Question 1

The only reaction in the citric acid cycle to generate a carbon-carbon bond is catalyzed by citrate synthase.

Accepted Answer

A) True 
 B)False

Question 2

Compounds like succinate,fumarate and α-ketoglutarate have a catalytic effect on the consumption of oxygen in a cell suspension.The rate of oxygen consumption is far more than that required for their own oxidation.This is evidence that ________.

Accepted Answer

A) they are intermediates in glycolysis 
B) they act as enzymes to cause the oxidation of other compounds 
C) they are involved in a cyclic pathway 
D) they must be cofactors for enzymes that are oxidoreductases 
A) they are intermediates in glycolysis 
B) they act as enzymes to cause the oxidation of other compounds 
C) they are involved in a cyclic pathway 
D) they must be cofactors for enzymes that are oxidoreductases

Question 3

Citrate can react asymmetrically in the citric acid cycle because the enzyme aconitase

Accepted Answer

A) binds citrate asymmetrically. 
B) binds either form of citrate. 
C) binds both forms of isocitrate. 
D) does not distinguish the -CH₂COO- group. 
A) binds citrate asymmetrically. 
B) binds either form of citrate. 
C) binds both forms of isocitrate. 
D) does not distinguish the -CH₂COO- group.

Question 4

Mammalian pyruvate dehydrogenase is inactivated when pyruvate dehydrogenase kinase is activated by

Accepted Answer

A) NADH. 
B) ADP. 
C) pyruvate. 
D) AMP. 
A) NADH. 
B) ADP. 
C) pyruvate. 
D) AMP.

Question 5

The order of prosthetic groups as they act in the three proteins of the PDH(pyruvate dehydrogenase)complex is:

Accepted Answer

A) FAD → thiamine pyrophosphate → NAD+ 
B) FAD → thiamine pyrophosphate → dihydrolipoamide 
C) thiamine pyrophosphate → dihydrolipoamide → FAD 
D) NAD+ → FAD → dihydrolipoamide 
A) FAD → thiamine pyrophosphate → NAD+ 
B) FAD → thiamine pyrophosphate → dihydrolipoamide 
C) thiamine pyrophosphate → dihydrolipoamide → FAD 
D) NAD+ → FAD → dihydrolipoamide

Question 6

The arrangement of subunits in the PDH(pyruvate dehydrogenase)complex ensures that ________.

Accepted Answer

A) ATP is formed 
B) the product of one enzyme is delivered to the next in turn 
C) the dihydrolipoamide arm can react with NAD+ 
D) acetyl CoA enters into the series of reactions 
A) ATP is formed 
B) the product of one enzyme is delivered to the next in turn 
C) the dihydrolipoamide arm can react with NAD+ 
D) acetyl CoA enters into the series of reactions

Question 7

Pyruvate dehydrogenase kinase catalyzes

Accepted Answer

A) the dephosphorylation and activation of E1. 
B) the dephosphorylation and inactivation of E1. 
C) the phosphorylation and inactivation of E1. 
D) the phosphorylation and activation of E1. 
A) the dephosphorylation and activation of E1. 
B) the dephosphorylation and inactivation of E1. 
C) the phosphorylation and inactivation of E1. 
D) the phosphorylation and activation of E1.

Question 8

Synthases do not require ATP as a cofactor while synthetases are coupled to ATP (or GTP)hydrolysis.Both types of enzymes are found in the citric acid cycle.

Accepted Answer

A) True 
 B)False

Question 9

Most of the energy released in citric acid cycle reactions is conserved in ________.

Accepted Answer

A) GTP 
B) ATP 
C) NADH and QH² 
D) ADP 
A) GTP 
B) ATP 
C) NADH and QH² 
D) ADP

Question 10

A racemic mixture of the enantiomeric forms of isocitrate is produced during the citric acid cycle reactions.

