Glycogen Metabolism - Breakdown and Synthesis

What are the four enzymes required for glycogen breakdown?

What kind of reaction is glycogen phosphorylase? What happens in this reaction.

True or false: glycogen phosphorylase breaks off glucose from glycogen at the reducing end of the chain.

What is the function of the transferase enzyme in glycogen breakdown?

What is the function of the enzyme a-1,6-glucosidase?

What is the function of the final enzyme in glycogen breakdown - phosphoglucomutase?

What is the key regulatory point in glycogen breakdown in muscle?

Which form of glycogen phosphorylase is active - a or b?

What are the other forms of glycogen phosphorylase (other than a and b) and which one is active?

If glycogen phosphorylase is in its a form then will the equilibrium be pushed to R state or T state?

What enzyme performs the phosphorylation/activation reaction of glycogen phosphorylase?

What enzyme performs the dephosphorylation reaction for glycogen phosphorylase and glycogen synthase?

Does phosphorylation of glycogen phosphorylase use or make ATP?

How is the b form of glycogen phosphorylase allosterically regulated in muscle?

What is the importance of the override mechanism where AMP activates glycogen phosphorylase b?

Why is regulation of glycogen phosphorylase different in the liver?

Which form of glycogen phosphorylase is allosterically regulated by glucose in the liver?

True or false: the b form of glycogen phosphorylase still has adenylate control and override in the liver.

What is the effect of increased glucose on the b form of glycogen phosphorylase in the liver?

What is the enzyme called that activates glycogen phosphorylase?

What are the two key methods used to regulate the phosphorylase kinase enzyme?

What is the effect of either hormones or Ca2+ binding to phosphorylase kinase enzyme?

What is the significance of Ca2+ being used to regulate phosphorylase kinase enzyme and therefore breakdown of glycogen?

What is the effect on phosphorylase kinase enzymes if both Ca2+ and hormones bind?

What are the three enzymes required for glycogen synthesis?

Which of the three enzymes involved in glycogen synthesis is a key regulatory step?

What is the purpose of the first step in glycogen synthesis? Where is energy released from to drive the process?

What is the function of the second reaction in glycogen synthesis?

True or false: glycogen synthase only adds UDP-glucose to chains that are over 6 units long.

What is the function of the third enzyme in glycogen synthesis?

What are the three specific requirements of the enzyme glycogen transferase to allow it to branch?

What is the purpose of branching in glycogen?

What is the active form of glycogen synthase: a or b?

What is the enzyme that phosphorylates glycogen synthase? Does phosphorylating it activate or inactivate it?

What is the pathway that allosterically activates the b form of glycogen synthase?

What inhibits and activates the enzyme protein phosphatase 1 which is responsible for dephosphorylates of glycogen phosphorylase and synthase?

True or false: the enzyme protein phosphatase 1 switches on glycogen breakdown and switches off glycogen synthesis.

What is the role of fructose 2,6-bisphosphate with regard to glycolysis and gluconeogenesis?

What are the two enzymes that regulate Fructose 2,6-bisphosphate? Why is it significant that it is these two enzymes?

True or false: PFK2 and PBPase2 can never be on at the same time.

When PFK2 and PBPase2 are dephosphorylated which one is on? Does this result in upregulation or downregulation of glycolysis?

Does glucagon stimulate phosphorylation or dephosphorylation of PFK2 and PBPase2? Explain your answer.