Question 1

Isozymes are enzymes

Accepted Answer

A)  from one species that catalyze the same reaction. 
B)  from different species that catalyze the same reaction. 
C)  that have isomers as substrates. 
D)  that have products that are isomers. 
A)  from one species that catalyze the same reaction. 
B)  from different species that catalyze the same reaction. 
C)  that have isomers as substrates. 
D)  that have products that are isomers.

Question 2

How does mannose enter the glycolytic pathway?

Accepted Answer

A)  It is converted mannose 6-phosphate and then isomerized to fructose 6-phosphate which enters the pathway. 
B)  It can enter directly into the first step of glycolysis because hexokinase converts mannose to glucose 6-phosphate. 
C)  Mannose is first split into two trioses that are directly converted to glyceraldehyde 3-phosphate. 
D)  Mannose is not metabolized via glycolysis. It enters a separate pathway. 
A)  It is converted mannose 6-phosphate and then isomerized to fructose 6-phosphate which enters the pathway. 
B)  It can enter directly into the first step of glycolysis because hexokinase converts mannose to glucose 6-phosphate. 
C)  Mannose is first split into two trioses that are directly converted to glyceraldehyde 3-phosphate. 
D)  Mannose is not metabolized via glycolysis. It enters a separate pathway.

Question 3

What happens to pyruvate if it is destined for the citric acid cycle?

Accepted Answer

A)  It is converted to carbon dioxide and acetaldehyde. 
B)  It is converted to ethanol. 
C)  It is converted to lactate. 
D)  Nothing, pyruvate enters the citric acid cycle directly. 
A)  It is converted to carbon dioxide and acetaldehyde. 
B)  It is converted to ethanol. 
C)  It is converted to lactate. 
D)  Nothing, pyruvate enters the citric acid cycle directly.

Question 4

Seven of the ten reactions in the glycolytic pathway have free energy values close to zero. What does this tell us about those reactions?

Accepted Answer

A)  They are near equilibrium reactions. 
B)  They are not control points for pathway regulation. 
C)  They are reversible reactions. 
D)  All of the above 
E)  None of the above 
A)  They are near equilibrium reactions. 
B)  They are not control points for pathway regulation. 
C)  They are reversible reactions. 
D)  All of the above 
E)  None of the above

Question 5

How does the number of molecules of ATP produced compare for conversion of one molecule of either glucose or fructose to pyruvate?

Accepted Answer

A)  fructose produces one less ATP than glucose 
B)  fructose and glucose produce the same number of ATPʹs 
C)  fructose produces one more ATP than glucose 
D)  fructose produces twice the number of ATP compared to glucose 
A)  fructose produces one less ATP than glucose 
B)  fructose and glucose produce the same number of ATPʹs 
C)  fructose produces one more ATP than glucose 
D)  fructose produces twice the number of ATP compared to glucose

Question 6

Phosphofructokinase I deficiency results in

Accepted Answer

A)  an overproduction of Fructose 6-phosphate. 
B)  an overproduction of Fructose 1,6-bisphosphate. 
C)  fructose 1,6-bisphosphate deficiency. 
D)  A and C only 
E)  All of the above 
A)  an overproduction of Fructose 6-phosphate. 
B)  an overproduction of Fructose 1,6-bisphosphate. 
C)  fructose 1,6-bisphosphate deficiency. 
D)  A and C only 
E)  All of the above

Question 7

Yeast will normally convert pyruvate to ethanol. Why is this better for the yeast than a conversion to lactate?

Accepted Answer

A)  Conversion to ethanol releases more NAD+ per mole than the conversion to lactate. 
B)  The carbon atoms are more oxidized in ethanol than in lactate. 
C)  Ethanol is neutral, but lactate production is accompanied by a sharp decrease in pH. 
D)  Ethanol production is not better. Yeast normally produces ethanol and lactate in equilmolar amounts. 
A)  Conversion to ethanol releases more NAD+ per mole than the conversion to lactate. 
B)  The carbon atoms are more oxidized in ethanol than in lactate. 
C)  Ethanol is neutral, but lactate production is accompanied by a sharp decrease in pH. 
D)  Ethanol production is not better. Yeast normally produces ethanol and lactate in equilmolar amounts.

Question 8

Mutases are described as

Accepted Answer

A)  polymerases that catalyze phosphoryl group transfers. 
B)  isomerases that catalyze the transfer of phosphoryl groups from one part of a substrate molecule to another. 
C)  forming intermediate free phosphate Pi). 
D)  All of the above 
A)  polymerases that catalyze phosphoryl group transfers. 
B)  isomerases that catalyze the transfer of phosphoryl groups from one part of a substrate molecule to another. 
C)  forming intermediate free phosphate Pi). 
D)  All of the above

Question 9

The activity of which glycolytic enzyme shown below is not used to control the rate of glycolysis?

Accepted Answer

A)  PFK-1 
B)  pyruvate kinase 
C)  triose phosphate isomerase 
D)  hexokinase 
A)  PFK-1 
B)  pyruvate kinase 
C)  triose phosphate isomerase 
D)  hexokinase

Question 10

2,3-bisphosphoglycerate is

Accepted Answer

A)  an essential component of glycolysis for ATP production. 
B)  converted to 3-phosphoglycerate with formation of ATP. 
C)  essential for the efficient release of O2 from hemoglobin. 
D)  a product of the enzyme phosphofructokinase. 
A)  an essential component of glycolysis for ATP production. 
B)  converted to 3-phosphoglycerate with formation of ATP. 
C)  essential for the efficient release of O2 from hemoglobin. 
D)  a product of the enzyme phosphofructokinase.

Question 11

What are the effects of protein kinase A on PFK-2 and pyruvate kinase?

