Campbell Biology, 10e (Reece)
Chapter 9 Cellular Respiration and Fermentation
1) Substrate-level phosphorylation occurs _____.
A) in glycolysis
B) in the citric acid cycle
C) in both glycolysis and the citric acid cycle
D) during oxidative phosphorylation
2) The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-
reduction reaction _____.
A) gains electrons and gains potential energy
B) loses electrons and loses potential energy
C) gains electrons and loses potential energy
D) loses electrons and gains potential energy
3) When electrons move closer to a more electronegative atom, what happens? The more
electronegative atom is _____.
A) reduced, and energy is released
B) reduced, and energy is consumed
C) oxidized, and energy is consumed
D) oxidized, and energy is released
4) Which of the listed statements describes the results of the following reaction?
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
A) C6H12O6 is oxidized and O2 is reduced.
B) O2 is oxidized and H2O is reduced.
C) CO2 is reduced and O2 is oxidized.
D) O2 is reduced and CO2 is oxidized.
5) When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction
reaction, the molecule becomes _____.
A) hydrolyzed
B) oxidized
C) reduced
D) an oxidizing agent
6) When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a
proton), the molecule becomes _____.
A) dehydrogenated
B) oxidized
C) reduced
D) redoxed
7) Which of the following statements about NAD+ is true?
A) NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.
B) NAD+ has more chemical energy than NADH.
C) NAD+ can donate electrons for use in oxidative phosphorylation.
D) In the absence of NAD+, glycolysis can still function.
8) The oxygen consumed during cellular respiration is involved directly in which process or
event?
A) glycolysis
B) accepting electrons at the end of the electron transport chain
C) the citric acid cycle
D) the oxidation of pyruvate to acetyl CoA
9) Carbohydrates and fats are considered high-energy foods because they _____.
A) have a lot of oxygen atoms.
B) have no nitrogen in their makeup.
C) have a lot of electrons associated with hydrogen.
D) are easily reduced.
10) A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to
happen when an athlete exhausts his or her ATP supply?
A) He or she has to sit down and rest.
B) Catabolic processes are activated that generate more ATP.
C) ATP is transported into the cell from the circulatory system.
D) Other cells take over, and the muscle cells that have used up their ATP cease to function.
11) Substrate-level phosphorylation accounts for approximately what percentage of the ATP
formed by the reactions of glycolysis?
A) 0%
B) 2%
C) 38%
D) 100%
12) The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mol and the free
energy for the reduction of NAD+ to NADH is +53 kcal/mol. Why are only two molecules of
NADH formed during glycolysis when it appears that as many as a dozen could be formed?
A) Most of the free energy available from the oxidation of glucose is used in the production of
ATP in glycolysis.
B) Glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat.
C) Most of the free energy available from the oxidation of glucose remains in pyruvate, one of
the products of glycolysis.
D) There is no CO2 or water produced as products of glycolysis.
13) Starting with one molecule of glucose, the energy-containing products of glycolysis are
_____.
A) 2 NAD+, 2 pyruvate, and 2 ATP
B) 2 NADH, 2 pyruvate, and 2 ATP
C) 2 FADH2, 2 pyruvate, and 4 ATP
D) 6 CO2, 2 pyruvate, and 2 ATP
14) In glycolysis, for each molecule of glucose oxidized to pyruvate _____.
A) two molecules of ATP are used and two molecules of ATP are produced.
B) two molecules of ATP are used and four molecules of ATP are produced.
C) four molecules of ATP are used and two molecules of ATP are produced.
D) two molecules of ATP are used and six molecules of ATP are produced.
15) Which kind of metabolic poison would most directly interfere with glycolysis?
A) an agent that reacts with oxygen and depletes its concentration in the cell
B) an agent that binds to pyruvate and inactivates it
C) an agent that closely mimics the structure of glucose but is not metabolized
D) an agent that reacts with NADH and oxidizes it to NAD+
16) Most of the CO2 from the catabolism of glucose is released during _____.
A) glycolysis
B) electron transport
C) chemiosmosis
D) the citric acid cycle
17) Following glycolysis and the citric acid cycle, but before the electron transport chain and
oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with
some net gain of ATP. Most of the energy from the original glucose molecule at that point in the
process, however, is in the form of _____.
A) acetyl-CoA
B) glucose
C) pyruvate
D) NADH
18) Which electron carrier(s) function in the citric acid cycle?
