Campbell Biology in Focus, 2e (Urry)
Chapter 7 Cellular Respiration and Fermentation
7.1 Multiple-Choice Questions
1) Metabolic pathways that release stored energy by breaking down complex molecules are
known as
A) catabolic pathways.
B) anabolic pathways.
C) bioenergetic pathways.
D) endergonic pathways.
2) In an oxidation-reduction reaction, the reducing agent
A) gains electrons and gains potential energy.
B) gains electrons and loses potential energy.
C) loses electrons and loses potential energy.
D) loses electrons and gains potential energy.
3) As a result of an oxidation-reduction reaction the oxidizing agent
A) gains electrons and gains potential energy.
B) gains electrons and loses potential energy.
C) loses electrons and loses potential energy.
D) loses electrons and gains potential energy.
4) As a result of the transfer of an electron from a less electronegative atom to a more
electronegative atom,
A) the more electronegative atom is reduced, and energy is released.
B) the more electronegative atom is reduced, and energy is consumed.
C) the more electronegative atom is oxidized, and energy is consumed.
D) the more electronegative atom is oxidized, and energy is released.
5) 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 and molecular oxygen have more kinetic energy
than the covalent bonds 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 releases less energy than the energy stored in the
covalent bonds of CO2 and water.
D) The electrons have higher potential energy when associated with water and CO2 than they do
in the organic compounds.
E) The covalent bond in O2 is unstable and easily broken by electrons from organic molecules.
6) The complete reactions of cellular respiration in the presence of oxygen (C6H12O6 + 6 O2 →
6 CO2 + 6 H2O + energy) result in which of the following?
A) oxidation of O2 and reduction of H2O
B) oxidation of C6H12O6 and reduction of O2
C) reduction of CO2 and oxidation of O2
D) reduction of C6H12O6 and oxidation of CO2
7) When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction
reaction, the glucose molecule becomes
A) hydrolyzed.
B) hydrogenated.
C) oxidized.
D) reduced.
E) an oxidizing agent.
8) Which of the following statements about NAD+ is true?
A) NAD+ is the source of electrons used in oxidative phosphorylation.
B) NAD+ has more chemical energy than NADH.
C) NAD+ is oxidized by the action of dehydrogenase enzymes.
D) NAD+ is reduced to NADH during glycolysis.
9) In animal cells, glycolysis occurs in the
A) cytosol.
B) outer mitochondrial membrane.
C) inner mitochondrial membrane.
D) mitochondrial matrix.
E) nucleus.
10) The ATP produced in glycolysis is generated by
A) chemiosmosis.
B) electron transport.
C) photophosphorylation.
D) oxidative phosphorylation.
E) substrate-level phosphorylation.
11) The ATP produced in the citric acid cycle is generated by
A) chemiosmosis.
B) electron transport.
C) photophosphorylation.
D) oxidative phosphorylation.
E) substrate-level phosphorylation.
12) When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not
a proton), the NAD+ molecule becomes
A) dehydrogenated.
B) oxidized.
C) reduced.
D) redoxed.
E) hydrolyzed.
13) 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
14) When an electron is transferred to a more electronegative atom
A) it loses potential energy.
B) it gains potential energy.
C) it gains kinetic energy.
D) it oxidizes the more electronegative atom.
15) Why are carbohydrates and fats considered high-energy foods?
A) They have a lot of oxygen atoms.
B) They have few nitrogen atoms.
C) They have a large number of electrons associated with hydrogen.
D) They have a lot of carbon atoms bound together by single covalent bonds.
E) They are easily reduced.
16) Which of the following indicates a primary path by which electrons travel downhill
energetically during aerobic respiration?
A) glucose → citric acid cycle → ATP → NAD+
B) glucose → NADH → electron transport chain → oxygen
C) glucose → pyruvate → acetyl CoA → ATP → oxygen
D) glucose → glycolysis → electron transport chain → NADH → ATP
E) glucose → glycolysis → citric acid cycle → NADH → ATP
17) The complete oxidation of glucose in aerobic respiration occurs through which of the
following sequence of metabolic reactions?
