Biology, 7e (Campbell) Chapter 9: Cellular Respiration: Harvesting Chemical Energy Chapter
Questions
1) What is the term for metabolic pathways that release stored energy by breaking down
complex molecules? A) anabolic pathways B) catabolic pathways C) fermentation pathways D)
thermodynamic pathways E) bioenergetic pathways
2) What is the term used for the metabolic pathway in which glucose (C6H12O6) is degraded to
carbon dioxide (CO2 ) and water? A) cellular respiration B) glycolysis C) fermentation D) citric
acid cycle E) oxidative phosphorylation
3) Which of the following statements concerning the metabolic degradation of glucose (C6H12
O6) to carbon dioxide (CO2 ) and water is (are) true? A) The breakdown of glucose to carbon
dioxide and water is exergonic. B) The breakdown of glucose to carbon dioxide and water has a
free energy change of -686 kcal/mol. C) The breakdown of glucose to carbon dioxide and water
involves oxidation-reduction or redox reactions. D) Only A and B are correct. E) A, B, and C are
correct.
4) Which of the following statements is (are) correct about an oxidation-reduction (or redox)
reaction? A) The molecule that is reduced gains electrons. B) The molecule that is oxidized loses
electrons. C) The molecule that is reduced loses electrons. D) The molecule that is oxidized gains
electrons. E) Both A and B are correct.
5) Which statement is not correct with regard to redox (oxidation-reduction) reactions? A) A
molecule is reduced if it loses electrons. B) A molecule is oxidized if it loses electrons. C) An
electron donor is called a reducing agent. D) An electron acceptor is called an oxidizing agent. E)
Oxidation and reduction always go together. Answer: A Topic: Concept 9.1 Skill: Knowledge
6) The molecule that functions as the reducing agent (electron donor) in a redox or oxidationreduction reaction A) gains electrons and gains energy. B) loses electrons and loses energy. C)
gains electrons and loses energy. D) loses electrons and gains energy. E) neither gains nor loses
electrons, but gains or loses energy.
7) When electrons move closer to a more electronegative atom, what happens? A) Energy is
released. B) Energy is consumed. C) The more electronegative atom is reduced. D) The more
electronegative atom is oxidized. E) A and C are correct.
8) Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and
water release free energy? A) The covalent bonds in organic molecules are higher energy bonds
than those in water and carbon dioxide. B) Electrons are being moved from atoms that have a
lower affinity for electrons (such as) C) to atoms with a higher affinity for electrons (such as O).
C) The oxidation of organic compounds can be used to make ATP. D) The electrons have a
higher potential energy when associated with water and CO 2 than they do in organic
compounds. E) The covalent bond in O2 is unstable and easily broken by electrons from organic
molecules.
9) Which of the following statements describes the results of this reaction? C6H12 O6 + 6 O2 6
CO2 + 6 H2 O + 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) C6H12O6is reduced and CO2 is
oxidized. E) O2 is reduced and CO2 is oxidized.
10) When a glucose molecule loses a hydrogen atom (not a hydrogen ion) as the result of an
oxidation-reduction reaction, the molecule becomes A) dehydrogenated. B) hydrogenated. C)
oxidized. D) reduced. E) an oxidizing agent.
11) When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not
a hydrogen ion) the molecule becomes A) hydrogenated. B) oxidized. C) reduced. D) redoxed. E)
a reducing agent.
12) Which of the following statements about NAD+ is false? A) NAD+ is reduced to NADH
during both glycolysis and the citric acid cycle. B) NAD+ has more chemical energy than
NADH. C) NAD+ is reduced by the action of dehydrogenases. D) NAD+ can receive electrons
for use in oxidative phosphorylation. E) In the absence of NAD+, glycolysis cannot function.
13) In order for NAD+ to remove electrons from glucose or other organic molecules, which of
the following must be true? A) The organic molecule or glucose must be negatively charged in
order to reduce the positively charged NAD +. B) Oxygen must be present to oxidize the NADH
produced back to NAD+. C) The free energy liberated when electrons are removed from the
organic molecules must be greater than the energy required to give the electrons to NAD+. D) A
and B are both correct. E) A, B, and C are all correct.