A) NAD+ only
B) NADH and FADH2
C) the electron transport chain
D) ADP and ATP
19) If you were to add one of the eight citric acid cycle intermediates to the culture medium of
yeast growing in the laboratory, what do you think would happen to the rates of ATP and carbon
dioxide production?
A) There would be no change in ATP production, but we would observe an increased rate of
carbon dioxide production.
B) The rates of ATP production and carbon dioxide production would both increase.
C) The rate of ATP production would decrease, but the rate of carbon dioxide production would
increase.
D) Rates of ATP and carbon dioxide production would probably both decrease.
20) Carbon dioxide (CO2) is released during which of the following stages of cellular
respiration?
A) glycolysis and the oxidation of pyruvate to acetyl CoA
B) oxidation of pyruvate to acetyl CoA and the citric acid cycle
C) oxidative phosphorylation and fermentation
D) fermentation and glycolysis
21) If glucose is the sole energy source, what fraction of the carbon dioxide exhaled by animals
is generated by the reactions of the citric acid cycle?
A) 1/6
B) 1/3
C) 2/3
D) all of it
Use the following figure to answer the questions below.
The citric acid cycle.
22) For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of
CO2 are released in the citric acid cycle (see the accompanying figure)?
A) 2
B) 4
C) 6
D) 32
23) If pyruvate oxidation is blocked, what will happen to the levels of oxaloacetate and citric
acid in the citric acid cycle shown in the accompanying figure?
A) Oxaloacetate will decrease and citric acid will accumulate.
B) Oxaloacetate will accumulate and citric acid will decrease.
C) Both oxaloacetate and citric acid will decrease.
D) Both oxaloacetate and citric acid will accumulate.
24) Starting with citrate, which of the following combinations of products would result from
three acetyl CoA molecules entering the citric acid cycle (see the accompanying figure)?
A) 1 ATP, 2 CO2, 3 NADH, and 1 FADH2
B) 3 ATP, 3 CO2, 3 NADH, and 3 FADH2
C) 3 ATP, 6 CO2, 9 NADH, and 3 FADH2
D) 38 ATP, 6 CO2, 3 NADH, and 12 FADH2
Use the following information to answer the questions below.
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric
acid cycle. First, however, the pyruvate (1) loses a carbon, which is given off as a molecule of
CO2, (2) is oxidized to form a two-carbon compound called acetate, and (3) is bonded to
coenzyme A.
25) The three listed steps result in the formation of _____.
A) acetyl CoA, O2, and ATP
B) acetyl CoA, FADH2, and CO2
C) acetyl CoA, NADH, and CO2
D) acetyl CoA, NAD+, ATP, and CO2
26) Which one of the following is formed by the removal of a carbon (as CO2) from a molecule
of pyruvate?
A) glyceraldehyde 3-phosphate
B) oxaloacetate
C) acetyl CoA
D) citrate
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27) Which of the following events takes place in the electron transport chain?
A) the breakdown of glucose into two pyruvate molecules
B) the breakdown of an acetyl group to carbon dioxide
C) the extraction of energy from high-energy electrons remaining from glycolysis and the citric
acid cycle
D) substrate-level phosphorylation
28) The electron transport chain _____.
A) is a series of redox reactions
B) is a series of substitution reactions
C) is driven by ATP consumption
D) takes place in the cytoplasm of prokaryotic cells
29) The chemiosmotic hypothesis is an important concept in our understanding of cellular
metabolism in general because it explains _____.
A) how ATP is synthesized by a proton motive force
B) how electron transport can fuel substrate-level phosphorylation
C) the sequence of the electron transport chain molecules
D) the reduction of oxygen to water in the final steps of oxidative metabolism
30) During aerobic respiration, electrons travel downhill in which sequence?
A) glucose → NADH → electron transport chain → oxygen
B) glucose → pyruvate → ATP → oxygen
C) glucose → ATP → electron transport chain → NADH
D) food → glycolysis → citric acid cycle → NADH → ATP
31) Where are the proteins of the electron transport chain located?
A) mitochondrial outer membrane
B) mitochondrial inner membrane
C) mitochondrial intermembrane space
D) mitochondrial matrix
32) During aerobic respiration, which of the following directly donates electrons to the electron
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transport chain at the lowest energy level?
A) NADH
B) ATP
C) ADP + i
D) FADH2
33) The primary role of oxygen in cellular respiration is to _____.
