Download Science 1.3 Assessment schedule 10

Assessment Schedule – 2010
Science 1.3: Describe aspects of biology (90188)
Evidence Statement
Q
Achievement
Achievement with Merit
ONE
Correct statement
about why viruses can’t
be cultured on agar (a)
Examples:
Viruses do not carry out
life processes/are not
living.
OR
Viruses require living
cells to
reproduce/replicate.
Correct explanation why
viruses can’t be cultured on
agar AND why bacteria can
(m)
Examples:
Viruses can only
reproduce/replicate in living
cells which are not on agar
(a)
Correct statement
about why bacteria can
(a)
Examples: Agar contains
food/ moisture that
bacteria need to
grow/reproduce etc
(b)
Correct statements.
(a)
eg
Viruses or bacteria
spread through
contact/air (a)
Viruses replicate in
living cells then burst out
to spread (or diagram ok)
(a)
Bacteria reproduce using
binary fission /cell
divides in two. (a)
As bacteria build up over
time they excrete waste
which makes a person ill
(a)
Q1
Suff
3 x a statements from
Parts (a)and (b)
3 x a =A
Achievement with Excellence
AND
Bacteria need food/moisture,
which is in agar, to reproduce/
carry out life processes etc
Correct explanation
comparing infection OR
replication of bacteria and
viruses OR why person gets
ill (m)
Discusses fully how bacteria and
viruses enter the body AND
reproduce AND cause illness (e)
Eg:
Both viruses and bacteria are spread
Both bacteria and viruses can through air/contact and are
be swallowed after contact/
swallowed.
from the air (m)
Bacteria reproduce rapidly by binary
fission in warm, moist conditions, all
Viruses inject genetic
excreting toxins/waste which make
material into a living cell,
you sick when sufficient numbers are
which makes viruses. They
present. Viruses inject DNA into
burst out and infect more cells living cells, when then are used to
and Bacteria reproduce by
make more viruses. These burst from
binary fission/ cell divides in the cell, killing it and then infect more
two (m)
cells, causing more damage (e)
Viruses burst the cells causing
sickness/ immune system
response, and bacteria
produce toxins/cause sickness
with their excretion (m)
2 x m from part (a) or/and (b)
=M
1xe=E
(can only be from part (b)
Q2
Correct statement (a)
(a)
Eg:
The dry sachet has no
moisture (a)
Explains why sachet has
long life AND prepared
yoghurt does not (m)
Eg:
The bacteria are
dormant/inactive until
water is added (a)
The dried sachet has no
moisture/water so the bacteria
can’t grow/ are dormant, OR
the bacteria are dormant until
water is added
Harmful bacteria may
enter the yoghurt after it
is made (a)
AND
The cold fridge temp
stops the bacteria
growing/reproducing etc
(a)
Prepared yoghurt spoils as
bacteria are active/eat the
yoghurt and excrete waste/
can contain airborne
bacteria/cold temp slows the
life processes (m)
(b)
Correct statement
about a step or life
process or conditions
(a)
Correct explanation of
conditions needed OR
explanation of a step OR a
life process (m)
Eg:
Eg:
Step 1 – need clean jars
or water to avoid other
bacterial contamination
(a)
Step 2-leaving no air
space/screwing lid on
ensures no other bacteria
can enter (a)
Adding water activates
the dormant bacteria/
bacteria need moisture to
grow/respire/reproduce
(a)
Step 3 – Hot water
provides warmth (a)
Milk curdles/clots when
acid is produced by
bacteria or acid is
excreted to make the
yoghurt thick (a)
The bacteria have/need
warmth, food and
moisture (a)
Q2
Suff
3 x a from Parts (a)
and/or (b) = A
Links at least 2 step explanations to
conditions and life processes (e)
Eg:
Bacteria need food, moisture and
warmth to carry out life processes.
Bacteria need food, moisture
Yoghurt is made when the bacteria eat
and warmth (at least 2) to
the milk/lactose (powder) and excrete
carry out life processes.
(lactic) acid to make the milk proteins
Yoghurt is made when the
clot/clump. Step 1 adds water to
bacteria eat the milk/lactose
activate the bacteria /needs to be clean
(powder) and excrete (lactic)
to avoid contamination by other
acid to make the milk proteins bacteria which may make you sick.
clot/clump. (m)
The yoghurt bacteria start growing,
reproducing by binary fission and
Step 1- stops other bacteria
eating by extracellular digestion,
etc contaminating and
secreting enzymes to break down food
growing in the jar to spoil the and then absorbing it. The heat of the
yoghurt or cause illness (m)
hot water in step 2 ensures that these
OR
processes are carried out quickly as
Step 2 - leaving no air
heat speeds up reactions.
