Glycogen Metabolism

Question 1

Where are glycogen stores found?

Answer 1

Liver and MM

Question 2

When is glycogenesis upregulated in liver and muscle cells?

Answer 2

In Liver, it is upregulated in the fed state when glucose is more available to be stored. In muscle cells, it is upregulated after exercise

Question 3

What is the starting reactant in glycogenesis?

Answer 3

Glucose

Question 4

Phosphoglucomutase

Answer 4

Catalyzes the step of G6P–> G1P in glycogenesis

Question 5

UDP-Glucose Phosphorylase

Answer 5

Catalyzes G1P–> UDP-Glucose in glycogenesis. It produces inorganic phosphate

Question 6

Glycogen Synthase

Answer 6

Creates alpha 1,4 glyosidic linkages from UDP-Glucose to form linear glycogen

Question 7

Glycogen Branching Enzyme

Answer 7

Creates alpha 1,6 glycosidic linkages for branched glycogen

Question 8

Glycogen Phosphorylase

Answer 8

Is the first major enzyme in glycogenolysis. It catalyzes the step of Glycogen–> G1P

Question 9

Phosphoglucomutase

Answer 9

G1P–> G6P in glycogenolysis (2nd step)

Question 10

Glycogen Debranching Enzyme

Answer 10

Breaks down the alpha 1,6Linkages

Question 11

G6P Phosphatase

Answer 11

Catalyzes the final step of glycogenolysis. It is also the final step of gluconeogenesis.

Question 12

What upregulates glycogenolysis in skeletal muscle?

Answer 12

Epinephrine, Ca2+, AMP (Glycogen phosphorylase is the control point)

Question 13

What upregulates glycogenolysis in the liver?

Answer 13

Glucagon

Question 14

What downregulates glycogenolysis in the liver?

Answer 14

Insulin and glucose

Question 15

What upregulates glycogenesis in both liver and mm?

Answer 15

Insulin