Question 1

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is

Accepted Answer

A)  oxygen. 
B)  water. 
C)  NAD⁺. 
D)  pyruvate. 
A)  oxygen. 
B)  water. 
C)  NAD⁺. 
D)  pyruvate.

Question 2

The enzyme phosphofructokinase (PFK) catalyses a key step in glycolysis. About 10% of Springer spaniels suffer from canine PFK deficiency. Given its critical role in glycolysis, which of the following conditions would be a likely consequence for dogs afflicted with this disorder?

Accepted Answer

A)  They would die as embryos. 
B)  They would have elevated blood-glucose levels, which may result in a high incidence of diabetes. 
C)  They would be lethargic and readily tire from exercise. 
D)  They would carry out elevated levels of oxidative phosphorylation. 
A)  They would die as embryos. 
B)  They would have elevated blood-glucose levels, which may result in a high incidence of diabetes. 
C)  They would be lethargic and readily tire from exercise. 
D)  They would carry out elevated levels of oxidative phosphorylation.

Question 3

Which of the following processes generates a proton-motive force in mitochondria?

Accepted Answer

A)  The flow of protons through ATP synthase down their concentration gradient. 
B)  The reduction of NAD⁺ by the first electron carrier in the electron transport chain. 
C)  Lowering of pH in the mitochondrial matrix. 
D)  Pumping of hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space. 
A)  The flow of protons through ATP synthase down their concentration gradient. 
B)  The reduction of NAD⁺ by the first electron carrier in the electron transport chain. 
C)  Lowering of pH in the mitochondrial matrix. 
D)  Pumping of hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space.

Question 4

Which of the following sequences describes the path by which electrons travel downhill energetically in aerobic respiration?

Accepted Answer

A)  glucose → NADH → electron transport chain → oxygen 
B)  glucose → pyruvate → ATP → oxygen 
C)  glucose → pyruvate → electron transport chain → NADH → ATP 
D)  food → glycolysis → citric acid cycle → NADH → ATP 
A)  glucose → NADH → electron transport chain → oxygen 
B)  glucose → pyruvate → ATP → oxygen 
C)  glucose → pyruvate → electron transport chain → NADH → ATP 
D)  food → glycolysis → citric acid cycle → NADH → ATP

Question 5

During aerobic respiration, which of the following molecules directly donates electrons to the electron transport chain at the lowest energy level?

Accepted Answer

A)  NADH 
B)  ATP 
C)  water 
D)  FADH₂ 
A)  NADH 
B)  ATP 
C)  water 
D)  FADH₂

Question 6

Which of the following metabolic processes normally occurs regardless of whether or not oxygen (O₂) is present?

Accepted Answer

A)  citric acid cycle 
B)  glycolysis 
C)  lactate fermentation 
D)  oxidative phosphorylation 
A)  citric acid cycle 
B)  glycolysis 
C)  lactate fermentation 
D)  oxidative phosphorylation

Question 7

In mitochondria, exergonic redox reactions

Accepted Answer

A)  are the source of energy driving prokaryotic ATP synthesis. 
B)  provide the energy that establishes the proton gradient. 
C)  reduce carbon atoms to carbon dioxide. 
D)  are coupled via phosphorylated intermediates to endergonic processes. 
A)  are the source of energy driving prokaryotic ATP synthesis. 
B)  provide the energy that establishes the proton gradient. 
C)  reduce carbon atoms to carbon dioxide. 
D)  are coupled via phosphorylated intermediates to endergonic processes.

Question 8

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?

Accepted Answer

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. 
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.

Question 9

In the presence of oxygen, the three-carbon compound pyruvate can be catabolised in the citric acid cycle. First, however, the pyruvate (1) loses a carbon, which is given off as a molecule of CO₂, (2) is oxidised to form a two-carbon compound called acetate, and (3) is bonded to coenzyme A. Which of the following sets of products result from these reactions?

Accepted Answer

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 
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

Question 10

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 which of the following processes?

Accepted Answer

A)  active transport 
B)  allosteric regulation 
C)  a reaction with a positive ΔG 
D)  coupling of an endergonic reaction to an exergonic reaction 
A)  active transport 
B)  allosteric regulation 
C)  a reaction with a positive ΔG 
D)  coupling of an endergonic reaction to an exergonic reaction

Question 11

In glycolysis, for each molecule of glucose oxidised to pyruvate, ________.

Accepted Answer

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 
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

Question 12

Which of the following events takes place in the electron transport chain?

Accepted Answer

A)  the breakdown of glucose into six carbon dioxide molecules 
B)  the breakdown of an acetyl group to carbon dioxide 
C)  the harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle 
D)  substrate-level phosphorylation 
A)  the breakdown of glucose into six carbon dioxide molecules 
B)  the breakdown of an acetyl group to carbon dioxide 
C)  the harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle 
D)  substrate-level phosphorylation

Question 13

Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C₆H₁₂O₆) in aerobic cellular respiration?