A) yield energy in the form of ATP as it is passed down the respiratory chain
B) act as an acceptor for electrons and hydrogen, forming water
C) combine with carbon, forming CO2
D) combine with lactate, forming pyruvate
34) During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation of
the water come from?
A) carbon dioxide (CO2)
B) glucose (C6H12O6)
C) molecular oxygen (O2)
D) pyruvate (C3H3O3–)
35) In chemiosmosis, what is the most direct source of energy that is used to convert ADP + i
to ATP?
A) energy released as electrons flow through the electron transport system
B) energy released from substrate-level phosphorylation
C) energy released from movement of protons through ATP synthase, down their
electrochemical gradient
D) No external source of energy is required because the reaction is exergonic.
36) Energy released by the electron transport chain is used to pump H+ into which location in
eukaryotic cells?
A) mitochondrial outer membrane
B) mitochondrial inner membrane
C) mitochondrial intermembrane space
D) mitochondrial matrix
37) When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane
and into the intermembrane space, the result is the _____.
A) formation of ATP
B) reduction of NAD+
C) creation of a proton-motive force
D) lowering of pH in the mitochondrial matrix
38) Approximately how many molecules of ATP are produced from the complete oxidation of
one molecule of glucose (C6H12O6) in aerobic cellular respiration?
A) 2
B) 4
C) 18-24
D) 30-32
39) The synthesis of ATP by oxidative phosphorylation, using the energy released by movement
of protons across the membrane down their electrochemical gradient, is an example of _____.
A) active transport
B) an endergonic reaction coupled to an exergonic reaction
C) a reaction with a positive ΔG
D) allosteric regulation
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40) If a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely
oxidized to carbon dioxide and water, approximately how many ATP molecules can the cell
synthesize for each molecule of pyruvate oxidized to carbon dioxide and water?
A) 0
B) 12
C) 14
D) 26
41) In liver cells, the inner mitochondrial membranes are about five times the area of the outer
mitochondrial membranes. What purpose must this serve?
A) It allows for an increased rate of glycolysis.
B) It allows for an increased rate of the citric acid cycle.
C) It increases the surface for oxidative phosphorylation.
D) It increases the surface for substrate-level phosphorylation.
42) You have a friend who lost 7 kg (about 15 pounds) of fat on a regimen of strict diet and
exercise. How did the fat leave his body?
A) It was released as CO2 and H2O.
B) It was converted to heat and then released.
C) It was converted to ATP, which weighs much less than fat.
D) It was converted to urine and eliminated from the body.
Use the following information to answer the questions below.
Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes.
However, the fragments will reseal “inside out.” The little vesicles that result can still transfer
electrons from NADH to oxygen and synthesize ATP.
43) After the disruption, when electron transfer and ATP synthesis still occur, what must be
present?
A) all of the electron transport proteins and ATP synthase
B) all of the electron transport system and the ability to add CoA to acetyl groups
C) the ATP synthase system
D) the electron transport system
44) These inside-out membrane vesicles will _____.
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A) become acidic inside the vesicles when NADH is added
B) become alkaline inside the vesicles when NADH is added
C) make ATP from ADP and i if transferred to a pH 4 buffered solution after incubation in a
pH 7 buffered solution
D) hydrolyze ATP to pump protons out of the interior of the vesicle to the exterior
45) Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in _____.
A) all cells, but only in the presence of oxygen
B) only eukaryotic cells, in the presence of oxygen
C) only in mitochondria, using either oxygen or other electron acceptors
D) all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron
acceptors
46) Which of the following normally occurs regardless of whether or not oxygen (O2) is present?
A) glycolysis
B) fermentation
C) citric acid cycle
D) oxidative phosphorylation (chemiosmosis)
47) Which of the following occurs in the cytosol of a eukaryotic cell?
A) glycolysis and fermentation
B) fermentation and chemiosmosis
C) oxidation of pyruvate to acetyl CoA
D) citric acid cycle
48) In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the
production of _____.
A) ATP, CO2, and ethanol (ethyl alcohol)
B) ATP, CO2, and lactate
C) ATP, NADH, and pyruvate
D) ATP, pyruvate, and acetyl CoA
49) One function of both alcohol fermentation and lactic acid fermentation is to _____.
A) reduce NAD+ to NADH
B) reduce FAD+ to FADH2
C) oxidize NADH to NAD+
D) reduce FADH2 to FAD+
50) An organism is discovered that thrives in both the presence and absence of oxygen in the air.
