Glycogen Synthesis and Glycogenolysis

These flashcards cover key concepts related to glycogen synthesis, glycogenolysis, associated enzymes, hormonal regulation, and related disorders.

What is glycogen synthesis?

The process of storing glucose primarily in the liver and skeletal muscle.

What hormone initiates glycogenolysis in the liver?

Glucagon.

What is the primary function of glycogenolysis?

To release glucose into the bloodstream for homeostasis.

What are the two primary enzymes involved in glycogen synthesis?

Glycogen synthase and branching enzyme.

What is the role of UDP-glucose in glycogen synthesis?

It serves as the source for glycosyl residues added to the growing glycogen chain.

What molecule is glucose phosphorylated to during glycogen synthesis?

Glucose-6-phosphate.

What happens to glycogen phosphorylase during the fasted state?

It becomes active due to the phosphorylation by cyclic AMP-dependent protein kinase.

What is von Gierke disease associated with?

Deficiency of glucose-6-phosphatase.

What is McArdle syndrome associated with?

Deficiency in muscle phosphorylase.

How does insulin affect glycogen synthase?

It promotes the dephosphorylation and activation of glycogen synthase.

What type of linkage occurs at branch points in glycogen?

1,6 linkage.

What are the products of glycogenolysis?

Glucose-1-phosphate and free glucose.

Why is skeletal muscle glycogen not released into the blood?

Because it is used locally and does not contribute to blood glucose levels.