Which statement best describes insulin's role in glucose metabolism?

Which statement best describes insulin's role in glucose metabolism?

• A. It triggers glucose export from cells
• B. It inhibits glucose uptake
• C. It facilitates the uptake of glucose into cells for energy
• D. It converts glucose into glycogen immediately

Answer: (C)

Insulin’s main action is to promote glucose entry into cells so it can be used for energy or stored. In muscle and fat, insulin stimulates GLUT4 transporters to move to the cell surface, increasing glucose uptake. Inside cells, that glucose can fuel glycolysis for immediate energy or be stored as glycogen (in liver and muscle) or converted to other storage forms. This makes the statement that insulin facilitates glucose uptake into cells for energy the best description of its role. The other ideas don’t fit as well: insulin doesn’t drive glucose out of cells, it promotes uptake rather than inhibition, and while it promotes glycogen synthesis, glucose is not converted to glycogen instantaneously—the process follows uptake and subsequent enzymatic steps.

Insulin’s main action is to promote glucose entry into cells so it can be used for energy or stored. In muscle and fat, insulin stimulates GLUT4 transporters to move to the cell surface, increasing glucose uptake. Inside cells, that glucose can fuel glycolysis for immediate energy or be stored as glycogen (in liver and muscle) or converted to other storage forms. This makes the statement that insulin facilitates glucose uptake into cells for energy the best description of its role.

The other ideas don’t fit as well: insulin doesn’t drive glucose out of cells, it promotes uptake rather than inhibition, and while it promotes glycogen synthesis, glucose is not converted to glycogen instantaneously—the process follows uptake and subsequent enzymatic steps.