
Interpret
Plan
and
possible
or
of
skills
and
are
Pancreatin
/
time
°C
to
for
go
the
clear
student
A
/
is
digest
minutes
turn
from
milk
powder.
14.0
10.0
25
11.5
8.0
30
10.0
6.5
35
7.0
4.0
40
6.0
2.5
1
are
such
a
together
as
the
mixture
in
one
of
the
methods
selection
of
data.
and
suggest
techniques,
an
alternative
to
practical
paper
below.
enzymes,
Pancreatin
white
given
the
powder
2
Mix
3
Record
The
the
to
clear.
table
a
Plot
the
the
will
T
wo
following
milk
powder
including
make
a
trypsin,
sample
students,
A
and
of
B,
that
will
skimmed
are
given
milk
dried
the
on
instructions:
in
water
and
stir
until
there
is
left.
dissolved
experiment
SKILLS
evaluate
and
materials).
proteins.
Dissolve
no
EXPERIMENTAL
observations
B
They
20
following
1
solution
student
(including
measurements.
experimental
(including
assessment
appropriate).
and
investigations,
tested
test
QUESTION
temperature
out
improvements
for
materials
where
observations
evaluate
carry
abilities
and
instructions,
and
practical
and
apparatus,
record
apparatus
These
skills
time
the
at
taken
left
ve
results
milk
and
for
obtained
pancreatin
the
shows
different
a
milk
their
to
solution
go
results
together.
clear.
when
they
carried
out
their
temperatures.
for
student
B
in
the
form
of
a
suitable
graph.
•
Following
a
sequence
[4]
of
instructions
•
Interpret
experimental
data:
Example
1
STUDY
12
•
Select
suitable
scales
TIP
and
Examination
axes
Draw
graphs
from
given
data
requiring
the
rae lc
T
his
the
graph:
make
possible
and
the
to
graph
be
easy
as
to
•
Plots
is
•
Scale
•
Plots
•
Axis
clear
clear
but
but
not
not
too
too
large.
emit
Line
are
thick.
graph
292
that
f ul l
in
this
that
we
th e
ch ange
ex periment
is
is
with
ruled
T
his
th e
independent
variab l e
6
is
used
as
co lumn
4
the
of
the
x-axis
T
he
‘time
to
goes
2
into
co lumn
tabl e
the
go
clear ’
righ t
the
and
gr aph .
variabl e
the
of
straight
axis
with
labels
are
headings.
units.
the
Note
same
as
that
the
20
25
30
temperature
35
/
°C
40
of
the
and
lef t-h and
the
of
dependent
0
labelled
th e
temperature.
is
th e
wh ic h
h and
tabl e
labelled.
joined
lines.
table
the
paper
.
gains
No te
variable
y-axis
the
include
on
8
rof
read.
eht
as
to
noitulos
large
drawing
chosen
printed
marks.
ot
for
Scale
graph
examination
og
•
grid
a
10
/
Tips
questions
graphs
se tunim
•
from
graph .
and
th e
Example
2
STUDY
TIP
14
T
he
plots
there
In
in
are
this
seven
bio logy
graph
errors.
graphs
are
perfect
What
points
are
are
but
they?*
joined
*
Answer
1
Cur ves
for
bo th
students
were
12
with
ruled
freehand
be
10
used
but
straigh t
lines.
if
Lines
requested
normally
r ae l c
bio logy.
lines,
they
of
in
best
the
are
Uncertainty
no t
t
plo tted,
can
question,
no t
is
with
used
was
2
in
common
T
he
even
asked
plo t
shown
3
T
he
4
T
here
only
one
for
.
markers
in
red
though
red
line
for
student
too
large.
are
is
too
A
thick.
8
in
bio logy
where
ot
emit
variation
and
to
all
contro l
there
it
can
o ther
is
be
gene tic
difcult
variables.
T
his
6
uncertainty
points
4
with
chemistry
less
are
is
shown
ruled
and
joining
In
with
and
lines
then
of
5
physics,
mathematics
uncertainty
drawn
by
lines.
there
best
t.
no
units
y-axis
and
has
numbers
T
he
no
x-axis
chosen
is
graphs
are
is
no t
6
Lines
7
T
he
as
large
lines
are
on
has
and
best
on
x-axis
scale
well
of
the
the
as
t
it
the
scale
it.
no t
been
graph
could
have
been
be.
used.
extrapo lated.
2
Example
2
markers
for
good
has
used
the
practice
two
when
different
cur ves.
two
plo t
T
his
cur ves
is
are
0
t e m p e rat u r e
b
From
this
your
graph,
enzyme
/ºC
required
describe
between
and
20°C
explain
and
on
the
the
same
effect
of
grid.
temperature
35°C.
on
EXPERIMENTAL
•
Example
Interpret
1
greater
milk
and
to
4
faster
go
6
A
good
‘T
he
have
changes
T
he
the
answer
practice
good
ideas
co llisions
The
At
of
means
very
STUDY
Example
is
do
a
Second,
answer
2
to
be
T
he
trend
changed
the
well
carry
to
as
out
do
the
less
includes
as
more
time
at
a
a
is
the
10
are
to
moving
collide
for
At
faster
wi th
the
is
•
Recall
should
say
how
independent
time
least
is
for
gures
calculation
In
of
a
the
the
the
the
enzyme.
from
In
of
this
milk
the
question
rate
physiological
TIPS
dependent
variable.
needed
two
the
simple
experiments
35 °C
and
data
the
minutes
reaction
temperature.
calculation.
to
case
go
graph
such
change
Join
points
ruled
on
straight
a
graph
with
lines.
to
as
this,
without
so.
moving
likely
gives
at
the
20
is
10
faster
2
at
marks
minutes
reaction
temperatures
higher
temperatures
and
(of
maximum
marks).
the
3
of
rate
and
falls
enzymes
at
will
2.5
the
minutes
higher
denature
so
at
40.
temperature.
the
rate
falls.
makes
know
the
and
the
asks
effect
when
40
refer
Units
for
the
trying
to
should
effect
be tween
‘20’
to
because
describe
units
always
be tween
and
be
given
20°C
‘40’,
so
the
are
and
the
effect.
no t
in
First,
given.
an
35°C
example
T
his
answer
.
but
has
the
no t
question.
that
confusing
graph.
mistakes
20
mistake.
question
the
means
two
what
describes
discussion
this
graph
mo lecules
common
answered
‘T
his
so
likely
20°C
that
needed
TIP
no t
very
to
that
high
reaction
we
higher
is
evaluate
observations
2
reaction
This
also
asked
of
being
Example
a
we
change
directly
two
of
as
it
T
he
at
means
energy
more
temperature
the
being
the
time
time
TOP
illustrate
is
This
less
TIP
greater
clear ‘.
at
more
are
the
reaction
35 °C.
minutes
description
variable
The
at
molecules
STUDY
temperature
clear.
molecules
milk
the
minutes
by
and
experimental
and
The
SKILLS
[3]
the
time
of
No
reaction
with
rate
rate
enzymes
of
falls
at
the
higher
temperature’
seems
reaction.
denaturing
is
true
but
it
is
no t
relevant
to
marks.
293
EXPERIMENTAL
SKILLS
c
Suggest
reasons
for
differences
between
the
results
of
the
two
students.
•
Interpret
and
experimental
and
observations
Example
data
Student
to
•
Evaluate
[3]
evaluate
methods
B
an
the
have
milk
used
more
milk
powder
or
less
water
in.
used
Student
in
may
dissolve
B
may
have
may
have
had
used
a
greater
volume
of
the
enzyme
investigation
solution.
They
STUDY
T
his
T
he
as
rst
would
two
milk
concentration
suggestion
care
these
d
EXPERIMENTAL
Interpret
and
to
It
or
Suggest
write
and
can
be
the
change
and
no t
B
clear
3
the
were
PH
has
the
that
vo lume,
rate
of
carried
or
the
from
marks.
identify
enzyme
reactions
pH
of
o ther
have
variables,
no t
enzyme
out
at
a
been
such
contro lled.
reactions
different
so
pH
the
is
good.
ph.
smaller
answer
times
so
whe ther
the
larger
rate
of
concentrations
are
explain
at
what
would
happen
if
student
A
carried
out
80°C.
[2]
evaluate
1
observations
enzyme
will
be
denatured.
data
Example
The
milk
2
would
denatured.
work
1
makes
de tailed
a
only
eggs.
their
eggs
The
banded
form
The
non-banded
of
Cepaea
form
of
C.
clear
at
that
the
all
b ecause
active
the
sites
of
enzyme
the
will
be
enzymes
do
not
pair
eggs
snail,
of
hortensis
Figure
2.1
so
gains
Cepaea
These
banded
placed
hatched
hortensis
explanation
and
2
so
then
only
goes
scores
on
to
1
mark.
give
a
Example
correct,
more
marks.
2
population.
A
an
suggestion
explanation
banded
single
gives
correct
QUESTION
The
go
means
TIP
Example
2
not
This
anymore.
STUDY
294
out
and
student
must
experiment
The
and
pH
the
2
correctly
smaller
.
Example
experimental
pH.
SKILLS
the
•
and
that
results
reaction.
greater
gain
sentences
T
emperature
In
different
TIP
answer
T
ake
a
the
in
a
hortensis,
forms
snails
glass
number
can
was
tank
of
exists
breed
with
to
food.
was
two
with
allowed
snails
as
forms
each
breed
T
wo
other
and
together
months
counted.
within
a
lay
and
after
the
a
i
Count
the
the
tank
number
shown
non-banded
in
of
banded
Figure
columns
in
2.1
the
snails
and
table
and
non-banded
complete
the
snails
banded
ii
of
Make
and
•
Perform
the
total
number
of
snails
and
complete
the
table
above.
[1]
number
TIPS
Make
your
one
iii
for
numbers.
snails
18
Tip:
clear,
snails
especially
STUDY
handwriting
non-banded
of
Figure
mathematical
calculations
TOP
total
in
simple
number
snails
1
of
observations
snails
banded
number
record
2.1
Calculate
Example
•
non-banded
of
Figure
SKILLS
[2]
total
in
EXPERIMENTAL
and
below.
banded
number
in
6
24
2.1
TIP
cross
twice
out
or
Calculate
Fraction
Answer
the
of
snail
in
pencil
as
fraction
banded
of
banded
snails
count
so
that
you
do
no t
count
snails
in
the
sample.
[2]
=
1
of
banded
snails
=
number
total
Answer
you
one.
=
Example
Fraction
each
miss
of
banded
number
of
snails
snails
2
/
=
3
Example
Fraction
Answer
2
of
=
banded
snails
numb er
=
total
18
/
of
banded
numb er
of
snails
snails
24
STUDY
TIP
Example
and
in
the
the
only
Care
b
1
1mark
is
about
STUDY
is
and
that
the
fraction
what
of
do
paper
handwritten
the
have
may
given
fraction
units
require
is
numbers
these
the
how
no t
no t
are
results
banding
in
but
units.
was
calculated
o ther
calculations
Example
2
gains
simplied.
clear
.
the
pattern
table
in
above
indicate
snails.
[3]
is
EXPERIMENTAL
•
example
data.
a
of
Marks
3:1
a
question
would
ratio,
be
banded
that
given
:
tests
interpre tation
of
for:
Interpret
and
experimental
and
SKILLS
evaluate
observations
data
non -banded.
dominant.
3. Non -banded
original
is
recessive.
parents
were
he terozygous,
or
the
non -banded
snails
homozygous.
