Question 1

Which of the following best describes the function of cytochrome c oxidase?

Accepted Answer

A) Cytochrome c oxidase oxidizes four consecutive cytochrome c molecules,via one-electron transfers,while simultaneously reducing one O2 to two H2O. 
B) Cytochrome c oxidase oxidizes two consecutive cytochrome c molecules,via two-electron transfers,while simultaneously reducing one O2 to two H2O. 
C) Cytochrome c oxidase oxidizes four consecutive cytochrome c molecules,via one-electron transfers,while simultaneously reducing two O2 to two H2O. 
D) Cytochrome c oxidase oxidizes two consecutive cytochrome c molecules,via two- electron transfers,while simultaneously reducing two O2 to two H2O. 
A) Cytochrome c oxidase oxidizes four consecutive cytochrome c molecules,via one-electron transfers,while simultaneously reducing one O2 to two H2O. 
B) Cytochrome c oxidase oxidizes two consecutive cytochrome c molecules,via two-electron transfers,while simultaneously reducing one O2 to two H2O. 
C) Cytochrome c oxidase oxidizes four consecutive cytochrome c molecules,via one-electron transfers,while simultaneously reducing two O2 to two H2O. 
D) Cytochrome c oxidase oxidizes two consecutive cytochrome c molecules,via two- electron transfers,while simultaneously reducing two O2 to two H2O. A

Question 2

Which of the following correctly ranks redox centers found in Complex I from lower to higher potential? A correct answer will contain redox centers which are found in only Complex I and will also rank those redox centers in order of lower to higher reduction potential.

Accepted Answer

A) FMN,Heme b560,[2Fe-2S],CoQ 
B) ubiquinone,[4Fe-4S],[2Fe-2S],FMN 
C) FMN,[2Fe-2S],[4Fe-4S] 
D) Heme b560,[2Fe-2S],[4Fe-4S],FAD 
E) FAD,[2Fe-2S],[4Fe-4S],Heme b560 
A) FMN,Heme b560,[2Fe-2S],CoQ 
B) ubiquinone,[4Fe-4S],[2Fe-2S],FMN 
C) FMN,[2Fe-2S],[4Fe-4S] 
D) Heme b560,[2Fe-2S],[4Fe-4S],FAD 
E) FAD,[2Fe-2S],[4Fe-4S],Heme b560 C

Question 3

Matching
Choose the correct answer from the list.Not all the answers will be used.

-Electrons from cytosolic NADH are transferred to the matrix via electron ______ systems.

Accepted Answer

A)  shuttle 
B)  matrix 
C)  respiration 
D)  copper 
E)  heme
F) tunnel
G) plasma membrane
H) coenzyme Q
I) cytosol
J) antioxidant
K) wire
L) proton pump 
A)  shuttle 
B)  matrix 
C)  respiration 
D)  copper 
E)  heme
F) tunnel
G) plasma membrane
H) coenzyme Q
I) cytosol
J) antioxidant
K) wire
L) proton pump A

Question 4

Based on the estimation presented in the chapter,how many ATP per glucose are synthesized by the aerobic metabolism in eukaryotes?

Accepted Answer

A) 2 
B) 4 
C) 32 
D) 38 
E) 60 
A) 2 
B) 4 
C) 32 
D) 38 
E) 60

Question 5

In the electron transport chain,electrons are passed from redox center to redox center ____.

Accepted Answer

A) spontaneously due to the redox potential gradient. 
B) in an ATP dependent fashion. 
C) as a result of the addition of free energy. 
D) as a result of the proton gradient. 
E) with the assistance of a carrier protein. 
A) spontaneously due to the redox potential gradient. 
B) in an ATP dependent fashion. 
C) as a result of the addition of free energy. 
D) as a result of the proton gradient. 
E) with the assistance of a carrier protein.

Question 6

Which statement concerning Complex II of the electron transport chain is FALSE?
(I)This complex oxidizes FADH2 and reduces coenzyme Q.
(II)This complex includes the covalently bound enzyme succinate dehydrogenase.
(III)This complex pumps protons from the matrix to the intermembrane space.
IV)This complex also oxidizes succinate to fumarate in the citric acid cycle.

