Question 1

Which enzyme catalyzes the primary regulation site of glycolysis?

Accepted Answer

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

Question 2

If a residue of glucose in glycogen is removed from the glycogen molecule and then allowed to proceed through glycolysis to pyruvate,what is the net production of ATP?

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  5

Question 3

Under conditions of strenuous exercise,gluconeogenesis occurs primarily in the _______ using _______ formed in the skeletal muscle

Accepted Answer

A)  kidney;alanine
B)  muscle;glycerol
C)  liver;propionate
D)  kidney;acetyl-CoA
E)  liver;lactate

Question 4

What sequence of enzymes allows for the synthesis of glycogen from glucose-6-phosphate?

Accepted Answer

A)  UDP-glucose pyrophosphorylase,phosphoglucomutase,glycogen synthase,amylo-(1,4 →	o→ 1,6) -transglycosylase
B)  phosphoglucomutase,UDP-glucose pyrophosphorylase,amylo-(1,4 →	o→ 1,6) -transglycosylase,glycogen synthase
C)  phosphoglucomutase,amylo-(1,4 →	o→ 1,6) -transglycosylase,UDP-glucose pyrophosphorylase,glycogen synthase
D)  UDP-glucose pyrophosphorylase,phosphoglucomutase,amylo-(1,4 →	o→ 1,6) -transglycosylase,glycogen synthase
E)  phosphoglucomutase,UDP-glucose pyrophosphorylase,glycogen synthase,amylo-(1,4 →	o→ 1,6) -transglycosylase

Question 5

Which of the following enzymes is activated when acted on by phosphoprotein phosphatase 1?

Accepted Answer

A)  glycogen synthase
B)  glycogen phosphorylase
C)  phosphorylase kinase
D)  phosphoprotein phosphatase inhibitor 1
E)  protein kinase A

Question 6

Besides its role in glycogen synthesis,which of the following directly relies on UDP-glucose?

Accepted Answer

A)  glycolysis
B)  gluconeogenesis
C)  fructose metabolism
D)  sucrose metabolism
E)  galactose metabolism

Question 7

With respect to carbons 1 and 2 of the intermediate in the conversion of glucose-6-phosphate to fructose-6-phosphate,which of the following would best describe this intermediate?

Accepted Answer

A)  vicinal diol
B)  enediol
C)  aldehyde
D)  ketone
E)  enol

Question 8

Which isoform of hexokinase is found in the vertebrate liver?

Accepted Answer

A)  hexokinase I
B)  hexokinase II
C)  hexokinase III
D)  hexokinase IV
E)  all of the above

Question 9

When lipid biosynthesis is active using carbohydrates as a source of carbon,three things are needed: NADPH,ATP and acetyl-CoA (from pyruvate) .Which of the following best explains the operation of the pentose phosphate pathway (PPP) under such conditions? G6P = glucose-6-phosphate,F6P = fructose-6-phosphate,G3P = glyceraldehyde-3-phosphate

Accepted Answer

A)  3 G6P  →	o→  2 F6P + 1 G3P with the F6P recycled to G6P to re-enter the PPP while G3P continues through glycolysis to make acetyl-CoA and ATP
B)  6 G6P  →	o→  4 F6P + 2 G3P with 1 G3P converted to DHAP,the other G3P + DHAP giving F6P with all F6P recycled to G6P to re-enter the PPP
C)  3 G6P  →	o→  2 F6P + 1 G3P with the F6P and G3P continuing through glycolysis to make acetyl-CoA and ATP
D)  3 G6P  →	o→  2 F6P + 1 G3P with all G3P continuing through glycolysis.Some F6P is recycled to G6P while some continues through glycolysis-the amount dependent upon the requirements for NADPH,ATP and acetyl-CoA
E)  none of the above

Question 10

If unregulated,which of the following pairs of enzymes would represent a futile cycle?

Accepted Answer

A)  pyruvate kinase and pyruvate carboxylase
B)  pyruvate carboxylase and phosphoenolpyruvate carboxykinase
C)  pyruvate kinase and fructose-1,6-bisphosphatase
D)  fructose-1,6-bisphosphatase and phosphofructokinase
E)  glucose-6-phosphatase and phosphofructokinase

Question 11

Which of the following pairs of phosphorylated molecules contains an intermediate of glycolysis with high phosphate transfer potential and one with low phosphate transfer potential?

