Question 1

Which of the following statements about the pentose phosphate pathway is incorrect?

Accepted Answer

A)  It generates CO2 from C-1 of glucose.
B)  It involves the conversion of an aldohexose to an aldopentose.
C)  It is prominant in lactating mammary gland.
D)  It is principally directed toward the generation of NADPH.
E)  It requires the participation of molecular oxygen.F) A) and B)
G) All of the above

Question 2

Which of the following enzymes acts in the pentose phosphate pathway?

Accepted Answer

A)  6-Phosphogluconate dehydrogenase
B)  Aldolase
C)  Glycogen phosphorylase
D)  Phosphofructokinase-1
E)  Pyruvate kinaseF) A) and D)
G) A) and E)

Question 3

Which of the following statements is incorrect?

Accepted Answer

A)  Aerobically,oxidative decarboxylation of pyruvate forms acetate that enters the citric acid cycle.
B)  In anaerobic muscle,pyruvate is converted to lactate.
C)  In yeast growing anaerobically,pyruvate is converted to ethanol.
D)  Reduction of pyruvate to lactate regenerates a cofactor essential for glycolysis.
E)  Under anaerobic conditions pyruvate does not form because glycolysis does not occur.F) A) and E)
G) A) and D)

Question 4

Which of the following statements 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.F) B) and D)
G) D) and E)

Question 5

What are the biological functions of the pentose phosphate pathway?

Accepted Answer

The pentose phosphate pathway ...

Question 6

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.F) A) and D)
G) A) and B)

Question 7

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

Accepted Answer

Phosphorolysis yields glucose 1-phosphat...

Question 8

Glycolysis is the name given to a metabolic pathway occurring in many different cell types.It consists of 11 enzymatic steps that convert glucose to lactic acid.Glycolysis is an example of:

Accepted Answer

A)  aerobic metabolism.
B)  anabolic metabolism.
C)  a net reductive process.
D)  fermentation.
E)  oxidative phosphorylation.F) A) and D)
G) C) and D)

Question 9

During strenuous activity,muscle tissue demands large quantities of ATP,compared with resting muscle.In white skeletal muscle (in contrast with red muscle),ATP is produced almost exclusively by fermentation of glucose to lactate.If a person had white muscle tissue devoid of the enzyme lactate dehydrogenase,how would this affect his or her metabolism at rest and during strenuous exercise?

Accepted Answer

Lactate dehydrogenase allows cells to pa...

Question 10

Which of the following reactions in glycolysis is a ketose to aldose isomerization?

Accepted Answer

A)  Hexokinase
B)  Phosphoglycerate mutase
C)  Enolase
D)  Aldolase
E)  Triose phosphate isomeraseF) C) and D)
G) B) and D)

Question 11

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.F) None of the above
G) B) and C)

Question 12

Glucose,labeled with 14C in different carbon atoms,is added to a crude extract of a tissue rich in the enzymes of the pentose phosphate pathway.The most rapid production of 14CO2 will occur when the glucose is labeled in:

Accepted Answer

A)  C-1.
B)  C-3.
C)  C-4.
D)  C-5.
E)  C-6.F) A) and E)
G) A) and B)

Question 13

If brewer's yeast is mixed with pure sugar (glucose)in the absence of phosphate (Pi),no ethanol is produced.With the addition of a little Pi,ethanol production soon begins.Explain this observation in 25 words or less.

Accepted Answer

The reaction catalyzed by glyc...

Question 14

Which of the following reactions in glycolysis requires ATP as a substrate?

Accepted Answer

A)  Hexokinase
B)  Glyceraldehyde-3-phosphate dehydrogenase
C)  Pyruvate kinase
D)  Aldolase
E)  Phosphoglycerate kinaseF) C) and D)
G) C) and E)

Question 15

In glycolysis,fructose 1,6-bisphosphate is converted to two products with a standard free-energy change ( Δ\DeltaΔ G'°) of 23.8 kJ/mol.Under what conditions (encountered in a normal cell) will the free-energy change ( Δ\DeltaΔ G) be negative,enabling the reaction to proceed to the right?

