Question 1

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 2

Which of the following 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 3

An extract of adipose (fat)tissue can metabolize glucose to CO2.When glucose labeled with 14C in either C-1 or C-6 was added to the extract,14CO2 was released with the time courses shown below.What is the major path of glucose oxidation in this extract? Explain how you reached this conclusion.

Accepted Answer

The tissue must be oxidizing glucose pri

Question 4

The first reaction in glycolysis that results in the formation of an energy-rich compound is catalyzed by:

Accepted Answer

A) glyceraldehyde 3-phosphate dehydrogenase. 
B) hexokinase. 
C) phosphofructokinase-1. 
D) phosphoglycerate kinase. 
E) triose phosphate isomerase. 
A) glyceraldehyde 3-phosphate dehydrogenase. 
B) hexokinase. 
C) phosphofructokinase-1. 
D) phosphoglycerate kinase. 
E) triose phosphate isomerase.

Question 5

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

The glycolytic pathway is so c

Question 6

In comparison with the resting state,actively contracting human muscle tissue has a:

Accepted Answer

A) higher concentration of ATP. 
B) higher rate of lactate formation. 
C) lower consumption of glucose. 
D) lower rate of consumption of oxygen 
E) lower ratio of NADH to NAD+. 
A) higher concentration of ATP. 
B) higher rate of lactate formation. 
C) lower consumption of glucose. 
D) lower rate of consumption of oxygen 
E) lower ratio of NADH to NAD+.

Question 7

Which of the following reactions in glycolysis utilizes a covalent enzyme intermediate?

Accepted Answer

A) Phosphofructokinase-1 
B) Glyceraldehyde-3-phosphate dehydrogenase 
C) Phosphohexose isomerase 
D) Enolase 
E) Triose phosphate isomerase 
A) Phosphofructokinase-1 
B) Glyceraldehyde-3-phosphate dehydrogenase 
C) Phosphohexose isomerase 
D) Enolase 
E) Triose phosphate isomerase

Question 8

The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following except:

Accepted Answer

A) ATP synthesis. 
B) catalysis by phosphoglycerate kinase. 
C) oxidation of NADH to NAD+. 
D) the formation of 1,3-bisphosphoglycerate. 
E) utilization of Pi. 
A) ATP synthesis. 
B) catalysis by phosphoglycerate kinase. 
C) oxidation of NADH to NAD+. 
D) the formation of 1,3-bisphosphoglycerate. 
E) utilization of Pi.

Question 9

When a mixture of glucose 6-phosphate and fructose 6-phosphate is incubated with the enzyme phosphohexose isomerase,the final mixture contains twice as much glucose 6-phosphate as fructose 6-phosphate.Which one of the following statements is most nearly correct,when applied to the reaction below (R = 8.315 J/mol·K and T = 298 K)?
Glucose 6-phosphate ↔ fructose 6-phosphate

Accepted Answer

A) ($\Delta$G'° is +1.7 kJ/mol.) 
B) ($\Delta$G'° is -1.7 kJ/mol.) 
C) ($\Delta$G'° is incalculably large and negative.) 
D) ($\Delta$G'° is incalculably large and positive.) 
E) ($\Delta$G'° is zero.) 
A) ($\Delta$G'° is +1.7 kJ/mol.) 
B) ($\Delta$G'° is -1.7 kJ/mol.) 
C) ($\Delta$G'° is incalculably large and negative.) 
D) ($\Delta$G'° is incalculably large and positive.) 
E) ($\Delta$G'° is zero.)

Question 10

The conversion of glucose into glucose 6-phosphate,which must occur in the breakdown of glucose,is thermodynamically unfavorable (endergonic).How do cells overcome this problem?

Accepted Answer

Cells often drive a thermodynamically un

Question 11

If you incubate 14C-CO2 with liver extracts capable of performing gluconeogenesis,where does the radioactive label end up?

Accepted Answer

It ends up in carbon dioxide a

Question 12

The metabolic function of the pentose phosphate pathway is to:

Accepted Answer

A) act as a source of ADP biosynthesis. 
B) generate NADPH and pentoses for the biosynthesis of fatty acids and nucleic acids. 
C) participate in oxidation-reduction reactions during the formation of H2O. 
D) provide intermediates for the citric acid cycle. 
E) synthesize phosphorus pentoxide. 
A) act as a source of ADP biosynthesis. 
B) generate NADPH and pentoses for the biosynthesis of fatty acids and nucleic acids. 
C) participate in oxidation-reduction reactions during the formation of H2O. 
D) provide intermediates for the citric acid cycle. 
E) synthesize phosphorus pentoxide.

Question 13

Inorganic fluoride inhibits enolase.In an anaerobic system that is metabolizing glucose as a substrate,which of the following compounds would you expect to increase in concentration following the addition of fluoride?

Accepted Answer

A) 2-Phosphoglycerate 
B) Glucose 
C) Glyoxylate 
D) Phosphoenolpyruvate 
E) Pyruvate 
A) 2-Phosphoglycerate 
B) Glucose 
C) Glyoxylate 
D) Phosphoenolpyruvate 
E) Pyruvate

Question 14

Describe the glycolytic pathway from glucose to glyceraldehyde 3-phosphate.Show structures of intermediates,enzyme names,and indicate where any cofactors participate.

