Question 1

Which reaction in glycolysis is an aldose to ketose isomerization?

Accepted Answer

A)  enolase 
B)  phosphoglycerate mutase 
C)  phosphohexose isomerase 
D)  aldolase 
E)  glyceraldehyde-3-phosphate dehydrogenase 
A)  enolase 
B)  phosphoglycerate mutase 
C)  phosphohexose isomerase 
D)  aldolase 
E)  glyceraldehyde-3-phosphate dehydrogenase

Question 2

Which process is NOT considered a general function of the pentose phosphate pathway?

Accepted Answer

A)  the production of NADPH for reductive biosynthesis in adipose cells 
B)  the production of NADPH to help prevent oxidative stress in erythrocytes 
C)  the production of pentoses necessary for nucleotide synthesis 
D)  the production of erythrose 4-phosphate for synthesis of aromatic amino acids 
E)  the transfer of electrons to NADP+ for eventual entry into the electron transport chain 
A)  the production of NADPH for reductive biosynthesis in adipose cells 
B)  the production of NADPH to help prevent oxidative stress in erythrocytes 
C)  the production of pentoses necessary for nucleotide synthesis 
D)  the production of erythrose 4-phosphate for synthesis of aromatic amino acids 
E)  the transfer of electrons to NADP+ for eventual entry into the electron transport chain

Question 3

Which item is a cofactor in the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase?

Accepted Answer

A)  ATP 
B)  Cu2+ 
C)  heme 
D)  NAD+ 
E)  NADP+ 
A)  ATP 
B)  Cu2+ 
C)  heme 
D)  NAD+ 
E)  NADP+

Question 4

Explain why the phosphorolysis of glycogen is more efficient than the hydrolysis of glycogen in mobilizing glucose for the glycolytic pathway.

Accepted Answer

The phosphorolysis of glycogen is more e

Question 5

What is the net yield of ATP produced by the anaerobic fermentation of one molecule of galactose to two molecules of lactate in myocytes

Accepted Answer

A)  2 
B)  3 
C)  4 
D)  6 
E)  None of the answers is correct. 
A)  2 
B)  3 
C)  4 
D)  6 
E)  None of the answers is correct.

Question 6

Show how NADH is recycled to NAD+ under aerobic conditions and under anaerobic conditions. Why is it important to recycle NADH produced during glycolysis to NAD+?

Accepted Answer

Under aerobic conditions, NADH is recycl

Question 7

The conversion of glyceraldehyde 3-phosphate to dihydroxyacetone phosphate is catalyzed by triose phosphate isomerase. The standard free-energy change ($\Delta$ G'°) for this reaction is -7.5 kJ/mol. Define the equilibrium constant for the reaction and calculate it using only the data given here. (R = 8.315 J/mol · K; T = 298 K)

Accepted Answer

The equilibrium constant for a chemical

Question 8

What would be the products of the reaction, if aldolase used glucose-6-phosphate instead of fructose-1,6-bisphosphate? Based on your answer, can you suggest a possible rationale for why nature chose to include two extra steps prior to the aldolase step?

Accepted Answer

If aldolase used glucose-6-phosphate ins

Question 9

Which statement is NOT true concerning glycolysis in anaerobic muscle?

Accepted Answer

A)  Fructose 1,6-bisphosphatase is one of the enzymes of the pathway. 
B)  It is an endergonic process. 
C)  It results in net synthesis of ATP. 
D)  It results in synthesis of NADH. 
E)  Its rate is slowed by a high [ATP]/[ADP] ratio. 
A)  Fructose 1,6-bisphosphatase is one of the enzymes of the pathway. 
B)  It is an endergonic process. 
C)  It results in net synthesis of ATP. 
D)  It results in synthesis of NADH. 
E)  Its rate is slowed by a high [ATP]/[ADP] ratio.

Question 10

Glucose is frequently administered to patients as a source of energy. Given that transformation of glucose to glucose 6-phosphate consumes energy in the form of ATP, why not administer glucose 6-phosphate?

Accepted Answer

While it is true that the transformation

Question 11

An enzyme used in both glycolysis and gluconeogenesis is:

Accepted Answer

A)  3-phosphoglycerate kinase. 
B)  glucose 6-phosphatase. 
C)  hexokinase. 
D)  phosphofructokinase-1. 
E)  pyruvate kinase. 
A)  3-phosphoglycerate kinase. 
B)  glucose 6-phosphatase. 
C)  hexokinase. 
D)  phosphofructokinase-1. 
E)  pyruvate kinase.

Question 12

If glucose labeled with 14C in C-1 were fed to yeast carrying out the ethanol fermentation, where would the 14C label be in the products?

Accepted Answer

A)  in C-1 of ethanol and CO2 
B)  in C-1 of ethanol only 
C)  in C-2 (methyl group) of ethanol only 
D)  in C-2 of ethanol and CO2 
E)  in CO2 only 
A)  in C-1 of ethanol and CO2 
B)  in C-1 of ethanol only 
C)  in C-2 (methyl group) of ethanol only 
D)  in C-2 of ethanol and CO2 
E)  in CO2 only

Question 13

Which statement is TRUE regarding the glycolytic pathway?

Accepted Answer

A)  It includes reactions catalyzed by three isomerase enzymes. 
B)  It includes five phosphate transfer reactions. 
C)  It includes three enzymes that are regulated by product inhibition. 
D)  All of the statements are true. 
E)  None of the statements is true. 
A)  It includes reactions catalyzed by three isomerase enzymes. 
B)  It includes five phosphate transfer reactions. 
C)  It includes three enzymes that are regulated by product inhibition. 
D)  All of the statements are true. 
E)  None of the statements is true.