14) Where does glycolysis takes place? A) mitochondrial matrix B) mitochondrial outer
membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E) cytosol
Answer: E Topic: Concept 9.1 Skill: Knowledge
15) The ATP made during glycolysis is generated by A) substrate-level phosphorylation. B)
electron transport. C) photophosphorylation. D) chemiosmosis. E) oxidation of NADH to NAD+.
16) 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 E) the phosphorylation of ADP to form
ATP
17) Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or
absent? A) electron transport B) glycolysis C) the citric acid cycle D) oxidative phosphorylation
E) chemiosmosis
18) Which of the following statements about glycolysis false? A) Glycolysis has steps involving
oxidation-reduction reactions. B) The enzymes of glycolysis are located in the cytosol of the cell.
C) Glycolysis can operate in the complete absence of O2 . D) The end products of glycolysis are
CO2 and H2O. E) Glycolysis makes ATP exclusively through substrate-level phosphorylation.
Refer to Figure 9.1 to answer the following questions. Figure 9.1 illustrates some of the steps
(reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to
answer the questions. Figure 9.1
19) Which step shows a split of one molecule into two smaller molecules? Answer: B
20) In which step is an inorganic phosphate added to the reactant? Answer: C
21) In which reaction does an intermediate pathway become oxidized? Answer: C
22) Which step involves an endergonic reaction? Answer: A
23) Which step consists of a phosphorylation reaction in which ATP is the phosphate source?
Answer: A
24) Substrate-level phosphorylation accounts for approximately what percentage of the ATP
formed during glycolysis? A) 0% B) 2% C) 10% D) 38% E) 100%
25) During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is
A) transferred to ADP, forming ATP. B) transferred directly to ATP. C) retained in the pyruvate.
D) stored in the NADH produced. E) used to phosphorylate fructose to form fructose-6phosphate.
26) In addition to ATP, what are the end products of glycolysis? A) CO2 and H2 O B) CO2 and
pyruvate C) NADH and pyruvate D) CO2 and NADH E) H2O, FADH2, and citrate
27) The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mole and the free
energy for the reduction of NAD+ to NADH is +53 kcal/mole. 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. E) Glycolysis consists of many enzymatic reactions, each of which extracts some
energy from the glucose molecule. \
28) Starting with one molecule of glucose, the "net" products of glycolysis are 6 A) 2 NAD+ , 2
H+, 2 pyruvate, 2 ATP, and 2 H2O. B) 2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O. C) 2
FADH2, 2 pyruvate, 4 ATP, and 2 H2O. D) 6 CO2, 6 H2O, 2 ATP, and 2 pyruvate. E) 6 CO2, 6
H2 O, 36 ATP, and 2 citrate.
29) In glycolysis, for each molecule of glucose oxidized to pyruvate A) 2 molecules of ATP are
used and 2 molecules of ATP are produced. B) 2 molecules of ATP are used and 4 molecules of
ATP are produced. C) 4 molecules of ATP are used and 2 molecules of ATP are produced. D) 2
molecules of ATP are used and 6 molecules of ATP are produced. E) 6 molecules of ATP are used
and 6 molecules of ATP are produced.
30) A molecule that is phosphorylated A) has an increased chemical reactivity; it is primed to do
cellular work. B) has a decreased chemical reactivity; it is less likely to provide energy for
cellular work. C) has been oxidized as a result of a redox reaction involving the gain of an
inorganic phosphate. D) has been reduced as a result of a redox reaction involving the loss of an
inorganic phosphate. E) has less energy than before its phosphorylation and therefore less energy
for cellular work.
31) 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+ E) An agent that
blocks the passage of electrons along the electron transport chain
32) 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 twocarbon compound called acetate, and
3) is bonded to coenzyme A. These three steps result in the formation of
A) acetyl CoA, O2, and ATP. B) acetyl CoA, FADH2, and CO2. C) acetyl CoA, FAD, H2 , and
CO2. D) acetyl CoA, NADH, H+, and CO2 . E) acetyl CoA, NAD+, ATP, and CO2.