Accepted Answer

A)  phosphorylates PFK-2; dephosphorylated pyruvate kinase; both enzymes are inhibited 
B)  phosphorylates both enzymes; inhibits both enzymes 
C)  dephosphorylates both enzymes; inhibits both enzymes 
D)  dephosphorylates PFK-2; phosphorylates pyruvate kinase; activates PFK-2; inhibits pyruvate kinase 
A)  phosphorylates PFK-2; dephosphorylated pyruvate kinase; both enzymes are inhibited 
B)  phosphorylates both enzymes; inhibits both enzymes 
C)  dephosphorylates both enzymes; inhibits both enzymes 
D)  dephosphorylates PFK-2; phosphorylates pyruvate kinase; activates PFK-2; inhibits pyruvate kinase

Question 12

Glucose is the only monosaccharide that can enter the glycolytic pathway at the first step. All other monosaccharides enter at a subsequent step in the pathway.

Accepted Answer

A) True 
 B)False

Question 13

Transfer of the phosphoryl group from PEP to ADP is an example of

Accepted Answer

A)  a mutase reaction. 
B)  isomerization. 
C)  dehydrogenase. 
D)  substrate-level phosphorylation. 
A)  a mutase reaction. 
B)  isomerization. 
C)  dehydrogenase. 
D)  substrate-level phosphorylation.

Question 14

Glucose 6-phosphate allosterically inhibits

Accepted Answer

A)  hexokinase I. 
B)  glucokinase. 
C)  hexokinase II. 
D)  All of the above 
E)  A and C only 
A)  hexokinase I. 
B)  glucokinase. 
C)  hexokinase II. 
D)  All of the above 
E)  A and C only

Question 15

Glyceraldehyde 3-phosphate dehydrogenase causes

Accepted Answer

A)  the reduction and phosphorylation of glyceraldehyde 3-phosphate to produce 1,3-bisphosphoglycerate. 
B)  the oxidation of a molecule of NAD+ to NADH. 
C)  Neither A nor B 
D)  Both A and B 
A)  the reduction and phosphorylation of glyceraldehyde 3-phosphate to produce 1,3-bisphosphoglycerate. 
B)  the oxidation of a molecule of NAD+ to NADH. 
C)  Neither A nor B 
D)  Both A and B

Question 16

What chemical species activates the GLUT4 protein to transport glucose into cells?

Accepted Answer

A)  adrenaline 
B)  insulin 
C)  protein kinase A 
D)  PFK-2 
A)  adrenaline 
B)  insulin 
C)  protein kinase A 
D)  PFK-2

Question 17

An intramolecular phosphoryl-group transfer occurs when

Accepted Answer

A)  2-phosphoglycerate is converted to phosphoenolpyruvate. 
B)  1,3-bisphosphoglycerate is converted to 3-phosphoglycerate. 
C)  Both A and B 
D)  None of the above 
A)  2-phosphoglycerate is converted to phosphoenolpyruvate. 
B)  1,3-bisphosphoglycerate is converted to 3-phosphoglycerate. 
C)  Both A and B 
D)  None of the above

Question 18

Isozymes are different proteins from one species which catalyze different chemical reactions.

Accepted Answer

A) True 
 B)False

Question 19

Which of the following mutases catalyze the formation of a 2,3-BPG intermediate?

Accepted Answer

A)  muscle phosphoglycerate mutases 
B)  plant phosphoglycerate mutases 
C)  yeast phosphoglycerate mutases 
D)  A and C only 
E)  All of the above 
A)  muscle phosphoglycerate mutases 
B)  plant phosphoglycerate mutases 
C)  yeast phosphoglycerate mutases 
D)  A and C only 
E)  All of the above

Question 20

In some diabetic patients, glucose increases disproportionately and is unresponsive to an insulin challenge; under these conditions, how would oneʹs liver normally respond?

Accepted Answer

A)  phosphorylating glucose for entry into the glycolytic pathway 
B)  saturating glucokinase with glucose 
C)  phosphorylating glucose for entry into the glycogen synthesis pathways 
D)  A and B only 
E)  A and C only 
A)  phosphorylating glucose for entry into the glycolytic pathway 
B)  saturating glucokinase with glucose 
C)  phosphorylating glucose for entry into the glycogen synthesis pathways 
D)  A and B only 
E)  A and C only

Exam 11: Glycolysis

Isozymes are enzymes

How does mannose enter the glycolytic pathway?

What happens to pyruvate if it is destined for the citric acid cycle?

Seven of the ten reactions in the glycolytic pathway have free energy values close to zero. What does this tell us about those reactions?

How does the number of molecules of ATP produced compare for conversion of one molecule of either glucose or fructose to pyruvate?

Phosphofructokinase I deficiency results in

Yeast will normally convert pyruvate to ethanol. Why is this better for the yeast than a conversion to lactate?

Mutases are described as

The activity of which glycolytic enzyme shown below is not used to control the rate of glycolysis?

2,3-bisphosphoglycerate is

What are the effects of protein kinase A on PFK-2 and pyruvate kinase?

Glucose is the only monosaccharide that can enter the glycolytic pathway at the first step. All other monosaccharides enter at a subsequent step in the pathway.

Transfer of the phosphoryl group from PEP to ADP is an example of

Glucose 6-phosphate allosterically inhibits

Glyceraldehyde 3-phosphate dehydrogenase causes

What chemical species activates the GLUT4 protein to transport glucose into cells?

An intramolecular phosphoryl-group transfer occurs when

Isozymes are different proteins from one species which catalyze different chemical reactions.

Which of the following mutases catalyze the formation of a 2,3-BPG intermediate?

In some diabetic patients, glucose increases disproportionately and is unresponsive to an insulin challenge; under these conditions, how would oneʹs liver normally respond?

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

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Dna Replication, Repair, and Recombination

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

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