Accepted Answer

A)  2 
B)  4 
C)  18-24 
D)  30-32 
A)  2 
B)  4 
C)  18-24 
D)  30-32

Question 14

Starting with one molecule of glucose, glycolysis results in the net production of which of the following sets of energy-containing products?

Accepted Answer

A)  2 NAD⁺, 2 pyruvate, and 2 ATP 
B)  2 NADH, 2 pyruvate, and 2 ATP 
C)  4 NADH, 2 pyruvate, and 4 ATP 
D)  6 CO₂, 2 pyruvate, and 2 ATP 
A)  2 NAD⁺, 2 pyruvate, and 2 ATP 
B)  2 NADH, 2 pyruvate, and 2 ATP 
C)  4 NADH, 2 pyruvate, and 4 ATP 
D)  6 CO₂, 2 pyruvate, and 2 ATP

Question 15

When a molecule of NAD⁺ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes ________.

Accepted Answer

A)  dehydrogenated 
B)  oxidised 
C)  reduced 
D)  redoxed 
A)  dehydrogenated 
B)  oxidised 
C)  reduced 
D)  redoxed

Question 16

If a cell is able to synthesise 30 ATP molecules for each molecule of glucose completely oxidised to carbon dioxide and water, approximately how many ATP molecules can the cell synthesise for each molecule of pyruvate oxidised to carbon dioxide and water?

Accepted Answer

A)  8 
B)  12.5 
C)  16 
D)  25 
A)  8 
B)  12.5 
C)  16 
D)  25

Question 17

-The citric acid cycle.
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?

Accepted Answer

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. 
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.

Question 18

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 stored in the form of which of the following molecules?

Accepted Answer

A)  acetyl-CoA 
B)  NAD⁺ 
C)  pyruvate 
D)  NADH 
A)  acetyl-CoA 
B)  NAD⁺ 
C)  pyruvate 
D)  NADH

Question 19

Which of the following statements describes a primary function of both alcohol fermentation and lactic acid fermentation?

Accepted Answer

A)  reduction of NAD⁺ to NADH 
B)  reduction of FAD to FADH₂ 
C)  oxidation of NADH to NAD⁺ 
D)  hydrolysis of ATP to ADP +   i 
A)  reduction of NAD⁺ to NADH 
B)  reduction of FAD to FADH₂ 
C)  oxidation of NADH to NAD⁺ 
D)  hydrolysis of ATP to ADP +   i

Question 20

In chemiosmosis, what is the most direct source of energy that is used to convert ADP +   i to ATP?

Accepted Answer

A)  energy released as electrons flow through the electron transport chain 
B)  energy released from substrate-level phosphorylation 
C)  energy released from movement of protons through ATP synthase, down their electrochemical gradient 
D)  energy released as electrons are transported across the inner mitochondrial membrane 
A)  energy released as electrons flow through the electron transport chain 
B)  energy released from substrate-level phosphorylation 
C)  energy released from movement of protons through ATP synthase, down their electrochemical gradient 
D)  energy released as electrons are transported across the inner mitochondrial membrane

Exam 9: Cellular Respiration and Fermentation

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is

The enzyme phosphofructokinase (PFK) catalyses a key step in glycolysis. About 10% of Springer spaniels suffer from canine PFK deficiency. Given its critical role in glycolysis, which of the following conditions would be a likely consequence for dogs afflicted with this disorder?

Which of the following processes generates a proton-motive force in mitochondria?

Which of the following sequences describes the path by which electrons travel downhill energetically in aerobic respiration?

During aerobic respiration, which of the following molecules directly donates electrons to the electron transport chain at the lowest energy level?

Which of the following metabolic processes normally occurs regardless of whether or not oxygen (O₂) is present?

In mitochondria, exergonic redox reactions

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?

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 which of the following processes?

In glycolysis, for each molecule of glucose oxidised to pyruvate, ________.

Which of the following events takes place in the electron transport chain?

Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C₆H₁₂O₆) in aerobic cellular respiration?

Starting with one molecule of glucose, glycolysis results in the net production of which of the following sets of energy-containing products?

When a molecule of NAD⁺ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes ________.

If a cell is able to synthesise 30 ATP molecules for each molecule of glucose completely oxidised to carbon dioxide and water, approximately how many ATP molecules can the cell synthesise for each molecule of pyruvate oxidised to carbon dioxide and water?

-The citric acid cycle. 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?

Which of the following statements describes a primary function of both alcohol fermentation and lactic acid fermentation?

In chemiosmosis, what is the most direct source of energy that is used to convert ADP + i to ATP?

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