Glycogenolysis

The video tutorial explores the breakdown of glycogen, focusing on the role of enzymes and signaling pathways. It begins with an introduction to glycogen phosphorylase, the enzyme responsible for glycogen breakdown. The tutorial then explains how epinephrine binds to beta adrenergic receptors, activating a G protein that triggers a cascade involving cyclic AMP and protein kinase A. This cascade ultimately activates glycogen phosphorylase, leading to the production of glucose 1 phosphate. The video also covers the conversion of glucose 1 phosphate to glucose 6 phosphate, which can enter glycolysis.

What is the initial point of attack for glycogen catabolism?

• Both ends simultaneously

• Middle of the chain

• Non-reducing end

• Reducing end

Which enzyme is responsible for breaking down glycogen?

• Glycogen phosphorylase

• Amylase

• Lipase

• Glycogen synthase

What molecule binds to the beta adrenergic receptor to initiate glycogen breakdown?

• Epinephrine

• Cortisol

• Glucagon

• Insulin

What is the role of cyclic AMP in the activation of glycogen phosphorylase?

• It directly breaks down glycogen

• It activates protein kinase A

• It inhibits glycogen phosphorylase

• It converts glucose to glycogen

What is the immediate product of glycogen breakdown?

• Glucose-1-phosphate

• Fructose-6-phosphate

• Glucose-6-phosphate

• Glucose

Which enzyme converts glucose-1-phosphate to glucose-6-phosphate?

• Phosphoglucomutase

• Glycogen synthase

• Hexokinase

• Phosphofructokinase

What is the common name for epinephrine?

• Noradrenaline

• Adrenaline

• Dopamine

• Serotonin