Question 1

What did Carl and Gerti Cori discover about the cause of von Gierke disease? Briefly explain how this information helps to explain the symptoms of the disease.

Accepted Answer

They discovered that the cause of von Gi...

Question 2

Why is glycogen branching important?

Accepted Answer

A)   Branching significantly alters the melting point.
B)   Branching decreases the solubility of glycogen.
C)   Branching increases the rates of glycogen synthesis and degradation by increasing the potential sites of action.
D)   Branching allows glycogen to be transported to other areas of the cell.
E)   None of the answers is correct.F) A) and C)
G) None of the above

Question 3

How is phosphorylase b converted into phosphorylase a?

Accepted Answer

A)   Addition of a phosphate to a serine residue
B)   Dimerization, which forms the active site pocket
C)   Cleavage of 10 amino acids from the N-terminal end of the protein
D)   Binding of glucose, an allosteric modifier
E)   None of the answers is correct.F) B) and D)
G) A) and B)

Question 4

What protein serves as the primer for glycogen synthase?

Accepted Answer

A)   branching enzyme
B)   debranching enzyme
C)   glycogenin
D)   calmodulin
E)   None of the answers is correct.F) B) and E)
G) A) and C)

Question 5

The complete oxidation of a glucose residue from glycogen produces ________________ molecules of ATP in the muscle.

Accepted Answer

The answer of The complete oxidation of a glucose residue...

Question 6

Conversion of glucose 1-phosphate to glucose 6-phosphate is carried out by the enzyme

Accepted Answer

A)   phosphoglucomutase.
B)   kinase 1-P.
C)   phosphoglycerate mutase.
D)   hexose-phosphate isomerase.
E)   None of the answers is correct.F) B) and C)
G) A) and E)

Question 7

Glycogen synthase is converted into the active form by the action of _________________.

Accepted Answer

protein phosphatase 1,PP1

Question 8

How does insulin stimulate glycogen synthesis?

Accepted Answer

Insulin triggers a pathway that activate...

Question 9

Critical hormones that signal for glycogen breakdown are

Accepted Answer

A)   insulin and epinephrine.
B)   glucagon and epinephrine.
C)   glucagon and insulin.
D)   insulin, glucagon, and epinephrine.
E)   None of the answers is correct.F) C) and D)
G) B) and D) B

Question 10

What molecule must be excluded from the active site of glycogen phosphorylase?

Accepted Answer

A)   glucose
B)   glucose 1-phosphate
C)   water
D)   phosphate
E)   None of the answers is correct.F) B) and D)
G) C) and D)

Question 11

Why does liver possess a specific enzyme that can cleave glucose 6-phosphate to form glucose and orthophosphate?

Accepted Answer

The liver controls the blood g...

Question 12

The action of which of the following enzymes both activates glycogen breakdown and inhibits glycogen synthesis?

Accepted Answer

A)   protein kinase A
B)   protein kinase C
C)   phosphorylase kinase
D)   protein phosphatase 1
E)   None of the answers is correct.F) A) and C)
G) C) and D)

Question 13

Give the reaction catalyzed by UDP-glucose pyrophosphorylase.

Accepted Answer

Glucose-1-...

Question 14

What enzyme(s) is (are) required to cleave  α\alphaα -1,6-glycosidic branches in glycogen?

Accepted Answer

A)   transferase
B)    α\alphaα -1,6-glucosidase
C)   glycogen phosphatase
D)   transferase and  α\alphaα -1,6-glucosidase
E)    α\alphaα -1,6-glucosidase and glycogen phosphatase F) B) and E)
G) None of the above

Question 15

Phosphoglucomutase requires the intermediate ____________________ for the interconversion of glucose-1-phosphate and glucose-6-phosphate.

Accepted Answer

glucose 1,6-bisphosphate

Question 16

What are some of the advantages of having glycogen as a glucose source?

Accepted Answer

Glycogen is readily accessible and can b...

Question 17

What are the three steps in glycogen degradation?

Accepted Answer

The steps are 1)release of glu...

Question 18

Why is the formation of glucose-1-phosphate energetically favorable even though the ΔG°′ is very small?

