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• Glycolysis occurs in the cytosol of all cells and uses water-soluble enzymes; therefore it does
not require sophisticated electron transport chains or cellular organelles in order to operate.
• Glycolysis
provides
energy,
is vital.
4.
The electron
transport
chainwhich
facilitates
the transfer of electrons from NADH and FADH2 to
2.
Glycolysis
is
not
very
efficient
at
converting
glucose
to and
ATP:
only
2.2
% efficient. Other highO
of 182
four protein complexes:
I, II, III,
IV,
with
increasing
2. The chain
Q#3-6,
9 &consists
10 pg.
energy products of
glycolysis
are Electron
two pyruvate
and two to
NADH
molecules,
which
electronegativity
along
the chain.
flow molecules
from one complex
another
is facilitated
by will
continue
to electron
stages 2,shuttles.
3, and 4Oxygen
of aerobic
respiration,
and eventually
to ATP.
two
mobile
is highly
electronegative
and isconvert
the driving
force in the
3. NADH,
FADH2chain.
, ADP,It and
Pi two electrons from cytochrome c (cyt c), causing a chain
electron
transport
takes
reaction with electrons being passed from molecules that are more electronegative to molecules
4. The electron transport chain facilitates the transfer of electrons from NADH and FADH2 to
that are less electronegative.
O2. The chain consists of four protein complexes: I, II, III, and IV, with increasing
5. (a) The electrons in NADH have the most free energy in the electron transport chain.
electronegativity along the chain. Electron flow from one complex to another is facilitated by
(b) These bond formations result in energy being released as the electrons form stronger and
two mobile electron shuttles. Oxygen is highly electronegative and is the driving force in the
stronger
bonds
as they move
through
the electron transport chain.
Copyrighttransport
© 2012 Nelson
Ltd. electrons from cytochrome
Chapter
4:c),
Cellular
Respiration
electron
chain.Education
It takes two
c (cyt
causing
a chain 4.2-1
6. The stage of aerobic cellular respiration that does not occur in the mitochondria is glycolysis.
reaction with electrons being passed from molecules that are more electronegative to molecules
Glycolysis occurs in the cytosol. All of the other stages of aerobic respiration—pyruvate
that are less electronegative.
oxidation, the citric acid cycle, the electron transport chain, and chemiosmosis—occur in the
5. (a) The electrons in NADH have the most free energy in the electron transport chain.
mitochondria.
(b) These bond formations result in energy being released
as the electrons form stronger and
7. (a) glycolysis: glucose + 2 ADP + 2 P + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 2H+
stronger bonds as they move through thei electron
transport chain.
+
(b) pyruvate oxidation: 2 pyruvate + 2NAD + 2CoA 2 acetyl-CoA + 2 NADH + 2H+ + 2CO
6. The stage of aerobic cellular respiration+that does not occur in the mitochondria is glycolysis. 2
(c) citric acid cycle: acetyl-CoA + 3 NAD + FAD + ADP + Pi + 2 H2O
Glycolysis occurs in the cytosol.+ All of the other stages of aerobic
respiration—pyruvate
2 CO + 3 NADH + 3 H + FADH + ATP + CoA
oxidation, the2 citric acid cycle, the electron2 transport chain, and chemiosmosis—occur in the
8. The important molecule is needed for oxidative phosphorylation but not needed for substratemitochondria.
level phosphorylation is oxygen.
7. (a) glycolysis: glucose + 2 ADP + 2 Pi + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 2H+
9. The primary function of the proton-motive force is the establishment of a chemical and
(b) pyruvate oxidation: 2 pyruvate + 2NAD+ + 2CoA 2 acetyl-CoA + 2 NADH + 2H+ + 2CO2
concentration gradient of protons across the membrane. This represents a source of energy that
(c) citric acid cycle: acetyl-CoA + 3 NAD+ + FAD + ADP + Pi + 2 H2O
can be harnessed to do work. Cells
use the proton-motive force in the process called
2 CO2 + 3 NADH + 3 H+ + FADH2 + ATP + CoA
chemiosmosis,
which synthesizes ATP.
8. The important molecule is needed for oxidative phosphorylation but not needed for substrate10. An example of uncoupling is brown adipose fat. This fat can use uncoupling to generate
level phosphorylation is oxygen.
thermal energy from the electron transport chain instead of generating ATP. Uncoupling
9. The primary function of the proton-motive force is the establishment of a chemical and
produces energy to maintain body temperature in hibernating animals and in very young
concentration gradient of protons across the membrane. This represents a source of energy that
offspring, including human infants.
can be harnessed to do work. Cells use the proton-motive force in the process called
11. Answers may vary. Sample answer: Ionophores are compounds that help move ions across
chemiosmosis, which synthesizes ATP.
lipid membranes by altering the membrane’s permeability. Ionophores are used as antibiotics and
10. An example of uncoupling is brown adipose fat. This fat can use uncoupling to generate
as a feed additive in the cattle industry to increase disease resistance and increase weight gain
thermal energy from the electron transport chain instead of generating ATP. Uncoupling
and feed efficiency.
produces energy to maintain body temperature in hibernating animals and in very young
12. (a) The product that is produced is water.
offspring, including human infants.
(b) For every mole of oxygen you breathe in, one mole of water is formed.
11. Answers may vary. Sample answer: Ionophores are compounds that help move ions across
(c) Answers may vary. Sample answer: Many desert animals have an adaptation in their nasal
lipid membranes by altering the membrane’s permeability. Ionophores are used as antibiotics and
passages that allows them to reabsorb this normally “lost” water of metabolism from the air they
as a feed additive in the cattle industry to increase disease resistance and increase weight gain
exhale, and reduce the amount of water lost.
and feed efficiency.
12. (a) The product that is produced is water.
(b) For every mole of oxygen you breathe in, one mole of water is formed.
(c) Answers may vary. Sample answer: Many desert animals have an adaptation in their nasal
passages that allows them to reabsorb this normally “lost” water of metabolism from the air they
exhale, and reduce the amount of water lost.
Copyright © 2012 Nelson Education Ltd.
Chapter 4: Cellular Respiration
4.2-2
Copyright © 2012 Nelson Education Ltd.
Chapter 4: Cellular Respiration
4.2-2