5. Correct
a
showing
TIP
ano ther
2. Banded
T
o
practical
explain
1. Recognising
were
to
for
Fractions
inheritance
experimental
4
. T
he
marks
because
needed
the
2
answer
.
alternative
Suggest
T
his
gains
correct
use
of
maximum
the
of
term
3
‘allele’;
e.g.
the
banded
allele
is
dominant.
marks.
295
EXPERIMENTAL
c
SKILLS
Figure
Cape
•
Make
and
record
2.2
shows
Rock
Make
a
clear
drawing
from
a
of
Make
labelled
a
Thrush,
observations
Monticola
•
a
a
labelled
drawing
specimen
head
photograph
of
Ensure
of
×2
the
thrush.
your
has
magnication
compared
the
the
that
drawing
a
rupestris.
with
photograph.
[3]
Figure
DRAWING
2.2
TIP
Example
1
nostril
beak
Draw
a
grid
with
a
ruler
over
the
eye
relevant
and
part
draw
onto
help
and
the
you
of
the
the
same
grid
lightly
answer
space.
get
proportions
the
magnication
This
will
STUDY
T
he
correct.
TIP
drawing
is
of
the
head
only
˙
a
T
he
Magnication
x2
asked
to
beak
the
magnication
of
are
smoo th
giving
a
clear
is
in
eye
perfect
correct
and
pro portion
nostril
are
T
he
in
label
lines
precisely
place.
Tip:
to
are
avoid
the
clear
part
and
go
labelled.
arrows.
calculate
T
here
the
lines
outline.
˙
the
be
magnication.
˙
and
could
T
he
˙
at
You
markings
photograph
your
is
minimum
shading.
˙
T
he
drawing
is
accurately
labelled.
˙
3
marks
drawing:
drawing
Magnication
size
=
actual
size
Example
If
the
photograph
already
magnication,
do
include
your
that
in
not
has
forget
nal
2
eye
a
to
answer.
wing
TOP
TIPS
STUDY
Use
smooth
much
lines
shading
without
for
TIP
too
drawings.
T
he
drawing
the
body
includes
some
of
˙
T
he
lines
are
no t
smoo th;
they
do
˙
no t
x2
and
the
head
part
is
no t
magnication.
give
a
clear
lines
outline.
T
he
label
the
part
labelled.
do
T
he
line
for
no t
go
precisely
to
˙
T
he
beak
is
out
of
pro portion
˙
and
the
eye
and
nostril
are
the
eye
goes
to
the
˙
in
the
T
here
wrong
is
too
places.
much
shading.
feathers
is
above
labelled
but
the
the
eye
and
the
question
wing
asks
for
˙
a
296
drawing
of
the
head.
No
marks
QUESTION
3
EXPERIMENTAL
•
Describe
an
investigation
to
compare
the
rate
of
water
loss
Plan
and
carry
SKILLS
out
between
investigations
plants
in
Figure
3.1.
as
the
reliable
light
In
and
your
and
plants
answer
valid
as
in
the
dark,
describe
how
using
you
the
will
apparatus
make
the
in
results
possible.
[5]
TOP
cut
leafy
from
TIPS
Keep
shoot
plant
controlled
constant
Good
capillar y
air
tube
taking
3.1
Shows
uptake
Example
a
potometer
by
leafy
that
is
used
to
readings
to
your
distance
minutes.
will
get
measure
the
rate
of
resul ts
travelled
Divide
the
the
rate
in
by
by
measuring
the
bubble
distance
mm
per
by
2
in
and
2
variable)
you
✓Gives
how
minute.
2
sure
your
apparatus
has
no
that
the
kept
the
temperature
same.
Use
and
the
check
Do
for
the
in
anomalies
same
in
the
the
and
light
take
dark.
three
an
Draw
times,
✓T
he
average.
a
compare
If
you
the
bar
chart
✓A
you
water
can
lost
diameter
Example
work
per
in
have
the
of
the
be
out
the
rate
as
mm
bar
one
A
minute.
set
and
the
this
of
apparatus
another
distance
with
the
experiment
b ecause
is
important
with
the
the
plant
plant
in
the
•
variables,
are
leaks.
T
his
temperature,
contro lled.
carry
is
out
of
repeat
the
and
explains
student
wind
Humidity
has
speed
could
readings,check
average
suggested
de tail
careful
used
and
also
the
have
is
because
for
anomalies
stated.
there
are
only
two
values
variable.
about
when
maximum
T
he
rates
writing
is
given.
Candidates
superscript
numbers
should
by
hand.
of
5
marks
is
given.
TIP
rst
✓How
bubble
moves.
When
to
✓Time
the
bubble
did
not
sentence
measure
our
apparatus
was
the
to
time
keep
with
everything
a
stop
the
whole
an
average.
experiment
the
measured
Variables
kept
bubble
with
the
repeats
dependent
is
the
question.
variable
by
measuring
the
explained.
sto pwatch.
same
the
experiment
3
need
times’
to
is
be
named.
acceptable
as
referring
to
broken.
the
readings.
same.
‘T
ake
an
average’
is
too
vague,
which
gures
are
averaged?
watch.
3
Do
of
simply
the
move
•
Measure
prevent
independent
repeat
It
to
chart
the
✓‘Do
all
time
of
•
at
to
calculation
movement
did
standard
capillary
light.
we
the
2
dark
Measure
as
mentioned.
STUDY
You
(dependent
averages.
the
3
tube
need
plant
✓Further
know
bubble
measured.
contro l
of
need
and
of
to
the
the
of
been
experiment
is
of
speed
piece
plant.
the
movement
explained.
apparatus.
piece
Do
collected.
leaks
wind
same
the
is
minutes
rate
✓T
hree
are
the
data
TIP
✓Measuring
the
and
the
water
✓Shows
Make
improve
of
1
collect
the
always
repeated
shoots.
STUDY
You
investigation.
bubble
reliability
Figure
an
investigations
involve
rule
in
variables
three
times
and
marks
awarded
out
of
5.
take
297
Glossary
This
glossary
some
used
of
in
words
the
this
are
provides
denitions
important
book.
key
The
terms
of
biological
relatively
terms
underlined
as
dened
from
glucose,
in
which
you
are
required
in
for
the
examinations.
Y
ou
be
expected
to
than
energy
presence
of
Antitoxin
as
a
lymphocytes
oxygen.
poisonous
chemical
that
waste
by
explain
–
result
a
collection
from
a
of
diseases
weakening
of
the
Arteriole
type
artery
capillaries.
and
of
immune
by
any
forms
system
following
relaxation
HIV
.
ow
of
of
of
a
two
or
more
Absorption
movement
molecules
intestine
of
through
into
the
of
muscle
blood
Artery
digested
the
blood
wall
or
Alveolus
where
of
lymph.
the
a
tiny
air
exchange
air
and
sac
of
blood
in
gases
the
Acid
of
the
the
rain
acidic.
rain
and
react
with
form
acid
the
lens
adjustment
so
as
to
of
focus
into
or
the
snow
gases
in
which
such
oxides
water
acid
carbon,
hydrogen,
of
the
as
acids
bonds
to
amino
acids
a
molecule
link
consists
form
made
oxygen
together
protein
a
and
by
up
nitrogen.
chemical
molecules.
of
and
Some
Articial
Amnion
nitrogen
atmosphere
the
antigen,
either
pathogen
or
on
in
a
in
body
to
produces
response
the
surface
also
the
the
contain
site
enzyme
fetus
in
that
the
surrounds
uterus.
means
of
part
of
the
to
of
uid
an
a
is
contained
and
which
the
within
liquid
the
protects
mechanical
of
which
fetus
from
of
high
the
through
the
cell
in
or
movement
out
of
membrane
a
down
of
their
lower
without
enzyme
of
region
of
their
higher
steroid
substance
production
from
that
a
a
crop
gradient,
that
increases
released
from
of
protein
to
a
build
that
to
survive
in
its
cells
to
the
feature
that
tness,
i.e.
an
increases
small
in
the
helping
amount
of
energy
absence
of
red
reproduce
in
its
a
drug
so
when
a
regularly
a
disorder
blood
of
cells
the
blood
without
the
a
for
carry
person
that
has
they
taken
cannot
glands
produced
that
emergencies
by
a
which
joint.
muscles
brings
other
When
relaxes,
which
move
one
e.g.
the
pollen
the
a
pair
about
the
biceps
of
deposits
the
internal
of
walls
slows
down
the
of
rate
of
a
chamber
blood
of
from
the
veins
heart
and
that
pumps
to
a
ventricle
(plural
atria).
a
plant
growth
controls
cell
hormone
elongation.
the
and
triceps
B
arm.
increasing
of
the
in
cells
a
ower
where
produced.
the
a
drug
that
is
stop
the
growth
of
consisting
a
bacterial
taken
bacteria.
to
kill
of
type
cell
surrounded
cell
wall,
single
of
microorganism
has
by
but
cells.
Each
cytoplasm
a
cell
has
no
membrane
and
nucleus.
glucose
a
protein
released
by
Balanced
diet
a
diet
that
provides
blood.
respiration
happens
are
of
stress,
the
process
pathogens.
298
narrowing
by
movement
prepares
and
lymphocytes
that
a
of
contracts,
lower
part
grains
Antibody
concentration
Aerobic
cells.
sufcient
which
or
example
the
ow.
Auxin
Antibiotic
for
of
environment.
hormone
adrenal
body
cells
used,
it.
Adrenaline
the
are
means
survive
Anther
by
of
the
haemoglobin
which
cannot
in
Bacterium
do
into
oxygen.
at
Addiction
they
caused
which
receives
muscles
and
where
part
arteries
Atrium
the
organism’s
to
molecules
oxygen.
an
inherited
it
parent.
from
environment.
an
the
movement
a
blood
Antagonistic
by
gametes.
process
release
it
feature
reproduction
of
genetically
of
the
food
body
arteries
that
Adaptive
are
(clones)
cholesterol
in
organism
formation
individuals
the
the
in
using
helps
called
up
respiration.
feature
Also
reproduction
the
Atherosclerosis
respiration
happens
Anaemia
Adaptation
yield.
breeding
characteristics,
the
to
glucose
energy
useful
hormone-
concentration
concentration
their
selection
for
breaks
a
relatively
against
a
muscle.
cell
concentration
the
animals
Assimilation
that
a
as
starch.
Anaerobic
region
placing
oviduct
breeding.
becoming
ions
(AI)
or
infertility
selection
of
or
jointed
exoskeleton.
uterus
and
digested
transport
the
treating
plants
Asexual
ts.
molecules
that
have
amnion
the
the
like
Active
which
heart.
that
damage.
the
Anabolic
substrate
that
of
New
surface
into
phylum
Articial
because
vaccine.
molecule
the
insemination
into
identical
an
the
sulfur
.
membrane
developing
Amylase
Active
through
from
protective
semen
e.g.
antibodies
See
is
rain.
immunity
own
and
controls
vasodilation.
vessel
away
animals
a
selective
its
wall
of
sulfur
Amniotic
Active
the
capillaries.
and
blood
travels
Arthropods
occurs.
Amino
Amino
retina.
Polluting
dioxide
in
lungs
between
legs
Accommodation
onto
between
alternative
gene.
blood
shape
vessel
Contraction
these.