33) Which of the following intermediary metabolites enters the citric acid cycle and is formed, in
part, by the removal of a carbon (CO2) from one molecule of pyruvate? A) lactate B)
glyceraldehydes-3-phosphate C) oxaloacetate D) acetyl CoA E) citrate
34) During cellular respiration, acetyl CoA accumulates in which location? A) cytosol B)
mitochondrial outer membrane C) mitochondrial inner membrane D) mitochondrial
intermembrane space E) mitochondrial matrix
35) How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one
molecule of pyruvate? A) 2 B) 4 C) 6 D) 8 E) 10
36) All of the following are functions of the citric acid cycle except A) production of ATP. B)
production of NADH. C) production of FADH2. D) release of carbon dioxide. E) adding
electrons and protons to oxygen, forming water
Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.
Figure 9.2
37) Starting with one molecule of isocitrate and ending with fumarate, what is the maximum
number of ATP molecules that could be made through substrate-level phosphorylation? A) 1 B) 2
C) 11 D) 12 E) 24
38) Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid
cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino
acid? A) succinate B) malate C) citrate D) -ketoglutarate E) isocitrate
39) Starting with one molecule of citrate and ending with oxaloacetate, how many ATP
molecules can be formed from oxidative phosphorylation (chemiosmosis)? A) 1 B) 3 C) 4 D) 11
E) 12
40) How many ATP molecules could be made through substrate-level phosphorylation plus
oxidative phosphorylation (chemiosmosis) if you started with three molecules of succinyl CoA
and ended with o xaloacetate? A) 6 B) 12 C) 18 D) 24 E) 36
41) How many molecules of carbon dioxide (CO2) would be produced by five turns of the citric
acid cycle? A) 2 B) 5 C) 10 D) 12 E) 60
42) How many reduced dinucleotides would be produced with four turns of the citric acid cycle?
A) 1 FADH2 and 4 NADH B) 2 FADH2 and 8 NADH C) 4 FADH2 and 12 NADH D) 1 FAD
and 4 NAD+ E) 4 FAD+ and 12 NAD+
43) Starting with citrate, how many of the following would be produced with three turns of the
citric acid cycle? A) 1 ATP, 2 CO2 , 3 NADH, and 1 FADH2 B) 2 ATP, 2 CO2 , 1 NADH, and 3
FADH2 C) 3 ATP, 3 CO2 , 3 NADH, and 3 FADH2 D) 3 ATP, 6 CO2 , 9 NADH, and 3 FADH2
E) 38 ATP, 6 CO2, 3 NADH, and 12 FADH2
44) 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) the citric acid cycle and oxidative phosphorylation D)
oxidative phosphorylation and fermentation E) fermentation and glycolysis
45) For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what
is the total number of NADH + FADH2 molecules produced? A) 4 10 B) 5 C) 6 D) 10 E) 12
46) A young relative of yours has never had much energy. He goes to a doctor for help and is sent
to the hospital for some tests. There they discover his 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 his 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 contain something that inhibits oxygen use in
his mitochondria. D) His cells lack the enzyme in glycolysis that forms pyruvate. E) His cells
have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA.
47) Cellular respiration harvests the most chemical energy from which of the following? A)
substrate-level phosphorylation B) chemiosmotic phosphorylation C) converting oxygen to ATP
D) transferring electrons from organic molecules to pyruvate E) generating carbon dioxide and
oxygen in the electron transport chain
48) During aerobic respiration, electrons travel downhill in which sequence? A) food citric acid
cycle ATP NAD+ B) food NADH electron transport chain oxygen C) glucose pyruvate ATP
oxygen D) glucose ATP electron transport chain NADH E) food glycolysis citric acid cycle
NADH ATP
49) Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle? A)
pyruvate B) malate or fumarate C) acetyl CoA D) -ketoglutarate E) succinyl CoA
50) Where are the proteins of the electron transport chain located? A) cytosol B) mitochondrial
outer membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E)
mitochondrial matrix
51) Which of the following describes the sequence of electron carriers in the electron transport
chain, starting with the least electronegative? A) ubiquinone (Q), cytochromes (Cyt), FMN, Fe S
B) cytochromes (Cyt), FMN, ubiquinone, FeS C) Fe S, FMN, cytochromes (Cyt), ubiquinone D)
FMN, Fe S, ubiquinone, cytochromes (Cyt) E) cytochromes (Cyt), Fe S, ubiquinone, FMN
52) During aerobic respiration, which of the following directly donates electrons to the electron
transport chain at the lowest energy level? A) NAD+ B) NADH C) ATP D) ADP + P i E) FADH2
53) 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. E)
catalyze the reactions of glycolysis.
