Question 1

Give the net equation of the citric acid cycle.

Accepted Answer

Acetyl-CoA + 3 NAD⁺ +...

Question 2

E2 of the pyruvate dehydrogenase complex contains a lipoyl group that is covalently attached to a _______________ residue of the enzyme.

Accepted Answer

The answer of E2 of the pyruvate dehydrogenase complex contains...

Question 3

Where does the citric acid cycle take place in the cell?

Accepted Answer

A)   cytosol
B)   mitochondria
C)   nucleus
D)   endoplasmic reticulum
E)   lysosomeF) A) and D)
G) C) and D)

Question 4

Which of the following functions as a "flexible swinging arm" when it transfers the reaction intermediate from one active site to the next?

Accepted Answer

A)   FAD
B)   NAD+
C)   lipoamide
D)   thiamine pyrophosphate
E)   coenzyme AF) B) and C)
G) A) and E) C

Question 5

What are the steps involved (in order)  in the conversion of pyruvate to acetyl-CoA?

Accepted Answer

A)   decarboxylation, oxidation, transfer to CoA
B)   decarboxylation, transfer to CoA, oxidation
C)   oxidation, decarboxylation, transfer to CoA
D)   oxidation, transfer to CoA, decarboxylation
E)   None of the answers is correct.F) B) and E)
G) C) and E)

Question 6

Which of the following conditions will activate pyruvate dehydrogenase kinase, which catalyzes the phosphorylation and inactivation of E1 in the pyruvate dehydrogenase complex?

Accepted Answer

A)   elevated concentrations of NADH and ATP
B)   elevated concentrations of NAD+ and ADP
C)   Ca2+
D)   glucagon
E)   elevated concentrations of coenzyme AF) A) and B)
G) B) and D)

Question 7

How does the decarboxylation of $\alpha$-ketoglutarate resemble that of pyruvate decarboxylation?

Accepted Answer

Both are <img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30">-ketoacids, which are decarboxy...

Question 8

What cycle allows for the net synthesis of glucose from acetyl-CoA?

Accepted Answer

A)   Calvin cycle
B)   glyoxylate cycle
C)   C4 pathway
D)   urea cycle
E)   None of the answers is correct.F) B) and C)
G) All of the above

Question 9

What type of enzymes are tightly associated with FAD or FMN?

Accepted Answer

A)   transferases
B)   cytochrome P450 enzymes
C)   metalloenzymes
D)   flavoproteins
E)   None of the answers is correct.F) A) and D)
G) B) and D) D

Question 10

When intermediates of the citric acid cycle are depleted by biosynthetic pathways, _____ reactions are used to replenish the citric acid cycle intermediates.

Accepted Answer

A)   anaplerotic
B)   amphibolic
C)   amphoteric
D)   biosynthetic
E)   None of the answers is correct.F) A) and B)
G) A) and E)

Question 11

What molecule initiates the citric acid cycle by reacting with oxaloacetate?

Accepted Answer

A)   pyruvate
B)   acetyl CoA
C)   oxaloacetate
D)   glucose
E)   None of the answers is correct.F) C) and D)
G) B) and D)

Question 12

Give the reaction in the citric acid cycle by which the energy is conserved in the formation of a phosphoanhydride bond by substrate level phosphorylation. Give the name of the enzyme that catalyzes this reaction and give the structures of the reactants and products of this reaction.

Accepted Answer

The answer of Give the reaction in the citric acid...

Question 13

In addition to pyruvate dehydrogenase, which of the following enzymes is a key regulatory site in the citric acid cycle?

Accepted Answer

A)   malate dehydrogenase
B)    α\alphaα -ketoglutarate dehydrogenase
C)   succinyl CoA synthetase
D)   succinate dehydrogenase
E)   None of the answers is correct. F) A) and B)
G) A) and C)

Question 14

Which of the following vitamins are precursors to coenzymes that are necessary for the formation of acetyl CoA from pyruvate?

Accepted Answer

A)   thiamine, riboflavin, niacin, lipoic acid, and pantothenic acid
B)   thiamine, riboflavin, niacin, lipoic acid, pantothenic acid, and biotin
C)   thiamine, riboflavin, niacin, and biotin
D)   thiamine, riboflavin, and folic acid
E)   None of the answers is correct.F) B) and C)
G) B) and E) A

Question 15

The citric acid cycle is also known as the

Accepted Answer

A)   Krebs cycle.
B)   Cori cycle.
C)   tricarboxylic acid cycle.
D)   acetate cycle.
E)   Krebs cycle and tricarboxylic acid cycle.F) None of the above
G) B) and E)

Question 16

Which of the following citric acid cycle intermediates is found at the traditional start and finish of the cycle?