Allele
light
blood
terms
A
the
(toxins)
bacteria.
immunodeciency
vasoconstriction
the
products
by
the
to
infection
food
released
neutralises
may,
body’s
other
of
such
produced
that
however
,
the
Acquired
syndrome
know
amount
substances,
the
AIDS
syllabus,
large
food
to
release
a
to
protect
against
sufcient
and
all
correct
energy
the
food
for
a
person’s
nutrients
proportions.
in
needs
the
Glossary
Bile
an
liver
and
It
is
alkaline
stored
released
through
the
uid
in
into
bile
made
the
the
gall
small
duct
to
in
the
Carbohydrase
bladder.
intestine
help
with
the
an
enzyme
digests
carbohydrates
sugars,
e.g.
amylase
to
that
Chloroplast
simple
digests
starch
to
and
absorption
of
plant
Carries
cells.
ssion
a
in
type
of
which
asexual
one
substance
that
a
class
of
provides
food
by
energy,
a
two.
Bacteria
cell
divides
starch
and
glucose.
Composed
reproduce
by
carbon,
hydrogen
an
intestinal
Binomial
naming
system
a
organisms
two
names:
method
in
a
which
genus
for
compounds
each
name
cycle
is
and
trivial
name,
e.g.
Homo
the
caused
e.g.
in
the
a
lipid-based
liver
and
chemical
found
in
the
oxygen.
ow
through
decomposers
High
levels
of
cholesterol
and
of
carbon
plants,
their
animals,
environment.
the
blood
risk
of
are
linked
to
atherosclerosis
an
in
increased
and
heart
disease.
and
Carbon
a
disease
ssion.
Carbon
given
in
of
blood.
binary
found
bacterium.
made
into
is
photosynthesis.
sugars.
Cholesterol
reproduction
that
out
fats.
Carbohydrate
Binary
structure
chlorophyll
Cholera
digestion
small
containing
sapiens
dioxide
the
gas
produced
Chromosome
a
thread-like
structure
for
as
a
waste
product
during
respiration
made
up
of
genes.
They
are
found
humans.
and
Biodegradable
broken
down
something
by
biological
that
can
be
processes.
absorbed
during
by
plants
photosynthesis
and
to
used
make
inside
simple
the
when
a
plastics
Biomass
in
a
are
the
of
living
material
Carnivore
an
animals
meat-eater.
–
a
animal
that
eats
other
that
the
Carrier
the
use
of
organisms
has
a
(1)
an
recessive
individual
allele
for
useful
and
useful
products,
medicines,
services,
such
or
as
such
to
as
carry
making
disease
out
wastes
harmless.
next
is
and
infected
by
infectious
control
prevention
of
a
by
contraception
or
a
muscular
sac
and
passes
it
out
(2)
the
of
a
it
to
person
only
process
found
pathogen
the
does
that
and
oviducts
they
for
not
disease,
microbes
the
on
it
to
have
but
Ciliary
an
is
that
(plural:
beat
out
the
muscle
controls
cells
to
e.g.
cilia).
move
In
dust
of
the
lungs
and
up
during
a
the
muscle
shape
in
of
the
the
eye
lens
focussing.
able
system
the
organ
others.
system
a
organs,
throat.
Circulatory
transmit
tubular
the
who
abortion.
substance
that
speeds
and
made
the
up
heart
of
that
blood
vessels
transports
blood.
stores
up
urine
transmit
disease,
Catalyst
Bladder
visible
genetic
birth
to
either
can
generation;
symptoms
Birth
are
who
a
to
make
tiny
some
airways,
and
foods
a
line
airways
area.
Biotechnology
to
and
dividing.
biodegradable.
mass
particular
is
sugars.
Cilium
Some
nucleus
cell
through
a
chemical
reaction
and
is
not
Mammals
have
a
double
circulation
the
changed
by
the
reaction.
with
blood
passing
through
the
heart
urethra.
twice
Cell
Blind
spot
part
of
the
retina
structural
are
no
organisms.
the
unit
part
of
the
central
All
organisms
coordinates
of
the
of
cells.
membrane
Viruses
are
Classify
not.
groups
which
a
small
branch
of
sort
living
to
organisms
features
into
they
the
boundary
of
in
common.
the
which
ends
in
alveoli
into
controls
and
out
the
of
materials
that
it.
Clone
an
identical
organism
to
its
that
is
genetically
parent.
a
Cell
bronchus
to
according
body.
pass
Bronchiole
body.
most
cell
activities
the
of
are
have
that
of
nervous
Cell
system
circuit
receptors.
composed
Brain
functional
one
where
living
there
and
in
sap
the
liquid
that
lls
the
Clotting
a
series
of
chemical
(air
vacuole
of
a
plant
cell.
reactions
that
cause
blood
cells
to
sacs).
stick
Cell
Bronchus
one
of
the
two
tubes
wall
the
outer
layer
of
a
the
trachea
and
pass
made
of
cellulose,
which
(plural:
this
stops
loss
of
blood
and
results
in
the
into
the
lungs
wound
supports
formation
the
a
plant
the
off
At
that
cell
branch
together.
cell
and
gives
it
of
a
scab.
shape.
bronchi).
Codominance
Cellulose
a
complex
alleles
that
makes
up
the
the
existence
of
two
carbohydrate
cell
walls
of
for
a
particular
characteristic
plant
C
where
neither
is
dominant
over
the
cells.
Capillary
the
smallest
blood
other
Central
vessel
with
walls
only
one
cell
are
exchanged
system
brain
walls
between
heterozygous
blood
Chemical
and
of
uid.
digestion
the
large,
small,
a
disease
uncontrolled
more
parts
resulting
division
of
the
of
body.
in
individuals.
insoluble
from
cells
in
soluble
molecules
or
rectum
found
in
absorbs
the
many
light
of
the
the
alimentary
small
where
the
intestine
absorption
and
of
molecules.
water
Chlorophyll
part
between
into
the
one
the
breakdown
the
Cancer
expressed
through
canal
tissue
are
cord.
Colon
capillary
both
and
thick.
spinal
Substances
nervous
and
green
plant
for
occurs.
pigment
cells
that
photosynthesis.
299
Glossary
Community
and
a
all
the
animals,
microorganisms
particular
that
are
plants
found
Cuticle
in
habitat.
the
epidermis
that
waxy
in
covering
plant
reduces
the
stems
loss
of
of
and
movements
the
leaves
water
out
of
the
cause
air
to
ow
in
and
lungs.
by
Diarrhoea
a
condition
where
the
transpiration.
Competition
contest
organisms
for
water
mates.
and
faeces
between
resources
such
as
food,
Cystic
brosis
affecting
the
an
lungs
inherited
and
the
disease
released
symptom
of
decaying
plant
remains
caused
by
a
faulty,
loose
diseases,
and
such
watery.
as
A
cholera.
digestive
Dicotyledon
system,
Compost
are
a
type
of
owering
recessive
plant
used
with
an
embryo
that
has
allele.
as
a
source
of
nutrients
in
two
gardens.
Cytoplasm
Concentration
gradient
in
substance
between
e.g.
either
between
concentration
side
air
in
of
a
the
two
cell
of
not
including
the
the
of
the
arrangement
(Also
nucleus.
of
alveolus
known
Diffusion
membrane,
and
molecules
D
a
blood
the
process,
as
higher
with
place
in
the
liver,
the
or
sensory
cell
in
the
where
retina
of
nitrogen-containing
part
of
eye
that
intensity
responds
and
detects
to
light
of
high
colour.
acids
is
removed
Ammonia
is
to
then
form
a
condition
faeces
are
a
lower
of
the
where
difcult
to
Decay
pass
body.
the
organisms
converted
breakdown
and
waste
its
energy
an
by
organism
on
that
gains
Decomposers
other
mainly
organisms.
into
urea.
Digestion
their
feature
variation
that
of
with
many
shows
a
range
between
two
intermediates,
energy
of
by
and
Deciency
extremes
when
e.g.
a
human
an
and
fungi
breaking
waste
disease
Contraception
any
method
of
birth
important
vitamin
results
gradient
prevents
the
that
breaks
into
the
down
any
fertilisation.
device
prevents
arteries
from
a
the
in
or
a
nutrient,
mineral,
is
such
missing
humans
in
the
removal
order
Denitrication
fertilisation.
ions
into
to
that
to
of
exploit
conversion
nitrogen
Denitrifying
supply
which
live
to
heart
muscle.
such
as
convert
in
down
nucleus
gas
in
two
of
the
transparent
eye
which
rays
onto
the
layer
at
body
heart
helps
to
refract
retina.
by
bacteria
anaerobic
water-logged
nitrate
ions
Development
complexity
disease
by
muscle
with
new
an
as
an
of
heart
intermediates,
no
which
embryo
of
plant
–
a
seed
leaf.
In
of
of
the
cotyledons
are
food
stores
groups.
the
molecule
material.
in
DNA
that
The
forms
the
sequence
codes
for
the
of
sequence
bacteria
amino
acids
in
soil,
into
an
proteins.
allele
that
is
expressed
and
nitrogen
it
is
present
(e.g.
T
or
G).
gas.
increase
any
grows
organs
substance
taken
into
the
in
that
and
modies
or
affects
chemical
and
in
the
body.
organ
the
rst
part
of
the
a
medical
the
blood
condition
glucose
not
diabetes
to
is
controlled.
the
failure
One
of
E
the
secrete
the
use
of
all
the
living
organisms
insulin.
(the
permeable
transfer
is
intestine.
Ecosystem
Dialysis
the
feature
human
bacteria.
for
embryo.
Cross-pollination
e.g.
nitrate
many
pancreas
plants
a
a
cause
owering
limited
for
land.
Duodenum
Diabetes
in
the
variation
phenotypes
of
supply
blood.
part
chromosomes
conditions,
embryo
tissues,
concentration
Cotyledon
of
heart
blockage
that
a
interactions
partially
membrane
to
community)
separate
physical
in
a
between
place,
them
and
and
the
their
environment.
of
substances.
pollen
ower
grains
to
different
the
from
the
stigma
plant
of
the
anther
of
a
of
ower
same
Egestion
a
on
species.
a
Diaphragm
and
the
300
it
cells).
with
small
arteries
system
absorbs
trees
the
systems.
caused
coronary
organ
and
nucleus
of
reactions
disease
processes.
the
gains
Coronary
a
number
body
light
the
food
sets
Discontinuous
Drug
front
using
chemical
as
and
disease.
Deforestation
by
or
arteries
aorta
blood
the
large,
small,
condition
if
Cornea
molecules
and
Dominant
oxygenated
of
into
blood.
Diploid
of
branch
of
dead
material.
bases
Coronary
a
result
gain
genetic
that
down
a
breakdown
molecules
system
that
DNA
Contraceptive
substance
as
by
blood
that
with
place
variation
height.
control
a
dead
material
(e.g.
phenotypes
to
concentration
food
containing
a
of
place
microorganisms,
bacteria
organisms
in
a
decomposers.
feeding
Continuous
movement
from
movement.
Digestive
Consumer
leaves.
ammonia.
mechanical
out
its
the
water-soluble
compacted
net
concentration
insoluble
Constipation
in
amino
random
the
veins
eudicotyledon.)
ions,
concentration
a
net-like
which
lungs.
takes
Cone
a
a
places,
Deamination
in
contents
and
the
cell
difference
jelly-like
cotyledons
brous
thorax
a
sheet
tissue
from
of
that
the
muscular
separates
abdomen.
Its
that
has
absorbed,
anus.
the
not
as
passing
been
out
digested
faeces,
of
food
or
through
the
Glossary
Embryo
animal
the
or
fertilised
early
plant
which
are
the
broken
surface
stage
it
of
an
develops
from
a
egg.
