ISSA Nutritionist Practice Exam

What role does insulin play in energy metabolism?

1. Increases glucose levels

2. Stimulates glycogen breakdown

3. Promotes glucose uptake

4. Inhibits lipid storage

The correct answer is: Promotes glucose uptake

Insulin plays a crucial role in energy metabolism primarily by promoting glucose uptake into cells. After a meal, when blood glucose levels rise, insulin is secreted by the pancreas and facilitates the transport of glucose from the bloodstream into muscle and fat cells. This process is vital for providing cells with the necessary energy to function, as glucose is a primary source of energy for many bodily processes. When insulin binds to its receptors on cell surfaces, it activates a series of intracellular signaling pathways that increase the number of glucose transporters on the cell membrane. This increase allows for more glucose to enter the cells, effectively lowering blood glucose levels and enabling their utilization for energy or storage as glycogen in the liver and muscle tissues. This action prevents excessive accumulation of glucose in the blood, which can be harmful. Additionally, insulin also helps regulate other metabolic processes, such as fatty acid synthesis and protein synthesis, but its most immediate and critical role involves facilitating glucose uptake.