Question 1

Which of the reactions of the citric acid cycle requires FAD as a coenzyme?

Accepted Answer

A)  the conversion of isocitrate to α-ketoglutarate 
B)  the conversion of citrate to isocitrate 
C)  the conversion of succinate to fumarate 
D)  the conversion of malate to oxaloacetate 
E)  none of these 
A)  the conversion of isocitrate to α-ketoglutarate 
B)  the conversion of citrate to isocitrate 
C)  the conversion of succinate to fumarate 
D)  the conversion of malate to oxaloacetate 
E)  none of these

Question 2

Which group of small molecules best fit the boxes associated with the reaction shown?  
$$\begin{array} { l l l } 
& \text { a } & \text { b } \
\text { I. } & \mathrm { ADP } ^ { 2 } + 2 \mathrm { P } _ { \mathrm { i } } & \mathrm { ATP } \
\text { II. } & \mathrm { NAD } ^ { + } & \mathrm { NADH } \
\text { III. } & \mathrm { NADP } ^ { + } & \mathrm { NADPH } \
\text { IV. } & \mathrm { FAD } ^ { \mathrm { FAD } } & \mathrm { FADH } _ { 2 }
\end{array}$$

Accepted Answer

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

Question 3

Exhibit 19A The following compounds are all intermediates in the citric acid cycle.
  
-Refer to Exhibit 19A. Which intermediate is formed from acetyl-CoA and oxaloacetate.

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 4

Which of the following is not a component of the pyruvate dehydrogenase complex?

Accepted Answer

A)  pyruvate dehydrogenase 
B)  dihydrolipoyl transacetylase 
C)  dihydrolipoyl dehydrogenase 
D)  pyruvate dehydrogenase kinase 
E)  aconitase 
A)  pyruvate dehydrogenase 
B)  dihydrolipoyl transacetylase 
C)  dihydrolipoyl dehydrogenase 
D)  pyruvate dehydrogenase kinase 
E)  aconitase

Question 5

Which enzyme catalyzes the reaction shown?

Accepted Answer

A)  isocitrate dehydrogenase 
B)  malate dehydrogenase 
C)  fumarase 
D)  succinate dehydrogenase 
E)  none of these 
A)  isocitrate dehydrogenase 
B)  malate dehydrogenase 
C)  fumarase 
D)  succinate dehydrogenase 
E)  none of these

Question 6

An organism that undergoes the glyoxylate cycle can make sugar from fat because:

Accepted Answer

A)  there is a specific isomerase that converts a six carbon fatty acid to glucose 
B)  the unique reactions of the glyoxylate cycle bypass the two decarboyxlation reactions of the citric acid cycle 
C)  glyoxysomes lack succinate dehydrogenase 
D)  none of these 
A)  there is a specific isomerase that converts a six carbon fatty acid to glucose 
B)  the unique reactions of the glyoxylate cycle bypass the two decarboyxlation reactions of the citric acid cycle 
C)  glyoxysomes lack succinate dehydrogenase 
D)  none of these

Question 7

A control point outside the citric acid cycle is the reaction catalyzed by

Accepted Answer

A)  the pyruvate dehydrogenase complex. 
B)  citrate synthetase. 
C)  isocitrate dehydrogenase. 
D)  the α-ketoglutarate dehydrogenase complex. 
A)  the pyruvate dehydrogenase complex. 
B)  citrate synthetase. 
C)  isocitrate dehydrogenase. 
D)  the α-ketoglutarate dehydrogenase complex.

Question 8

Which of the following is true regarding the control of pyruvate dehydrogenase?

Accepted Answer

A)  It is inhibited by ATP 
B)  It is inhibited by NAD+ 
C)  It is activated by acetyl-CoA 
D)  It is inhibited by succinyl-CoA 
E)  none of these are true 
A)  It is inhibited by ATP 
B)  It is inhibited by NAD+ 
C)  It is activated by acetyl-CoA 
D)  It is inhibited by succinyl-CoA 
E)  none of these are true

Question 9

The citric acid cycle is considered part of aerobic metabolism even though oxygen does not appear explicitly in any reaction because

Accepted Answer

A)  the NADH and FADH2 produced are reoxidized in the electron transport chain linked to oxygen 
B)  the reoxidation of NADH and FADH2 leads to the production of considerable quantities of ATP 
C)  it takes place in the mitochondrion 
D)  it contains oxidation reactions 
A)  the NADH and FADH2 produced are reoxidized in the electron transport chain linked to oxygen 
B)  the reoxidation of NADH and FADH2 leads to the production of considerable quantities of ATP 
C)  it takes place in the mitochondrion 
D)  it contains oxidation reactions

Question 10

Which of the following describes a use for acetyl-CoA as an important intermediate in metabolism?

Accepted Answer

A)  Breakdown to CO2 and water, yielding much energy. 
B)  Synthesis of terpenes and steroids. 
C)  Synthesis of oxaloacetate in plants. 
D)  Synthesis of fatty acids. 
E)  All of these are reasons why acetyl-CoA is a central molecule in metabolism. 
A)  Breakdown to CO2 and water, yielding much energy. 
B)  Synthesis of terpenes and steroids. 
C)  Synthesis of oxaloacetate in plants. 
D)  Synthesis of fatty acids. 
E)  All of these are reasons why acetyl-CoA is a central molecule in metabolism.