Emphysema
in
as
a
medical
walls
of
down.
area
for
This
gas
condition
the
alveoli
reduces
exchange
Fermenter
a
which
fungi
or
under
sterile,
and
female
egg,
to
that
the
sex
form
grows
container
bacteria
are
controlled
Fertilisation
and
the
large
a
into
a
of
e.g.
zygote
the
a
a
length
Gene
and
base
egg)
to
that
the
person
cannot
mutation
new
oxygen
into
their
large
fat
the
globules
breakdown
into
on
for
a
alleles
a
of
of
change
DNA
in
that
the
gives
rise
genes.
individual.
chemicals
that
provide
the
engineering
genetic
material
changing
of
an
organism
blood.
plant
Emulsication
found
codes
get
Fertilisers
enough
DNA,
that
characteristic.
sequence
Genetic
means
of
chromosome,
particular
male
sperm
(fertilised
new
Gene
conditions.
fusion
cells,
in
grown
many
of
tiny
land
and
nutrients
to
and
increase
produce
a
are
the
put
on
growth
higher
the
of
a
by
crop
removing,
individual
changing
or
inserting
genes.
yield.
Genotype
the
genetic
makeup
of
globules.
Fertility
Energy
energy
transfer
from
one
the
transfer
trophic
of
to
(feeding)
drug
increase
becoming
a
the
drug
that
chances
of
is
a
used
an
woman
organism
possesses
to
the
Enhanced
greenhouse
increase
greenhouse
in
a
concentration
gases
in
the
of
a
to
global
speed
up
reactions
in
rate
the
with
of
catalysts
that
chemical
the
plant
growth
inherited
all
the
major
of
a
group
organs
the
characteristics,
leo
the
indigestible
cellulose
provides
food
bulk
plant
and
to
through
material,
lignin
and
the
same
enrichment
nutrients
of
algae
process
features
assist
the
gut
the
by
the
passage
of
peristalsis.
to
tiger
,
a
Excretion
that
and
of
can
in
surviving
and
environment
of
an
of
reproducing
in
which
it
the
is
in
the
removal
toxic
products
a
plant
osmosis
longer
over
time.
from
materials,
of
wall
is
Food
the
metabolism
excess
when
the
a
are
in
produced
so
push
cell
that
that
the
has
cell
outwards
described
as
chain
this
relationships
in
lost
by
of
and
requirements.
beginning
species
no
organism
with
is
organism
in
show
the
ow
no
the
as
a
an
complex
energy
a
by
the
chain.
of
the
liver
Goblet
cells
mucus-secreting
cells.
plant
to
the
a
growth
stimulus
response
of
by
gravity.
warm
effect
food
because
the
Earth
carbon
is
dioxide
Each
other
greenhouse
gases
in
the
next
Food
energy
network
interconnected
in
muscles.
atmosphere
reduce
heat
into
escape
of
energy
space.
Greenhouse
nutrients.
of
and
chains
the
chains
and
gases
web
carbohydrate
store
feeding
Earth.
Food
so
accid.
producer
.
on
the
and
glucose
cell
longer
the
of
community
a
fed
glucose
concentration
liver
water
contents
against
shows
a
to
the
blood.
found
and
in
tigris
stimulates
glycogen
the
Glycogen
found.
and
by
in
organisms
the
of
substances
on
similar
organism
plants.
which
change
probability
convert
kept
exists
with
lion, Panthera
Panthera
that
Greenhouse
Extinct
species
the
hormone
pancreas
increase
a
waste
of
e.g.
Gravitropism
populations
organisms
it
GG).
genus.
Glucagon
that
in
Flaccid
Evolution
when
development
body.
Eutrophication
stimulate
alleles
atmosphere
Fitness
waters
or
the
warming.
biological
the
during
recognisable.
mainly
Enzymes
stage
mammal
are
Fibre
leading
Tt
of
next.
Fetus
effect
(e.g.
terms
pregnant.
Genus
level
in
showing
the
radiate
heat
maintain
than
it
the
would
be
towards
the
temperature
Earth
higher
otherwise.
F
energy
ow
through
an
ecosystem.
Growth
Fats
lipid
molecules
that
consist
and
glycerol
and
three
fatty
acids.
energy
rich
proportion
of
as
they
carbon
contain
and
a
hydrogen
number
Gall
bladder
stores
the
with
acids
glycerol
molecules
to
form
that
bile
bile
respiration
converted
dioxide;
which
in
an
or
sac
into
it
in
is
the
the
liver
released
small
useful
increase
increase
in
in
size
cell
cell
size
or
both.
H
intestine.
combine
fats.
Haemoglobin
Gametes
glucose
ethanol
and
industrial
microorganisms
a
an
which
down
sex
of
cells
with
the
haploid
chromosomes.
red
blood
oxygen
to
is
process
are
Gas
carbon
used
in
to
exchange
system
system
comprising
and
lungs
into
the
that
alveoli
organ
trachea,
involves
where
Haploid
bronchi
cells
the
that
form
red
pigment
combines
in
with
oxyhaemoglobin.
moving
oxygen
air
product.
carbon
dioxide
are
exchanged
a
a
single
chromosomes
(e.g.
nucleus
set
of
unparied
sperm
and
egg).
and
portal
vein
the
vein
with
through
the
nucleus
containing
Hepatic
make
by
anaerobic
which
into
(2)
(1)
a
before
duct
number
Fermentation
permanent
mass
high
atoms.
Fatty
dry
Fats
G
are
a
of
which
absorbed
food
travels
blood.
from
the
small
intestine
to
the
liver.
301
Glossary
Herbicide
a
chemical
that
kills
weeds.
Ingestion
the
process
of
taking
in
Leaf
food.
Herbivore
an
animal
that
feeds
the
light
plants.
Inheritance
of
Heroin
a
highly
addictive,
derived
from
from
poppies.
opium
genetic
a
genotype
alleles
of
a
gene
to
(Human
chemical
photosynthesis.
transmission
the
from
one
Lens
next.
disorders
by
dominant
are
light
part
rays
of
the
onto
eye
the
that
focuses
retina.
disorders
or
Limiting
recessive
is
in
the
factor
the
shortest
factor
supply
that
and
that
are
passed
from
one
restricts
processes,
such
as
the
rate
different.
generation
HIV
during
where
alleles
two
absorbs
into
extracted
caused
the
the
information
Inherited
Heterozygous
that
convert
depressant
generation
drug
organ
to
only
energy
on
plant
energy
to
the
next.
of
photosynthesis
or
the
rate
of
immunodeciency
growth.
Insulin
virus)
the
virus
that
causes
a
pancreas
HIV
attacks
and
destroys
the
body’s
ability
to
against
by
the
that
to
stimulates
store
the
glucose
as
liver
and
glycogen
Lipase
so
to
a
reduction
in
the
Liver
of
glucose
in
the
maintenance
of
environment.
controlling
factors,
such
in
and
the
the
Homologous
concentration
chromosomes
chromosomes
a
that
for
same
the
muscles
amino
the
ribs;
external
intercostal
during
inspiration;
intercostal
muscles
contract
same
expiration.
vitro
acids
ammonia
the
form
characteristics
fertilisation
outside
and
the
eggs
(IVF)
body
by
fertilisation
mixing
Lymph
uid
in
a
laboratory
embryo
is
placed
a
a
genotype
a
gene
are
chemical
an
the
activity
in
the
blood
of
one
organs.
the
the
drains
to
living
in
do
not
the
action
have
to
or
coloured
the
an
action
that
think
part
like
pupil.
It
the
alters
eye
the
size
a
e.g.
formed
lymph
system
vessels
lymph
cells
are
when
tissue
vessels.
that
system
of
transport
thin-
lymph
nodes
where
white
blood
found.
Magnesium
pupil
and
so
controls
the
for
light
entering
the
that
is
the
element
needed
amount
the
synthesis
of
chlorophyll.
It
is
eye.
absorbed
by
the
roots
in
the
form
of
ions.
adapted
Malnutrition
hyphae)
a
uid
K
that
of
chemicals,
M
liver.
plant
(plural:
structure
toxic
of
are
water.
(mycelium)
in
out
about.
of
more
Hormones
Kidney
Hypha
of
into
magnesium
Hydrophyte
carries
dish.
and
of
by
and
gland
the
target
destroyed
glycogen
messenger
endocrine
transported
specic
of
uterus.
around
alters
converts
glucose
identical.
Iris
is
stores
where
we
that
urea,
into
and
of
by
into
Lymphatic
resulting
Involuntary
produced
down
ammonia,
in
the
Hormone
into
detoxication
walled
Homozygous
alleles
abdomen
alcohol.
positions.
The
both
the
breaks
pair
sperm
the
in
bile,
carry
occurs
genes
organ
of
in
matching
the
produces
blood.
during
of
muscles
contract
internal
glucose
fats
as
muscles
temperature
digests
This
between
involves
that
glycerol.
a
Intercostal
internal
and
blood.
that
constant
enzyme
acids
concentration
disease.
Homeostasis
the
fatty
defend
causing
itself
produced
lymphocytes
muscles
reducing
hormone
AIDS.
is
thin
part
mould
of
the
organ
that
lters
waste
by
eating
an
the
condition
unbalanced
caused
diet.
thread-
the
chemicals
out
the
and
of
the
blood
and
controls
Undernutrition
occurs
when
a
diet
is
body
water
salt
levels
in
the
body
.
decient
in
one
or
more
food
types.
fungus.
Overnutrition
coronary
can
heart
lead
to
obesity
and
disease.
L
I
Maltase
Lactase
Ileum
the
part
of
the
small
the
enzyme
that
down
down
between
the
duodenum
the
and
lactose
(milk
maltose
the
major
function
of
absorption
which
is
Lacteal
a
of
digested
food.
inside
a
lymph
villus,
capillary
system
tissues,
cells
which
that
act
against
together
to
give
a
pathogens.
Lactic
in
acid
muscles
the
chemical
when
anaerobically.
protection
without
food
glucose
by
chemical
change
to
molecules.
produced
is
Some
a
type
of
division
of
the
respired
bacteria
to
reduce
the
chromosome
also
number
provided
the
smaller
against
produce
disease
into
contains
nucleus
Immunity
food
fats.
Meiosis
defence
digestion
of
and
the
chemicals
breaks
found
pieces
absorbed
Immune
that
glucose.
sugar).
breakdown
the
to
the
Mechanical
colon,
enzyme
breaks
intestine
the
lactic
acid
during
by
half.
Diploid
nuclei
give
anaerobic
immune
rise
to
haploid
nuclei.
Also
called
a
respiration.
system,
including
lymphocytes
and
reduction
antibodies.
Large
intestine
the
nal
parts
of
Memory
the
Implantation
the
embedding
of
alimentary
canal
that
the
lining
of
the
and
store
the
rst
invasion
of
produced
a
faeces.
uterus.
pathogen
302
lymphocytes
an
water
into
cells
absorb
during
embryo
division.
or
to
a
vaccine;
these
cells
Glossary
provide
a
fast
immune
response
to
about
infection.
movement
Muscle
our
Menstrual
cycle
the
sequence
tissue
gut
and
of
also
bones
moves
keeps
our
at
joints.
food
heart
Nutrition
along
beating.
are
that
occurs
in
a
ions,
woman,
Mutation
a
change
in
a
gene
or
in
the
thickens
lining
in
of
order
the
to
uterus
receive
a
after
ovulation.
