Question 1

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

Accepted Answer

The liver controls the blood glucose concentration. Thus, it must be able to remove the phosphate so the glucose can be released from liver cells.

Question 2

In skeletal muscle, the binding of ______________ stabilizes phosphorylation b into the active form.

Accepted Answer

The answer of In skeletal muscle, the binding of ______________...

Question 3

The transferase enzyme shifts a block of ______________ glycosyl units.

Accepted Answer

The answer of The transferase enzyme shifts a block of...

Question 4

____________ is the end of glycogen where interconversion between the open and closed conformation of the anomeric carbon is possible

Accepted Answer

A)  reducing
B)  ɑ-1,6-glycosidic
C)  phosphorylase kinase
D)  ɑ-1,4-glycoside
E)  nonreducingF) phosphorylase aG) glucose 6-phosphataseH) UTP-glucoseI) calmodulinJ) phosphorolysisK) epinephrineL) glucagonM) E) and L)
N) H) and K)

Question 5

Muscle phosphorylase is mostly inactive when:

Accepted Answer

A)   the enzyme is in the b conformation
B)   in the R state.
C)   bound to AMP.
D)   All of the above.
E)   None of the above.F) B) and D)
G) C) and D) D

Question 6

The key enzyme in glycogen degradation is:

Accepted Answer

A)   glycogen phosphatase.
B)   glycogen phosphorylase.
C)   glucose 1-phosphate synthase.
D)   All of the above.
E)   None of the above.F) B) and E)
G) A) and B)

Question 7

Which GTP binding protein is activated by epinephrine binding to the adrenergic 7TM receptor?

Accepted Answer

The answer of Which GTP binding protein is activated by...

Question 8

The ____________ enzyme serves as the glucose "sensor" enzyme in liver cells.

Accepted Answer

A)  reducing
B)  ɑ-1,6-glycosidic
C)  phosphorylase kinase
D)  ɑ-1,4-glycoside
E)  nonreducingF) phosphorylase aG) glucose 6-phosphataseH) UTP-glucoseI) calmodulinJ) phosphorolysisK) epinephrineL) glucagonM) J) and K)
N) A) and B)

Question 9

Two critical hormones that signal for glycogen breakdown are:

Accepted Answer

A)   insulin and epinephrine.
B)   glucagon and epinephrine.
C)   glucagon and insulin.
D)   All of the above.
E)   None of the above.F) A) and B)
G) B) and C)

Question 10

How does epinephrine stimulate glycogen breakdown in muscle? (Describe the series of events.)

Accepted Answer

Epinephrine binds to the β-adrenergic re...

Question 11

Why must glycogen control be manifested differently in muscle and liver?

Accepted Answer

Because the muscle maintains g...

Question 12

Phosphorylase a and b both exist in equilibrium between R and T states. Which are the most active and least active combinations?

Accepted Answer

The most active is phosphoryla...

Question 13

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

Accepted Answer

glucose-1,...

Question 14

How is phosphorylase b converted into phosphorylase a?

Accepted Answer

A)   through the addition of a phosphate to a serine residue
B)   through dimerization, which forms the active-site pocket
C)   through cleavage of 10 amino acids from the N-terminal end of the protein
D)   All of the above.
E)   None of the above.F) B) and E)
G) B) and C)

Question 15

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

Accepted Answer

Glycogen is easily broken down, is a rea...

Question 16

Which molecule(s)  must be excluded from the active site of glycogen phosphorylase?

Accepted Answer

A)   glucose
B)   glucose 1-phosphate
C)   water
D)   All of the above.
E)   None of the above.F) A) and E)
G) B) and E) C

Question 17

In the liver, glycogen synthesis and degradation are regulated to maintain levels of ______________ in the blood.

Accepted Answer

The answer of In the liver, glycogen synthesis and degradation...

Question 18

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)   All of the above.
E)   None of the above.F) B) and D)
G) All of the above

Question 19

What are the three steps in glycogen degradation?

Accepted Answer

The steps are 1) release of gl...

Question 20

What is required to remove branches in glycogen?

Accepted Answer

A)   a debranching enzyme
B)   a transferase enzyme
C)   a glycosidase enzyme.
D)   A and C
E)   All of the above.F) D) and E)
G) A) and B)

Exam 24: Glycogen Degradation

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

Correct AnswerverifiedThe liver controls the blood glucose concentration. Thus, it must be able to remove the phosphate so the glucose can be released from liver cells.

In skeletal muscle, the binding of ______________ stabilizes phosphorylation b into the active form.

Correct AnswerverifiedShow Answer

The transferase enzyme shifts a block of ______________ glycosyl units.

Correct AnswerverifiedShow Answer

____________ is the end of glycogen where interconversion between the open and closed conformation of the anomeric carbon is possible

Correct AnswerverifiedShow Answer

Muscle phosphorylase is mostly inactive when:

Correct AnswerverifiedD

The key enzyme in glycogen degradation is:

Correct AnswerverifiedShow Answer

Which GTP binding protein is activated by epinephrine binding to the adrenergic 7TM receptor?

Correct AnswerverifiedShow Answer

The ____________ enzyme serves as the glucose "sensor" enzyme in liver cells.

Correct AnswerverifiedShow Answer

Two critical hormones that signal for glycogen breakdown are:

Correct AnswerverifiedShow Answer

How does epinephrine stimulate glycogen breakdown in muscle? (Describe the series of events.)

Correct AnswerverifiedEpinephrine binds to the β-adrenergic re...View AnswerShow Answer

Why must glycogen control be manifested differently in muscle and liver?

Correct AnswerverifiedBecause the muscle maintains g...View AnswerShow Answer

Phosphorylase a and b both exist in equilibrium between R and T states. Which are the most active and least active combinations?

Correct AnswerverifiedThe most active is phosphoryla...View AnswerShow Answer

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

Correct Answerverifiedglucose-1,...View AnswerShow Answer

How is phosphorylase b converted into phosphorylase a?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedGlycogen is easily broken down, is a rea...View AnswerShow Answer

Which molecule(s) must be excluded from the active site of glycogen phosphorylase?

Correct AnswerverifiedC

In the liver, glycogen synthesis and degradation are regulated to maintain levels of ______________ in the blood.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What are the three steps in glycogen degradation?

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

What is required to remove branches in glycogen?

Correct AnswerverifiedShow Answer

Correct Answer
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The liver controls the blood glucose concentration. Thus, it must be able to remove the phosphate so the glucose can be released from liver cells.

Correct Answer
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D

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Epinephrine binds to the β-adrenergic re...
View Answer

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Because the muscle maintains g...
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The most active is phosphoryla...
View Answer

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glucose-1,...
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Glycogen is easily broken down, is a rea...
View Answer

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C

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The steps are 1) release of gl...
View Answer

Correct Answer
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