Accepted Answer

A)  If the concentrations of the two products are high relative to that of fructose 1,6-bisphosphate.
B)  The reaction will not go to the right spontaneously under any conditions because the  Δ\DeltaΔ G'° is positive.
C)  Under standard conditions,enough energy is released to drive the reaction to the right.
D)  When there is a high concentration of fructose 1,6-bisphosphate relative to the concentration of products.
E)  When there is a high concentration of products relative to the concentration of fructose 1,6-bisphosphate. F) C) and D)
G) D) and E)

Question 16

Which of the following substrates cannot contribute to net gluconeogenesis in mammalian liver?

Accepted Answer

A)  Alanine
B)  Glutamate
C)  Palmitate
D)  Pyruvate
E)  ( α\alphaα -ketoglutarate)  F) A) and B)
G) None of the above

Question 17

The ultimate electron acceptor in the fermentation of glucose to ethanol is:

Accepted Answer

A)  acetaldehyde.
B)  acetate.
C)  ethanol.
D)  NAD+.
E)  pyruvate.F) B) and D)
G) D) and E)

Question 18

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

Accepted Answer

There are at least three reasons (1)so t...

Question 19

Describe the glycolytic pathway from glyceraldehyde 3-phosphate to pyruvate,showing structures of intermediates and names of enzymes.Indicate where any cofactors participate.

Accepted Answer

The answer should show the rea...

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

Which of the following statements about the pentose phosphate pathway is incorrect?

Correct Answer
verified

Correct Answer
verified
Lactate dehydrogenase allows cells to pa...
View Answer

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:

Correct Answer
verified

If brewer's yeast is mixed with pure sugar (glucose)in the absence of phosphate (P_i),no ethanol is produced.With the addition of a little P_i,ethanol production soon begins.Explain this observation in 25 words or less.

Correct Answer
verified
The reaction catalyzed by glyc...
View Answer

Which of the following statements is incorrect?

Correct Answer
verified

Describe the glycolytic pathway from glyceraldehyde 3-phosphate to pyruvate,showing structures of intermediates and names of enzymes.Indicate where any cofactors participate.

Correct Answer
verified
The answer should show the rea...
View Answer

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

Correct Answer
verified

Glucose,labeled with ¹⁴C in different carbon atoms,is added to a crude extract of a tissue rich in the enzymes of the pentose phosphate pathway.The most rapid production of ¹⁴CO₂ will occur when the glucose is labeled in:

Correct Answer
verified

Which of the following reactions in glycolysis requires ATP as a substrate?

Correct Answer
verified

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

Correct Answer
verified
There are at least three reasons (1)so t...
View Answer

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

Correct Answer
verified
Phosphorolysis yields glucose 1-phosphat...
View Answer

Which of the following substrates cannot contribute to net gluconeogenesis in mammalian liver?

Correct Answer
verified

Which of the following enzymes acts in the pentose phosphate pathway?

Correct Answer
verified

Which of the following reactions in glycolysis is a ketose to aldose isomerization?

Correct Answer
verified

Glycolysis is the name given to a metabolic pathway occurring in many different cell types.It consists of 11 enzymatic steps that convert glucose to lactic acid.Glycolysis is an example of:

Correct Answer
verified

Which of the following statements is not true concerning glycolysis in anaerobic muscle?

Correct Answer
verified

In glycolysis,fructose 1,6-bisphosphate is converted to two products with a standard free-energy change ( $\Delta$ G'°) of 23.8 kJ/mol.Under what conditions (encountered in a normal cell) will the free-energy change ( $\Delta$ G) be negative,enabling the reaction to proceed to the right?

Correct Answer
verified

The ultimate electron acceptor in the fermentation of glucose to ethanol is:

Correct Answer
verified

What are the biological functions of the pentose phosphate pathway?