The
containing
by
cycle
hormones
a
network
of
thin
for
gland
and
the
growth
and
from
that
make
up
the
body
the
tissue
or
repair
,
assimilating
them.
of
a
O
the
Obesity
when
a
person
is
extremely
ovaries.
overweight
Menstruation
materials
and
threads
is
fungus.
pituitary
raw
which
mineral
chromosome.
(hyphae)
controlled
nutrients
and
fertilised
Mycelium
egg
of
a
absorbing
where
in
substances
of
energy
events,
taking
organic
breakdown
of
the
in
which
(see
this
is
page
75
for
two
ways
determined).
N
soft
lining
of
the
uterus,
discharging
Oesophagus
Natural
blood
and
cells
through
the
selection
factors
such
connecting
competition
Metabolism
all
the
that
take
place
microscopic
sp ecies.
fungi
Mineral
salts
those
and
such
individu a ls
a
as
have
pass
on
as
iron
and
for
by
in
plants
feedback
such
Mitochondrion
aerobic
as
respiration
near
constant
to
a
type
that
of
cells
in
which
where
central
nervous
part
the
of
the
to
which
number
nerve
pass
peristalsis.
hormone
ovaries
that
of
secondary
the
in
females
menstrual
nerve
from
eye
to
Nerve
the
exact
duplication
and
helps
to
cycle.
from
the
retina
in
brain.
system
to
the
a
certain
Organ
a
together
number
to
carry
of
tissues
out
of
a
nerve
a
working
function
in
the
cell.
the
Organ
conversion
of
organs
to
nitrate
ions
by
system
a
number
of
different
ammonium
genetically
that
work
together
to
carry
bacteria.
out
bacteria
bacteria
functions
for
the
body.
found
maintained
Osmoregulation
the
the
sexual
body.
in
by
secreted
stimulates
cells
the
is
a
body.
body.
Nitrifying
chromosome
in
occurs.
rise
the
the
ions
identical
of
the
muscular
mechanism
conditions
bundle
of
acids.
structure
division
gives
called
Oestrogen
Optic
a
down
wave
maintaining
make
Nitrication
nucleus
n ext
control
Neurone
Mitosis
the
diet.
amino
cell
the
for
a
chan ce
to
by
homeostasis
(neurones)
compounds,
grea ter
gen es
passes
by
characteristics
used
Nerve
required
Food
development
that
balanced
tube
the
to
generation.
nutrients
calcium
a
the
their
with
result,
adapted
viruses.
inorganic
muscular
mouth
aff ect
As
contraction
to
Negative
needed
the
oesophagus
(microbe)
organisms,
bacteria,
Also
a
a
survive
are
of
organism.
Microorganism
such
preda t ion
stomach.
inside
survival
only
living
and
chemical
the
reactions
the
as
vagina.
the
soil
that
convert
the
control
of
the
ammonium
of
water
ions
into
into
nitrate
nitrite
ions
and
nitrite
content
of
the
body.
ions
chromosomes.
Monocotyledon
a
type
of
ions.
Nitrogen-xing
plant
with
an
embryo
with
Osmosis
the
molecules
through
bacteria
permeable
and
parallel
veins
in
its
both
in
the
soil
and
in
Monohybrid
inheritance
inheritance
one
of
legume
plants
that
with
higher
membrane,
from
concentration
molecules
two
nitrogen
into
a
region
to
a
concentration
compounds
water
region
of
lower
nitrogen-
or
containing
of
convert
the
atmospheric
more
water
the
of
gene
of
partially
leaves.
roots
of
a
bacteria
one
found
cotyledon
diffusion
owering
such
as
of
water
molecules
amino
alleles.
(or
from
a
region
of
higher
water
acids.
Motor
(effector)
neurone
a
potential
neurone
Nitrogen
that
transmits
or
spinal
impulses
cord
to
away
from
effector
muscles
and
organism
or
an
plant
growth,
taken
in
the
form
part
of
an
by
an
Chemical
nitrate
a
change
that
in
a
traps
the
air
slimy,
of
position
dust
sticky
or
and
pathways.
It
fertilisers
acts
to
help
the
passage
the
will
not
break
e.g.
as
female
are
sex
organ
where
ova
produced.
supply
from
the
the
release
of
an
ovum
ovary.
materials
Nucleus
part
down
many
in
the
Ovule
plastics.
of
of
a
the
plant
gamete.
the
of
the
cell
develops
genetic
information
structure
that
After
inside
contains
the
the
fertilisation
ovary
female
an
ovule
which
a
in
into
a
seed.
the
food
of
chromosomes.
The
nucleus
Ovum
the
female
sex
cell
(gamete)
gut.
controls
Muscle
eggs
Ovulation
environment,
form
along
water
place.
contains
lubricant
often
ions.
microbes
also
lower
by
(egg)
substance
some
of
nitrate
organism
that
Mucus
of
or
Non-biodegradable
causing
up
Ovary
roots
glands.
action
region
for
the
ions.
Movement
needed
organs,
plant
e.g.
element
a
potential).
healthy
brain
an
to
tissue
contracting
that
and
is
capable
relaxing
to
of
Nuclei
the
may
activities
be
of
haploid
the
or
cell.
diploid.
produced
the
in
the
ovary.
Also
called
egg.
bring
303
Glossary
Oxygen
that
is
lactic
debt
the
needed
acid
by
extra
the
produced
oxygen
body
to
during
Pituitary
respire
anaerobic
gland
of
the
brain
to
control
that
the
a
gland
at
secretes
activity
of
the
base
hormones
other
Protease
down
an
enzyme
proteins
to
e.g.
kidneys,
testes
and
Placenta
through
Palisade
mesophyll
tissue
in
that
contain
many
chloroplasts
the
main
site
of
the
in
the
digestive
insulin
in
the
the
and
glucagon
and
on
not
allow
that
to
large
molecules
a
mixture
of
food
remains,
body.
bacteria
the
surface
which
of
can
teeth;
build
(2)
and
an
the
animal;
to
does
antibodies
himself
not
or
in
the
the
lining
liquid
transports
carbon
Plasmid
of
an
part
a
an
used
as
a
of
the
blood
foods,
sexual
cell
and
piece
of
vector
the
membrane
plant
receiving
make
and
by
the
the
enzyme
in
genetic
of
cell
that
that
when
the
heart
separation
from
when
the
water
cell
of
leaves
causes
of
pulse
the
of
small
pieces
substances
cell
of
that
cells
cause
in
the
elements
oxygen,
nitrogen
at
which
secondary
appear
in
boys
in
as
transfer
of
the
anther
of
a
ower
to
pollen
the
system
Pollution
nerves
the
release
by
and
ventricle
forces
along
the
this
various
the
of
the
blood
out
arteries.
The
can
parts
be
of
felt
the
as
body,
wrist.
Pupil
the
hole
enters
the
eye.
Pyramid
show
the
left
it
by
through
The
the
size
which
of
the
light
pupil
is
iris.
that
blood
clot.
Pollination
breaks
plants.
nervous
tissues
the
a
an
of
biomass
biomass
at
a
each
ecosystem.
The
way
to
trophic
area
of
level
each
from
bar
is
proportional
to
the
stigma.
mass
Peripheral
of
the
wall
osmosis.
release
the
swell
horizontal
walls
age
contracts,
controlled
to
cell
of
for
girls.
heart
in
down
up
needed
hormones.
circular
herself.
organism
an
repair
contain
characteristics
arteries
Plasmolysis
disease.
Pectinase
made
are
artery.
dissolved
dioxide
small
Platelets
Pathogen
which
hydrogen,
Puberty
DNA
pass
person
person
does
and
They
Pulse
but
providing
another
the
antibodies
e.g.
sulfur.
such
or
compounds
acids,
carbon,
fatty
a
from
diet,
waste.
small
through,
immunity
the
and
engineering.
antibodies
in
kwashiorkor.
dioxide
glucose
through.
Passive
limited
and
and
membrane
allows
pass
form
energy
that
of
urea,
membrane
carbon
which
and
which
molecules
(1)
Plasma
permeable
are
marasmus
in
abdomen
enzymes
concentration
protein
growth
blood.
Partially
removes
chemical
deposit
regulate
food
a
and
amino
up
makes
receives
mother
photosynthesis.
organ
produces
it
connects
its
malnutrition
Proteins
saliva
that
which
and
Plaque
Pancreas
that
to
and
and
are
organ
embryo
leaves
oxygen
a
the
mammalian
malnutrition
ovaries.
of
P
breaks
acids.
organs,
Protein-energy
respiration.
that
amino
humans
of
living
material
at
each
trophic
of
level.
that
arise
from
the
brain
and
spinal
cord
materials
or
energy
that
will
harm
the
Pyramid
and
go
to
all
the
organs
of
the
show
Peristalsis
a
contraction
that
wave
of
Population
muscular
a
group
of
food
down
of
the
same
species
living
in
the
oesophagus
to
the
habitat
stomach.
at
the
same
a
chemical
that
kills
a
white
pests.
Population
type
of
blood
ingests
and
destroys
way
to
of
growth
a
at
of
level
each
in
an
ecosystem.
horizontal
growth
proportional
population.
In
to
the
bar
number
of
in
at
each
trophic
level.
absence
cell
of
that
trophic
area
individuals
numbers
Phagocyte
a
organisms
time.
is
Pesticide
of
same
The
the
numbers
numbers
individuals
each
squeezes
of
environment.
body
.
limiting
factors
growth
is
usually
pathogens.
Q
exponential.
Phagocytosis
the
ingestion
of
food
Quota
Predators
particles
into
a
animals
that
hunt
and
of
other
Phenotype
the
physical
or
of
an
organism
genotype
and
its
for
their
due
to
a
limited
animals
that
are
resource
number
that
can
or
be
quantity
taken
from
food.
the
hunted
environment,
e.g.
timber
and
sh.
and
both
killed
its
animals
other
Prey
features
a
kill
cell.
for
food
by
predators.
environment.
R
Producer
Phloem
the
plant
tissue
an
organism
that
makes
that
Receptor
its
transports
sugars
and
amino
own
organic
nutrients,
sensitive
using
Photosynthesis
process
by
energy
from
sunlight
manufacture
materials
or
organs
that
are
stimulus.
Recessive
an
allele
that
is
expressed
carbohydrates
Progesterone
raw
a
through
only
from
to
which
photosynthesis.
plants
cells
usually
acids.
using
energy
a
hormone
when
there
is
no
dominant
allele
secreted
from
of
by
the
ovaries
and
by
the
the
gene
present
(e.g.
t
or
g).
placenta
light.
that
Phototropism
a
growth
response
maintains
plant
to
the
direction
of
of
Rectum
the
during
the
second
half
of
the
intestine
the
last
where
part
faeces
of
the
are
large
stored
light.
menstrual
304
lining
of
uterus
a
the
cycle
and
during
pregnancy.
before
passing
out
through
the
anus.
Glossary
Recycle
a
form
to
convert
that
Reex
can
action
response
to
a
be
an
material
useful
back
to
automatic,
stimulus
into
humans.
Self-pollination
pollen
grains
the
from
ower
to
the
ower
or
different
transfer
the
stigma
anther
of
the
Stem
of
of
the
leaves,
a
contains
same
organ
owers
xylem
that
and
supports
fruits
tissue
to
of
a
the
plant.
transport
It
water
rapid
which
is
ower
on
and
the
mineral
salts
and
phloem
tissue
to
often
same
transport
plant.
sugars
and
amino
acids.
protective.
