Question

Questions from study guide for biochem exam. Please answer as many as you can. Thank you

1. Where is glycogen found? What is the glycogen granule comprised of and what is its overall structure? What types of linkages are found in glycogen? How do they differ from cellulose?

2. What is glycogen phosphorylase? What are the two activities of the debranching enzyme? What does phosphoglucomutase do in both breakdown and synthesis of the glycogen particle? What are the two products of glycogen breakdown? In what proportion will they be found?

3. What is UDP-glucose pyrophosphorylase and what does it do? What is glycogen synthase? What is glycogenin?

4. What signals lead to the breakdown/synthesis of glycogen?

5. When is phosphorylase active/inactive? When is glycogen synthase active/inactive? What role do phosphorylase kinase, PP1c, GSK-3, and the GL or GM proteins play in regulation of glycogen synthesis/breakdown?

6. What role does Ca2+ and AMP play in the breakdown of glycogen in the skeletal muscle?

7. Based on the questions above (#4-6) you should be prepared to fully diagram the regulation of glycogen synthesis and breakdown.