Accepted Answer

A) True 
 B)False

Question 11

When fumarate is positioned in the active site of fumarase,the double bond of the substrate can be attacked from only one side.Therefore,fumarate is a ________ molecule.

Accepted Answer

A) asymmetric 
B) prochiral 
C) isomeric 
D) duplicate 
A) asymmetric 
B) prochiral 
C) isomeric 
D) duplicate

Question 12

The activity of dihydrolipoamide dehydrogenase (E3)is inhibited by a high NADH/NAD+ ratio.

Accepted Answer

A) True 
 B)False

Question 13

A carbon atom that has single bond to four substituents with exactly two of the four substituents identical is called a ________.

Accepted Answer

A) prochiral carbon atom 
B) tetrahedral stereocenter 
C) divalent carbon atom 
D) anomeric carbon atom 
A) prochiral carbon atom 
B) tetrahedral stereocenter 
C) divalent carbon atom 
D) anomeric carbon atom

The only reaction in the citric acid cycle to generate a carbon-carbon bond is catalyzed by citrate synthase.

Compounds like succinate,fumarate and α-ketoglutarate have a catalytic effect on the consumption of oxygen in a cell suspension.The rate of oxygen consumption is far more than that required for their own oxidation.This is evidence that ________.

Citrate can react asymmetrically in the citric acid cycle because the enzyme aconitase

Mammalian pyruvate dehydrogenase is inactivated when pyruvate dehydrogenase kinase is activated by

The order of prosthetic groups as they act in the three proteins of the PDH(pyruvate dehydrogenase)complex is:

The arrangement of subunits in the PDH(pyruvate dehydrogenase)complex ensures that ________.

Pyruvate dehydrogenase kinase catalyzes

Synthases do not require ATP as a cofactor while synthetases are coupled to ATP (or GTP)hydrolysis.Both types of enzymes are found in the citric acid cycle.

Most of the energy released in citric acid cycle reactions is conserved in ________.

A racemic mixture of the enantiomeric forms of isocitrate is produced during the citric acid cycle reactions.

When fumarate is positioned in the active site of fumarase,the double bond of the substrate can be attacked from only one side.Therefore,fumarate is a ________ molecule.

The activity of dihydrolipoamide dehydrogenase (E3)is inhibited by a high NADH/NAD+ ratio.

A carbon atom that has single bond to four substituents with exactly two of the four substituents identical is called a ________.

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

Electron Transport and Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

Filters

Exam 13: The Citric Acid Cycle

The only reaction in the citric acid cycle to generate a carbon-carbon bond is catalyzed by citrate synthase.

Compounds like succinate,fumarate and α-ketoglutarate have a catalytic effect on the consumption of oxygen in a cell suspension.The rate of oxygen consumption is far more than that required for their own oxidation.This is evidence that ________.

Citrate can react asymmetrically in the citric acid cycle because the enzyme aconitase

Mammalian pyruvate dehydrogenase is inactivated when pyruvate dehydrogenase kinase is activated by

The order of prosthetic groups as they act in the three proteins of the PDH(pyruvate dehydrogenase)complex is:

The arrangement of subunits in the PDH(pyruvate dehydrogenase)complex ensures that ________.

Pyruvate dehydrogenase kinase catalyzes

Synthases do not require ATP as a cofactor while synthetases are coupled to ATP (or GTP)hydrolysis.Both types of enzymes are found in the citric acid cycle.

Most of the energy released in citric acid cycle reactions is conserved in ________.

A racemic mixture of the enantiomeric forms of isocitrate is produced during the citric acid cycle reactions.

When fumarate is positioned in the active site of fumarase,the double bond of the substrate can be attacked from only one side.Therefore,fumarate is a ________ molecule.

The activity of dihydrolipoamide dehydrogenase (E3)is inhibited by a high NADH/NAD+ ratio.

A carbon atom that has single bond to four substituents with exactly two of the four substituents identical is called a ________.

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

Electron Transport and Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

Filters