Accepted Answer

This part of the pathway invol

Question 15

In glycolysis there are two reactions that require one ATP each and two reactions that produce one ATP each.This being the case,how can fermentation of glucose to lactate lead to the net production of two ATP molecules per glucose?

Accepted Answer

The two reactions that produce ATP in gl

Question 16

What are the two reactions in glycolysis in which aldose to ketose isomerization is catalyzed by an enzyme? For both reactions the $\Delta$G'° is positive.Briefly explain how the reactions are able to proceed without the input of additional energy.

Accepted Answer

The two reactions are those catalyzed by

Question 17

The compound [18F]2-fluoro-2-deoxyglucose is:

Accepted Answer

A) an intermediate in glycolysis 
B) a positive regulator of glycolysis 
C) a potent anti-cancer agent 
D) an antibiotic 
E) an imaging agent used to detect tumors 
A) an intermediate in glycolysis 
B) a positive regulator of glycolysis 
C) a potent anti-cancer agent 
D) an antibiotic 
E) an imaging agent used to detect tumors

Question 18

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 19

Which of these cofactors participates directly in most of the oxidation-reduction reactions in the fermentation of glucose to lactate?

Accepted Answer

A) ADP 
B) ATP 
C) FAD/FADH2  
D) Glyceraldehyde 3-phosphate 
E) NAD+/NADH 
A) ADP 
B) ATP 
C) FAD/FADH2  
D) Glyceraldehyde 3-phosphate 
E) NAD+/NADH

Question 20

Which one of the following statements about gluconeogenesis is false?

Accepted Answer

A) For starting materials,it can use carbon skeletons derived from certain amino acids. 
B) It consists entirely of the reactions of glycolysis,operating in the reverse direction. 
C) It employs the enzyme glucose 6-phosphatase. 
D) It is one of the ways that mammals maintain normal blood glucose levels between meals. 
E) It requires metabolic energy (ATP or GTP). 
A) For starting materials,it can use carbon skeletons derived from certain amino acids. 
B) It consists entirely of the reactions of glycolysis,operating in the reverse direction. 
C) It employs the enzyme glucose 6-phosphatase. 
D) It is one of the ways that mammals maintain normal blood glucose levels between meals. 
E) It requires metabolic energy (ATP or GTP).

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

Glycogen is converted to monosaccharide units by:

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

An extract of adipose (fat)tissue can metabolize glucose to CO2.When glucose labeled with 14C in either C-1 or C-6 was added to the extract,14CO2 was released with the time courses shown below.What is the major path of glucose oxidation in this extract? Explain how you reached this conclusion.

The first reaction in glycolysis that results in the formation of an energy-rich compound is catalyzed by:

In comparison with the resting state,actively contracting human muscle tissue has a:

Which of the following reactions in glycolysis utilizes a covalent enzyme intermediate?

The steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate involve all of the following except:

The conversion of glucose into glucose 6-phosphate,which must occur in the breakdown of glucose,is thermodynamically unfavorable (endergonic).How do cells overcome this problem?

If you incubate 14C-CO2 with liver extracts capable of performing gluconeogenesis,where does the radioactive label end up?

The metabolic function of the pentose phosphate pathway is to:

Inorganic fluoride inhibits enolase.In an anaerobic system that is metabolizing glucose as a substrate,which of the following compounds would you expect to increase in concentration following the addition of fluoride?

Describe the glycolytic pathway from glucose to glyceraldehyde 3-phosphate.Show structures of intermediates,enzyme names,and indicate where any cofactors participate.

In glycolysis there are two reactions that require one ATP each and two reactions that produce one ATP each.This being the case,how can fermentation of glucose to lactate lead to the net production of two ATP molecules per glucose?

What are the two reactions in glycolysis in which aldose to ketose isomerization is catalyzed by an enzyme? For both reactions the Δ\DeltaΔ G'° is positive.Briefly explain how the reactions are able to proceed without the input of additional energy.

The compound [18F]2-fluoro-2-deoxyglucose is:

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:

Which of these cofactors participates directly in most of the oxidation-reduction reactions in the fermentation of glucose to lactate?

Which one of the following statements about gluconeogenesis is false?

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

Recombinant Dna Technology

Lipids

Biological Membranes and Transport

Biosignaling

Principles of Bioenergetics

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

Integration and Hormonal Regulation of Mammalian Metabolism

Genes and Chromosomes

Dna Metabolism

Rna Metabolism

Protein Metabolism

Regulation of Gene Expression

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If you incubate ¹⁴C-CO₂ with liver extracts capable of performing gluconeogenesis,where does the radioactive label end up?

What are the two reactions in glycolysis in which aldose to ketose isomerization is catalyzed by an enzyme? For both reactions the $\Delta$ G'° is positive.Briefly explain how the reactions are able to proceed without the input of additional energy.

The compound [¹⁸F]2-fluoro-2-deoxyglucose is: