Question 1

What is the net yield of ATP produced by the anaerobic fermentation of one molecule of sucrose in myocytes?

Accepted Answer

A)  2 
B)  3 
C)  4 
D)  6 
E)  8 
A)  2 
B)  3 
C)  4 
D)  6 
E)  8 C

Question 2

Which statement describes the activity of hexokinase I CORRECTLY?

Accepted Answer

A)  It catalyzes the conversion of glucose-6-phosphate into fructose 1,6-bisphosphate. 
B)  It requires Mn2+ for maximal activity. 
C)  It uses inorganic phosphate to form glucose-6-phosphate. 
D)  It is relatively nonspecific in its choice of monosaccharides. 
E)  This enzyme is classified as a ligase enzyme, as it couples the phosphorylation of glucose to the cleavage of ATP. 
A)  It catalyzes the conversion of glucose-6-phosphate into fructose 1,6-bisphosphate. 
B)  It requires Mn2+ for maximal activity. 
C)  It uses inorganic phosphate to form glucose-6-phosphate. 
D)  It is relatively nonspecific in its choice of monosaccharides. 
E)  This enzyme is classified as a ligase enzyme, as it couples the phosphorylation of glucose to the cleavage of ATP. D

Question 3

Which statement about the pentose phosphate pathway is CORRECT?

Accepted Answer

A)  It generates 36 mol of ATP per mole of glucose consumed. 
B)  It generates 6 moles of CO2 for each mole of glucose consumed 
C)  It is a reductive pathway; it consumes NADH. 
D)  It is present in plants, but not in animals. 
E)  It provides precursors for the synthesis of nucleotides. 
A)  It generates 36 mol of ATP per mole of glucose consumed. 
B)  It generates 6 moles of CO2 for each mole of glucose consumed 
C)  It is a reductive pathway; it consumes NADH. 
D)  It is present in plants, but not in animals. 
E)  It provides precursors for the synthesis of nucleotides. E

Question 4

Explain why a mutation in the gene for fructose 1,6-bisphosphatase in the liver maybe associated with metabolic acidosis.

Accepted Answer

Fructose 1,6-bisphosphatase is an enzyme

Question 5

In an anaerobic muscle preparation, lactate formed from glucose labeled in C-3 and C-4 would be labeled in:

Accepted Answer

A)  all three carbon atoms. 
B)  only the carbon atom carrying the OH. 
C)  only the carboxyl carbon atom. 
D)  only the methyl carbon atom. 
E)  the methyl and carboxyl carbon atoms. 
A)  all three carbon atoms. 
B)  only the carbon atom carrying the OH. 
C)  only the carboxyl carbon atom. 
D)  only the methyl carbon atom. 
E)  the methyl and carboxyl carbon atoms.

Question 6

In a tissue that metabolizes glucose via the pentose phosphate pathway, C-1 of glucose would be expected to end up principally in:

Accepted Answer

A)  carbon dioxide. 
B)  glycogen. 
C)  phosphoglycerate. 
D)  pyruvate. 
E)  ribulose 5-phosphate. 
A)  carbon dioxide. 
B)  glycogen. 
C)  phosphoglycerate. 
D)  pyruvate. 
E)  ribulose 5-phosphate.

Question 7

What is the energetic cost of running the Cori cycle per glucose molecule?

Accepted Answer

A)  2 NTP 
B)  3 NTP 
C)  4 NTP 
D)  5 NTP 
E)  6 NTP 
A)  2 NTP 
B)  3 NTP 
C)  4 NTP 
D)  5 NTP 
E)  6 NTP

Question 8

Which enzyme catalyzes an energy-capture reaction in glycolysis?

Accepted Answer

A)  hexokinase. 
B)  pyruvate kinase 
C)  glyceraldehyde-3-phosphate dehydrogenase 
D)  pyruvate kinase and glyceraldehyde-3-phosphate dehydrogenase 
E)  hexokinase, pyruvate kinase, and glyceraldehyde-3-phosphapate dehydrogenase 
A)  hexokinase. 
B)  pyruvate kinase 
C)  glyceraldehyde-3-phosphate dehydrogenase 
D)  pyruvate kinase and glyceraldehyde-3-phosphate dehydrogenase 
E)  hexokinase, pyruvate kinase, and glyceraldehyde-3-phosphapate dehydrogenase

Question 9

Which reaction in glycolysis is a ketose to aldose isomerization?

Accepted Answer

A)  hexokinase 
B)  phosphoglycerate mutase 
C)  enolase 
D)  aldolase 
E)  triose phosphate isomerase 
A)  hexokinase 
B)  phosphoglycerate mutase 
C)  enolase 
D)  aldolase 
E)  triose phosphate isomerase

Question 10

Which process is NOT involved in the steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate?