Accepted Answer

A) I,II 
B) II only 
C) II,III 
D) III only 
E) IV only 
A) I,II 
B) II only 
C) II,III 
D) III only 
E) IV only

Question 7

Electrons from FADH2 are delivered to ____ and electrons from NADH are delivered to ____ of the electron transport chain.

Accepted Answer

A) Complex I;Complex II 
B) Complex I;Complex III 
C) Complex II;Complex III 
D) Complex II;Complex I 
E) Complex I;Complex IV 
A) Complex I;Complex II 
B) Complex I;Complex III 
C) Complex II;Complex III 
D) Complex II;Complex I 
E) Complex I;Complex IV

Question 8

Matching
Choose the correct answer from the list.Not all the answers will be used.

-Complexes I and II each transfer electrons to ______.

Accepted Answer

A)  shuttle 
B)  matrix 
C)  respiration 
D)  copper 
E)  heme
F) tunnel
G) plasma membrane
H) coenzyme Q
I) cytosol
J) antioxidant
K) wire
L) proton pump 
A)  shuttle 
B)  matrix 
C)  respiration 
D)  copper 
E)  heme
F) tunnel
G) plasma membrane
H) coenzyme Q
I) cytosol
J) antioxidant
K) wire
L) proton pump

Question 9

Which of the prosthetic groups listed can accept or donate either one or two electrons due to the stability of the semiquinone state?

Accepted Answer

A) cytochrome c 
B) NADH 
C) CoQ 
D) [2Fe-2S] 
E) Rieske center 
A) cytochrome c 
B) NADH 
C) CoQ 
D) [2Fe-2S] 
E) Rieske center

Question 10

In theory how many protons could be pumped under standard state conditions by Complex III per mol of CoQ oxidized,considering the following information? (NOTE: mt = mitochondria)
Coenzyme Q + 2H+ + 2 e- → coenzyme QH2 $\varepsilon$o ' ≈ 0.040 V
Cytochrome c (Fe3+)+ e- → cytochrome c (Fe2+)$\varepsilon$o' ≈ 0.270 V
H+ (outside mt)→ H+ (inside mt)∆G ≈ -20kJ/mol
Faraday constant (F)≈ 100 kJ/Vmol ∆Gº' = -nF∆E0'

Accepted Answer

A) four or less protons 
B) greater than four protons but less than or equal to six protons 
C) greater than six protons but less than or equal to eight protons 
D) greater than 8 protons 
E) Cannot be determined from the information provided. 
A) four or less protons 
B) greater than four protons but less than or equal to six protons 
C) greater than six protons but less than or equal to eight protons 
D) greater than 8 protons 
E) Cannot be determined from the information provided.

Question 11

Which of the following are TRUE statements regarding the structure of ATP synthase?

Accepted Answer

A) It has a membrane-embedded component called F0 and a component found in the matrix referred to as F1. 
B) The $\gamma$ subunit acts as the proton "wire" allowing equilibration of the ion gradient. 
C) Research indicates that the F1 portion of the protein rotates in a circular counterclockwise direction. 
D) A and B 
E) A,B,and C 
A) It has a membrane-embedded component called F0 and a component found in the matrix referred to as F1. 
B) The $\gamma$ subunit acts as the proton "wire" allowing equilibration of the ion gradient. 
C) Research indicates that the F1 portion of the protein rotates in a circular counterclockwise direction. 
D) A and B 
E) A,B,and C

Question 12

In the electron transport chain,FMN can adopt ____ oxidation state(s)and is capable of accepting or donating ____ electron(s).

Accepted Answer

A) 2;2 
B) 2;1 or 2 
C) 3;2 
D) 3;1 or 2 
E) 3;1 
A) 2;2 
B) 2;1 or 2 
C) 3;2 
D) 3;1 or 2 
E) 3;1

Question 13

One method used by newborn mammals to generate heat is referred to as nonshivering thermogenesis.This method utilizes a protein channel called ________ which is present in high levels inside the mitochondria of _____tissue.

