Question 1

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

Accepted Answer

protein phosphatase 1,PP1

Question 2

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

Question 3

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

Accepted Answer

glucose 1,6-bisphosphate

Question 4

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

Question 5

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

Accepted Answer

Comparison of the binding sites for gluc

Question 6

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

Accepted Answer

It is favored becaus

Question 7

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 8

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

Question 9

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. 
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.

Question 10

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. 
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.

Question 11

What are the three steps in glycogen degradation?

Accepted Answer

The steps are 1)release of glu

Question 12

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

Question 13

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

Accepted Answer

A)  transferase 
B)  $\alpha$-1,6-glucosidase 
C)  glycogen phosphatase 
D)  transferase and $\alpha$-1,6-glucosidase 
E)  $\alpha$-1,6-glucosidase and glycogen phosphatase 
A)  transferase 
B)  $\alpha$-1,6-glucosidase 
C)  glycogen phosphatase 
D)  transferase and $\alpha$-1,6-glucosidase 
E)  $\alpha$-1,6-glucosidase and glycogen phosphatase

Question 14

Give the reaction catalyzed by UDP-glucose pyrophosphorylase.

Accepted Answer

Glucose-1-

Question 15

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 16

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 17

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

Accepted Answer

Glycogen is readily accessible and can b

Question 18

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

Question 19

How does insulin stimulate glycogen synthesis?

Accepted Answer

Insulin triggers a pathway that activate

Question 20

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...

Exam 21: Glycogen Metabolism

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

Critical hormones that signal for glycogen breakdown are

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

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

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

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

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

What protein serves as the primer for glycogen synthase?

Why is glycogen branching important?

How is phosphorylase b converted into phosphorylase a?

What are the three steps in glycogen degradation?

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

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

Give the reaction catalyzed by UDP-glucose pyrophosphorylase.

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

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.

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

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

How does insulin stimulate glycogen synthesis?

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.

Biochemistry: An Evolving Science

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Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

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Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

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Metabolism: Basic Concepts and Design

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The Citric Acid Cycle

Oxidative Phosphorylation

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The Calvin Cycle and the Pentose Phosphate Pathway

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Protein Turnover and Amino Acid Catabolism

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Nucleotide Biosynthesis

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The Integration of Metabolism

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