Question 1

Which of the following components of the electron transport chain can only participate in one-electron transfers?

Accepted Answer

A)  NAD 
B)  FAD 
C)  coenzyme Q 
D)  cytochrome C 
A)  NAD 
B)  FAD 
C)  coenzyme Q 
D)  cytochrome C

Question 2

In the conformational coupling mechanism for oxidative phosphorylation, the effect of the proton gradient is

Accepted Answer

A)  to inhibit conformational changes in the ATP synthase 
B)  to create more sites for ATP synthesis 
C)  the release of tightly bound ATP from the synthase 
D)  all of these 
E)  none of these 
A)  to inhibit conformational changes in the ATP synthase 
B)  to create more sites for ATP synthesis 
C)  the release of tightly bound ATP from the synthase 
D)  all of these 
E)  none of these

Question 3

Which complex contains succinate dehydrogenase?

Accepted Answer

A)  Complex I 
B)  Complex II 
C)  Complex III 
D)  Complex IV 
E)  It is not known where succinate dehydrogenase is located. 
A)  Complex I 
B)  Complex II 
C)  Complex III 
D)  Complex IV 
E)  It is not known where succinate dehydrogenase is located.

Question 4

The factor that couples electron transport to phosphorylation of ADP is

Accepted Answer

A)  a protein oligomer 
B)  a protein monomer 
C)  gramicidin A 
D)  valinomycin 
A)  a protein oligomer 
B)  a protein monomer 
C)  gramicidin A 
D)  valinomycin

Question 5

Brown adipose tissue is partially responsible for generating heat in the young human body.

Accepted Answer

A) True 
 B)False

Question 6

Which of the following is an advantage of using multiple steps in electron transport?

Accepted Answer

A)  By using several steps the net −ΔG is higher (more energy is released). 
B)  More heat can be generated by using small steps. 
C)  More energy can be captured to synthesize ATP by using small steps. 
D)  Small steps allow for both more heat generation and more ATP synthesis. 
E)  All of these statements are advantages of using multiple steps. 
A)  By using several steps the net −ΔG is higher (more energy is released). 
B)  More heat can be generated by using small steps. 
C)  More energy can be captured to synthesize ATP by using small steps. 
D)  Small steps allow for both more heat generation and more ATP synthesis. 
E)  All of these statements are advantages of using multiple steps.

Question 7

Uncouplers are compounds that inhibit the phosphorylation of ADP

Accepted Answer

A)  by enhancing the proton gradient across the outer mitochondrial membrane. 
B)  by enhancing the proton gradient across the inner mitochondrial membrane. 
C)  because they are transmembrane proteins in the outer mitochondrial membrane. 
D)  without affecting electron transport. 
A)  by enhancing the proton gradient across the outer mitochondrial membrane. 
B)  by enhancing the proton gradient across the inner mitochondrial membrane. 
C)  because they are transmembrane proteins in the outer mitochondrial membrane. 
D)  without affecting electron transport.

Question 8

An alternative mode of entry into the electron transport chain is the oxidation of

Accepted Answer

A)  malate to oxalosuccinate. 
B)  succinate to fumarate. 
C)  isocitrate to α-ketoglutarate. 
D)  α-ketoglutarate to succinyl-CoA. 
A)  malate to oxalosuccinate. 
B)  succinate to fumarate. 
C)  isocitrate to α-ketoglutarate. 
D)  α-ketoglutarate to succinyl-CoA.

Question 9

Coenzyme Q can act as an intermediate electron carrier, since the ketone group of the quinone structure is readily reduced to an alcohol.

Accepted Answer

A) True 
 B)False

Question 10

Complex III of the electron transport chain oxidizes ____, reduces ____, and ____ protons in the process.

Accepted Answer

A)  coenzyme Q; cytochrome c; pumps 
B)  coenzyme Q; cytochrome c; doesn't pump 
C)  cytochrome c; coenzyme Q; pumps 
D)  cytochrome c; coenzyme Q; doesn't pump 
A)  coenzyme Q; cytochrome c; pumps 
B)  coenzyme Q; cytochrome c; doesn't pump 
C)  cytochrome c; coenzyme Q; pumps 
D)  cytochrome c; coenzyme Q; doesn't pump

Question 11

To calculate the ΔG of a redox reaction, you need:

Accepted Answer

A)  the reduction potential (E°) of the half reactions 
B)  the Faraday constant 
C)  the number of electrons involved in the transfer 
D)  none of these 
E)  all of these 
A)  the reduction potential (E°) of the half reactions 
B)  the Faraday constant 
C)  the number of electrons involved in the transfer 
D)  none of these 
E)  all of these

Question 12

Most athletes make better aerobic use of energy sources than non-athletes, since they actually have more mitochondria in their cells.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following terms describes ATP synthesis in mitochondria?