Accepted Answer

A) thermogenin;muscle 
B) UCP-1;muscle 
C) thermogenin;brown adipose 
D) UCP-1;white adipose 
E) UCP-2;brown adipose 
A) thermogenin;muscle 
B) UCP-1;muscle 
C) thermogenin;brown adipose 
D) UCP-1;white adipose 
E) UCP-2;brown adipose

Question 14

Matching
Choose the correct answer from the list.Not all the answers will be used.

-The stoichiometric relationship of ATP synthesis to ______ is referred to as the P/O ratio.

Accepted Answer

A)  shuttle 
B)  matrix 
C)  respiration 
D)  copper 
E)  heme
F) tunnel
G) plasma membrane
H) coenzyme Q
I) cytosol
J) antioxidant
K) wire
L) proton pump 
A)  shuttle 
B)  matrix 
C)  respiration 
D)  copper 
E)  heme
F) tunnel
G) plasma membrane
H) coenzyme Q
I) cytosol
J) antioxidant
K) wire
L) proton pump

Question 15

The structure of ATP synthase changes in conformation as a result of

Accepted Answer

A) the rotation of the α and β subunits. 
B) the rotation of the β subunit. 
C) the rotation of ATP. 
D) the rotation of the $\gamma$ subunit. 
E) all of the above. 
A) the rotation of the α and β subunits. 
B) the rotation of the β subunit. 
C) the rotation of ATP. 
D) the rotation of the $\gamma$ subunit. 
E) all of the above.

Question 16

ATP forms (is produced)
(I)upon transition from the loose to the tight form of the α and β subunit complex of ATP synthase.
(II)as a result of the flux of electrons through the channel formed by Fo
(III)as a result of the positive ions pumped into the matrix of the mitochondrion.

Accepted Answer

A) I,II,III 
B) II,III 
C) I,III 
D) I only 
E) II only 
A) I,II,III 
B) II,III 
C) I,III 
D) I only 
E) II only

Question 17

Which of the following statements is(are)TRUE about oxidative phosphorylation?
(I)Electron transport provides energy to pump protons into the intermembrane space.
(II)An electrochemical gradient is formed across the inner mitochondrial membrane.
(III)Potassium and sodium ions form an ionic gradient across the inner mitochondrial membrane.
(IV)Complexes I,II,III,IV actively transport protons into the intermembrane space during electron transport.

Accepted Answer

A) I,II,III,IV 
B) I,II,IV 
C) II,III,IV 
D) I,IV 
E) II,IV 
A) I,II,III,IV 
B) I,II,IV 
C) II,III,IV 
D) I,IV 
E) II,IV

Question 18

In a newly discovered electron transport complex a researcher has identified the redox center Fe-S,cytochrome c,and coenzyme Q.The researcher also knows that this complex ultimately passes its electrons to oxygen.What is most likely the redox center which completes this task?

Accepted Answer

A) Fe-S 
B) 2Fe-2S 
C) coenzyme Q 
D) cytochrome c 
E) None of the above 
A) Fe-S 
B) 2Fe-2S 
C) coenzyme Q 
D) cytochrome c 
E) None of the above

Question 19

The effects of a poison on actively respiring mitochondria are being studied to determine its mode of action.When the poison is added,every component of the electron transport chain is found to be in its reduced form based on spectroscopic analysis,and ATP production ceases entirely.It is reasoned that the poison is either blocking the final transfer of electrons to oxygen or is blocking the ATP synthase.Which of the following experiments will help unravel this dilemma?

Accepted Answer

A) Add a second blocking agent to interfere with either Complex I or Complex II along with the poison. 
B) Add an artificial electron donor along with the poison. 
C) Add an uncoupling agent along with the poison. 
D) Any of the above would allow differentiation between these two possibilities. 
E) None of the above will help distinguish between these two possibilities. 
A) Add a second blocking agent to interfere with either Complex I or Complex II along with the poison. 
B) Add an artificial electron donor along with the poison. 
C) Add an uncoupling agent along with the poison. 
D) Any of the above would allow differentiation between these two possibilities. 
E) None of the above will help distinguish between these two possibilities.

