Question 1

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

Accepted Answer

Citrate synthase catalyzes the condensation of acetyl CoA and oxalacetate to form citryl CoA. This reaction is easily reversible. The hydrolysis of the thioester of citryl CoA forms citrate and regenerates the CoA. The hydrolysis of the high-energy thioester drives the reaction toward citrate.

Question 2

_______________ is the first citric acid cycle intermediate to be oxidized.

Accepted Answer

Isocitrate

Question 3

In what organisms and by what mechanism can carbon from fat be converted to sugar?

Accepted Answer

The glyoxylate cycle enables plants and bacteria to convert fats into carbohydrates.

Question 4

What is/are the chemical change(s) involved in the conversion of citrate into isocitrate?

Accepted Answer

A)  hydration followed by dehydration 
B)  oxidation 
C)  oxidation followed by reduction 
D)  dehydration followed by hydration 
E)  A and B 
A)  hydration followed by dehydration 
B)  oxidation 
C)  oxidation followed by reduction 
D)  dehydration followed by hydration 
E)  A and B

Question 5

_______________ are organelles in plants and some bacteria where two-carbon acetyl units are converted into four-carbon units (succinate) for glucose synthesis, energy production, and biosynthesis.

Accepted Answer

The answer of _______________ are organelles in plants and some...

Question 6

Succinate dehydrogenase deficiency or genetic mutation results in:

Accepted Answer

A)  cancer through HIF-1. 
B)  decreased rate of gylcolysis. 
C)  depletion of succinate in mitochondria. 
D)  A and B. 
E)  A, B, and C. 
A)  cancer through HIF-1. 
B)  decreased rate of gylcolysis. 
C)  depletion of succinate in mitochondria. 
D)  A and B. 
E)  A, B, and C.

Question 7

What reaction serves to link glycolysis and the citric acid cycle?

Accepted Answer

Pyruvate + CoA + NAD

Question 8

Draw each reaction and the name of the enzyme for the production of CO2 from pyruvate.

Accepted Answer

Use the pathways from chapters

Question 9

Which of the following vitamins are precursors to coenzymes that are necessary for the formation of succinyl CoA from α-ketoglutarate?

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 lipoic acid 
E)  None of the above. 
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 lipoic acid 
E)  None of the above.

Question 10

The direct channeling of proteins from one enzyme to the next will happen in a(n):

Accepted Answer

A)  protein complex. 
B)  metabolon. 
C)  linker coenzyme. 
D)  cell with sufficient available water. 
E)  electron acceptor. 
A)  protein complex. 
B)  metabolon. 
C)  linker coenzyme. 
D)  cell with sufficient available water. 
E)  electron acceptor.

Question 11

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
-The function of the citric acid cycle is to ____________ high-energy electrons.

Accepted Answer

A) cytosol 
B) isocitrate dehydrogenase 
C) anaplerotic 
D) harvest 
E) cis-aconitate
F)melonate
G)metabolon
H)oxaloacetate
I)inner membrane
J)citrate
K)carbon dioxide
L)glyoxylate cycle
M)malate dehydrogenase 
A) cytosol 
B) isocitrate dehydrogenase 
C) anaplerotic 
D) harvest 
E) cis-aconitate
F)melonate
G)metabolon
H)oxaloacetate
I)inner membrane
J)citrate
K)carbon dioxide
L)glyoxylate cycle
M)malate dehydrogenase

Question 12

In the α-ketoglutarate dehydrogenase enzyme complex, why is the observed electron transfer from FADH2 to NAD+ unusual?

Accepted Answer

It is unusual because the elec

Question 13

The free energy at standard state for MDH in the direction of the citric acid cycle is _______________.

Accepted Answer

The answer of The free energy at standard state for...

Question 14

In which step of the citric acid cycle is FADH2 formed?

Accepted Answer

A)  the conversion of succinate to malate 
B)  the conversion of succinate to oxaloacetate 
C)  the conversion of succinate to fumarate 
D)  the conversion of malate to oxaloacetate 
E)  None of the above. 
A)  the conversion of succinate to malate 
B)  the conversion of succinate to oxaloacetate 
C)  the conversion of succinate to fumarate 
D)  the conversion of malate to oxaloacetate 
E)  None of the above.

Question 15

In addition to pyruvate dehydrogenase, what other enzymes are key regulatory sites in the citric acid cycle?

Accepted Answer

A)  isocitrate dehydrogenase 
B)  ɑ-ketoglutarate dehydrogenase 
C)  citrate synthase (in bacteria) 
D)  A and B 
E)  A, B, and C 
A)  isocitrate dehydrogenase 
B)  ɑ-ketoglutarate dehydrogenase 
C)  citrate synthase (in bacteria) 
D)  A and B 
E)  A, B, and C

Question 16

During the oxidation of isocitrate, the intermediate that is decarboxylated to form α-ketoglutarate is _______________.

Accepted Answer

The answer of During the oxidation of isocitrate, the intermediate...

