Question 1

Give the net equation of the citric acid cycle.

Accepted Answer

Acetyl-CoA + 3 NAD⁺ +

Question 2

How is succinate dehydrogenase unique when compared to the other enzymes in the citric acid cycle?

Accepted Answer

It is the only enzyme embedded

Question 3

What enzyme(s)is (are)responsible for the following reaction?
Pyruvate + CoA + NAD+ $\rarr$ acetyl CoA + NADH + H+ + CO2

Accepted Answer

A)  acetyl CoA synthetase 
B)  pyruvate decarboxylase 
C)  pyruvate dehydrogenase complex 
D)  pyruvate carboxylase 
E)  None of the answers is correct. 
A)  acetyl CoA synthetase 
B)  pyruvate decarboxylase 
C)  pyruvate dehydrogenase complex 
D)  pyruvate carboxylase 
E)  None of the answers is correct.

Question 4

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

Question 5

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)  $\alpha$-ketoglutarate dehydrogenase 
C)  succinyl CoA synthetase 
D)  succinate dehydrogenase 
E)  None of the answers is correct. 
A)  malate dehydrogenase 
B)  $\alpha$-ketoglutarate dehydrogenase 
C)  succinyl CoA synthetase 
D)  succinate dehydrogenase 
E)  None of the answers is correct.

Question 6

_______________ is a citric acid cycle enzyme that is also an example of an iron-sulfur protein.

Accepted Answer

Aconitase

Question 7

The ____________ cycle is a process by which plants and some bacteria can convert two-carbon acetyl units into four-carbon units (succinate)for glucose synthesis,energy production,and biosynthesis.

Accepted Answer

The answer of The ____________ cycle is a process by...

Question 8

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. 
A)  10 
B)  6 
C)  9 
D)  12 
E)  None of the answers is correct.

Question 9

Where in the cell is succinate dehydrogenase located?

Accepted Answer

A)  inner mitochondrial membrane 
B)  outer mitochondrial membrane 
C)  mitochondrial matrix 
D)  intermembrane space 
E)  cytosol 
A)  inner mitochondrial membrane 
B)  outer mitochondrial membrane 
C)  mitochondrial matrix 
D)  intermembrane space 
E)  cytosol

Question 10

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. 
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.

Question 11

In general,the citric acid cycle is inhibited under ________ (high,low)energy conditions.

Accepted Answer

The answer of In general,the citric acid cycle is inhibited...

Question 12

What is the energy source that drives the condensation of oxaloacetate and acetyl CoA to produce citrate?

Accepted Answer

Citrate synthase catalyzes the condensat

Question 13

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

Accepted Answer

Both are @#LAT-DLM&-ketoacids,which are decarboxyl

Question 14

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

Question 15

Which of the following enzymes are found in the glyoxylate cycle but not in the citric acid cycle?

Accepted Answer

A)  malate synthase and isocitrate dehydrogenase 
B)  glyoxylate synthase and malate synthase 
C)  isocitrate lyase and malate dehydrogenase 
D)  malate synthase and isocitrate lyase 
E)  succinyl CoA synthetase and glyoxylate synthase 
A)  malate synthase and isocitrate dehydrogenase 
B)  glyoxylate synthase and malate synthase 
C)  isocitrate lyase and malate dehydrogenase 
D)  malate synthase and isocitrate lyase 
E)  succinyl CoA synthetase and glyoxylate synthase

Question 16

Which of the following is the primary mode of regulation for the pyruvate dehydrogenase complex?

Accepted Answer

A)  feedback inhibition by citrate 
B)  feed-forward activation by glucose 
C)  allosteric activation by ATP and NADH 
D)  allosteric inhibition by ADP and CO2 
E)  inhibition by phosphorylation 
A)  feedback inhibition by citrate 
B)  feed-forward activation by glucose 
C)  allosteric activation by ATP and NADH 
D)  allosteric inhibition by ADP and CO2 
E)  inhibition by phosphorylation

Question 17

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. 
A)  Krebs cycle. 
B)  Cori cycle. 
C)  tricarboxylic acid cycle. 
D)  acetate cycle. 
E)  Krebs cycle and tricarboxylic acid cycle.

Question 18

The glyoxylate cycle enables plants to survive using only

Accepted Answer

A)  pyruvate. 
B)  acetate. 
C)  oxaloacetate. 
D)  lactate. 
E)  None of the answers is correct. 
A)  pyruvate. 
B)  acetate. 
C)  oxaloacetate. 
D)  lactate. 
E)  None of the answers is correct.

Question 19

Why is the isomerization of citrate to isocitrate a necessary step of the citric acid cycle?

Accepted Answer

Citrate is a tertiary alcohol

Question 20

Beri-beri is caused by a deficiency of __________________.

Accepted Answer

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

Exam 17: The Citric Acid Cycle

Give the net equation of the citric acid cycle.

How is succinate dehydrogenase unique when compared to the other enzymes in the citric acid cycle?

What enzyme(s)is (are)responsible for the following reaction? Pyruvate + CoA + NAD+ →\rarr→ acetyl CoA + NADH + H+ + CO2

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

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

_______________ is a citric acid cycle enzyme that is also an example of an iron-sulfur protein.

The ____________ cycle is a process by which plants and some bacteria can convert two-carbon acetyl units into four-carbon units (succinate)for glucose synthesis,energy production,and biosynthesis.

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

Where in the cell is succinate dehydrogenase located?

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

In general,the citric acid cycle is inhibited under ________ (high,low)energy conditions.

What is the energy source that drives the condensation of oxaloacetate and acetyl CoA to produce citrate?

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

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

Which of the following enzymes are found in the glyoxylate cycle but not in the citric acid cycle?

Which of the following is the primary mode of regulation for the pyruvate dehydrogenase complex?

The citric acid cycle is also known as the

The glyoxylate cycle enables plants to survive using only

Why is the isomerization of citrate to isocitrate a necessary step of the citric acid cycle?

Beri-beri is caused by a deficiency of __________________.

Biochemistry: An Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Membrane Channels and Pumps

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

Oxidative Phosphorylation

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Nucleotide Biosynthesis

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

DNA Replication, repair, and Recombination

RNA Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

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What enzyme(s)is (are)responsible for the following reaction? Pyruvate + CoA + NAD⁺ $\rarr$ acetyl CoA + NADH + H⁺ + CO₂

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