Biochemistry of Glycogenolysis EXPLAINED

The video explains glycogenolysis, the process of breaking down glycogen into glucose units for energy. It details the structure of glycogen, the role of glycogenin, and the catalytic mechanism of glycogen phosphorylase. The video highlights the energetic benefits of producing glucose 1 phosphate over glucose and describes the function of the glycogen debranching enzyme in processing glycogen branches.

What is the primary role of glycogenin in glycogen structure?

• It breaks down glycogen into glucose.

• It converts glucose to glycogen.

• It acts as a primer for glycogen synthesis.

• It transports glucose into cells.

Which enzyme is responsible for cleaving glucose from glycogen as glucose 1 phosphate?

• Hexokinase

• Glycogen phosphorylase

• Glycogen synthase

• Phosphoglucomutase

What is the final product when glycogen is broken down by glycogen phosphorylase?

• Fructose 1 phosphate

• Glucose 1 phosphate

• Maltose

• Glucose 6 phosphate

What is the significance of the oxonium cation in the catalytic mechanism of glycogen phosphorylase?

• It stabilizes the enzyme structure.

• It facilitates the nucleophilic attack by phosphate.

• It inhibits the enzyme activity.

• It converts glucose to glycogen.

Why is glucose 1 phosphate more energetically favorable than glucose for the cell?

• It can directly enter glycolysis.

• It is easier to store in the cell.

• It is more stable than glucose.

• It requires less ATP to enter glycolysis.

What is the role of phosphoglucomutase in glycolysis?

• It converts glucose to fructose.

• It converts glucose 1 phosphate to glucose 6 phosphate.

• It phosphorylates glucose.

• It dephosphorylates glucose.

What happens when glycogen phosphorylase reaches a branch of four glucose units?

• It phosphorylates glucose.

• It converts glucose to glycogen.

• It stops functioning.

• It continues to cleave glucose units.

What are the two activities of the glycogen debranching enzyme?

• Transferase and glucosidase

• Phosphorylase and synthase

• Hydrolase and ligase

• Kinase and isomerase

What is the role of the transferase activity in the glycogen debranching enzyme?

• It removes glucose units from the primary chain.

• It phosphorylates glucose units.

• It transfers glucose units to the primary chain.

• It adds glucose units to glycogen.

How does the A16 glucosidase activity of the debranching enzyme differ from the phosphorylase activity?

• It uses ATP to cleave glucose.

• It uses glucose to cleave phosphate.

• It uses phosphate to cleave glucose.

• It uses water to cleave glucose.