space/screwing lid on ensures
no other bacteria can enter to
spoil the yoghurt or cause
illness (m)
OR
Step 3 – Hot water provides
the warmth to make the
bacteria reproduce quickly/
carry out life processes faster
to make the yoghurt (m)
Explains a relevant life
process – eg. bacteria eat by
extracellular digestion
secreting enzymes to break
down food and then absorbing
it (m)
3 x m from Part (a) and/or (b)
=M
1 x e from Part (b) =E
Q3
(a)
Correct genotypes (a)
Explains why the genotypes
must be Dd (m)
Dd or heterozygous
(Allow other letters if
clearly heterozygous)
(b)
Correct statement or
punnet. (a)
Eg:
Description/ diagram of
meiosis (a)
Variation in meiosis can
be caused by crossing
over / shuffling/
independent assortment
(a)
D
d
D
d
DD Dd
Dd dd
(a)
Defines 2 of allele
(different versions of a
gene), phenotype
(physical/observed trait),
gene (length of DNA
coding for a trait) (a)
Next child has ¾ chance
of dimples (a)
Only 1 has dimples due
to chance / each baby has
same chances (a)
Eg:
Both parents have the
dominant trait so can be DD
or Dd. Must be Dd so they
can produce a dd child with
no dimples (or parents can’t
be dd or would have no
dimples)
Correct punnet AND
explanation of outcomes of
meiosis OR outcome related
to chance. (m)
Must use terms allele and
gene correctly if used.
Eg:
Explains meiosis process
(may be annotated diagram)
(m)
OR
Meiosis is the production of
gametes / sex cells, so
produces cells with half the
number of chromosomes.
These mix at fertilization, the
dominant D will show if
present (m)
OR
Both parents have both
alleles, D and d, how these
combine is random for each
child / not related to previous
events.
Chance of dimpled child
phenotype is still ¾ as in
punnet even though it hasn’t
shown up as often as this so
far. 75% chance will only be
displayed in a large sample,
not necessarily in only 4
children (m)
AND
Correct Punnett square.
Discusses how meiosis produces can
be produced AND links the outcome
to the statistical probability of it
happening.
MUST include Punnett square.
(e)
Because both parents are
heterozygous, they carry both
dominant and recessive alleles for the
gene. In meiosis, the homologous
pairs line up and are pulled apart, ie
the alleles are separated. Each gamete
receives one allele for each gene, ie
1/2 the genetic material of the parent.
This combines randomly at
fertilization with another gamete to
give the various outcomes dd, DD and
Dd. For a child to have no dimples it
must inherit the recessive allele from
both parents. As shown in the punnet
this should statistically happen ¼ of
the time, but each time is random
/unrelated to previous outcomes, so it
is quite possible to not get correct
ratios unless a very large number of
children are born.
AND
Correct Punnett square.
Q3
Suff
Q4
(a)
(b)
3 x a over Part a and b=
A
2 x m over Part a and/or b =
M
Correct genotype and
phenotype given (a)
Explanation of genotype and
phenotype given (m)
Genotype is aa,
phenotype is black. (a)
Eg:
Genotype is aa, phenotype is black.
Cat must have both recessive alleles
aa or it would be Agouti as Agouti
is dominant and only needs one A
allele to show (m)
Correct statement (a)
Explains process of test/back
cross (m)
Eg:
He needs to do a
test/back cross to find
AA cats to breed
together/AA are pure
breeding for agouti (a)
Breed agouti with black
to find out which are AA
AND punnet/s (a)
Eg:
He needs to do a test/back cross to
find AA cats to breed together/AA
are pure breeding for agouti. This
means breeding the agouti with the
black, if any black kittens result, the
agouti parent must be Aa and not
pure breeding (m)
OR
appropriately annotated punnets ie
Punnet 1 – all agouti
A
A
a Aa Aa
a Aa Aa
Punnet 2 – ½ agouti. ½ black
A
a
a Aa aa
a Aa aa
(m)
1xe=E
Discusses process of test cross
to establish pure breeding
group (e)
Eg:
The breeder first needs to find
the AA agouti cats to breed
from. By breeding the agouti
cats he has with the black ones,
he can see this as AA x aa will
only produce Aa agouti kittens
as in punnet 1. Quite a large
number are needed to ensure no
black kittens will result. If a
single black kitten is born, the
agouti parent must be Aa as in
punnet 2, it must have given an
a allele. When the breeder is
certain he has AA individuals he
can breed only these, as all
offspring will be AA true
breeding agouti, as no recessive
alleles are present.
Punnet 1 – all agouti
A
A
a Aa Aa
a Aa Aa
Punnet 2 – ½ agouti. ½ black
A
a
a Aa aa
a Aa aa
Q4
Suff
2xa =A
1 x a + 1 x m from (a) or (b) = M
1xe =E
OVERALL SUFFICIENCY:
Achieved:
3 questions out of 4 answered at achieved level or above.
Merit:
1 question at achieved or above and at least 2 questions at merit.
Excellence:
1 question at achieved or above, two questions at excellence.