Curiously, the consumption of sugar increases as oxygen is removed from the organism’s
environment, even though the organism does not gain much weight. This organism _____.
A) is a normal eukaryotic organism
B) is photosynthetic
C) is an anaerobic organism
D) is a facultative anaerobe
51) Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
A) It produces much less ATP than does oxidative phosphorylation.
B) It does not involve organelles or specialized structures, does not require oxygen, and is
present in most organisms.
C) It is found in prokaryotic cells but not in eukaryotic cells.
D) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.
52) Yeast cells that have defective mitochondria incapable of respiration will be able to grow by
catabolizing which of the following carbon sources for energy?
A) glucose
B) proteins
C) fatty acids
D) Such yeast cells will not be capable of catabolizing any food molecules, and therefore, will
die.
53) What is the oxidizing agent in the following reaction?
Pyruvate + NADH + H+ → Lactate + NAD+
A) NADH
B) NAD+
C) lactate
D) pyruvate
54) High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in
glycolysis. Citric acid binds to the enzyme at a different location from the active site. This is an
example of _____.
A) competitive inhibition
B) allosteric regulation
C) the specificity of enzymes for their substrates
D) positive feedback regulation
55) Glycolysis is active when cellular energy levels are _____; the regulatory enzyme,
phosphofructokinase, is _____ by ATP.
A) low; activated
B) low; inhibited
C) high; activated
D) high; inhibited
56) Canine phosphofructokinase (PFK) deficiency afflicts Springer spaniels, affecting an
estimated 10% of the breed. Given its critical role in glycolysis, one implication of the genetic
defect resulting in PFK deficiency in dogs is _____.
A) early embryonic mortality
B) elevated blood-glucose levels in the dog’s blood
C) an intolerance for exercise
D) a reduced life span
57) A young dog has never had much energy. He is brought to a veterinarian for help and she
decides to conduct several diagnostic tests. She discovers that the dog’s mitochondria can use
only fatty acids and amino acids for respiration, and his cells produce more lactate than normal.
Of the following, which is the best explanation of the dog’s condition?
A) His mitochondria lack the transport protein that moves pyruvate across the outer
mitochondrial membrane.
B) His cells cannot move NADH from glycolysis into the mitochondria.
C) His cells lack the enzyme in glycolysis that forms pyruvate.
D) His cells have a defective electron transport chain, so glucose goes to lactate instead of to
acetyl CoA.
58) Even though plants cells photosynthesize, they still use their mitochondria for oxidation of
pyruvate. This will occur in _____.
A) photosynthetic cells in the light, while photosynthesis occurs concurrently
B) cells that are storing glucose only
C) all cells all the time
D) photosynthesizing cells in the light and in other tissues in the dark
59) In respiration, beta oxidation involves the _____.
A) oxidation of glucose
B) oxidation of pyruvate
C) regulation of glycolysis
D) breakdown of fatty acids
60) Fatty acids usually have an even number of carbons in their structures. They are catabolized
by a process called beta-oxidation. The end products of the metabolic pathway are acetyl groups
of acetyl CoA molecules. These acetyl groups _____.
A) directly enter the electron transport chain
B) directly enter the energy-yielding stages of glycolysis
C) are directly decarboxylated by pyruvate dehydrogenase
D) directly enter the citric acid cycle
61) New biosensors, applied like a temporary tattoo to the skin, can alert serious athletes that
they are about to “hit the wall” and find it difficult to continue exercising. These biosensors
monitor lactate, a form of lactic acid, released in sweat during strenuous exercise.
Which of the statements below is the best explanation of why athletes would need to monitor
lactate levels?
A) During aerobic respiration, muscle cells cannot produce enough lactate to fuel muscle cell
contractions and muscles begin to cramp, thus athletic performance suffers.
B) During anaerobic respiration, lactate levels increase when muscles cells need more energy,
however muscles cells eventually fatigue, thus athletes should modify their activities to increase
aerobic respiration.
C) During aerobic respiration, muscles cells produce too much lactate which causes a rise in the
pH of the muscle cells, thus athletes must consume increased amounts of sports drinks, high in
electrolytes, to buffer the pH.
D) During anaerobic respiration, muscle cells receive too little oxygen and begin to convert
lactate to pyruvate (pyruvic acid), thus athletes experience cramping and fatigue.