What is glycogenolysis?

What is glycogenolysis?

• A. Breakdown of glycogen to glucose
• B. Formation of glycogen from glucose
• C. Conversion of glucose to glycerol
• D. Storage of glycogen

Answer: (A)

Glycogenolysis is the breakdown of glycogen into glucose. This process begins with glycogen phosphorylase cleaving glucose units from glycogen as glucose-1-phosphate, which is then converted to glucose-6-phosphate. In the liver, glucose-6-phosphatase can release free glucose into the bloodstream to raise blood sugar, while in muscle the glucose-6-phosphate typically feeds glycolysis for local energy. This activity is the opposite of glycogenesis, which is the formation of glycogen from glucose. The other options describe forming glycogen, converting glucose to glycerol, or storing glycogen, none of which are glycogenolysis. Hormones like glucagon and epinephrine stimulate this breakdown, whereas insulin inhibits it.

Glycogenolysis is the breakdown of glycogen into glucose. This process begins with glycogen phosphorylase cleaving glucose units from glycogen as glucose-1-phosphate, which is then converted to glucose-6-phosphate. In the liver, glucose-6-phosphatase can release free glucose into the bloodstream to raise blood sugar, while in muscle the glucose-6-phosphate typically feeds glycolysis for local energy. This activity is the opposite of glycogenesis, which is the formation of glycogen from glucose. The other options describe forming glycogen, converting glucose to glycerol, or storing glycogen, none of which are glycogenolysis. Hormones like glucagon and epinephrine stimulate this breakdown, whereas insulin inhibits it.