54) Inside an active mitochondrion, most electrons follow which pathway? A) glycolysis NADH
oxidative phosphorylation ATP oxygen B) citric acid cycle FADH2 electron transport chain ATP
C) electron transport chain citric acid cycle ATP oxygen D) pyruvate citric acid cycle ATP
NADH oxygen E) citric acid cycle NADH electron transport chain oxygen
55) During oxidative phosphorylation, H2O is formed. Where does the oxygen for the synthesis
of water the come from? A) carbon dioxide (CO2 ) B) glucose (C6H12 O6) C) molecular oxygen
(O2) D) pyruvate (C3H3O3 ) E) lactate (C3H5O3 -)
56) Which metabolic process is most closely associated with intracellular membranes? A)
substrate-level phosphorylation B) oxidative phosphorylation C) glycolysis D) the citric acid
cycle E) alcohol fermentation
57) In chemiosmotic phosphorylation, what is the most direct source of energy that is used to
convert ADP + P 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 ATP
synthase pumping hydrogen ions against their concentration gradient D) energy released from
movement of protons through ATP synthase E) No external source of energy is required because
the reaction is exergonic.
58) Energy released by the electron transport chain is used to pump H+ ions into which location?
A) cytosol B) mitochondrial outer membrane C) mitochondrial inner membrane D)
mitochondrial intermembrane space E) mitochondrial matrix
59) During aerobic cellular respiration, a proton gradient in mitochondria is generated by
________ and used primarily for ________. A) the electron transport chain; ATP synthesis B) the
electron transport chain; substrate-level phosphorylation C) glycolysis; production of H2O D)
fermentation; NAD+ reduction E) diffusion of protons; ATP synthesis
60) The direct energy source that drives ATP synthesis during respiratory oxidative
phosphorylation is A) oxidation of glucose to CO2 and water. B) the thermodynamically
favorable flow of electrons from NADH to the mitochondrial electron transport carriers. C) the
final transfer of electrons to oxygen. D) the difference in H+ concentrations on opposite sides of
the inner mitochondrial membrane. E) the thermodynamically favorable transfer of phosphate
from glycolysis and the citric acid cycle intermediate molecules of ADP.
61) A major function of the mitochondrial inner membrane is the conversion of energy from
electrons to the stored energy of the phosphate bond in ATP. To accomplish this function, the
inner mitochondrial membrane must have all of the following features except A) carrier proteins
to accept electrons from NADH. B) integral, transverse ATP synthase. C) proton pumps
embedded in the membrane. D) the electron transport chain of proteins. E) high permeability to
protons.
62) 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) restoration of the Na+/K+ balance across the membrane. D) creation of a proton gradient. E)
lowering of pH in the mitochondrial matrix.
63) Where is ATP synthase located in the mitochondrion? A) cytosol B) electron transport chain
C) outer membrane D) inner membrane E) mitochondrial matrix
64) It is possible to prepare vesicles from portions of the inner membrane of the mitochondrial
components. Which one of the following processes could still be carried on by this isolated inner
membrane? A) the citric acid cycle B) oxidative phosphorylation C) glycolysis and fermentation
D) reduction of NAD+ E) both the citric acid cycle and oxidative phosphorylation
65) The primary function of the mitochondrion is the production of ATP. To carry out this
function, the 14 mitochondrion must have all of the following except A) the membrane-bound
electron transport chain carrier molecules. B) proton pumps embedded in the inner mitochondrial
membrane. C) enzymes for glycolysis. D) enzymes for the citric acid cycle. E) mitochondrial
ATP synthase.
