Glycogen Metabolism

Question 1

Glycogenesis

Answer 1

Anabolism of glycogen (Synthesis of glycogen to store glucose)

Question 2

Glycogenolysis

Answer 2

Catabolism of glycogen (Breakdown of glycogen into glucose-6-phosphate)

Question 3

3 places glycogenolysis takes place:

Answer 3

Catabolism of glycogen/starch from the diet
Catabolism of endogenous glycogen (glycogen stored in liver and muscle tissue)

Question 4

Endogenous glycogen

Answer 4

glycogen stored in tissues if muscle and liver

Question 5

Where does glycogen metabolism occur

Answer 5

1. In the gut (postprandial (after a meal) period
2. In the liver
3. In the muscles

Question 6

Characteristics of glycogen metabolism in the gut

Answer 6

1) Digestive catabolism of food glycogen/starch
2) Allows the production of glucose for distribution to:
-Glycogen storage areas
-Organs (as energy source)

Question 7

Characteristics of glycogen metabolism in the liver

Answer 7

1) Glycogen synthesis: storage of glucose during postprandial period (right after a meal).
2) Glycogen breakdown: between meals, the liver provides energy to others tissues and organs.
3) The liver is a “glucostat”, it adjusts the synthesis and breakdown of glycogen to maintain appropriate levels of blood glucose.

Question 8

Explain and compare the usage and origins of blood glucose

Answer 8

Diet = lots of glucose intake from food, so then glycogen rises to store glucose, then glycogen gets broken down, and gluconeogenesis kicks in once all glycogen is gone
-Glucose in the blood will remain stable even after 40 days

Question 9

Characteristics of glycogen metabolism in the muscles

Answer 9

1) Glycogen synthesis when the muscle is at rest
2) Glycogen breakdown as energy source when muscles are contracting.
3) Muscle stores glycogen for its own use and to break down for energy