A) glucose → citric acid cycle → glycolysis → pyruvate oxidation → electron transport chain
B) glucose → pyruvate oxidation → glycolysis → electron transport chain → citric acid cycle
C) glucose → glycolysis → pyruvate oxidation → citric acid cycle → electron transport chain
D) glucose → glycolysis → citric acid cycle → pyruvate oxidation → electron transport chain
E) glucose → pyruvate oxidation → citric acid cycle → glycolysis → electron transport chain
18) The complete oxidation of glucose (C6H12O6) to carbon dioxide and water in aerobic
respiration consumes how many molecules of oxygen (O2)?
A) 1
B) 3
C) 6
D) 12
E) 36
19) In bacteria, ATP synthase is located
A) in the mitochondrial inner membrane.
B) in the mitochondrial outer membrane.
C) in the cytoplasm.
D) in the plasma membrane.
E) in the bacterial outer membrane.
20) 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
21) Substrate-level phosphorylation accounts for approximately what percentage of the ATP
formed by the reactions of glycolysis?
A) 0%
B) 2%
C) 10%
D) 38%
E) 100%
22) Substrate-level phosphorylation accounts for approximately what percentage of the ATP
formed by the electron transport chain?
A) 0%
B) 2%
C) 10%
D) 38%
E) 100%
23) During glycolysis, when each molecule of glucose is catabolized to two molecules of
pyruvate, most of the potential energy contained in glucose is
A) transferred to ADP, forming ATP.
B) released as heat.
C) retained in the two pyruvates.
D) stored in the NADH produced.
24) In addition to ATP, what are the end products of glycolysis?
A) CO2 and H2O
B) CO2 and pyruvate
C) NADH and pyruvate
D) CO2 and NADH
E) H2O, FADH2, and citrate
25) 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) Glycolysis consists of many enzyme-catalyzed reactions, each of which extracts a small
amount of energy from the glucose molecule.
26) 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.
E) 6 CO2, 2 pyruvate, and 30 ATP.
27) Glycolysis results in a net production of which of the following from each molecule of
glucose?
A) 2 NAD+, 2 pyruvate, and 2 ATP
B) 4 NADH, 2 pyruvate, and 4 ATP
C) 2 NADH, 2 pyruvate, and 2 ATP
D) 6 CO2, 2 NADH, 2 pyruvate, and 2 ATP
E) 6 CO2, 2 pyruvate, and 30 ATP
28) 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.
29) For each molecule of glucose consumed in glycolysis, there is a net consumption of which of
the following?
A) 2 NAD+, 2 pyruvate, and 2 ATP
B) 4 NAD+, 2 pyruvate, and 4 ADP
C) 2 NAD+ and 4 ADP
D) 2 NAD+ and 2 ADP
E) 2 NADH and 2 ADP
30) Why is glycolysis described as having an energy investment phase and an energy payoff
phase?
A) Early steps consume energy from ATP and NADH, and later steps store an equal amount of
energy in ATP and NAD+.
B) Early steps consume energy from ATP and NADH, and later steps store an increased amount
of energy in ATP and NADH.
C) Early steps consume energy from ATP and NADH and later steps store an increased amount
of energy in ATP.
D) Early steps consume energy from ATP, and later steps store an increased amount of energy in
ATP and NADH.
E) Early steps consume energy from NADH, and later steps store an increased amount of energy
in ATP and NADH.
31) A molecule that is phosphorylated
A) has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate.
B) has a decreased chemical energy and 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 increased chemical potential energy that may be used to do cellular work.
32) 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
33) 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
34) 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) glycolysis and the citric acid cycle
35) What fraction of the carbon dioxide exhaled by animals is generated by the reactions of the
citric acid cycle, if glucose is the sole energy source?
A) 1/6
B) 1/3
C) 1/2
D) 2/3
E) all of it
36) What fraction of the carbon dioxide exhaled by animals is generated by the oxidation of
pyruvate to acetyl CoA, if glucose is the sole energy source?
A) 1/6
B) 1/3
C) 1/2
D) 2/3
E) all of it
37) Where are the proteins of the electron transport chain located?
A) cytosol
B) outer mitochondrial membrane
C) inner mitochondrial membrane
D) mitochondrial intermembrane space
E) mitochondrial matrix
38) In the complete reactions of aerobic respiration, the energy for the majority of ATP synthesis
is provided by
A) transfer of electrons from organic molecules to acetyl CoA.