66) Which process could be compared to how rushing steam turns a water wheel? A) the citric
acid cycle B) ATP synthase activity C) formation of NADH in glycolysis D) oxidative
phosphorylation E) the electron transport system
67) How many molecules of carbon dioxide (CO2) would be released from the complete aerobic
respiration of a molecule of sucrose (C12 H22 O11), a disaccharide? A) 2 B) 3 C) 6 D) 12 E) 38
68) Each time a molecule of glucose (C6H12O6) is completely oxidized via aerobic respiration,
how many oxygen molecules (O2) are required? A) 1 B) 2 C) 6 D) 12 E) 38
69) Which of the following produces the most ATP when glucose (C6H12 O6 ) is completely
oxidized to carbon dioxide (CO2) and water? A) glycolysis B) fermentation C) oxidation of
pyruvate to acetyl CoA D) citric acid cycle E) oxidative phosphorylation (chemiosmosis)
70) Approximately how many molecules of ATP are produced from the complete oxidation of
two molecules of glucose (C6 H12 O6 ) in cellular respiration? 15 A) 2 B) 4 C) 15 D) 38 E) 76
71) Assume a mitochondrion contains 58 NADH and 19 FADH2. If each of the 77 dinucleotides
were used, approximately how many ATP molecules could be generated as a result of oxidative
phosphorylation (chemiosmosis)? A) 36 B) 77 C) 173 D) 212 E) 1102
72) Approximately what percentage of the energy of glucose (C6H12 O6) is transferred to
storage in ATP as a result of the complete oxidation of glucose to CO2 and water in cellular
respiration? A) 2% B) 4% C) 10% D) 25% E) 40%
73) Recall that the complete oxidation of a mole of glucose releases 686 kcal of energy (G =
-686 kcal/mol). The phosphorylation of ADP to form ATP stores approximately 7.3 kcal per mole
of ATP. What is the approximate efficiency of cellular respiration for a "mutant" organism that
produces only 29 moles of ATP for every mole of glucose oxidized, rather than the usual 36-38
moles of ATP? A) 0.4% B) 25% C) 30% D) 40% E) 60%
74) When glucose (C6H12O6) is oxidized to CO2 and water in cellular respiration,
approximately 40% of the energy content of glucose is transferred to A) the citric acid cycle. B)
glycolysis. C) ATP (adenosine triphosphate). D) heat. E) oxygen (O2 ).
75) Which of the following normally occurs whether or not oxygen (O2) is present? A)
glycolysis B) fermentation C) oxidation of pyruvate to acetyl CoA D) citric acid cycle E)
oxidative phosphorylation (chemiosmosis)
76) Which of the following occurs in the cytosol of the cell? A) glycolysis and fermentation B)
fermentation and chemiosmosis C) oxidation of pyruvate to acetyl CoA D) citric acid cycle E)
oxidative phosphorylation
77) Fermentation takes place in the A) cytosol. B) mitochondrial outer membrane. C)
mitochondrial inner membrane. D) mitochondrial intermembrane space. E) mitochondrial matrix.
78) Which metabolic pathway is common to both cellular respiration and fermentation? A) the
oxidation of pyruvate to acetyl CoA B) the citric acid cycle C) oxidative phosphorylation D)
glycolysis E) chemiosmosis
79) The ATP made during fermentation is generated by which of the following? A) the electron
transport chain B) substrate-level phosphorylation C) chemiosmosis D) oxidative
phosphorylation E) aerobic respiration
80) Muscle cells in oxygen deprivation convert pyruvate to ________, and in this step gain
________. A) lactate; ATP B) alcohol; CO2 C) alcohol; ATP D) ATP; NADH2 E) lactate; NAD+
81) In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the
production of A) ATP, CO2and ethanol (ethyl alcohol). B) ATP, CO2, and lactate. C) ATP,
NADH, and pyruvate. D) ATP, pyruvate, and oxygen. E) ATP, pyruvate, and acetyl CoA.
