$$\text{Glycogen} + \text{Pi} \rightarrow \text{Glycogen}_{n-1} + \text{Glucose-1-phosphate}$$

Question 1

Which enzyme is primarily responsible for breaking down glycogen by removing glucose subunits from the nonreducing end via phosphorolysis?

Accepted Answer

Glycogen phosphorylase

Question 2

What is the product formed when glycogen phosphorylase acts on glycogen?

Accepted Answer

Glucose-1-phosphate

Question 3

Which enzyme converts glucose-1-phosphate to glucose-6-phosphate during glycogen breakdown?

Accepted Answer

Phosphoglucomutase

Question 4

What is the role of AMP in the regulation of glycogen phosphorylase?

Accepted Answer

AMP activates glycogen phosphorylase

Question 5

Which process is catalyzed by the debranching enzyme during glycogen metabolism?

Accepted Answer

Transfer of 1,4-linked glucose units to another branch and removal of 1,6-linked glucose

Question 6

During glycogen breakdown, which molecule is released from the branch point after the action of the debranching enzyme?

Accepted Answer

Glucose

Question 7

Why does muscle tissue lack glucose-6-phosphatase, and what is the consequence?

Accepted Answer

Muscle cannot release free glucose into the bloodstream

Question 8

Which of the following best describes the effect of high blood glucose on glycogen metabolism?

Accepted Answer

Glycogen breakdown decreases, glycogen synthesis increases

Question 9

What is the function of phosphoglucomutase in glycogen metabolism?

Accepted Answer

It converts glucose-1-phosphate to glucose-6-phosphate

Question 10

Which statement best explains why the liver can release glucose into the bloodstream but muscle cannot?

Accepted Answer

Liver contains glucose-6-phosphatase, which converts glucose-6-phosphate to glucose

Question 11

Which of the following reactions is catalyzed by glycogen phosphorylase?

Accepted Answer

$$	ext{Glycogen} + 	ext{Pi} ightarrow 	ext{Glycogen}_{n-1} + 	ext{Glucose-1-phosphate}$$

Question 12

Which enzyme is responsible for transferring a block of three glucose residues from one branch to another during glycogen breakdown?

Accepted Answer

Debranching enzyme

Question 13

What is the fate of glucose-6-phosphate produced in muscle cells during glycogen breakdown?

Accepted Answer

It enters glycolysis to provide energy for muscle contraction

Question 14

Which of the following statements about glycogen metabolism regulation is correct?

Accepted Answer

Glycogen phosphorylase and glycogen synthase are regulated in opposite ways by phosphorylation

Question 15

A patient with a deficiency in the debranching enzyme would most likely present with which of the following symptoms?

Accepted Answer

Accumulation of abnormal glycogen with short outer branches

Question 16

Which of the following best describes the role of glucose-6-phosphatase in the liver?

Accepted Answer

It converts glucose-6-phosphate to glucose, allowing glucose release into the bloodstream

Question 17

Which of the following is a direct consequence of low blood glucose on glycogen metabolism?

Accepted Answer

Glycogen breakdown increases, glycogen synthesis decreases

Question 18

Which of the following statements about the regulation of glycogen phosphorylase is correct?

Accepted Answer

It is activated by phosphorylation and AMP

Question 19

Which of the following best explains why the liver can supply glucose to the blood during fasting, but muscle cannot?

Accepted Answer

Liver contains glucose-6-phosphatase, which converts glucose-6-phosphate to glucose

Glycogen Metabolism: Mechanisms and Regulation

Study Guide - Practice Questions