Accepted Answer

A)  fructose-1,6-bisphosphate and fructose-6-phosphate
B)  phosphoenolpyruvate and glyceraldehyde-3-phosphate
C)  fructose-1,6-bisphosphate and 3-phosphoglycerate
D)  1,3-bisphosphoglycerate and phosphoenolpyruvate
E)  1,3-bisphosphoglycerate and pyruvate

Question 12

The conversion of phosphoenolpyruvate and ADP to pyruvate and ATP occurs in two distinct steps,first the transfer of the phosphate from PEP to ADP,then the conversion of enolpyruvate to pyruvate.Which of the following describes the reversibility of this process?

Accepted Answer

A)  both steps are freely reversible
B)  step 1 is freely reversible,step 2 is irreversible
C)  step 1 is irreversible,step 2 is freely reversible
D)  both steps are irreversible
E)  the reversibility of the reaction depends completely upon the concentrations of products and reactants

Question 13

During the oxidation of glyceraldehyde-3-phosphate,what intermediate in the enzyme-catalyzed mechanism actually undergoes oxidation?

Accepted Answer

A)  enediol
B)  thioester
C)  thiohemiacetal
D)  carbinolamine
E)  Schiff base

Question 14

The conversion of 3-phosphoglycerate to phosphoenolpyruvate requires two reactions.Which of the following correctly identifies the types of reactions in the proper order of glycolysis?

Accepted Answer

A)  isomerization,hydration
B)  hydration,isomerization
C)  dehydration,isomerization
D)  isomerization,dehydration
E)  mutation,dehydration

Question 15

Which of the following glycolytic reactions is freely reversible?

Accepted Answer

A)  hexokinase
B)  phosphofructokinase
C)  triose phosphate isomerase
D)  pyruvate kinase
E)  none of the above

Question 16

Which of the following enzymes is used by the gluconeogenic pathway but not the glycolytic pathway?

Accepted Answer

A)  pyruvate kinase
B)  phosphoenolpyruvate carboxykinase
C)  glyceraldehyde-3-phosphate dehydrogenase
D)  triose phosphate isomerase
E)  hexokinase

Question 17

During the energy investment phase of glycolysis,_____ reaction(s) use ATP as a substrate while during the energy generation phase,_____ reactions produce ATP as a product.

Accepted Answer

A)  2;2
B)  2;4
C)  1;2
D)  1;4
E)  0;2

Question 18

A transketolase enzyme transfers a _____ carbon fragment from a(n) ________ to a(n) ________.

Accepted Answer

A)  2;aldose;ketose
B)  2;ketose;aldose
C)  2;ketose;ketose
D)  3;aldose;ketose
E)  3;ketose;aldose

Question 19

Which of the following activators is correctly paired with the glycolytic or gluconeogenic enzyme that it activates?

Accepted Answer

A)  glucose-6-phosphate: hexokinase
B)  AMP: fructose-1,6-bisphosphatase
C)  ATP: pyruvate kinase
D)  fructose-2,6-bisphosphate: phosphofructokinase
E)  citrate: fructose-1,6-bisphosphatase

Question 20

Besides two molecules of pyruvate,what are the net products of glycolysis?

Accepted Answer

A)  4 ATP and 2 NADH
B)  2 ATP and 2 NADH
C)  4 ATP and 4 NADH
D)  2 ATP and 4 NADH
E)  none of the above

Exam 13: Carbohydrate Metabolism: Glycolysis, gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Besides two molecules of pyruvate,what are the net products of glycolysis?

Correct Answer
verified

A transketolase enzyme transfers a _ carbon fragment from a(n) to a(n) ____.

Correct Answer
verified

If a residue of glucose in glycogen is removed from the glycogen molecule and then allowed to proceed through glycolysis to pyruvate,what is the net production of ATP?

Correct Answer
verified

Which of the following glycolytic reactions is freely reversible?

Correct Answer
verified

The conversion of phosphoenolpyruvate and ADP to pyruvate and ATP occurs in two distinct steps,first the transfer of the phosphate from PEP to ADP,then the conversion of enolpyruvate to pyruvate.Which of the following describes the reversibility of this process?

Correct Answer
verified

Besides its role in glycogen synthesis,which of the following directly relies on UDP-glucose?

Correct Answer
verified

Which of the following activators is correctly paired with the glycolytic or gluconeogenic enzyme that it activates?

Correct Answer
verified

During the energy investment phase of glycolysis,_ reaction(s) use ATP as a substrate while during the energy generation phase,_ reactions produce ATP as a product.

Correct Answer
verified

Correct Answer
verified

With respect to carbons 1 and 2 of the intermediate in the conversion of glucose-6-phosphate to fructose-6-phosphate,which of the following would best describe this intermediate?

Correct Answer
verified

If unregulated,which of the following pairs of enzymes would represent a futile cycle?