82) In alcohol fermentation, NAD+ is regenerated from NADH during the A) reduction of
acetaldehyde to ethanol (ethyl alcohol). B) oxidation of pyruvate to acetyl CoA. C) reduction of
pyruvate to form lactate. D) oxidation of NAD+ in the citric acid cycle. E) phosphorylation of
ADP to form ATP.
83) The 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+. E) none of the above
84) Which of the following is not true concerning the cellular compartmentation of the steps of
respiration or fermentation? A) Acetyl CoA is produced only in the mitochondria. B) Lactate is
produced only in the cytosol. C) NADH is produced only in the mitochondria. D) FADH2 is
produced only in the mitochondria. E) ATP is produced in the cytosol and the mitochondria.
85) An organism is discovered that consumes a considerable amount of sugar, yet does not gain
much weight when denied air. Curiously, the consumption of sugar increases as air is removed
from the organism's environment, but the organism seems to thrive even in the absence of air.
When returned to normal air, the organism does fine. Which of the following best describes the
organism? A) It must use a molecule other than oxygen to accept electrons from the electron
transport chain. B) It is a normal eukaryotic organism. C) The organism obviously lacks the citric
acid cycle and electron transport chain. D) It is an anaerobic organism. E) It is a facultative
anaerobe.
86) Glycolysis is thought to be one of the most ancient of metabolic processes. Which statement
supports this idea? A) Glycolysis is the most widespread metabolic pathway. B) Glycolysis
neither uses nor needs O2. C) Glycolysis is found in all eukaryotic cells. D) The enzymes of
glycolysis are found in the cytosol rather than in a membrane-enclosed organelle. E) Ancient
prokaryotic cells, the most primitive of cells, made extensive use of glycolysis long before
oxygen was present in Earth's atmosphere.
87) 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 is found in the cytosol, does
not involve oxygen, and is present in most organisms. C) It is found in prokaryotic cells but not
in eukaryotic cells. D) It relies on chemiosmosis which is a metabolic mechanism present only in
the first cells-prokaryotic cells. E) It requires the presence of membrane-enclosed cell organelles
found only in eukaryotic cells.
88) Molecules that can potentially be converted to intermediates of glycolysis and/or the citric
acid cycle include A) amino acids and proteins. B) glycerol and fatty acids. C) glucose and
sucrose. D) starch and glycogen. E) all of the above
89) Which of the following organic molecules cannot be converted to an intermediate of
glycolysis? A) fatty acids B) amino acids C) glucose and sucrose D) glycerol E) starch and
glycogen
90) Which of the following is not a true statement? A) Glycerol can be converted to
glyceraldehyde-3-phosphate, an intermediate of glycolysis. B) Beta oxidation breaks fatty acids
down to two-carbon fragments that can enter the citric acid cycle as acetyl CoA. C) A gram of
glucose oxidized by cellular respiration produces more than twice as much ATP as a gram of fat
oxidized by cellular respiration. D) Proteins can be used as a fuel for cellular respiration, but
their constituent amino acids must first be converted to intermediates of glycolysis or the citric
acid cycle. E) Polysaccharides such as glycogen and starch are hydrolyzed to their constituent
monosaccharides before they are used as fuel molecules for respiration.
91) You have a friend who lost 7 kg (about 15 pounds) of fat on a "low carb" diet. How did the
fat leave her body? A) It was released as CO2 and H2O. B) Chemical energy was converted to
heat and then released. C) It was converted to ATP, which weighs much less than fat. D) It was
broken down to amino acids and eliminated from the body. E) It was converted to urine and
eliminated from the body.
92) Phosphofructokinase is an important control enzyme in the regulation of cellular respiration.
Which of the following statements concerning phosphofructokinase is not true? A) It is activated
by AMP (derived from ADP). B) It is inhibited by ATP. C) It is activated by citrate, an
intermediate of the citric acid cycle. D) It specifically catalyzes the conversion of fructose-6phosphate to fructose-1,6-bisphosphate, an early step of glycolysis. E) It is an allosteric enzyme.
93) Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose-6phosphate to fructose1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an
increase in the amount ATP in a cell would be expected to A) inhibit the enzyme and thus slow
the rates of glycolysis and the citric acid cycle. B) activate the enzyme and thus slow the rates of
glycolysis and the citric acid cycle. C) inhibit the enzyme and thus increase the rates of
glycolysis and the citric acid cycle. D) activate the enzyme and increase the rates of glycolysis
and the citric acid cycle. E) inhibit the enzyme and thus increase the rate of glycolysis and the
concentration of citrate.
94) How many ATP molecules are produced by glycolysis? A) 1 B) 2 C) 3 D) 4 E) 5
95) Glycolysis is an ________ reaction. A) exergonic B) endothermic C) unregulated D)
endergonic E) abnormal
96) Pyruvate is formed A) on the inner mitochondrial membrane. B) in the mitochondrial matrix.
C) on the outer mitochondrial membrane. D) in the nucleus. E) in the cytosol.
97) Most of the energy that enters electron transport enters as A) ATP. B) acetyl CoA. C) glucose.
D) CO2. E) FADH2 and NADH.
98) In fermentation, ________ is ________. A) NADH; reduced B) NAD+ ; oxidized C) NADH;
oxidized D) pyruvate; oxidized E) ethanol; oxidized
99) What is the reducing agent in the following reaction? Pyruvate + NADH + H+ Lactate +
NAD+ A) oxygen B) NADH C) NAD+ D) lactate E) pyruvate
100) The immediate energy source that drives ATP synthesis by ATP synthase during oxidative
phosphorylation is A) the oxidation of glucose and other organic compounds. B) the flow of
electrons down the electron transport chain. C) the affinity of oxygen for electrons. D) the H+
concentration gradient across the inner mitochondrial membrane. E) the transfer of phosphate to
ADP.
101) Which metabolic pathway is common to both fermentation and cellular respiration? A) the
citric acid cycle B) the electron transport chain C) glycolysis D) synthesis of acetyl CoA from
pyruvate E) reduction of pyruvate to lactate
102) In mitochondria, exergonic redox reactions A) are the source of energy driving prokaryotic
ATP synthesis. B) are directly coupled to substrate-level phosphorylation. C) provide the energy
to establish the proton gradient. D) reduce carbon atoms to carbon dioxide. E) are coupled via
phosphorylated intermediates to endergonic processes.
103) The final electron acceptor of the electron transport chain that functions in oxidative
phosphorylation is A) oxygen. B) water. C) NAD+. D) pyruvate. E) ADP.
104) When electrons flow along the electron transport chains of mitochondria, which of the
following changes occurs? A) The pH of the matrix increases. B) ATP synthase pumps protons
by active transport. C) The electrons gain free energy. D) The cytochromes phosphorylate ADP
to form ATP. E) NAD+ is oxidized.
105) In the presence of a metabolic poison that specifically and completely inhibits all function
of mitochondrial ATP synthase, which of the following would you expect? A) a decrease in the
pH difference across the inner mitochondrial membrane B) an increase in the pH difference
across the inner mitochondrial membrane C) increased synthesis of ATP D) increased oxygen
consumption E) an accumulation of NAD+
106) Cells do not catabolize carbon dioxide because A) its double bonds are too stable to be
broken. B) CO2 has fewer bonding electrons than other organic compounds. C) CO2 is already
completely reduced. D) CO2 is already completely oxidized. E) the molecule has too few atoms.
107) Which of the following is a true distinction between fermentation and cellular respiration?
A) Only respiration oxidizes glucose. B) NADH is oxidized by the electron transport chain in
respiration only. C) Fermentation, but not respiration, is an example of a catabolic pathway. D)
Substrate-level phosphorylation is unique to fermentation. E) NAD+ functions as an oxidizing
agent only in respiration.
108) Most CO2 from catabolism is released during A) glycolysis. B) the citric acid cycle. C)
lactate fermentation. D) electron transport. E) oxidative phosphorylation