Sense
Reex
arc
the
arrangement
is
neurones
that
controls
a
reex
sensitive
(connector)
neurone
to
stimuli,
e.g.
in
the
transmits
central
nervous
impulses
from
motor
in
dialysis
remove
the
use
of
a
make
the
body’s
cells
divide
by
the
kidneys
light,
cells
sound,
that
specic
chemicals.
the
the
ability
to
the
processes
same
(stimuli)
the
neurone
that
reactions,
a
kind
of
complex
taking
impulses
brain
down
series
place
in
all
nutrient
living
Response
a
neurone
from
Stoma
that
receptors
to
or
spinal
in
the
gases
cord.
chromosomes
the
pair
organism
from
the
to
a
(plural:
to
diffuse
is
sex.
that
In
determine
humans,
XX
reaction
enzyme
of
XY
is
female
the
linkage
a
sex
the
location
chromosome,
an
of
of
the
sensitive
reproduction
to
hole
allows
and
out.
by
The
guard
size
of
cells.
muscular
that
sac
at
mixes
the
food
end
of
with
The
begins
chemical
in
the
digestion
of
stomach.
the
X
Suspensory
ligaments
hold
in
the
lens
the
eye
bres
in
that
place
the
alter
its
shape
when
the
ciliary
process
fusion
of
haploid
contract
and
relax.
nuclei
cut
form
a
diploid
eye
zygote
and
of
genetically
the
dissimilar
Sustainable
development
development
that
cell
is
able
to
so
that
they
conserve
that
natural
resources
are
cells.
Sexually
small
structure
transmitted
infection
in
the
future.
a
where
disease
that
is
transmitted
through
Sustainable
resource
a
resource,
made.
body
sensory
that
a
juice.
available
are
small
genes
usually
offspring.
Ribosome
a
that
places.
part
light
)
leaves
enzyme
production
eye
a
stimulus.
to
the
in
oesophagus
gastric
male.
involving
the
in
by
an
engineering
specic
of
controlled
Stomach
a
is
muscles
a
change
food.
particular
genetic
stomata
epidermis
hole
and
Rod
a
detected
to
Sexual
Restriction
proteins
is
of
chromosome.
contains
stimuli)
that
cells,
molecules
on
Retina
(plural:
of
Sex
energy
at
for
organ.
protein
DNA
specialised
organism.
and
break
in
become
make
person’s
used
can
environment
sense
responses.
chromosomes
Respiration
release
that
daughter
functions.
Stimulus
detect
environment
the
that
cells
produce
fail.
Sex
of
to
chemicals
the
Reproduction
more
unspecialised
mitosis
machine
waste
transmits
when
Stem
neurones.
Sensory
to
that
stimulus
system
and
Renal
organ
sensory
changes
to
touch,
and
Sensitivity
that
receptor
particular
a
temperature
neurone
a
a
action.
or
Relay
organ
of
cell
in
the
responds
to
retina
light
e.g.
of
of
uids
during
sexual
e.g.
activity,
as
HIV
.
timber
rapidly
or
as
it
environment
low
Sickle
cell
anaemia
an
sh,
is
so
which
is
removed
that
it
produced
from
does
the
not
run
out.
inherited
intensity.
disease
Root
the
organ
into
the
ground
and
mineral
that
and
anchors
absorbs
plants
water
alters
and
that
hairs
a
of
large
cells
surface
water
and
in
a
system
area
mineral
alimentary
for
endoplasmic
of
red
which
blood
cells
membranes
ribosomes
digestion
the
are
reticulum
inside
canal
and
the
region
that
are
in
the
to
heat
lose
neurones
absorbs
digested
food.
a
by
found
which
secrete
evaporation.
a
substance
that
dissolves
a
gap
between
in
is
which
released
the
second
a
two
chemical
to
stimulate
an
neurone.
in
a
liquid
that
T
dissolves
and
T
est
cross
a
genetic
cross
used
to
made.
with
are
Sclerotic
the
of
which
tough,
Secretion
the
substances
by
white
keeps
release
it
in
of
outer
layer
shape.
useful
a
group
similar
Sperm
of
the
which
interbreeding
fertile
and
sex
cell
or
T
estis
sex
offspring.
male
an
insoluble
the
genotype
(plural:
organs
gamete.
carbohydrate
testes,
from
glucose
breeding
see
articial
store
in
plant
molecules.
cells
An
of
the
an
organism.
and
an
human
the
sperm
male
cells
and
produced.
the
that
hormone,
stimulates
produced
the
of
secondary
sexual
males
the
energy
in
and
important
development
component
of
made
development
cells.
are
T
estosterone
the
testes)
where
testosterone
by
Starch
out
organisms
characteristics
capable
producing
of
characteristics
selection.
glands
skin
solvent.
cells
attached
S
Selective
the
across
transmitter
nd
eye
coiled
of
impulse
Species
the
glands
dermis
Synapse
of
completes
substances.
proteins
Sweat
sweat
anaemia.
salts.
Solvent
where
the
severe
intestine
root
Solute
Rough
in
haemoglobin,
of
salts.
specialised
provide
absorption
shape
results
Small
Root
affecting
the
of
sperm
cells.
diet.
305
Glossary
Tissue
a
together
Tissue
cells
group
to
uid
when
blood
of
similar
perform
the
uid
plasma
cells
pass
the
that
and
out
cells
same
the
act
bathes
some
of
that
function.
the
white
Urinary
lters
Urine
the
capillaries.
It
an
a
poisonous
substance.
organ
produces
excretory
kidneys
contains
excess
T
oxin
system
blood,
and
uid
stored
excess
system
and
urine.
produced
in
water,
surface
that
stores
the
in
bladder.
urea,
Virus
be
toxins
as
waste
nucleic
bring
disease,
about
e.g.
high
the
Uterus
the
womb;
a
symptoms
of
a
fever
.
the
and
amino
movement
acids
in
than
acid
a
disease
which
chamber
with
the
develops.
fetus
a
soft
lining
in
a
one
pathogen
host
to
can
phloem.
disease
be
passed
or
dead
a
Vitamin
preparation
pathogenic
stimulate
and
the
water
surfaces
consist
of
surrounded
coat.
They
can
reproduce
cells.
small
a
micronutrient,
amounts
in
the
needed
diet.
is
provided
evaporation
in
the
If
diet
not
a
V
Vaccine
another.
Transpiration
cannot
which
containing
disease
give
the
microorganisms
production
of
can
result.
mild
action
an
action
that
we
to
decide
from
for
microscope.
they
DNA)
living
Voluntary
in
that
light
bacteria,
intestine
food.
of
the
a
the
(e.g.
protein
inside
deciency
Transmissible
small
microorganism
under
enough
sucrose
the
digested
muscular
in
T
ranslocation
of
of
Bacteria
products
only
which
a
seen
Smaller
and
salts.
by
release
area
absorption
to
make.
antibodies
immunity
.
of
W
cells
from
in
water
the
leaves
followed
vapour
through
of
by
mesophyll
diffusion
stomata
of
Vaccination
provide
a
vaccine
to
Water
immunity.
water
into
Vacuole
the
giving
uid-lled
sac
Water
Trophic
level
the
position
of
sap
present
in
a
food
chain,
food
of
numbers,
biomass
For
example,
herbivores
consumers
and
form
a
to
tube
the
trophic
diffuses
potential
leading
outside.
from
It
water
potential.
during
birth
sexual
a
plant
to
a
stimulus,
by
e.g.
of
of
higher
lower
blood
of
the
body’s
Lymphocytes
differences
in
cells
they
form
intercourse
the
defence
features
release
system.
antibodies
and
between
that
may
to
combat
pathogens.
show
ingest
and
kill
pathogens.
part
continuous
of
area
area
canal.
antitoxins
response
an
an
the
level.
growth
to
the
receives
Phagocytes
a
from
water
part
the
individuals
Tropism
for
diffusion.
cells.
White
penis
is
Variation
second
plant
are
and
primary
most
or
erect
energy.
by
web,
uterus
pyramids
tendency
move
an
Vagina
organism
in
the
to
containing
atmosphere.
cell
potential
molecules
light
variation
or
discontinuous
or
Wilting
loss
leaves
droop
of
turgor
causes
plant
variation.
gravity.
Vasoconstriction
Thrombosis
a
blood
clot
that
a
vein
or
an
Withdrawal
in
arterioles
to
reduce
that
through
a
swollen
stem
of
a
potato
storage
and
asexual
plant
the
cell
pressure
onto
its
exerted
cell
wall.
by
arterioles
are
rm
because
through
this
can
they
support
relaxation
that
of
increases
addictive
side
they
effects
give
up
drug.
ow
are
Xerophyte
full
a
plant
blood
vessel
through
a
plant
adapted
to
dry
which
of
conditions.
travels
towards
the
heart.
organs
Xylem
as
when
capillaries.
Ventricle
such
feels
muscles
blood
T
urgid
blood
water;
symptoms
person
X
a
Vein
cells
a
reproduction.
in
Turgor
lacking.
for
Vasodilation
food
is
capillaries.
an
T
uber
water
blood
artery.
ow
if
of
occurs
muscles
in
contraction
to
the
lower,
more
the
plant
tissue
that
transports
muscular
stems.
water
chamber
of
the
heart.
In
and
right
the
lungs
ventricle
salts
from
roots
to
mammals,
leaves,
the
mineral
pumps
blood
owers
and
fruits.
to
U
Umbilical
the
cord
placenta
to
the
the
cord
connecting
fetus.
It
blood
to
and
the
umbilical
arteries
and
rest
left
of
ventricle
the
pumps
body.
Y
contains
Vertebrate
two
the
a
an
animal
with
a
backbone.
Urea
a
waste
product
formed
amino
acids
in
the
liver.
ltered
out
of
the
blood
and
in
small
and
passed
out
in
the
a
tube
through
which
from
the
kidney
to
by
membrane
the
made
that
by
cells,
Yield
crop
the
or
as
enzymes
or
the
bladder
306
tube
to
that
the
passes
outside
quantity
from
a
of
product
fermentation
(plural:
villi)
tiny,
nger-like
Z
bladder.
urine
at
dioxide.
neurotransmitters.
from
the
wall
of
the
Zygote
a
that
ethanol
structures
substances
projection
Urethra
fungus
produce
urine
Villus
passes
carbon
to
urine.
such
Ureter
cell
sugar
from
a
the
contain
kidneys
single-celled
It
surrounded
is
a
ferments
from
Vesicles
excess
Yeast
vein.
from
intervals.
small
intestine.
Villi
increase
the
a
fertilised
egg.
process.
Index
aorta
A
abiotic
environment
absorption
78,
accommodation
acid
rain
desert
pond
plants
asexual
the
temperature
respiration
effect
on
of
the
rate
by
using
respiring
energy
uptake
seeds
of
disadvantages
reproduction
brain
219
in
of
plants
seeds
78,
atherosclerosis
cleaning
control
plant
hormones
(BMI)
106–7
75
261
201
132
breathing
170
synthetic
to
82
depth
oxygen
adapted
107
function
index
breast-feeding
144
are
107
and
breadmaking
108
112–13
154
breathing
assimilation
of
germinating
auxin
the
184,
185
of
139
investigating
and
asexual
138
3,
vessels
vessels
mass
bolus
240–1
reproduction
advantages
164–5
respiration
investigating
selection
body
208
110–11
110,
functions
structure
(AI)
22,
cells
106
blood
shunt
107
insemination
articial
236
93
adrenaline
aerobic
articial
237
blood
their
11
113
cells
vessels
how
11
100
arterioles
236
adaptations
adhesion
arteries
34–5
features
blood
12–13
spinnerets
192
transport
adaptive
buds
110,
blood
white
96
arachnids
280–1
acrosome
active
apical
163
red
96
stylets
84–5
platelets
103
aphids
254
and
the
of
of
exercise
air
134–5
133
breathing
breathing
135
135
171
expiration
139
(breathing
inspiration
138
out)
(breathing
in)
133
132
B
afterbirth
vital
201
babies
agriculture
bronchi
breast-feeding
agricultural
chemicals
(Acquired
6,
can
C
cycle
253
calcium
HIV/AIDS
be
in
bacterial
growth
prevented?
capillaries
basal
metabolic
rate
(BMR)
pairing
carbohydrates
batch
culture
Benedict’s
solution
beta-blockers
alcohol
effects
social
problems
carbon
dioxide
effect
128,
amino
acids
223
chemical
uid
amniotic
sac
tests
for
the
steroids
anaemia
77
angina
breadmaking
environment
cells
membrane
cell
organelles
differences
birth
200–1
birth
control
diffusion
methods
methods
implications
size
methods
of
cells
cellulases
119,
218–19
specimens
cells
21
22–3
262
146
201
cellulose
blood
mitosis
41
239
112–13,
of
and
207
specialised
solution
bladder
39,
18
309
240–1
surgical
39,
cells
signicance
biuret
resistance
30–1
30–1
206–7
175
antibodies
and
207
9
social
antitoxins
methods
plant
natural
antibiotics
plant
18–19
28–9
cell
osmosis
(warm-blooded)
breeding
between
cells
206
18–19
chemical
selective
30
206
model
animals
6,
20–1
8–9
animal
homeothermic
34–5
18
254
141
barrier
antigens
transport
cell
4
cells
281
262–3
140
6
animal
converters
261
108
animals
36
46
260
and
234–5
birds
35
34,
18
active
biotic
anatomy
32,
262
cells
enzymes
140,
180
108
proteins
animal
acid
release
247
biofuels
anaemia
dioxide
washing
179
respiration
rate
262
262
biotechnology
lactic
arrest
catalytic
84,
the
biological
8
anabolic
cell
of
non-biological
powder
sickle
monoxide
cardiac
catalysts
biomass
anaerobic
powders
action
159
82,
carbon
carbon
catalase
and
79,
on
61
41
carrier
washing
comparing
amylase
C
198
biological
amphibians
dioxide
40–1
vitamin
198
amphetamines
carbon
photosynthesis
38–9
58
testing
amniotic
and
130
121
molecules
131
39,
air
261
biological
alveoli
of
measuring
biofuels
alleles
144
267
226–7
recessive
63,
inspired
261
of
and
57,
in
184
179
biodiversity
dominant
56,
dioxide
expired
ssion
222–3
codominance
200
250–1
84
179
biodiesel
anus
cycle
carbon
binary
alleles
carbon
159
178
bile
long-term
114–15
72,
40
178
of
38,
264–5
145
biology
capillaries
42–3
234
addiction
100
70
lymph
base
alcohol
200
255
211
albinism
128
250
210
phases
how
135
bronchioles
201
Immunodeciency
nitrogen
Syndrome)
and
275
bacteria
AIDS
capacity
200
270–1
110,
23,
38,
58
119
120
centipedes
blood
circulation
blood
clotting
120
central
nervous
system
(CNS)
154
113
86
cervix
oxygenated
10
100–1
blood
100,
194
110–11
307
Index
chlorophyll
12,
chloroplasts
cholera
on
the
symptomless
meiosis
87
86
108
disease
180–1
circulatory
single
22
system
circulation
circulation
binomial
101
system
4–5
286
diploid
93
disease
169
colon
activity
blindness
competition
228–9
244–5,
liquid
a
238–9,
DNA
6,
71,
109
role
digestion
number
118,
214,
3,
of
eye
diseases
against
disease
diseases
118–21
276
144
liver
144
145
and
exercise
134–5
10
286
160–1
of
focusing
124–5
lactose-free
40
control
122–3
making
105
extracts
255
in
products
the
extinctions
78
46
144
exoskeletons
220
47
129
breathing
78–9
protein
263
41
exercise
29
of
juice
263
excretory
28–9
50–1
work
lactase
excretion
29
solvent
transmissible
255
us?
262
47
48–9
eutrophication
70–1
for
diffusion
digestion
defences
254
of
milk
78
control
communities
bad
effect
autoimmune
86
colour
as
fruit
assimilation
mechanical
226–7
use
206
14–15
pH
powders
complex
made
enzymes
epiglottis
be
that
digestion
226
alleles
control)
28
versus
water
278–9,
and
are
temperature
13
fat
47
washing
enzymes
how
123
keys
and
chemical
codominance
cohesion
can
factors
194
multiple
sex
why
gas
change
1)
74
216
enzymes
ethanol
diffusion
4
DNA
70
age,
site
extracting
(birth
100
see
176
diaphragm
100
100
acid
128
100
circulation
78,
biological
blood
(Type
7,
244
output
enzyme-substrate
diaphragm
diet
active
252
48
dicotyledons
classication
climate
273
dichotomous
cells
double
244,
deforestation
diabetes
pulmonary
133
blood
decomposers
depressants
transfer
and
enzymes
145
deoxyribonucleic
214
intake
218
deoxygenated
73,
83
22,
cells
denaturation
220–1
ciliated
cold
daughter
86
therapy
obstructive
(COPD)
clitoris
64
86
71,
chromosomes
cilia
body
carriers
transmission
cholesterol
chyme
54,
deamination
rehydration
chronic
energy
D
23,
86
effects
oral
56
12,
rods
the
pupil
reex
162
162
and
cones
162–3
118
214
F
concentration
gradients
28,
30,
130
base
pairing
42–3
faeces
conservation
288–9
genetic
code
86
216–17
farming
reasons
for
conservation
289
sequence
of
bases
fats
constipation
75
structure
270–1
216
39,
71,
testing
consumers
244
double
helix
206–7
drugs
145,
for
acids
implications
309
41
39
174
feedback
social
fats
42
fatty
contraception
72
42
addiction
174,
166
176
fermenters
coordinators
155
excitatory
and
misuse
drugs
inhibitory
drugs
159
batch
cornea
160
coronary
arteries
angioplasty
108
of
recreational
109
duodenum
in
drugs
83,
sport
culture
264–5
179
industrial
fermentation
industrial
production
265
174
of
penicillin
84
264
coronary
artery
bypass
operation
ferns
12
108
E
coronary
heart
disease
(CHD)
fertilisation
ecosystems
risk
factors
for
CHD
108–9,
154,
78,
nerves
157
86,
implantation
145
cells
23,
seed
185,
192,
194
197,
formation
fertilisers
195
fertility
190
203
191
66,
270,
276
treatments
208–9
266
electrocardiograms
advantages
and
disadvantages
crops
monocultures
185
208
implications
bre,
dietary
brin
and
73,
309
75
270
84
brinogen
113
10
endocrine
system
164
sh
8
10
comparing
cephalothorax
the
compound
endocrine
and
shing
283
10
nervous
eyes
systems
165
accidity
33
10
endorphins
gills
drugs
social
181
emulsication
antennae
104
267
emphysema
crustaceans
(ECGs)
of
embryos
genetically-modied
176
owers
12–13,
186
10
energy
cytoplasm
36,
70
insect-pollinated
owers
186
6
communities
308
188,
196
154
ejaculation
crops
186,
fertilisation
13
egg
cranial
human
109
egestion
cotyledons
254
181
effectors
treatment
185,
108
244–5
energy
losses
energy
pyramids
248–9
248
wind-pollinated
ue
gas
owers
desulfurisation
focusing
162
187
281
Index
accommodation
follicles
gravitropism
163
203
follicle
stimulating
hormone
(FSH)
food
chains
food
preparation
food
production
social,
245,
food
fruit
food
webs
fruits
cells
passive
278
218,
economic
in
65
vitro
197,
habitat
destruction
272,
human
on
food
119
2,
78
214,
and
webs
and
alleles
need
to
7,
conserve
102,
coronary
heart
disease
linkage
(CHD)
fuels
(ECGs)
cell
11,
heart
action
11
103
7,
heart
and
heart
sounds
exercise
11
105
insulin
184
166–7
104
industrial
184
septum
muscles
intestines
102,
bladder
84–5,
heat
84
hepatic
184–5
portal
vein
and
female
gametes
192–3
herbicides
266,
exchange
heroin
29
159,
out
carbon
dioxide
social
130
problems
77,
200
(intra-uterine
exchange
at
gas
exchange
surfaces
plants
the
alveolus
131
heterozygous
HIV
130–1
structure
of
the
gas
exchange
how
genes
juices
42,
gene
what
genetic
109,
and
is
a
gene?
222–3
215
engineering
266,
vitamins
in
plants
advantages
and
disadvantages
genetically-modied
herbicide
resistance
insect
genetics
in
crops
crop
medicines
resistance
code
variation
genotypes
in
of
crop
insulin
plants
267
period
glucagon
glycerol
of
blood
38,
166–7
growth
human
256–7
population
257
destruction
167
272–3
287
lactic
85
acid
241
larynx
236
253,
a
56,
64–5
65
57,
lightning
lipase
immunity
leaf
63,
95
photosynthesis
84
response
276
64
stomata
light
124
141
86
128
inside
83
140,
intestine
leaves
hydrophytes
active
6–7
76
263
leaching
vigour
immune
36
4,
200
lacteals
large
95
acid
ileum
148
149
L
labour
I
glucose
2,
kwashiorkor
60,
58
39
glycogen
water
202–5
hydrochloric
hygiene
63
the
167
38,
control
198
production
in
164
population
hunting
hybrid
glasshouse
kingdoms
166
147
147,
151
energy
lactase
habitat
191
transplants
kinetic
223
7
humidity
232
4
gestation
organs
controlling
216–17
tubules
reabsorption
166
hormones
148
kidneys
277
growth
223
germination
164–5,
148
the
kidney
166–7
166
organisms
hormones
human
266
glucose
feedback
supply
sex
214
genetic
glucose
conditions
hosts
266
production
genetic
genus
controlling
267
plants
150–1
glomerulus
211
inside
blood
contraceptive
of
146
dialysis
135
controlling
target
184,
kidneys
prevented?
transmitted?