Question 17

Use the following to answer questions
Choose the correct answer from the list below. Not all of the answers will be used.
-The substance ____________ is a competitive inhibitor of succinate dehydrogenase.

Accepted Answer

A) cytosol 
B) isocitrate dehydrogenase 
C) anaplerotic 
D) harvest 
E) cis-aconitate
F)melonate
G)metabolon
H)oxaloacetate
I)inner membrane
J)citrate
K)carbon dioxide
L)glyoxylate cycle
M)malate dehydrogenase 
A) cytosol 
B) isocitrate dehydrogenase 
C) anaplerotic 
D) harvest 
E) cis-aconitate
F)melonate
G)metabolon
H)oxaloacetate
I)inner membrane
J)citrate
K)carbon dioxide
L)glyoxylate cycle
M)malate dehydrogenase

Question 18

Explain when GDP is used as a substrate with succinyl CoA synthetase, and when ADP is.

Accepted Answer

There are two forms of the enzyme, one f

Question 19

The ΔG˚′ = -21 kJ/mol for the reaction catalyzed by isocitrate dehydrogenase, yet the ΔG˚′ = +29.7 kJ/mol for the reaction catalyzed by malate dehydrogenase. Both of these reactions involve the oxidation of a secondary alcohol. Give an explanation about why the oxidation of isocitrate is so exergonic.

Accepted Answer

The oxidation of isocitrate produces oxa

Question 20

Isomerization of citrate is catalyzed by:

Accepted Answer

A)  citrate synthase. 
B)  aldolase. 
C)  ɑ-ketogutarate dehydrogenase. 
D)  Aconitase. 
E)  Citrate isomerase 
A)  citrate synthase. 
B)  aldolase. 
C)  ɑ-ketogutarate dehydrogenase. 
D)  Aconitase. 
E)  Citrate isomerase

Exam 19: Harvesting Electrons From the Cycle

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

_______________ is the first citric acid cycle intermediate to be oxidized.

In what organisms and by what mechanism can carbon from fat be converted to sugar?

What is/are the chemical change(s) involved in the conversion of citrate into isocitrate?

_______________ are organelles in plants and some bacteria where two-carbon acetyl units are converted into four-carbon units (succinate) for glucose synthesis, energy production, and biosynthesis.

Succinate dehydrogenase deficiency or genetic mutation results in:

What reaction serves to link glycolysis and the citric acid cycle?

Draw each reaction and the name of the enzyme for the production of CO2 from pyruvate.

Which of the following vitamins are precursors to coenzymes that are necessary for the formation of succinyl CoA from α-ketoglutarate?

The direct channeling of proteins from one enzyme to the next will happen in a(n):

Use the following to answer questions Choose the correct answer from the list below. Not all of the answers will be used. -The function of the citric acid cycle is to ____________ high-energy electrons.

In the α-ketoglutarate dehydrogenase enzyme complex, why is the observed electron transfer from FADH2 to NAD+ unusual?

The free energy at standard state for MDH in the direction of the citric acid cycle is _______________.

In which step of the citric acid cycle is FADH2 formed?

In addition to pyruvate dehydrogenase, what other enzymes are key regulatory sites in the citric acid cycle?

During the oxidation of isocitrate, the intermediate that is decarboxylated to form α-ketoglutarate is _______________.

Use the following to answer questions Choose the correct answer from the list below. Not all of the answers will be used. -The substance ____________ is a competitive inhibitor of succinate dehydrogenase.

Explain when GDP is used as a substrate with succinyl CoA synthetase, and when ADP is.

Isomerization of citrate is catalyzed by:

Biochemistry and the Unity of Life

Water, Weak Bonds, and the Generation of Order Out of Chaos

Amino Acids

Protein Three-Dimensional Structure

Techniques in Protein Biochemistry

Basic Concepts of Enzyme Action

Kinetics and Regulation

Mechanisms and Inhibitors

Hemoglobin: an Allosteric Protein

Carbohydrates

Lipids

Membrane Structure and Function

Signal Transduction Pathways

Digestion: Turning a Meal Into Cellular Biochemicals

Metabolism: Basic Concepts and Design

Glycolysis

Gluconeogenesis

Preparation for the Cycle

The Electron Transport Chain

The Proton-Motive Force

The Light Reactions

The Calvin Cycle

Glycogen Degradation

Glycogen Synthesis

The Pentose Phosphate Pathway

Fatty Acid Degredation

Fatty Acid Synthesis

Lipid Synthesis

Amino Acid Degradation and the Urea Cycle

Amino Acids Synthesis

Nucleotide Metabolism

The Structure of Informational Macromolecules: Dna and Rna

DNA Replication

DNA Repair and Recombination

RNA Synthesis and Regulation in Prokaryotes

Gene Expression in Eukaryotes

RNA Processing in Eukaryotes

The Genetic Code

The Mechanism of Protein Synthesis

Recombinant Dna Techniques

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