Accepted Answer

A)  a substrate-level phosphorylation reaction 
B)  catalysis by an isomerase enzyme 
C)  reduction of NAD+ to NADH 
D)  the formation of a mixed anhydride intermediate. 
E)  the indirect coupling of reactions catalyzed by a kinase and a dehydrogenase enzyme 
A)  a substrate-level phosphorylation reaction 
B)  catalysis by an isomerase enzyme 
C)  reduction of NAD+ to NADH 
D)  the formation of a mixed anhydride intermediate. 
E)  the indirect coupling of reactions catalyzed by a kinase and a dehydrogenase enzyme

Question 11

Define "fermentation" and explain, by describing relevant reactions, how it differs from glycolysis. Your explanation should include a discussion of the role of NADH in the reaction(s).

Accepted Answer

Fermentation is a metabolic process that

Question 12

In an anaerobic muscle preparation, lactate formed from glucose labeled in C-2 would be labeled in:

Accepted Answer

A)  all three carbon atoms. 
B)  only the carbon atom carrying the OH. 
C)  only the carboxyl carbon atom. 
D)  only the methyl carbon atom. 
E)  the methyl and carboxyl carbon atoms. 
A)  all three carbon atoms. 
B)  only the carbon atom carrying the OH. 
C)  only the carboxyl carbon atom. 
D)  only the methyl carbon atom. 
E)  the methyl and carboxyl carbon atoms.

Question 13

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

Question 14

The bacterium E. coli can grow in a medium in which the only carbon source is glucose. How does this organism obtain ribose 5-phosphate for the synthesis of ATP? (Do not describe ATP synthesis, just the origin of ribose 5-phosphate.) Show structures and indicate where cofactors participate.

Accepted Answer

E. coli, like many other organisms, can

Question 15

What is the general name for an enzyme that catalyzes an intramolecular phosphoryl shift?

Accepted Answer

A)  phosphatase 
B)  mutase 
C)  kinase 
D)  phosphoylase 
E)  phosphate translocase 
A)  phosphatase 
B)  mutase 
C)  kinase 
D)  phosphoylase 
E)  phosphate translocase

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

In glycolysis, the process by which gluc

Question 17

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 18

What are the biological functions of the pentose phosphate pathway?

Accepted Answer

The pentose phosphate pathway (PPP), als

Question 19

What is gluconeogenesis, and what useful purposes does it serve in people?

Accepted Answer

Gluconeogenesis is the process by which

Question 20

Glucose breakdown in certain mammalian and bacterial cells can occur by mechanisms other than classic glycolysis. In most of these, glucose 6-phosphate is oxidized to 6-phosphogluconate, which is then further metabolized by:

Accepted Answer

A)  an aldolase-type split to form glyceric acid and glyceraldehyde 3-phosphate. 
B)  an aldolase-type split to form glycolic acid and erythrose 4-phosphate. 
C)  conversion to 1,6-bisphosphogluconate. 
D)  decarboxylation to produce keto- and aldopentoses. 
E)  oxidation to a six-carbon dicarboxylic acid. 
A)  an aldolase-type split to form glyceric acid and glyceraldehyde 3-phosphate. 
B)  an aldolase-type split to form glycolic acid and erythrose 4-phosphate. 
C)  conversion to 1,6-bisphosphogluconate. 
D)  decarboxylation to produce keto- and aldopentoses. 
E)  oxidation to a six-carbon dicarboxylic acid.

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

What is the net yield of ATP produced by the anaerobic fermentation of one molecule of sucrose in myocytes?

Which statement describes the activity of hexokinase I CORRECTLY?

Which statement about the pentose phosphate pathway is CORRECT?

Explain why a mutation in the gene for fructose 1,6-bisphosphatase in the liver maybe associated with metabolic acidosis.

In an anaerobic muscle preparation, lactate formed from glucose labeled in C-3 and C-4 would be labeled in:

In a tissue that metabolizes glucose via the pentose phosphate pathway, C-1 of glucose would be expected to end up principally in:

What is the energetic cost of running the Cori cycle per glucose molecule?

Which enzyme catalyzes an energy-capture reaction in glycolysis?

Which reaction in glycolysis is a ketose to aldose isomerization?

Which process is NOT involved in the steps of glycolysis between glyceraldehyde 3-phosphate and 3-phosphoglycerate?

Define "fermentation" and explain, by describing relevant reactions, how it differs from glycolysis. Your explanation should include a discussion of the role of NADH in the reaction(s).

In an anaerobic muscle preparation, lactate formed from glucose labeled in C-2 would be labeled in:

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 bacterium E. coli can grow in a medium in which the only carbon source is glucose. How does this organism obtain ribose 5-phosphate for the synthesis of ATP? (Do not describe ATP synthesis, just the origin of ribose 5-phosphate.) Show structures and indicate where cofactors participate.

What is the general name for an enzyme that catalyzes an intramolecular phosphoryl shift?

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 metabolic function of the pentose phosphate pathway is to:

What are the biological functions of the pentose phosphate pathway?

What is gluconeogenesis, and what useful purposes does it serve in people?

Glucose breakdown in certain mammalian and bacterial cells can occur by mechanisms other than classic glycolysis. In most of these, glucose 6-phosphate is oxidized to 6-phosphogluconate, which is then further metabolized by:

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

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.