B) high-energy phosphate bonds from organic molecule intermediates in the citric acid cycle.
C) splitting water to produce oxygen.
D) a proton gradient across a membrane.
E) the production of carbon dioxide and oxygen in the electron transport chain.
39) 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) FAD
E) FADH2
40) During aerobic respiration, which of the following directly donates electrons to the electron
transport chain at the highest energy level?
A) NAD+
B) NADH
C) ATP
D) FAD
E) FADH2
41) The primary role of oxygen in cellular respiration is to
A) donate high energy electrons to the electron transport chain.
B) serve as an acceptor for released carbon, forming CO2.
C) serve as an acceptor for electrons and hydrogen, forming water.
D) combine with acetyl CoA, forming pyruvate.
42) Inside an active mitochondrion, most electrons follow which pathway?
A) NADH → oxidative phosphorylation → ATP → oxygen
B) citric acid cycle → FADH2 → electron transport chain → ATP
C) electron transport chain → citric acid cycle → ATP → oxygen
D) citric acid cycle → ATP → NADH → oxygen
E) citric acid cycle → NADH → electron transport chain → oxygen
43) What is the source of the oxygen used to form water in the complete reactions of cellular
respiration?
A) carbon dioxide (CO2)
B) glucose (C6H12O6)
C) pyruvate (C3H3O3–)
D) molecular oxygen (O2)
44) 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 dehydration synthesis reactions
D) energy released from movement of protons down their electrochemical gradient through ATP
synthase
45) The energy used to pump hydrogen ions from the mitochondrial matrix across the inner
membrane and into the intermembrane space is derived from
A) ATP hydrolysis.
B) redox reactions in the electron transport chain.
C) decreasing the pH in the mitochondrial matrix.
D) splitting water to form oxygen and protons.
14
46) Where in mitochondria is the enzyme ATP synthase localized?
A) mitochondrial matrix
B) electron transport chain
C) inner membrane
D) outer membrane
47) Approximately how many molecules of ATP are produced by substrate-level
phosphorylation during the complete oxidation of a molecule of glucose (C6H12O6) in aerobic
cellular respiration?
A) 2
B) 4
C) 8
D) 30-32
48) Energy released by the electron transport chain is used to pump H+ into which location in
eukaryotic cells?
A) cytosol
B) outer mitochondrial membrane
C) inner mitochondrial membrane
D) mitochondrial intermembrane space
E) mitochondrial matrix
49) The direct energy source that drives ATP synthesis during respiratory oxidative
phosphorylation in eukaryotic cells 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 proton-motive force across the inner mitochondrial membrane.
E) the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid
cycle intermediate molecules of ADP.
50) When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane
and into the intermembrane space, the result is
A) the formation of ATP.
B) the reduction of NAD+.
C) a decrease in the pH of the mitochondrial matrix.
D) the creation of a proton-motive force.
51) Which of the following produces the most ATP when glucose (C6H12O6) 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)
52) Approximately how many molecules of ATP are produced from the complete oxidation of
two molecules of glucose (C6H12O6) in aerobic cellular respiration?
A) 2
B) 4
C) 15
D) 30-32
E) 60-64
53) 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 redox reaction.
D) allosteric regulation.
54) 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 completely oxidized to carbon dioxide and water?
A) 2
B) 6
C) 14
D) 28
E) 60
55) What is the proton-motive force?
A) the force required to remove an electron from hydrogen
B) the force provided by a transmembrane hydrogen ion gradient
C) the force that moves hydrogen into the intermembrane space
D) the force that moves hydrogen into the mitochondrion
E) the force that moves hydrogen to NAD+
56) 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 increases the surface area for glycolysis.
B) It increases the surface area for the citric acid cycle.
C) It increases the surface area for oxidative phosphorylation.
D) It increases the surface area for substrate-level phosphorylation.
57) Brown fat cells produce a protein called thermogenin in their mitochondrial inner membrane.
Thermogenin is a channel for facilitated transport of protons across the membrane. What will
occur in the brown fat cells when they produce thermogenin?
A) ATP synthesis and heat generation will both increase.
B) ATP synthesis will increase, and heat generation will decrease.
C) ATP synthesis will decrease, and heat generation will increase.
D) ATP synthesis and heat generation will both decrease.