Question 1

All ten steps of the glycolytic pathway must have negative free energies for glycolysis to proceed.

Accepted Answer

A) True 
 B)False

Question 2

Glucagon triggers the adenylate cyclase signally pathway. This activates protein kinase A which phosphorylates serine residues.

Accepted Answer

A) True 
 B)False

Question 3

Which amino acidʹs residue plays a role in the phosphoglycerate mutase reaction in glycolysis for muscle and yeast?

Accepted Answer

A)  leucine 
B)  lysine 
C)  alanine 
D)  histidine 
A)  leucine 
B)  lysine 
C)  alanine 
D)  histidine

Question 4

Which substance is a product of glycolysis, a precursor of gluconeogenesis and a precursor of the citric acid cycle?

Accepted Answer

A)  glucose 
B)  pyruvate 
C)  ATP 
D)  coenzyme A 
A)  glucose 
B)  pyruvate 
C)  ATP 
D)  coenzyme A

Question 5

Citrate is an intermediate in the citric acid cycle, yet it is also an inhibitor of PFK-1. This is an example of feedback inhibition.

Accepted Answer

A) True 
 B)False

Question 6

Two molecules of ATP are consumed per glucose during the triose stage of glycolysis.

Accepted Answer

A) True 
 B)False

Question 7

Which of the following elements is required for the enzymatic reaction that produces phosphoenolpyruvate?

Accepted Answer

A)  potassium 
B)  calcium 
C)  magnesium 
D)  manganese 
A)  potassium 
B)  calcium 
C)  magnesium 
D)  manganese

Question 8

The conversion of pyruvate to ethanol also causes the .

Accepted Answer

A)  oxidation of NADH 
B)  production of ADP 
C)  consumption of O2 
D)  generation of an ion gradient across mitochondrial membranes 
A)  oxidation of NADH 
B)  production of ADP 
C)  consumption of O2 
D)  generation of an ion gradient across mitochondrial membranes

Question 9

Once inside a cell, glucose is rapidly phosphorylated to glucose-6-phosphate. What is the main purpose of this phosphorylation?

Accepted Answer

A)  to keep glucose inside the cell 
B)  to form a high-energy compound 
C)  to activate PFK-1 
D)  to prevent mutarotation 
A)  to keep glucose inside the cell 
B)  to form a high-energy compound 
C)  to activate PFK-1 
D)  to prevent mutarotation

Question 10

Which is not part of the Entner-Doudoroff pathway?

Accepted Answer

A)  consumption of ATP 
B)  the enzyme gluconolactonase 
C)  an unusual dehydrase reaction from 6-phosphogluconate to KDPG 
D)  the production of pyruvate 
E)  the production of NADPH 
A)  consumption of ATP 
B)  the enzyme gluconolactonase 
C)  an unusual dehydrase reaction from 6-phosphogluconate to KDPG 
D)  the production of pyruvate 
E)  the production of NADPH

Question 11

Glucose is normally transported into cells by an active transport protein since the concentration of glucose inside cells is normally higher than that in the blood.

Accepted Answer

A) True 
 B)False

Question 12

During glycolysis, isomerization occurs during which of the following reactions?

Accepted Answer

A)  Fructose 1,6-bisphosphate → dihydroxyacetone phosphate and glyceraldehyde 3-phosphate 
B)  Fructose 6-phosphate → fructose 1,6-bisphosphate 
C)  Glucose 6- phosphate → fructose 6- phosphate 
D)  Glucose → glucose 6- phosphate 
A)  Fructose 1,6-bisphosphate → dihydroxyacetone phosphate and glyceraldehyde 3-phosphate 
B)  Fructose 6-phosphate → fructose 1,6-bisphosphate 
C)  Glucose 6- phosphate → fructose 6- phosphate 
D)  Glucose → glucose 6- phosphate

Question 13

ATP is a cosubstrate of the enzyme PFK-1. In most species ATP is also an inhibitor of PFK-1 at higher concentrations. This seems to violate Le Chatelierʹs Principle. Which statement below would provide a suitable explanation?

Accepted Answer

A)  PFK-1 must be phosphorylated by ATP in the active site and the phosphorylated PFK-1 must be the less active form. 
B)  There must be another cofactor interacting with ATP at high concentrations to achieve inhibition of PFK-1. 
C)  ATP actually activates the reverse of the reaction preceding the PFK-1 step in the pathway. It likely has no direct effect on PFK-1. 
D)  There are two sites on PFK-1 that bind ATP. One is the active site; the other is the regulatory site where inhibition occurs. 
A)  PFK-1 must be phosphorylated by ATP in the active site and the phosphorylated PFK-1 must be the less active form. 
B)  There must be another cofactor interacting with ATP at high concentrations to achieve inhibition of PFK-1. 
C)  ATP actually activates the reverse of the reaction preceding the PFK-1 step in the pathway. It likely has no direct effect on PFK-1. 
D)  There are two sites on PFK-1 that bind ATP. One is the active site; the other is the regulatory site where inhibition occurs.