Question 11

Weight loss in humans can be difficult to achieve, since we lack the ability to convert our fats to sugars, and it is difficult to change our metabolism to using fats as a primary energy source.

Accepted Answer

A) True 
 B)False

Question 12

Intermediates of the citric acid cycle are especially important in the synthesis of fatty acids and amino acids.

Accepted Answer

A) True 
 B)False

Question 13

All but one of the enzymes of the citric acid cycle are found in this part of the mitochondrion:

Accepted Answer

A)  The outer membrane. 
B)  The inner membrane. 
C)  The mitochondrial matrix. 
D)  The intermembrane space. 
E)  It is not known where these enzymes are located. 
A)  The outer membrane. 
B)  The inner membrane. 
C)  The mitochondrial matrix. 
D)  The intermembrane space. 
E)  It is not known where these enzymes are located.

Question 14

The citric acid cycle produces one high energy phosphate molecule per cycle directly in the form of ____

Accepted Answer

A)  ATP 
B)  GTP 
C)  CTP 
D)  AMP 
E)  none of these 
A)  ATP 
B)  GTP 
C)  CTP 
D)  AMP 
E)  none of these

Question 15

Which of the following enzymes is allosterically inhibited by ATP?

Accepted Answer

A)  pyruvate dehydrogenase complex 
B)  succinyl-CoA synthetase 
C)  succinate dehydrogenase 
D)  fumarase 
A)  pyruvate dehydrogenase complex 
B)  succinyl-CoA synthetase 
C)  succinate dehydrogenase 
D)  fumarase

Question 16

The only difference between succinate and fumarate is the geometry around their double bonds, one contains a cis double bond and the other contains a trans double bond.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following enzymes contains a non-heme iron?

Accepted Answer

A)  citrate synthase 
B)  succinyl-CoA synthetase 
C)  succinate dehydrogenase 
D)  fumarase 
A)  citrate synthase 
B)  succinyl-CoA synthetase 
C)  succinate dehydrogenase 
D)  fumarase

Question 18

The citric acid cycle uses anaplerotic reactions to get rid of the many intermediates of the cycle that accumulate during catabolism of amino acids.

Accepted Answer

A) True 
 B)False

Question 19

Which of the following does not play a role in the overall aerobic metabolism of glucose?

Accepted Answer

A)  citric acid cycle 
B)  electron transport 
C)  oxidative phosphorylation 
D)  urea cycle 
E)  all of these play a role in overall aerobic metabolism of glucose 
A)  citric acid cycle 
B)  electron transport 
C)  oxidative phosphorylation 
D)  urea cycle 
E)  all of these play a role in overall aerobic metabolism of glucose

Question 20

Which enzyme catalyzes the reaction shown?

Accepted Answer

A)  succinyl-CoA synthetase 
B)  succinate dehydrogenase 
C)  pyruvate dehydrogenase 
D)  α-ketoglutarate dehydrogenase 
A)  succinyl-CoA synthetase 
B)  succinate dehydrogenase 
C)  pyruvate dehydrogenase 
D)  α-ketoglutarate dehydrogenase

Exam 19: The Citric Acid Cycle

Which of the reactions of the citric acid cycle requires FAD as a coenzyme?

Which group of small molecules best fit the boxes associated with the reaction shown? a b I. +2 II. III. IV.

Exhibit 19A The following compounds are all intermediates in the citric acid cycle. -Refer to Exhibit 19A. Which intermediate is formed from acetyl-CoA and oxaloacetate.

Which of the following is not a component of the pyruvate dehydrogenase complex?

Which enzyme catalyzes the reaction shown?

An organism that undergoes the glyoxylate cycle can make sugar from fat because:

A control point outside the citric acid cycle is the reaction catalyzed by

Which of the following is true regarding the control of pyruvate dehydrogenase?

The citric acid cycle is considered part of aerobic metabolism even though oxygen does not appear explicitly in any reaction because

Which of the following describes a use for acetyl-CoA as an important intermediate in metabolism?

Weight loss in humans can be difficult to achieve, since we lack the ability to convert our fats to sugars, and it is difficult to change our metabolism to using fats as a primary energy source.

Intermediates of the citric acid cycle are especially important in the synthesis of fatty acids and amino acids.

All but one of the enzymes of the citric acid cycle are found in this part of the mitochondrion:

The citric acid cycle produces one high energy phosphate molecule per cycle directly in the form of ____

Which of the following enzymes is allosterically inhibited by ATP?

The only difference between succinate and fumarate is the geometry around their double bonds, one contains a cis double bond and the other contains a trans double bond.

Which of the following enzymes contains a non-heme iron?

The citric acid cycle uses anaplerotic reactions to get rid of the many intermediates of the cycle that accumulate during catabolism of amino acids.

Which of the following does not play a role in the overall aerobic metabolism of glucose?

Which enzyme catalyzes the reaction shown?

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

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

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