Download Section 4.3: The Efficiency and Regulation of Cellular Respiration

across the inner mitochondrial membrane for the synthesis of each molecule of ATP.
2. (a) From the complete oxidation of one glucose molecule during each phase of aerobic cellular
respiration
following
maximum numbers
of ATP can beof
produced:
2 ATP
from glycolysis
Section the
4.3:
The Efficiency
and Regulation
Cellular
Respiration
Read
pgs.
183-188
Do
Q#1-4,
6-10
pg.
189
(substrate
level
phosphorylation),
2
ATP
from
the
citric
acid
cycle
(substrate
level),
and 34 ATP
Section 4.3 Questions, page 189
from
electron
transport
(oxidative
phosphorylation).
In total,
38 ATP
molecules
are produced.
1. One
molecule
of NADH
can yield
three ATP and one
molecule
of FADH
2 can yield two ATP.
+
(b)
The
ATP
produced
in
glycolysis
and
the
citric
acid
cycle
is
produced
using
substrate-level
These numbers are not exact because an approximate number of H ions is required to move
phosphorylation.
The ATP produced
in thefor
electron
transport
is produced
using oxidative
across the inner mitochondrial
membrane
the synthesis
of chain
each molecule
of ATP.
phosphorylation.
2. (a) From the complete oxidation of one glucose molecule during each phase of aerobic cellular
3.
A lower than
expected maximum
yield of ATP
per gram
of glucose
the result2ofATP
an inexact
conversion
respiration
the following
numbers
of ATP
can be isproduced:
from glycolysis
of
NADH level
and FADH
variable
efficiency
different
electron shuttles
transporting
2 to ATP. The
(substrate
phosphorylation),
2 ATP
from
the
citricofacid
cycle (substrate
level), and
34 ATP
+
NADH
into
the
mitochondrion,
and
the
use
of
H
energy
for
other
processes
all
have
an impact
from electron transport (oxidative phosphorylation). In total, 38 ATP molecules are produced.
on
yield. in glycolysis and the citric acid cycle is produced using substrate-level
(b)the
Thetotal
ATPATP
produced
(b)
The
energy
efficiency
glucose respiration
is only
about chain
40 % is
because
much
of the
phosphorylation. The ATPofproduced
in the electron
transport
produced
using
oxidative
potential
energy from glucose is lost as thermal energy.
phosphorylation.
4.
may expected
vary. Sample
Much
of this
thermalisenergy
given
offinexact
by metabolic
3. Answers
A lower than
yieldAnswer:
of ATP per
gram
of glucose
the result
of an
conversion
processes
used
to maintain
our
warm
body
temperature,
which
is
very
useful.
Our
warm
body
of NADH isand
FADH
to
ATP.
The
variable
efficiency
of
different
electron
shuttles
transporting
2
+
temperature
allows
other
important,
and
temperature-dependent,
reactions
to
take
place
in
our
NADH into the mitochondrion, and the use of H energy for other processes all have an impact
bodies.
In addition,
some of the thermal energy is breathed out, or released through sweating,
on the total
ATP yield.
such
as
during
exercise.
(b) The energy efficiency of glucose respiration is only about 40 % because much of the
5.
(a) In humans,
a significant
amount
creatine
phosphate is synthesized in the liver and
potential
energy from
glucose is
lost asofthermal
energy.
delivered
to
body
cells
through
the
bloodstream,
particularly
cells given
of the off
brain,
heart, and
4. Answers may vary. Sample Answer: Much of this thermal to
energy
by metabolic
skeletal
muscle.
processes is used to maintain our warm body temperature, which is very useful. Our warm body
(b)
Some people
ingest
creatine
to aid muscle
repair after
workouts.
temperature
allows
otherdietary
important,
andsupplements
temperature-dependent,
reactions
to take
place inThis
our is
their
benefit.
Evidence
suggests
that
modest
intake
of
these
supplements
is
safe,
but
that
excess
bodies. In addition, some of the thermal energy is breathed out, or released through sweating,
and
carries risks such as kidney or liver damage.
suchlong-term
as during consumption
exercise.
6.
Answers
may
vary:
Sample
During
rest,phosphate
your cellsisare
still doinginwork,
suchand
as
5. (a) In humans, a significant answer.
amount of
creatine
synthesized
the liver
breathing,
digestion,
and
brain activity.
These allparticularly
require energy,
andof
thethe
rate
of energy
delivered to
body cells
through
the bloodstream,
to cells
brain,
heart, use
and at
this
time
is
the
basal
metabolic
rate.