Question 14

The molecule 1,3-bisphosphoglycerate can be converted to 3-phosphoenolpyruvate two ways. One way is catalyzed by the glycolytic pathway enzyme phosphoglycerate kinase. The other route is a two step reaction sequence that uses the enzymes bisphosphoglycerate mutase and 2,3-bisphosphoglycerate phosphatase. The intermediate product of the two-step sequence is 2,3-BPG which is an allosteric inhibitor of hemoglobin. What disadvantage would there be if the glycolytic pathway only used the two-step reaction sequence?

Accepted Answer

A)  The step catalyzed by phosphoglycerate kinase is one of the ATP producing steps of glycolysis. Using only the two-step reaction sequence would reduce the number of ATPʹs produced. 
B)  There is no disadvantage to the two-step sequence other than having to use more than one enzyme. 
C)  The molecule 2,3-BPG is also a potent inhibitor of PFK-1. Even transient production of 2,3-BPG will significantly slow glycolysis. 
D)  Too much 2,3-BPG would be produced which would cause clumping of red blood cells. 
A)  The step catalyzed by phosphoglycerate kinase is one of the ATP producing steps of glycolysis. Using only the two-step reaction sequence would reduce the number of ATPʹs produced. 
B)  There is no disadvantage to the two-step sequence other than having to use more than one enzyme. 
C)  The molecule 2,3-BPG is also a potent inhibitor of PFK-1. Even transient production of 2,3-BPG will significantly slow glycolysis. 
D)  Too much 2,3-BPG would be produced which would cause clumping of red blood cells.

All ten steps of the glycolytic pathway must have negative free energies for glycolysis to proceed.

Glucagon triggers the adenylate cyclase signally pathway. This activates protein kinase A which phosphorylates serine residues.

Which amino acidʹs residue plays a role in the phosphoglycerate mutase reaction in glycolysis for muscle and yeast?

Which substance is a product of glycolysis, a precursor of gluconeogenesis and a precursor of the citric acid cycle?

Citrate is an intermediate in the citric acid cycle, yet it is also an inhibitor of PFK-1. This is an example of feedback inhibition.

Two molecules of ATP are consumed per glucose during the triose stage of glycolysis.

Which of the following elements is required for the enzymatic reaction that produces phosphoenolpyruvate?

The conversion of pyruvate to ethanol also causes the .

Once inside a cell, glucose is rapidly phosphorylated to glucose-6-phosphate. What is the main purpose of this phosphorylation?

Which is not part of the Entner-Doudoroff pathway?

Glucose is normally transported into cells by an active transport protein since the concentration of glucose inside cells is normally higher than that in the blood.

During glycolysis, isomerization occurs during which of the following reactions?

ATP is a cosubstrate of the enzyme PFK-1. In most species ATP is also an inhibitor of PFK-1 at higher concentrations. This seems to violate Le Chatelierʹs Principle. Which statement below would provide a suitable explanation?

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

Filters

Exam 11: Glycolysis

All ten steps of the glycolytic pathway must have negative free energies for glycolysis to proceed.

Glucagon triggers the adenylate cyclase signally pathway. This activates protein kinase A which phosphorylates serine residues.

Which amino acidʹs residue plays a role in the phosphoglycerate mutase reaction in glycolysis for muscle and yeast?

Which substance is a product of glycolysis, a precursor of gluconeogenesis and a precursor of the citric acid cycle?

Citrate is an intermediate in the citric acid cycle, yet it is also an inhibitor of PFK-1. This is an example of feedback inhibition.

Two molecules of ATP are consumed per glucose during the triose stage of glycolysis.

Which of the following elements is required for the enzymatic reaction that produces phosphoenolpyruvate?

The conversion of pyruvate to ethanol also causes the .

Once inside a cell, glucose is rapidly phosphorylated to glucose-6-phosphate. What is the main purpose of this phosphorylation?

Which is not part of the Entner-Doudoroff pathway?

Glucose is normally transported into cells by an active transport protein since the concentration of glucose inside cells is normally higher than that in the blood.

During glycolysis, isomerization occurs during which of the following reactions?

ATP is a cosubstrate of the enzyme PFK-1. In most species ATP is also an inhibitor of PFK-1 at higher concentrations. This seems to violate Le Chatelierʹs Principle. Which statement below would provide a suitable explanation?

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

Filters