Question 20

Which statement(s)concerning the mitochondrial F0F1 ATP synthase is FALSE?
(I)The F1 subunit includes rotating sets of $\alpha$$\beta$ dimers.
(II)The F0 subunit includes a ring of between 9 and 12 proton-carrying polypeptides.
(III)The F1 subunit undergoes a series of conformational changes throughout the course of reaction.

Accepted Answer

A) I,II,III 
B) II,III 
C) I only 
D) III only 
E) None of the options (I - III)is false.Options I-IV are all true. 
A) I,II,III 
B) II,III 
C) I only 
D) III only 
E) None of the options (I - III)is false.Options I-IV are all true.

Exam 18: Electron Transport and Oxidative Phosphorylation

Which of the following best describes the function of cytochrome c oxidase?

Which of the following correctly ranks redox centers found in Complex I from lower to higher potential? A correct answer will contain redox centers which are found in only Complex I and will also rank those redox centers in order of lower to higher reduction potential.

Matching Choose the correct answer from the list.Not all the answers will be used. -Electrons from cytosolic NADH are transferred to the matrix via electron ______ systems.

Based on the estimation presented in the chapter,how many ATP per glucose are synthesized by the aerobic metabolism in eukaryotes?

In the electron transport chain,electrons are passed from redox center to redox center ____.

Electrons from FADH2 are delivered to ____ and electrons from NADH are delivered to ____ of the electron transport chain.

Matching Choose the correct answer from the list.Not all the answers will be used. -Complexes I and II each transfer electrons to ______.

Which of the prosthetic groups listed can accept or donate either one or two electrons due to the stability of the semiquinone state?

Which of the following are TRUE statements regarding the structure of ATP synthase?

In the electron transport chain,FMN can adopt ____ oxidation state(s)and is capable of accepting or donating ____ electron(s).

One method used by newborn mammals to generate heat is referred to as nonshivering thermogenesis.This method utilizes a protein channel called ________ which is present in high levels inside the mitochondria of _____tissue.

Matching Choose the correct answer from the list.Not all the answers will be used. -The stoichiometric relationship of ATP synthesis to ______ is referred to as the P/O ratio.

The structure of ATP synthase changes in conformation as a result of

ATP forms (is produced) (I)upon transition from the loose to the tight form of the α and β subunit complex of ATP synthase. (II)as a result of the flux of electrons through the channel formed by Fo (III)as a result of the positive ions pumped into the matrix of the mitochondrion.

In a newly discovered electron transport complex a researcher has identified the redox center Fe-S,cytochrome c,and coenzyme Q.The researcher also knows that this complex ultimately passes its electrons to oxygen.What is most likely the redox center which completes this task?

Introduction to the Chemistry of Life

Water

Nucleotides, nucleic Acids, and Genetic Information

Amino Acids

Proteins: Primary Structure

Proteins: Three-Dimensional Structure

Protein Function Part I: Myoglobin and Hemoglobin

Carbohydrates

Lipids and Biological Membranes

Membrane Transport

Enzyme Catalysis

Enzyme Kinetics, inhibition and Control

Biochemical Signaling

Introduction to Metabolism

Glucose Catabolism

Glycogen Metabolism and Gluconeogenesis

Citric Acid Cycle

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Mammalian Fuel Metabolism: Integration and Regulation

Nucleotide Metabolism

Nucleic Acid Structure

DNA Replication, repair and Recombination

Transcription and Rna Processing

Protein Synthesis

Regulation of Gene Expression

Filters

Electrons from FADH₂ are delivered to and electrons from NADH are delivered to of the electron transport chain.

In the electron transport chain,FMN can adopt oxidation state(s)and is capable of accepting or donating electron(s).

One method used by newborn mammals to generate heat is referred to as nonshivering thermogenesis.This method utilizes a protein channel called ____ which is present in high levels inside the mitochondria of _tissue.

ATP forms (is produced) (I)upon transition from the loose to the tight form of the α and β subunit complex of ATP synthase. (II)as a result of the flux of electrons through the channel formed by F_o (III)as a result of the positive ions pumped into the matrix of the mitochondrion.