Glycogenolysis/Glycogenesis

Question 1

What is the most common linkage between glucosyl residues?

Answer 1

Alpha 1,4

Question 2

When is the most glycogen stored away (glycogen liver content the highest)

Answer 2

After dinner

Question 3

How much glycogen can the liver and muscle store?

Answer 3

Liver - 100 grams

Muscle - much more

Question 4

What is the key enzyme in glyogenesis

Answer 4

Glycogen synthase

Question 5

What is the function of glycogen synthase?

Answer 5

To add glucose1P to growing glycogen chain

Question 6

What happens to excess glucose in the liver?

Answer 6

It is redirected toward FA synthesis

Question 7

What is the key enzyme in glycogenolysis

Answer 7

Glycogen phosphorylase

Question 8

What does insulin stimulate?

Answer 8

Glycogenesis, FA biosynthesis, and glycolysis

Question 9

What does glucagon stimulate?

Answer 9

Glycogenolysis

Question 10

What stimulates glycogen breakdown in muscle?

Answer 10

Muscle contraction or epinephrine

Question 11

What high-energy molecule does the branching enzyme require?

Answer 11

UDP-glucose

Question 12

What are the 2 activities of the debranching enzyme?

Answer 12

1. transferase

2. alpha 1,6 glucosidase

Question 13

Multiple second messengers activate ____ and inhibit ____

Answer 13

glycogen phosphorylase; glycogen synthase

Question 14

What type of GSD is caused by a deficiency in glycogen phosphorylase?

Answer 14

GSD V and GSD VI

Question 15

How do cAMP, PI, and Ca2+ activate glycogen phosphorylase

Answer 15

They activate phosphorylase kinase, which phosphorylates and activates glycogen phosphorylase, leading to glycogen degradation

Question 16

What are the effects of glucose in ATP on activated phosphorylase a

Answer 16

Inhibit the activated form

Question 17

What is the effect of AMP on phosphorylase b

Answer 17

activates the inactive form

Question 18

What are the effects of cAMP and insulin on phosphoprotein phosphatase

Answer 18

cAMP inhibits dephosphorylation of the phosphatase, insulin romotes it

Question 19

Glucagon promotes glycogen degradation/synthesis?

Answer 19

degradation

Question 20

Insulin promotes glycogen degradation/synthesis?

Answer 20

Glycogen storage

Question 21

How does insulin inhibit glycogen phosphorylase?

Answer 21

Dephosphorylates and inactivates the glycogen phosphorylase

Question 22

What is a condition during which AMP may be high enough to override unphosphorylated form?

Answer 22

During exercise

Question 23

What is the effect of phosphorylation on glycogen synthase?

Answer 23

Glycogen synthase in phosphorylated in its inactive form

Question 24

What is the effect of insulin on glycogen synthase?

Answer 24

Promotes a form (dephosphorylated)

Question 25

Which second messengers inhibit glycogen synthase?

Answer 25

cAMP, Ca2+, and DAG

Question 26

____ (hormone) promotes glycogen degradation

Answer 26

Glucagon

Question 27

G6P overrides which form of glycogen synthase?

Answer 27

Phosphorylated inactive form to cause activity

Question 28

How is cAMP different in the muscle from the liver?

Answer 28

In the liver, it inhibits glycolysis; in the muscle, it activates glycolysis