Glycogen Synthesis and Breakdown Quiz

Which of the following is false about glycogen molecules?

• Glycogen is a polysaccharide

• Glycogen is a polymer of beta-D-Glucose

• Glycogen consists of α(1-4) and α (1-6) glycosidic linkage

• Glycogen have are a helical structure with branching.

Answer explanation

Glycogen is not a polymer of beta-D-Glucose. It is a polysaccharide consisting of α(1-4) and α (1-6) glycosidic linkage, with a helical structure and branching.

Which of the following organs does not have glycogen storage?

• Liver

• Muscle

• Intestine

• Erythrocytes

Answer explanation

Erythrocytes do not have glycogen storage. Liver, muscle, and intestine are organs that store glycogen.

Which of the following enzyme is responsible for glycogen breakdown?

• Glycogen phosphorylase

• Glycogen phosphatase

• Glycogen hydrolase

• Glycogen phospho beta-glucosidase

Answer explanation

Glycogen phosphorylase is responsible for glycogen breakdown. It catalyzes the cleavage of glucose units from the glycogen polymer.

Liver glycogen contributes to the maintenance of glucose but not muscle glycogen. Which of the following enzyme is absent in muscle?

• Glycogen phosphorylase

• Hexokinase

• Glucose-6-phosphatase

• Debranching enzyme

Glycogen phosphorylase is responsible for the breakdown of glycogen to............................................

• Glucose

• Glucose-1-phosphate

• Glucose-6-phosphate

• Maltose

Which of the following metabolite allosterically activate glycogen phosphorylase?

• ATP

• AMP

• Glucose-6-P

• Glucose-1-P

In response to glucagon and epinephrine, cells undergo a series of changes in signal-transducing molecules that phosphorylates and activates glycogen phosphorylase. Which of the following enzyme is responsible for covalent modification of glycogen phosphorylase?

• Protein kinase A

• Phosphorylase kinase

• Protein kinase C

• Protein kinase B

Which of the following is not the direct/ indirect activator of glycogen phosphorylase in muscle?

• AMP

• Ca++

• Epinephrine

• Insulin

Which of the following protein is required for de novo synthesis of glycogen?

• Glycoprotein

• Glycogenin

• Proteoglycan

• Glucogenin

Which of the following enzyme is responsible for the addition of UDP-Glucose to the existing chain?

• Glycogen synthase

• Glycogen polymerase

• Glycogen synthetase

• Glycogen lyase