Accepted Answer

It is favored becaus...

Question 19

The glycogen branching enzyme moves a block of __________ (or so)glucose residues to form a branch point at least four residues from a preexisting branch.

Accepted Answer

The answer of The glycogen branching enzyme moves a block...

Question 20

Compare the evolutionary history of the catalytic and regulatory features of glycogen phosphorylase.

Accepted Answer

Comparison of the binding sites for gluc...

Exam 21: Glycogen Metabolism

What did Carl and Gerti Cori discover about the cause of von Gierke disease? Briefly explain how this information helps to explain the symptoms of the disease.

Correct AnswerverifiedThey discovered that the cause of von Gi...View AnswerShow Answer

Why is glycogen branching important?

Correct AnswerverifiedShow Answer

How is phosphorylase b converted into phosphorylase a?

Correct AnswerverifiedShow Answer

What protein serves as the primer for glycogen synthase?

Correct AnswerverifiedShow Answer

The complete oxidation of a glucose residue from glycogen produces ________________ molecules of ATP in the muscle.

Correct AnswerverifiedShow Answer

Conversion of glucose 1-phosphate to glucose 6-phosphate is carried out by the enzyme

Correct AnswerverifiedShow Answer

Glycogen synthase is converted into the active form by the action of _________________.

Correct Answerverifiedprotein phosphatase 1,PP1

How does insulin stimulate glycogen synthesis?

Correct AnswerverifiedInsulin triggers a pathway that activate...View AnswerShow Answer

Critical hormones that signal for glycogen breakdown are

Correct AnswerverifiedB

What molecule must be excluded from the active site of glycogen phosphorylase?

Correct AnswerverifiedShow Answer

Why does liver possess a specific enzyme that can cleave glucose 6-phosphate to form glucose and orthophosphate?

Correct AnswerverifiedThe liver controls the blood g...View AnswerShow Answer

The action of which of the following enzymes both activates glycogen breakdown and inhibits glycogen synthesis?

Correct AnswerverifiedShow Answer

Give the reaction catalyzed by UDP-glucose pyrophosphorylase.

Correct AnswerverifiedGlucose-1-...View AnswerShow Answer

What enzyme(s) is (are) required to cleave α\alphaα -1,6-glycosidic branches in glycogen?

Correct AnswerverifiedShow Answer

Phosphoglucomutase requires the intermediate ____________________ for the interconversion of glucose-1-phosphate and glucose-6-phosphate.

Correct Answerverifiedglucose 1,6-bisphosphate

What are some of the advantages of having glycogen as a glucose source?

Correct AnswerverifiedGlycogen is readily accessible and can b...View AnswerShow Answer

What are the three steps in glycogen degradation?

Correct AnswerverifiedThe steps are 1)release of glu...View AnswerShow Answer

Why is the formation of glucose-1-phosphate energetically favorable even though the ΔG°′ is very small?

Correct AnswerverifiedIt is favored becaus...View AnswerShow Answer

The glycogen branching enzyme moves a block of __________ (or so)glucose residues to form a branch point at least four residues from a preexisting branch.

Correct AnswerverifiedShow Answer

Compare the evolutionary history of the catalytic and regulatory features of glycogen phosphorylase.

Correct AnswerverifiedComparison of the binding sites for gluc...View AnswerShow Answer

Correct Answer
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They discovered that the cause of von Gi...
View Answer

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
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protein phosphatase 1,PP1

Correct Answer
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Insulin triggers a pathway that activate...
View Answer

Correct Answer
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B

Correct Answer
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Correct Answer
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The liver controls the blood g...
View Answer

Correct Answer
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Correct Answer
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Glucose-1-...
View Answer

What enzyme(s) is (are) required to cleave $\alpha$ -1,6-glycosidic branches in glycogen?

Correct Answer
verified

Correct Answer
verified
glucose 1,6-bisphosphate

Correct Answer
verified
Glycogen is readily accessible and can b...
View Answer

Correct Answer
verified
The steps are 1)release of glu...
View Answer

Correct Answer
verified
It is favored becaus...
View Answer

Correct Answer
verified

Correct Answer
verified
Comparison of the binding sites for gluc...
View Answer