homozygous
266
industrial
be
ltration
HIV
hormones
266
human
is
negative
270
crop
IUS
virus)
211
HIV/AIDS
homeostasis
234
alleles
additional
tracing
can
how
216
mutations
genes
immunodeciency
211
83
and
206
223
K
contact
system
128–9
gastric
(human
organisms
210
67
device)
system)
177
(intra-uterine
gas
155
176–7
IUD
breathing
actions
40
270
iron
gas
86
10–11
85
iodine
male
267
169
involuntary
3,
insulin
103
invertebrates
gametes
of
128
102
ventricles
G
production
102
intercostal
valves
234–5
266
104
cuticle
282
228–9
anaemia
108–9
insects
electrocardiograms
fossil
233
224–5
103
spiracles
7,
mycelium
(atrium)
sickle
281
environment
inheritance
102–3
sex
atria
250
hyphae
gall
versus
220
monohybrid
261
222–3
77
inheritance
261
226–7
272–3
22,
number
100,
222
chains
genes
fuels
208–9
273
inuences
haemoglobin
haploid
sulfur
(IVF)
124
codominance
heart
low
201
241
inheritance
271
fuel
122,
286
ingestion
deforestation
272–3
neutral
system
203
fertilisation
barriers
271
fuels
carbon
immune
H
and
263
biofuels
the
immunity
implantation
219
infections
270–1
supply
245,
70,
inbreeding
191
fungi
gases
3,
of
122–3
278–9
124
environmental
juice
greenhouse
guard
272–3
implications
world
effect
growth
204
malfunction
170
greenhouse
120–1
121
liver
84,
84,
and
light
intensity
62
253
262
145
cirrhosis
179
309
Index
lungs
103,
lung
128–9
cancer
luteinising
lymphatic
lymph
nodes
lymph
vessels
lymphocytes
HIV
and
lysozyme
natural
hormone
system
ovules
N
181
(LH)
204
competition
114–15
115
119
lymphocytes
selection
241
variation
cells
medicine
meiosis
between
meiosis
219
70
rate
(BMR)
70
73
138,
between
meiosis
of
mitosis
and
157
bacteria
production
pepsin
resources
282
limbs
nervous
cycle
244,
cycle
2,
variation
phloem
2,
needs
nutrients
74–5
72–3
limiting
oxygen
stem
cells
of
monocultures
monohybrid
of
ratio)
parental
test
cross
mucus
causes
gene
sickle
swallowing
82
respiration
140–1
2–3,
mutations
cell
234
anaemia
156
10
234
234–5
plant
204
rate
6–7,
systems
orgasm
24
rate
58
54–5
62
and
light
intensity
and
temperature
organs
25
65,
animal
cells
33
osmosis
in
potato
cells
32
plants
in
outbreeding
(ovum)
effects
gas
194
of
199,
203
201
and
monocotyledons
nutrients
of
on
owering
growth
plants
12
exchange
inheritance
mineral
194
4
202
12
hydrophytes
241
192,
gland
198,
67
13
ferns
77
194,
6,
60–1
170–1
(phyla)
pituitary
features
33
32
osteomalacia
ovulation
respiration
dicotyledons
31
in
ovaries
56–7
plants
92
58–9
photosynthesis
requirements
placenta
30–1,
osmosis
ova
62
products
of
phylum
24
and
195
turgidity
mutations
the
59
phototropism
plasmolysis
234
202,
261
tissues
osmosis
163
of
myriapods
194,
osmometers
162,
on
61
62
61,
24
organ
2
anaerobic
dioxide
photosynthesis
photosynthesis
109
82
58
organs
4
and
75,
rape
organisms
224
24
mutations
seed
oils
82
muscles
oil
plant
movement
310
(3:1
82
chewing
myelin
oestrogen
224
generation
225
morphology
eye
F1
74,
oesophagus
224
cross
mouth
obesity
13
inheritance
96
54
photosynthesis
factors
58,
60,
O
270
the
38,
218–19
219
monocotyledons
crossing
mitosis
transport
23,
carbon
photosynthesis
signicance
119
232
photosynthesis
investigating
energy
112,
90–1
and
of
119
31,
223
importance
251
154
30
112,
12,
of
252–3
70–1
of
28,
phenotypic
effect
250–1
cycle
(PNS)
270
photosynthesis
250
system
82
phenotypes
aphids
42
4–5
50–1
phloem
42
264–5
83
phagocytosis
253
201
28
118
phagocytes
253
122,
263
pentadactyl
pH
253
25
192
pesticides
252
cycling
sources
movement
peripheral
xing-bacteria
balancing
218
156,
157
158
bacteria
nutrition
221
mitosis
156,
nitrifying
water
218
immunity
penis
23,
84
passive
permeability
nitrogen
193
neurones
253
carbon
65
20,
duct
passive
penicillin
158
158
cells
166
7
pectinases
157
neurones
lightning
nutrient
84,
peristalsis
acids
photosynthesis
111
mesophyll
pathogens
156,
neurones
nucleotides
10
nutrients
process
actions
66
nucleic
in
P
parasites
voluntary
neurones
cycle
141
oxyhaemoglobin
pancreatic
and
165
156
non-renewable
149
differences
154,
nitrogen
260–1
190
mitochondria
mitosis
and
denitrifying
38,
metabolic
minerals
238
180
nitrogen
microorganisms
millipedes
nitrates
203–5
25
3,
89,
endocrine
(connector)
nicotine
202
cycle
23,
microvilli
238
pancreas
systems
neurotransmitters
77,
mesophyll
metabolism
populations
neurones
sensory
203
meristems
micropyles
the
presynaptic
121
menstruation
menstrual
offspring
154
postsynaptic
and
relay
cells
menopause
plant
mitosis
221
234
memory
basal
motor
220–1
differences
melanin
neurones
produced
59
155
266
debt
oxygen
palisade
system
involuntary
109,
58
oxygen
239
within
nervous
76
218,
of
and
22
comparing
66
9
238–9
natural
nerve
M
marasmus
resources
185
oxygen
239
articial
reproduction
210
238,
between
nervous
mammals
for
over-population
115,
160
magnesium
189,
differences
115
112,
selection
223,
salts
nitrogen
in
plants
67
236
224–5
65
cycle
252–3
66
12–13
Index
pyramids
of
biomass
67
pyramids
of
energy
18–19
pyramids
of
numbers
photosynthesis
plants
plant
cells
plant
products
plant
tissues
selective
systems
plasma
rectum
reexes
90–1
roots
plastics
6,
artery
renal
vein
pollen
tubes
pollination
insect
pollen
tubes
female
190
male
190
13,
186,
pollination
self-pollination
186,
and
189
wind
pollination
pollution
land
274,
pollutants
pollution
size
products
care
200
photosynthesis
prokaryotes
protein
39,
enzymes
testing
puberty
58,
72,
(PEM)
76
stem
seeds
eye
202
in
boys
girls
reticulum
(ER)
20
tubers
stimulants
artery
investigating
103
the
effect
105
160
161,
sphincter
162
83
sulfur
of
exercise
for
germination
3,
valves
100
determination
sex
hormones
sex
inheritance
linkage
sex
organs
124–5,
276,
284
228
and
characteristics
195
closing
202
65
238
47
58
for
reducing
dioxide
to
sugars
40
280–1
resources
conserve
282
fossil
fuels
development
282
283
sustainable
shing
283
sustainable
timber
production
effect
156,
transmitter
of
drugs
of
on
the
substance
159
synapse
synaptic
transmission
bulbs
156
synaptic
gap
158
158
158–9
158
postsynaptic
presynaptic
282
158
synaptic
synaptic
sexual
intercourse
91
65
structure
228
stem
157
transmission
228
202–5
184
secondary
and
180
chemical
3
treatment
76–7
83
synapses
160–1
55
58
need
160
structure
sex
root
sustainable
organs
40,
207
154,
sustainable
191
270
192
sex
sexual
240–1,
56
starch
184
the
testing
77
breeding
184
12
sugars
192
286–7
193
needs
stem
sucrose
109
species
219
substrates
71,
of
193
76
cells
struggle
82
191
sewage
105
glands
survival
185,
154
for
opening
262
279
287
58
sterilisation
7
fats
76,
sensitivity
202
202
56,
salivary
semi-lunar
41
sense
in
41,
and
semen
216–17
protein
reex
38,
inside
92
253
180–1
29
154
stem
stems
91
180
184
stimuli
conditions
200
7
pulmonary
nerves
stomata
selective
puberty
pupil
216
275
40,
scurvy
malnutrition
puberty
pyloric
22,
and
endoplasmic
scrotum
192
262
47
for
rate
hairs
nodules
saprotrophs
204
synthesis
protocists
root
root
saturated
gland
protein
the
root
saliva
58–9
194,
energy
proteins
(mRNA)
13
safety
6
51,
spinal
starvation
S
progesterone
duct
testing
RNA
the
23,
cord
stomach
58
to
species
species
de-starching
207
20
smoke
smoking
232
sporangia
157
by
solutions
spinal
spores
138–41
169
96–7
4,
cells
starch
6,
and
sperm
184–5
244
47
protease
154,
tobacco
caused
nutrient
rubbish
208–9
3,
77
rough
206–7
treatments
by-products
prostate
3,
of
endangered
sperm
195
282–3
67,
method
inside
198–9
200–1
producers
2–3,
species
temperature
84
84–5
introduced
9
roots
255
fertility
238–9,
messenger
contraception
pupil
RNA
254–5
192–3
160
rickets
95
ante-natal
pulse
256–7
194–5
8
ribosomes
growth
solvents
threats
reproduction
rhythm
276–7
system
198–9
sexual
retina
254
population
pregnancy
185,
239
intercourse
respiration
275
population
potometers
selection
responses
water
predation
184,
system
sexual
resources
274
plastics
populations
reproductive
reptiles
188–9
275
waste
birth
187,
286–7
pollution
human
3,
sources
reproductive
pregnancy
188
cross-pollination
body
109
diseases
reproduction
natural
188
of
intestine
biology
184
234–5
168
smoking
219
185
anaemia
absorption
157
146
146
asexual
(STIs)
96–7
control
3,
184–5
infections
12–13
cell
small
arcs
renal
275
growing
skin
285
reproduction
260
sinks
157
155
reex
92–3
237
154,
3,
transmitted
210–11
246
86
recycling
110
plasmids
pollen
by
reproduction
sexually
sickle
receptors
240–1
94–5
uptake
sexual
247
248
R
25
96–7
transpiration
xerophytes
in
shoots
organs
breeding
transport
respiration
58–9
and
translocation
water
and
membrane
membrane
158
158
311
Index
trypsin
T
tar
teeth
80
healthy
tooth
teeth
decay
temperature
control
effect
of
on
and
body
169
and
48,
temperature
193,
tissues
uid
and
organs
translocation
96–7
146,
water
194
system
transpiration
transpiration
95
translocation
transpiration
pull
93
transpiration
stream
systems
90
100–1
124
and
63,
non-
materials
275
72
146
121,
96–7
23
3,
185,
types
of
contraceptive
veins
170
170–1
versus
within
environment
populations
hormones
potential
water
uptake
weight
loss
wilting
32,
and
seas
in
30,
92–3,
171
74
94
233
X
238
xerophytes
12,
237
22,
90–1
169
yellow
veins
103,
20
villi
89
8–9
203
115
115
Z
zidovudine
107
column
body
10
zygotes
(AZT)
185,
276–7
92
plants
Y
vesicles
35,
rivers
251
water
xylem
207
subclavian
vertebral
233
230
64
cava
232–3
variation
100
leaves
vertebrates
170
variation
of
cycle
weedkillers
189
variation
vasectomy
venules
244
of
vasodilation
93
water
125
194
discontinuous
vena
90
90–1
phototropism
56,
pollution
variation
95
and
gravitropism
29,
effects
inheritance
94
levels
155
biodegradable
continuous
and
affecting
ow
disposal
biodegradable
145
194
vagina
transpiration
312
waste
71
146
vacuoles
25
96
measuring
tropisms
144,
variation
transpiration
actions
194
W
198
fats
V
282
114
transpiration
76
77
277
128
translocation
trophic
cord
vaccination
animals
voluntary
32
108
production
plants
urea
uterus
24
mass
pressure
266
41,
U
urinary
202
tissues
transport
D
urethra
timber
factors
vitamin
ureter
62
thrombosis
trachea
32
unsaturated
61
128
tissue
turgidity
umbilical
48–9
temperature
testosterone
plant
C
vulva
193
thorax
vitamin
139
temperature
175
73,
181
turgor
95,
photosynthesis
testes
80–1
7,
vitamins
184
tumours
81
63,
enzymes
optimum
61,
gums
viruses
84
tubers
180
211
186,
193,
197
95
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