Question 14

Which compound links glycolysis and nucleotide synthesis?

Accepted Answer

A)  acetyl-CoA 
B)  oxaloacetate 
C)  citrate 
D)  glucose 6-phosphate 
E)  glucose 3-phosphate 
A)  acetyl-CoA 
B)  oxaloacetate 
C)  citrate 
D)  glucose 6-phosphate 
E)  glucose 3-phosphate

Question 15

Glycogen is converted to monosaccharide units by:

Accepted Answer

A)  glucokinase. 
B)  glucose-6-phosphatase 
C)  glycogen phosphorylase. 
D)  glycogen synthase. 
E)  glycogenase. 
A)  glucokinase. 
B)  glucose-6-phosphatase 
C)  glycogen phosphorylase. 
D)  glycogen synthase. 
E)  glycogenase.

Question 16

The conversion of 1 mol of fructose 1,6-bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of:

Accepted Answer

A)  1 mol of NAD+ and 2 mol of ATP. 
B)  1 mol of NADH and 1 mol of ATP. 
C)  2 mol of NAD+ and 4 mol of ATP. 
D)  2 mol of NADH and 2 mol of ATP. 
E)  2 mol of NADH and 4 mol of ATP. 
A)  1 mol of NAD+ and 2 mol of ATP. 
B)  1 mol of NADH and 1 mol of ATP. 
C)  2 mol of NAD+ and 4 mol of ATP. 
D)  2 mol of NADH and 2 mol of ATP. 
E)  2 mol of NADH and 4 mol of ATP.

Question 17

There are a variety of fairly common human genetic diseases in which enzymes required for the breakdown of fructose, lactose, or sucrose are defective. However, there are very few cases of people having a genetic disease in which one of the enzymes of glycolysis is severely affected. Why do you suppose such mutations are seen so rarely?

Accepted Answer

There are a few reasons why mutations af

Question 18

The anaerobic conversion of 1 mol of glucose to 2 mol of lactate by fermentation is accompanied by a net gain of:

Accepted Answer

A)  1 mol of ATP. 
B)  1 mol of NADH. 
C)  2 mol of ATP. 
D)  2 mol of NADH. 
E)  None of the answers is correct. 
A)  1 mol of ATP. 
B)  1 mol of NADH. 
C)  2 mol of ATP. 
D)  2 mol of NADH. 
E)  None of the answers is correct.

Question 19

Glucose labeled with 14C in C-1 and C-6 gives rise in glycolysis to pyruvate labeled in:

Accepted Answer

A)  both its carbonyl and carboxyl carbons. 
B)  all three carbons. 
C)  its carbonyl carbon. 
D)  its carboxyl carbon. 
E)  its methyl carbon. 
A)  both its carbonyl and carboxyl carbons. 
B)  all three carbons. 
C)  its carbonyl carbon. 
D)  its carboxyl carbon. 
E)  its methyl carbon.

Question 20

All of the intermediated in the glycolytic pathway are phosphorylated. Give two plausible reasons why this might be advantageous to the cell.

Accepted Answer

The glycolytic pathway is a series of en

Exam 14: Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Which reaction in glycolysis is an aldose to ketose isomerization?

Which process is NOT considered a general function of the pentose phosphate pathway?

Which item is a cofactor in the reaction catalyzed by glyceraldehyde 3-phosphate dehydrogenase?

Explain why the phosphorolysis of glycogen is more efficient than the hydrolysis of glycogen in mobilizing glucose for the glycolytic pathway.

What is the net yield of ATP produced by the anaerobic fermentation of one molecule of galactose to two molecules of lactate in myocytes

Show how NADH is recycled to NAD+ under aerobic conditions and under anaerobic conditions. Why is it important to recycle NADH produced during glycolysis to NAD+?

What would be the products of the reaction, if aldolase used glucose-6-phosphate instead of fructose-1,6-bisphosphate? Based on your answer, can you suggest a possible rationale for why nature chose to include two extra steps prior to the aldolase step?

Which statement is NOT true concerning glycolysis in anaerobic muscle?

Glucose is frequently administered to patients as a source of energy. Given that transformation of glucose to glucose 6-phosphate consumes energy in the form of ATP, why not administer glucose 6-phosphate?

An enzyme used in both glycolysis and gluconeogenesis is:

If glucose labeled with 14C in C-1 were fed to yeast carrying out the ethanol fermentation, where would the 14C label be in the products?

Which statement is TRUE regarding the glycolytic pathway?

Which compound links glycolysis and nucleotide synthesis?

Glycogen is converted to monosaccharide units by:

The conversion of 1 mol of fructose 1,6-bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of:

The anaerobic conversion of 1 mol of glucose to 2 mol of lactate by fermentation is accompanied by a net gain of:

Glucose labeled with 14C in C-1 and C-6 gives rise in glycolysis to pyruvate labeled in:

All of the intermediated in the glycolytic pathway are phosphorylated. Give two plausible reasons why this might be advantageous to the cell.

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

Show how NADH is recycled to NAD⁺ under aerobic conditions and under anaerobic conditions. Why is it important to recycle NADH produced during glycolysis to NAD⁺?

If glucose labeled with ¹⁴C in C-1 were fed to yeast carrying out the ethanol fermentation, where would the ¹⁴C label be in the products?

Glucose labeled with ¹⁴C in C-1 and C-6 gives rise in glycolysis to pyruvate labeled in: