What storage molecule is converted to glucose by glucagon?

The storage molecule that is converted to glucose by glucagon is glycogen. Glycogen is a carbohydrate that serves as a key energy reserve in the body, primarily stored in the liver and muscles. When blood glucose levels drop, glucagon is released by the pancreatic alpha cells, which signals the liver to break down glycogen into glucose through a process called glycogenolysis.

This release of glucose into the bloodstream is crucial for maintaining proper blood sugar levels, especially during periods of fasting or intense physical activity. The body's ability to convert glycogen to glucose helps ensure a steady supply of energy for metabolic processes and supports the functioning of vital organs, including the brain.

Other storage molecules mentioned in the choices serve different purposes. Starch is a plant polysaccharide used for energy storage in plants but is not directly converted by glucagon in the human body. Fat, primarily in the form of triglycerides, is stored for long-term energy needs but is not transformed into glucose by glucagon. Cellulose is a complex plant carbohydrate that serves a structural role in cell walls and cannot be converted into glucose by the human body.