Correct Answer
verified
The pentose phosphate pathway ...
View Answer

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

Which of the following statements about the pentose phosphate pathway is incorrect?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedLactate dehydrogenase allows cells to pa...View AnswerShow Answer

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:

Correct AnswerverifiedShow Answer

If brewer's yeast is mixed with pure sugar (glucose)in the absence of phosphate (Pi),no ethanol is produced.With the addition of a little Pi,ethanol production soon begins.Explain this observation in 25 words or less.

Correct AnswerverifiedThe reaction catalyzed by glyc...View AnswerShow Answer

Which of the following statements is incorrect?

Correct AnswerverifiedShow Answer

Describe the glycolytic pathway from glyceraldehyde 3-phosphate to pyruvate,showing structures of intermediates and names of enzymes.Indicate where any cofactors participate.

Correct AnswerverifiedThe answer should show the rea...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

Glucose,labeled with 14C in different carbon atoms,is added to a crude extract of a tissue rich in the enzymes of the pentose phosphate pathway.The most rapid production of 14CO2 will occur when the glucose is labeled in:

Correct AnswerverifiedShow Answer

Which of the following reactions in glycolysis requires ATP as a substrate?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedThere are at least three reasons (1)so t...View AnswerShow Answer

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

Correct AnswerverifiedPhosphorolysis yields glucose 1-phosphat...View AnswerShow Answer

Which of the following substrates cannot contribute to net gluconeogenesis in mammalian liver?

Correct AnswerverifiedShow Answer

Which of the following enzymes acts in the pentose phosphate pathway?

Correct AnswerverifiedShow Answer

Which of the following reactions in glycolysis is a ketose to aldose isomerization?

Correct AnswerverifiedShow Answer

Glycolysis is the name given to a metabolic pathway occurring in many different cell types.It consists of 11 enzymatic steps that convert glucose to lactic acid.Glycolysis is an example of:

Correct AnswerverifiedShow Answer

Which of the following statements is not true concerning glycolysis in anaerobic muscle?

Correct AnswerverifiedShow Answer

In glycolysis,fructose 1,6-bisphosphate is converted to two products with a standard free-energy change ( Δ\DeltaΔ G'°) of 23.8 kJ/mol.Under what conditions (encountered in a normal cell) will the free-energy change ( Δ\DeltaΔ G) be negative,enabling the reaction to proceed to the right?

Correct AnswerverifiedShow Answer

The ultimate electron acceptor in the fermentation of glucose to ethanol is:

Correct AnswerverifiedShow Answer

What are the biological functions of the pentose phosphate pathway?

Correct AnswerverifiedThe pentose phosphate pathway ...View AnswerShow Answer

Correct Answer
verified

Correct Answer
verified
Lactate dehydrogenase allows cells to pa...
View Answer

Correct Answer
verified

If brewer's yeast is mixed with pure sugar (glucose)in the absence of phosphate (P_i),no ethanol is produced.With the addition of a little P_i,ethanol production soon begins.Explain this observation in 25 words or less.

Correct Answer
verified
The reaction catalyzed by glyc...
View Answer

Correct Answer
verified

Correct Answer
verified
The answer should show the rea...
View Answer

Correct Answer
verified

Glucose,labeled with ¹⁴C in different carbon atoms,is added to a crude extract of a tissue rich in the enzymes of the pentose phosphate pathway.The most rapid production of ¹⁴CO₂ will occur when the glucose is labeled in:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
There are at least three reasons (1)so t...
View Answer

Correct Answer
verified
Phosphorolysis yields glucose 1-phosphat...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

In glycolysis,fructose 1,6-bisphosphate is converted to two products with a standard free-energy change ( $\Delta$ G'°) of 23.8 kJ/mol.Under what conditions (encountered in a normal cell) will the free-energy change ( $\Delta$ G) be negative,enabling the reaction to proceed to the right?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The pentose phosphate pathway ...
View Answer