Question 1

Which of the following statements concerning E° for an electron-transfer reaction is false?

Accepted Answer

A)  It is measured by comparison with the partial pressure of oxygen in the bloodstream rather than 1 atmosphere pressure. 
B)  It is measured by comparison with a standard hydrogen electrode. 
C)  It is related to DG° by a well known equation. 
D)  It cannot be determined for electron-transfer reactions involving coenzyme Q. 
A)  It is measured by comparison with the partial pressure of oxygen in the bloodstream rather than 1 atmosphere pressure. 
B)  It is measured by comparison with a standard hydrogen electrode. 
C)  It is related to DG° by a well known equation. 
D)  It cannot be determined for electron-transfer reactions involving coenzyme Q.

Question 2

Most of the reactions of electron transport in the mitochondria occur

Accepted Answer

A)  on the outer membrane 
B)  on the inner membrane. 
C)  in the mitochondrial matrix. 
D)  in the intermembrane space. 
E)  in the cytosol. 
A)  on the outer membrane 
B)  on the inner membrane. 
C)  in the mitochondrial matrix. 
D)  in the intermembrane space. 
E)  in the cytosol.

Question 3

Which of the following is true?

Accepted Answer

A)  Uncoupling agents can work by disrupting the flow of protons during ATP synthesis. 
B)  Uncoupling agents prevent the flow of electrons during electron transport 
C)  Uncoupling agents always block the flow of protons through the ATPase 
D)  none of these is true 
A)  Uncoupling agents can work by disrupting the flow of protons during ATP synthesis. 
B)  Uncoupling agents prevent the flow of electrons during electron transport 
C)  Uncoupling agents always block the flow of protons through the ATPase 
D)  none of these is true

Question 4

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 5

Mitochondrial membranes can be fragmented into small vesicles which still synthesize ATP; intact mitochondria are not required.

Accepted Answer

A) True 
 B)False

Question 6

Which of the following is true concerning mitochondrial DNA?

Accepted Answer

A)  mitochondria have their own DNA 
B)  DNA in mitochondria must be transcribed and translated outside of the mitochondria since mitochondria have no protein synthesis capability 
C)  Alzheimers disease is the only known disease related to mt DNA 
D)  all of these are true 
A)  mitochondria have their own DNA 
B)  DNA in mitochondria must be transcribed and translated outside of the mitochondria since mitochondria have no protein synthesis capability 
C)  Alzheimers disease is the only known disease related to mt DNA 
D)  all of these are true

Question 7

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

Accepted Answer

A)  FADH2; coenzyme Q; doesn't pump 
B)  FADH2; coenzyme Q; pumps 
C)  NADH; coenzyme Q; doesn't pump 
D)  NADH; coenzyme Q; pumps 
A)  FADH2; coenzyme Q; doesn't pump 
B)  FADH2; coenzyme Q; pumps 
C)  NADH; coenzyme Q; doesn't pump 
D)  NADH; coenzyme Q; pumps

Question 8

To calculate the DG 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 9

How do uncoupling agents affect the electron transport chain and oxidative phosphorylation?

Accepted Answer

A)  They block the flow of electrons, so protons aren't pumped, and ATP synthesis ceases. 
B)  They remove electrons from the chain, so less protons are pumped, and ATP synthesis decreases. 
C)  They block the flow of protons through the ATP synthase, so ATP synthesis ceases. Electron flow and proton pumping are also halted as a result. 
D)  They provide an alternative path for protons to re-enter the mitochondrial matrix, so ATP synthesis decreases. Electron flow and proton pumping are not affected. 
A)  They block the flow of electrons, so protons aren't pumped, and ATP synthesis ceases. 
B)  They remove electrons from the chain, so less protons are pumped, and ATP synthesis decreases. 
C)  They block the flow of protons through the ATP synthase, so ATP synthesis ceases. Electron flow and proton pumping are also halted as a result. 
D)  They provide an alternative path for protons to re-enter the mitochondrial matrix, so ATP synthesis decreases. Electron flow and proton pumping are not affected.

Question 10

The only reaction which actually uses molecular oxygen is

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 11

In mitochondria compound A is oxidized to compound B. The oxidation is not inhibited by rotenone but is inhibited by antimycin A and cyanide. What is the P/O ratio for this oxidation?

