Final answer:
Insulin facilitates the transport of glucose into cells by increasing the number of glucose transport proteins on cell membranes, enabling facilitated diffusion of glucose.
Step-by-step explanation:
What allows glucose to be transported across cell membranes for use within the cell? The hormone insulin plays a crucial role in facilitating the transport of glucose into cells. Insulin acts as a transport protein, carrying glucose across the cell membrane. It facilitates the movement of intracellular vesicles containing glucose transporters to the cell membrane, where they fuse and expose the transporters to the extracellular fluid. This allows glucose to be transported into the cell for use. It increases the number of glucose transport proteins, or GLUTs, on cell membranes, enabling the cells to take up glucose when blood glucose levels are high. Insulin activates a cascade of events, leading to the insertion of GLUT transporters into the cell membrane, thus promoting the facilitated diffusion of glucose into the cell.