Question 1

Choose the correct answer from the list below. Not all of the answers will be used.
-The type of bond that is located at the branch points in glycogen is ____________.

Accepted Answer

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

Question 2

Choose the correct answer from the list below. Not all of the answers will be used.
-The process by which a bond is cleaved by the addition of orthophosphate is ____________.

Accepted Answer

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

Question 3

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) A) and B)

Question 4

What are the two regulatory controls for phosphorylase kinase?

Accepted Answer

Phosphorylase kinase is activa...

Question 5

Both phosphorylase a and b 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 6

Why is the formation of glucose 1-phosphate advantageous?

Accepted Answer

It is advantageous because the...

Question 7

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 8

In order to degrade branches in glycogen, two enzymes are required: a transferase and ______________.

Accepted Answer

The answer of In order to degrade branches in glycogen,...

Question 9

What path, in addition to the cAMP-induced signal transduction, is used in the liver to stimulate glycogen breakdown by epinephrine?

Accepted Answer

In the liver, epinephrine also binds to a 7TM ɑ-adrenergic receptor, which activates phospholipase C and the phosphoinositide cascade. This causes calcium ions to be released, which bind to calmodulin, and further stimulates phosphorylase kinase and glycogen breakdown.

Question 10

Why is the T state of glycogen phosphorylase less active?

Accepted Answer

A)   The adjacent amino acids are not phosphorylated; thus the catalysis cannot be carried out.
B)   The active site is partially blocked.
C)   ATP cannot be bound by the T state.
D)   All of the above.
E)   None of the above.F) B) and E)
G) B) and D)

Question 11

What physiological conditions render phosphorylase b less active?

Accepted Answer

A)   high ATP, high AMP, and glucose 6-phosphate levels
B)   high ATP and low calcium ion levels
C)   high ATP and high glucose 6-phosphate levels
D)   All of the above.
E)   None of the above.F) B) and C)
G) A) and E)

Question 12

Which liver enzyme is deficient in Hers disease?

Accepted Answer

A)   phosphorylase
B)   transferase
C)   glucosidase
D)   phosphoglucomutase
E)   None of the above.F) A) and D)
G) A) and C)

Question 13

What are the three steps in glycogen degradation?

Accepted Answer

The steps are 1) release of glucose 1-phosphate from glycogen, 2) remodeling of glycogen substrate, and 3) formation of glucose 6-phosphate from glucose 1-phosphate.

Question 14

The transferase enzyme shifts a block of ______________ glycosyl units.

Accepted Answer

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

Question 15

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) A) and B)
G) A) and C)

Question 16

One mechanism for turning off glycogen degradation involves the removal of a phosphate group from glycogen phorphorylase by the enzyme ____________.

Accepted Answer

protein ph...

Question 17

The hydrolysis catalyzed by α-1,6-glucosidase releases a(n) ______________ molecule.

Accepted Answer

The answer of The hydrolysis catalyzed by α-1,6-glucosidase releases a(n)...

Question 18

Why can't the glucose 1-phosphate diffuse out of the cell?

Accepted Answer

There is no membrane transporter for glucose 1-phosphate and the negative charge traps it inside so it cannot diffuse through the cell membrane.

Question 19

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) None of the above

Question 20

Choose the correct answer from the list below. Not all of the answers will be used.
-____________: Most of the glucose residues in glycogen are linked by this type of bond.

Accepted Answer

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

Exam 24: Glycogen Degradation

Choose the correct answer from the list below. Not all of the answers will be used. -The type of bond that is located at the branch points in glycogen is ____________.

Correct AnswerverifiedShow Answer

Choose the correct answer from the list below. Not all of the answers will be used. -The process by which a bond is cleaved by the addition of orthophosphate is ____________.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What are the two regulatory controls for phosphorylase kinase?

Correct AnswerverifiedPhosphorylase kinase is activa...View AnswerShow Answer

Both phosphorylase a and b 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

Why is the formation of glucose 1-phosphate advantageous?

Correct AnswerverifiedIt is advantageous because the...View AnswerShow Answer

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

Correct AnswerverifiedShow Answer

In order to degrade branches in glycogen, two enzymes are required: a transferase and ______________.

Correct AnswerverifiedShow Answer

What path, in addition to the cAMP-induced signal transduction, is used in the liver to stimulate glycogen breakdown by epinephrine?

Correct AnswerverifiedIn the liver, epinephrine also binds to a 7TM ɑ-adrenergic receptor, which activates phospholipase C and the phosphoinositide cascade. This causes calcium ions to be released, which bind to calmodulin, and further stimulates phosphorylase kinase and glycogen breakdown.

Why is the T state of glycogen phosphorylase less active?

Correct AnswerverifiedShow Answer

What physiological conditions render phosphorylase b less active?

Correct AnswerverifiedShow Answer

Which liver enzyme is deficient in Hers disease?

Correct AnswerverifiedShow Answer

What are the three steps in glycogen degradation?

Correct AnswerverifiedThe steps are 1) release of glucose 1-phosphate from glycogen, 2) remodeling of glycogen substrate, and 3) formation of glucose 6-phosphate from glucose 1-phosphate.

The transferase enzyme shifts a block of ______________ glycosyl units.

Correct AnswerverifiedShow Answer

How is phosphorylase b converted into phosphorylase a?

Correct AnswerverifiedShow Answer

One mechanism for turning off glycogen degradation involves the removal of a phosphate group from glycogen phorphorylase by the enzyme ____________.

Correct Answerverifiedprotein ph...View AnswerShow Answer

The hydrolysis catalyzed by α-1,6-glucosidase releases a(n) ______________ molecule.

Correct AnswerverifiedShow Answer

Why can't the glucose 1-phosphate diffuse out of the cell?

Correct AnswerverifiedThere is no membrane transporter for glucose 1-phosphate and the negative charge traps it inside so it cannot diffuse through the cell membrane.

Two critical hormones that signal for glycogen breakdown are:

Correct AnswerverifiedShow Answer

Choose the correct answer from the list below. Not all of the answers will be used. -____________: Most of the glucose residues in glycogen are linked by this type of bond.

Correct AnswerverifiedShow 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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Phosphorylase kinase is activa...
View Answer

Correct Answer
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The most active is phosphoryla...
View Answer

Correct Answer
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It is advantageous because the...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
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In the liver, epinephrine also binds to a 7TM ɑ-adrenergic receptor, which activates phospholipase C and the phosphoinositide cascade. This causes calcium ions to be released, which bind to calmodulin, and further stimulates phosphorylase kinase and glycogen breakdown.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The steps are 1) release of glucose 1-phosphate from glycogen, 2) remodeling of glycogen substrate, and 3) formation of glucose 6-phosphate from glucose 1-phosphate.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
protein ph...
View Answer

Correct Answer
verified

Correct Answer
verified
There is no membrane transporter for glucose 1-phosphate and the negative charge traps it inside so it cannot diffuse through the cell membrane.

Correct Answer
verified

Correct Answer
verified