Accepted Answer

A)  substrate-level phosphorylation 
B)  oxidative phosphorylation 
C)  photophosphorylation 
D)  none of these 
A)  substrate-level phosphorylation 
B)  oxidative phosphorylation 
C)  photophosphorylation 
D)  none of these

Question 14

The only reaction which actually uses molecular oxygen is catalyzed by

Accepted Answer

A)  Cytochrome C oxidase. 
B)  NADH-CoQ reductase. 
C)  succinate-CoQ reductase. 
D)  Cytochrome A oxidase. 
E)  Cytochrome bc1 complex. 
A)  Cytochrome C oxidase. 
B)  NADH-CoQ reductase. 
C)  succinate-CoQ reductase. 
D)  Cytochrome A oxidase. 
E)  Cytochrome bc1 complex.

Question 15

Electron flow in the mitochondria follows this pathway:

Accepted Answer

A)  NADH → FMN → Coenzyme Q → Cyt A → Cyt B → Cyt C → O2 
B)  NADH → FMN → Cyt B → Coenzyme Q → Cyt C → Cyt A → O2 
C)  FMNH2 → NAD → Coenzyme Q → Cyt B → Cyt C → Cyt A → O2 
D)  NADH → FMN → Coenzyme Q → Cyt B → Cyt C → Cyt A → O2 
E)  NADH → FMN → Cyt B → Cyt C → Coenzyme Q → Cyt A → O2 
A)  NADH → FMN → Coenzyme Q → Cyt A → Cyt B → Cyt C → O2 
B)  NADH → FMN → Cyt B → Coenzyme Q → Cyt C → Cyt A → O2 
C)  FMNH2 → NAD → Coenzyme Q → Cyt B → Cyt C → Cyt A → O2 
D)  NADH → FMN → Coenzyme Q → Cyt B → Cyt C → Cyt A → O2 
E)  NADH → FMN → Cyt B → Cyt C → Coenzyme Q → Cyt A → O2

Question 16

Iron deficiency in a cell can adversely affect electron transport at which of the following sites?

Accepted Answer

A)  coenzyme Q and FADH2 
B)  NADH and FADH2 
C)  cytochrome b and cytochrome c 
D)  coenzyme Q and NADH 
A)  coenzyme Q and FADH2 
B)  NADH and FADH2 
C)  cytochrome b and cytochrome c 
D)  coenzyme Q and NADH

Question 17

Reduction potentials (E°) are measured by reading a voltmeter, which measures the electron flow between two reaction chambers.

Accepted Answer

A) True 
 B)False

Question 18

The pH of the mitochondrial matrix is ____ the pH of the intermembrane space.

Accepted Answer

A)  higher than 
B)  lower than 
C)  the same as 
A)  higher than 
B)  lower than 
C)  the same as

Question 19

The cytochrome that passes electrons directly to oxygen is

Accepted Answer

A)  the cytochrome a/a3 complex. 
B)  Cytochrome b. 
C)  cytochrome c. 
D)  cytochrome c1. 
A)  the cytochrome a/a3 complex. 
B)  Cytochrome b. 
C)  cytochrome c. 
D)  cytochrome c1.

Question 20

Another name for Complex I in the mitochondria is

Accepted Answer

A)  Cytochrome C oxidase. 
B)  NADH-CoQ oxidoreductase. 
C)  succinate-CoQ reductase. 
D)  Cytochrome A oxidase. 
E)  Cytochrome bc1 complex. 
A)  Cytochrome C oxidase. 
B)  NADH-CoQ oxidoreductase. 
C)  succinate-CoQ reductase. 
D)  Cytochrome A oxidase. 
E)  Cytochrome bc1 complex.

Exam 20: Electron Transport and Oxidative Phosphorylation

Which of the following components of the electron transport chain can only participate in one-electron transfers?

In the conformational coupling mechanism for oxidative phosphorylation, the effect of the proton gradient is

Which complex contains succinate dehydrogenase?

The factor that couples electron transport to phosphorylation of ADP is

Brown adipose tissue is partially responsible for generating heat in the young human body.

Which of the following is an advantage of using multiple steps in electron transport?

Uncouplers are compounds that inhibit the phosphorylation of ADP

An alternative mode of entry into the electron transport chain is the oxidation of

Coenzyme Q can act as an intermediate electron carrier, since the ketone group of the quinone structure is readily reduced to an alcohol.

Complex III of the electron transport chain oxidizes ____, reduces ____, and ____ protons in the process.

To calculate the ΔG of a redox reaction, you need:

Most athletes make better aerobic use of energy sources than non-athletes, since they actually have more mitochondria in their cells.

Which of the following terms describes ATP synthesis in mitochondria?

The only reaction which actually uses molecular oxygen is catalyzed by

Electron flow in the mitochondria follows this pathway:

Iron deficiency in a cell can adversely affect electron transport at which of the following sites?

Reduction potentials (E°) are measured by reading a voltmeter, which measures the electron flow between two reaction chambers.

The pH of the mitochondrial matrix is ____ the pH of the intermembrane space.

The cytochrome that passes electrons directly to oxygen is

Another name for Complex I in the mitochondria is

Biochemistry and the Organization of Cells

Water: the Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three-Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of RNA

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

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Complex III of the electron transport chain oxidizes , reduces , and protons in the process.