Correct Answer
verified

During the oxidation of glyceraldehyde-3-phosphate,what intermediate in the enzyme-catalyzed mechanism actually undergoes oxidation?

Correct Answer
verified

Which of the following enzymes is activated when acted on by phosphoprotein phosphatase 1?

Correct Answer
verified

Which of the following pairs of phosphorylated molecules contains an intermediate of glycolysis with high phosphate transfer potential and one with low phosphate transfer potential?

Correct Answer
verified

Which isoform of hexokinase is found in the vertebrate liver?

Correct Answer
verified

What sequence of enzymes allows for the synthesis of glycogen from glucose-6-phosphate?

Correct Answer
verified

The conversion of 3-phosphoglycerate to phosphoenolpyruvate requires two reactions.Which of the following correctly identifies the types of reactions in the proper order of glycolysis?

Correct Answer
verified

Which of the following enzymes is used by the gluconeogenic pathway but not the glycolytic pathway?

Correct Answer
verified

Which enzyme catalyzes the primary regulation site of glycolysis?

Correct Answer
verified

Under conditions of strenuous exercise,gluconeogenesis occurs primarily in the _ using _ formed in the skeletal muscle

Correct Answer
verified

Exam 13: Carbohydrate Metabolism: Glycolysis, gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Besides two molecules of pyruvate,what are the net products of glycolysis?

Correct AnswerverifiedShow Answer

A transketolase enzyme transfers a _____ carbon fragment from a(n) ________ to a(n) ________.

Correct AnswerverifiedShow Answer

If a residue of glucose in glycogen is removed from the glycogen molecule and then allowed to proceed through glycolysis to pyruvate,what is the net production of ATP?

Correct AnswerverifiedShow Answer

Which of the following glycolytic reactions is freely reversible?

Correct AnswerverifiedShow Answer

The conversion of phosphoenolpyruvate and ADP to pyruvate and ATP occurs in two distinct steps,first the transfer of the phosphate from PEP to ADP,then the conversion of enolpyruvate to pyruvate.Which of the following describes the reversibility of this process?

Correct AnswerverifiedShow Answer

Besides its role in glycogen synthesis,which of the following directly relies on UDP-glucose?

Correct AnswerverifiedShow Answer

Which of the following activators is correctly paired with the glycolytic or gluconeogenic enzyme that it activates?

Correct AnswerverifiedShow Answer

During the energy investment phase of glycolysis,_____ reaction(s) use ATP as a substrate while during the energy generation phase,_____ reactions produce ATP as a product.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

With respect to carbons 1 and 2 of the intermediate in the conversion of glucose-6-phosphate to fructose-6-phosphate,which of the following would best describe this intermediate?

Correct AnswerverifiedShow Answer

If unregulated,which of the following pairs of enzymes would represent a futile cycle?

Correct AnswerverifiedShow Answer

During the oxidation of glyceraldehyde-3-phosphate,what intermediate in the enzyme-catalyzed mechanism actually undergoes oxidation?

Correct AnswerverifiedShow Answer

Which of the following enzymes is activated when acted on by phosphoprotein phosphatase 1?

Correct AnswerverifiedShow Answer

Which of the following pairs of phosphorylated molecules contains an intermediate of glycolysis with high phosphate transfer potential and one with low phosphate transfer potential?

Correct AnswerverifiedShow Answer

Which isoform of hexokinase is found in the vertebrate liver?

Correct AnswerverifiedShow Answer

What sequence of enzymes allows for the synthesis of glycogen from glucose-6-phosphate?

Correct AnswerverifiedShow Answer

The conversion of 3-phosphoglycerate to phosphoenolpyruvate requires two reactions.Which of the following correctly identifies the types of reactions in the proper order of glycolysis?

Correct AnswerverifiedShow Answer

Which of the following enzymes is used by the gluconeogenic pathway but not the glycolytic pathway?

Correct AnswerverifiedShow Answer

Which enzyme catalyzes the primary regulation site of glycolysis?

Correct AnswerverifiedShow Answer

Under conditions of strenuous exercise,gluconeogenesis occurs primarily in the _______ using _______ formed in the skeletal muscle

Correct AnswerverifiedShow Answer

Correct Answer
verified

A transketolase enzyme transfers a _ carbon fragment from a(n) to a(n) ____.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

During the energy investment phase of glycolysis,_ reaction(s) use ATP as a substrate while during the energy generation phase,_ reactions produce ATP as a product.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

Under conditions of strenuous exercise,gluconeogenesis occurs primarily in the _ using _ formed in the skeletal muscle

Correct Answer
verified