Accepted Answer

A)   citrate
B)   isocitrate
C)    α\alphaα -ketoglutarate
D)   succinate
E)   oxaloacetate F) A) and E)
G) C) and E)

Question 17

Beri-beri is caused by a deficiency of __________________.

Accepted Answer

The answer of Beri-beri is caused by a deficiency of...

Question 18

How does the term "mad as a hatter" realistically reflect the condition?

Accepted Answer

Hatters used mercury in their craft. Fre...

Question 19

Explain why a GTP is energetically equivalent to an ATP in metabolism.

Accepted Answer

The enzyme nucleoside diphosphokinase re...

Question 20

Approximately how many ATP or GTP equivalents will be produced from energy molecules produced during one turn of the citric acid cycle?

Accepted Answer

A)   10
B)   6
C)   9
D)   12
E)   None of the answers is correct.F) All of the above
G) C) and D)

Exam 17: The Citric Acid Cycle

Give the net equation of the citric acid cycle.

Correct AnswerverifiedAcetyl-CoA + 3 NAD+ +...View AnswerShow Answer

E2 of the pyruvate dehydrogenase complex contains a lipoyl group that is covalently attached to a _______________ residue of the enzyme.

Correct AnswerverifiedShow Answer

Where does the citric acid cycle take place in the cell?

Correct AnswerverifiedShow Answer

Which of the following functions as a "flexible swinging arm" when it transfers the reaction intermediate from one active site to the next?

Correct AnswerverifiedC

What are the steps involved (in order) in the conversion of pyruvate to acetyl-CoA?

Correct AnswerverifiedShow Answer

Which of the following conditions will activate pyruvate dehydrogenase kinase, which catalyzes the phosphorylation and inactivation of E1 in the pyruvate dehydrogenase complex?

Correct AnswerverifiedShow Answer

How does the decarboxylation of α\alphaα -ketoglutarate resemble that of pyruvate decarboxylation?

Correct AnswerverifiedBoth are -ketoacids, which are decarboxy...View AnswerShow Answer

What cycle allows for the net synthesis of glucose from acetyl-CoA?

Correct AnswerverifiedShow Answer

What type of enzymes are tightly associated with FAD or FMN?

Correct AnswerverifiedD

When intermediates of the citric acid cycle are depleted by biosynthetic pathways, _____ reactions are used to replenish the citric acid cycle intermediates.

Correct AnswerverifiedShow Answer

What molecule initiates the citric acid cycle by reacting with oxaloacetate?

Correct AnswerverifiedShow Answer

Give the reaction in the citric acid cycle by which the energy is conserved in the formation of a phosphoanhydride bond by substrate level phosphorylation. Give the name of the enzyme that catalyzes this reaction and give the structures of the reactants and products of this reaction.

Correct AnswerverifiedShow Answer

In addition to pyruvate dehydrogenase, which of the following enzymes is a key regulatory site in the citric acid cycle?

Correct AnswerverifiedShow Answer

Which of the following vitamins are precursors to coenzymes that are necessary for the formation of acetyl CoA from pyruvate?

Correct AnswerverifiedA

The citric acid cycle is also known as the

Correct AnswerverifiedShow Answer

Which of the following citric acid cycle intermediates is found at the traditional start and finish of the cycle?

Correct AnswerverifiedShow Answer

Beri-beri is caused by a deficiency of __________________.

Correct AnswerverifiedShow Answer

How does the term "mad as a hatter" realistically reflect the condition?

Correct AnswerverifiedHatters used mercury in their craft. Fre...View AnswerShow Answer

Explain why a GTP is energetically equivalent to an ATP in metabolism.

Correct AnswerverifiedThe enzyme nucleoside diphosphokinase re...View AnswerShow Answer

Approximately how many ATP or GTP equivalents will be produced from energy molecules produced during one turn of the citric acid cycle?

Correct AnswerverifiedShow Answer

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Acetyl-CoA + 3 NAD⁺ +...
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C

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Which of the following conditions will activate pyruvate dehydrogenase kinase, which catalyzes the phosphorylation and inactivation of E₁ in the pyruvate dehydrogenase complex?

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How does the decarboxylation of $\alpha$ -ketoglutarate resemble that of pyruvate decarboxylation?

Correct Answer
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Both are -ketoacids, which are decarboxy...
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D

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A

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Hatters used mercury in their craft. Fre...
View Answer

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The enzyme nucleoside diphosphokinase re...
View Answer

Correct Answer
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