On
the
other
hand,
your
metabolic
rate
varies
based
on how
skeletal muscle.
active
youpeople
are. For
example,
if you
run marathons,
metabolic
will
be workouts.
higher thanThis
thatisof
(b) Some
ingest
dietary
creatine
supplementsyour
to aid
muscle rate
repair
after
someone
who
isn’t
active
at
all.
Your
basal
metabolic
rates,
however,
may
be
the
same.
their benefit. Evidence suggests that modest intake of these supplements is safe, but that excess
7.
a person’sconsumption
diet contained
only sugar
and protein
(noorfat),
they
could still increase their
andIf long-term
carries
risks such
as kidney
liver
damage.
percentage
of
body
fat
because
our
cells
are
capable
of
synthesizing
from
othersuch
starting
6. Answers may vary: Sample answer. During rest, your cells are stillfats
doing
work,
as
molecules
the carbohydrates
and proteins
theenergy,
necessary
synthesize
breathing, and
digestion,
and brain activity.
These contain
all require
andmolecules
the rate oftoenergy
use atfat.
If
more
is consumed
thanrate.
is used,
noother
matter
whatyour
typemetabolic
of food the
energy
the
this
timeenergy
is the basal
metabolic
On the
hand,
rate
variescomes
based from,
on how
body
can
store
the
excess
energy
as
fat.
active you are. For example, if you run marathons, your metabolic rate will be higher than that of
8.
(a) Thewho
process
prevents
from
overmetabolic
producing
ATPhowever,
is feedback
In feedback
someone
isn’tthat
active
at all. us
Your
basal
rates,
mayinhibition.
be the same.
inhibition,
the
end
products
of
the
metabolic
pathway
(here,
ATP)
inhibit
enzymes
from
7. If a person’s diet contained only sugar and protein (no fat), they could still increase their
catalyzing
stop further
production
of ATP.
percentageglucose
of bodyand
fat because
our cells
are capable
of synthesizing fats from other starting
(b)
Since
ATP
is
unstable
and
breaks
down
easily,
if
produced
more ATP
than we fat.
molecules and the carbohydrates and proteins containour
thecells
necessary
molecules
to synthesize
needed,
it wouldislikely
degrade
be wasted.
Producing
excess
ATPthe
would
be wasted
effort.the
If more energy
consumed
thanand
is used,
no matter
what type
of food
energy
comes from,
body
can store theare
excess
energy
as fat.
9.
Carbohydrates
bound
to large
amounts of water because they are extremely hydrophilic
8. (a) The
process
that prevents us
from over producing
ATP isoffeedback
inhibition.
In feedback
whereas
lipids
are hydrophobic.
Additionally,
the metabolism
carbohydrates
requires
the
inhibition,
endwhereas
productsthe
ofmetabolism
the metabolic
(here,
inhibit
from of
addition
of the
water
of pathway
lipids does
not. ATP)
This need
forenzymes
large amounts
catalyzing
glucose
and stop further
ATP.
water
to digest
carbohydrates
meansproduction
that water of
contributes
significantly to an organism’s body
(b) Since©ATP
unstable
and breaks
produced
more ATP
than we 4.3-1
mass.
Copyright
2012isNelson
Education
Ltd. down easily, if our cells
Chapter
4: Cellular
Respiration
needed,
it would
and be wasted.
Producing
be wasted
effort.
10.
Answers
maylikely
vary. degrade
Sample answer:
The advantages
ofexcess
havingATP
largewould
carbohydrate
molecules
in the stem are that they provide rigidity, they are insoluble, they form cross linkages, they form
long stable chains, they are not easily digestible by the plant, and they are difficult for herbivores
to digest. Lipids, conversely, provide large amounts of energy per gram compared to
carbohydrates, have low melting points and are easily digested by mitochondria. These features
are
important
in young
plants as they
in the
soil andRespiration
begin to grow.
Copyright
© 2012
Nelson Education
Ltd. try to establish themselves
Chapter
4: Cellular
4.3-1
Additionally, the high energy content of lipids costs a plant a great deal of energy to produce per
gram. Therefore, carbohydrates provide a much lower-energy building block for the plant to use
for structural purposes.
11. Answers may vary. Sample answer: According to Health Canada, a balanced diet should
contain approximately 20 % of calories from protein, 30 % from fat, and 50 % from
carbohydrates. Clearly carbohydrates are very important since they are the main source of energy