Accepted Answer

A)  zero 
B)  1.5 
C)  2.5 
D)  impossible to determine from the information given 
A)  zero 
B)  1.5 
C)  2.5 
D)  impossible to determine from the information given

Question 12

A characteristic of the glycerol phosphate shuttle is

Accepted Answer

A)  it shuttles NADH across the mitochondrial membrane to yield 5 ATP/NADH 
B)  it shuttles the electrons from NADH across the mitochondrial membrane to FADH2, yielding 5 ATP/NADH 
C)  it only operates efficiently at high levels of NADH 
D)  malate is a key component in the shuttle process 
A)  it shuttles NADH across the mitochondrial membrane to yield 5 ATP/NADH 
B)  it shuttles the electrons from NADH across the mitochondrial membrane to FADH2, yielding 5 ATP/NADH 
C)  it only operates efficiently at high levels of NADH 
D)  malate is a key component in the shuttle process

Question 13

The only complex which actually uses molecular oxygen is

Accepted Answer

A)  Complex I. 
B)  Complex II. 
C)  Complex III. 
D)  Complex IV. 
E)  It is not known where oxygen is used. 
A)  Complex I. 
B)  Complex II. 
C)  Complex III. 
D)  Complex IV. 
E)  It is not known where oxygen is used.

Question 14

Uncoupling in mitochondria refers to:

Accepted Answer

A)  Interruption of electron flow. 
B)  Stopping electron flow but not stopping ATP synthesis. 
C)  Stopping ATP synthesis but not stopping electron flow. 
D)  Blocking the electrons from NADH from entering the electron transport system. 
E)  All of these describe uncoupling. 
A)  Interruption of electron flow. 
B)  Stopping electron flow but not stopping ATP synthesis. 
C)  Stopping ATP synthesis but not stopping electron flow. 
D)  Blocking the electrons from NADH from entering the electron transport system. 
E)  All of these describe uncoupling.

Question 15

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 16

Evidence for chemiosmotic coupling as the mechanism for oxidative phosphorylation is based on the observation that

Accepted Answer

A)  mitochondrial membrane fragments without compartmentalization can carry out oxidative phosphorylation 
B)  submitochondrial preparations that contain closed vesicles can carry out oxidative phosphorylation 
C)  many different kinds of substances can serve as uncouplers 
D)  it has proved impossible to duplicate the process in model systems 
A)  mitochondrial membrane fragments without compartmentalization can carry out oxidative phosphorylation 
B)  submitochondrial preparations that contain closed vesicles can carry out oxidative phosphorylation 
C)  many different kinds of substances can serve as uncouplers 
D)  it has proved impossible to duplicate the process in model systems

Question 17

Depending on how NADH is shuttled from the cytoplasm into the mitochondria,different molar amounts of ATP will be synthesized as each NADH is oxidized.

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

Which of the following is not true?

Accepted Answer

A)  The synthesis of ATP in mitochondria is driven by a proton or pH gradient. 
B)  The synthesis of ATP is directly linked to the oxidation of NADH 
C)  The reoxidation of NADH and FADH2 indirectly creates a proton gradient that is involved in ATP synthesis 
D)  All of these are true 
A)  The synthesis of ATP in mitochondria is driven by a proton or pH gradient. 
B)  The synthesis of ATP is directly linked to the oxidation of NADH 
C)  The reoxidation of NADH and FADH2 indirectly creates a proton gradient that is involved in ATP synthesis 
D)  All of these are true

Question 20

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

Exam 20: Electron Transport and Oxidative Phosphorylation

Which of the following statements concerning E° for an electron-transfer reaction is false?

Most of the reactions of electron transport in the mitochondria occur

Which of the following is true?

Which complex contains succinate dehydrogenase?

Mitochondrial membranes can be fragmented into small vesicles which still synthesize ATP; intact mitochondria are not required.

Which of the following is true concerning mitochondrial DNA?

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

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

How do uncoupling agents affect the electron transport chain and oxidative phosphorylation?

The only reaction which actually uses molecular oxygen is

In mitochondria compound A is oxidized to compound B. The oxidation is not inhibited by rotenone but is inhibited by antimycin A and cyanide. What is the P/O ratio for this oxidation?

A characteristic of the glycerol phosphate shuttle is

The only complex which actually uses molecular oxygen is

Uncoupling in mitochondria refers to:

Uncouplers are compounds that inhibit the phosphorylation of ADP

Evidence for chemiosmotic coupling as the mechanism for oxidative phosphorylation is based on the observation that

Depending on how NADH is shuttled from the cytoplasm into the mitochondria,different molar amounts of ATP will be synthesized as each NADH is oxidized.

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

Which of the following is not true?

The factor that couples electron transport to phosphorylation of ADP 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 II of the electron transport chain oxidizes ,reduces ,and protons in the process.