Glycogen Metabolism

Question 1

Constant levels of ______ in blood are absolute requirement for glycogen metabolism

Answer 1

Glucose

Question 2

What is the preferred energy source for the brain? And required for RBCs?

Answer 2

Glucose

Question 3

Glucose is essential for exercising muscle

T/F

Answer 3

True

Question 4

3 main ways the body obtained Glucose

Answer 4

Food/catabolism (diet)
Anabolism (GNG)
Storage (as glycogen)

Question 5

Mechanism for storing a supply of glucose in a reap idly mobilizable form

Answer 5

Glycogen

Question 6

What cells can contain glycogen?

Answer 6

(Virtually) any cell

Question 7

Where are the main stores of glycogen found?

Answer 7

Skeletal
-for its own use of fuel

Liver
-to maintain blood glucose during early fasting

Question 8

Correlation between glycogen storage and water storage?

Answer 8

Glycogen storage is associated with significant amounts of water storage, therefore your weight can vary significantly based on the amount of glycogen you have stored

Question 9

When is glycogen degraded to glucose?

Answer 9

When there is an absence of a dietary source

Question 10

Where is glycogen released from?

Answer 10

the liver, and the kidney as kidney glycogen

Question 11

When is muscle glycogen degraded?

Answer 11

When the exercising muscle needs an energy source

Question 12

As glycogen stores are depleted, but the body still needs energy, what happens?

Answer 12

GNG takes over to provide glucose

Question 13

Glycogen structure

Answer 13

Branched chain polysaccharide

Alpha(1,4) linkage

After around 8-10 alpha(1,4) linkages, there is a branch containing alpha(1,6)linkage

Question 14

discrete cytoplasmic granules (beta-particles)

Answer 14

Large molecules of glucose that are associated with the enzymes necessary for synthesis and degradation

Question 15

Steps of Glycogenesis

Answer 15

1. Synthesis of Uridine diphosphate glucose
2. Synthesis of a primer to initiate glycogen synthesis
3. Elongation of glycogen chains
4. Formation of branches

Question 16

Why are branches important in glycogen?

Answer 16

Because they increase the solubility and they increase the number of nonreducing ends that allow faster synthesis and degradation

Question 17

What energy source is used in step one of Glycogenesis?

Answer 17

UTP, to create UDP-glucose

Creates 2 Pi’s as byproducts

Question 18

In step 2 of Glycogenesis, UDP-glucose serves as a….

Answer 18

Primer, to elongate existing glycogen chains.

Question 19

If no glycogen primers are available, what happens?

Answer 19

Glycogenin can serve as a primer.

Question 20

How do the glycogen chains elongate in step 3 of Glycogenesis ?

Answer 20

Glycogen synthase transfers UDP-glucose to the non-reducing end of the primer

Rate-limiting enzyme

Question 21

How are branches formed in step 4 of Glycogenesis?

Answer 21

The branching enzyme removed a chains of 6-8 glucosyl residues from the ends of the glycogen chain and attached is to a non-terminal glucosyl residue by alpha(1,6)bond

Question 22

Steps of Glycogenolysis

Answer 22

1. Shortening of chains
2. Removal of branches
3. Conversion of G-1-P to G-6-P
4. Dephosporylation of G-6-P to glucose

Question 23

Where is the dephosphorylation of G-6-P primarily expressed? Where else, to a lesser extent?

Answer 23

In the liver and the kidney cortex.

In the pancreatic Beta cells and intestinal mucosa.

Question 24

What enzyme causes the degradation of glycogen in Lysosomes?

Answer 24

Lysosomal alpha-1,4-glucosidase

Only 1-3% of glycogen.

Question 25

In the muscle, when will Glycogenesis occur?

Answer 25

In well-fed state

Excess glucose

Question 26

In the liver, when will Glycogenolysis occur?

Answer 26

During fasting

NEED MAS GLUCOSE

Question 27

In the muscle, when will Glycogenesis occur?

Answer 27

Begins at rest

Ready to store glucose, sir.

Question 28

When will Glycogenolysis occur in the muscle?

Answer 28

During exercise.

WE NEED ENERGY FAST

Question 29

Glycogen synthase and glycogen phosphorylase are the…

Answer 29

Regulatory enzymes of Glycogenolysis and Glycogenesis

Question 30

The regulatory enzymes of Glycogenolysis and Glycogenesis are accomplished at 2 levels, which are:

Answer 30

Hormonal regulation to meet the needs of the body as a whole

Allosteric regulation to meet the needs of particular tissue!

Question 31

Glycogen phosphorylase is activated in the liver by:

Answer 31

Epinephrine and glucagon (hormonal)

Question 32

Glycogen phosphorylase is activated in the muscle by:

Answer 32

Epinephrine (hormonal)

AMP and Ca2+ (Allosteric)

Question 33

Glycogen phosphorylase is inhibited in the liver by:

Answer 33

Insulin (hormonal)

G6P, glucose, and ATP (Allosteric)

Question 34

Glycogen phosphorylase is inhibited in the muscle by:

Answer 34

Insulin (hormonal)

G6P and ATP (Allosteric)

Question 35

Glycogen synthase is activated in the liver by:

Answer 35

Insulin (hormonal)

G6P (Allosteric)

Question 36

Glycogen synthase is activated in the muscle by:

Answer 36

Insulin (hormonal)

G6P (Allosteric)

Question 37

Glycogen synthase is inhibited in the liver by:

Answer 37

Glucagon and epinephrine

Question 38

Glycogen synthase is inhibited in the muscle by:

Answer 38

Epinephrine

Question 39

Types of Glycogen Storage Diseases (GSD)

Answer 39

Von Gierke

Pompe

Cori

Andersen

McCardle

Hers

KNOW MORE ABOUT EACH??