physiology , diffusion

Question

At a given glucose concentration, does the rate of diffusion change with a change in the number of carrier molecules? Why or why not? If so, describe the change.

Answer 1

Glucose crossed cell membranes by facilitated diffusion, requiring a carrier molecule. The diffusion is down a concentration gradient of glucose, and does not require energy. Each carrier molecule binds with a glucose, and changes conformation to allow the glucose to cross the membrane. Thus, the more carrier molecules, the faster the rate of glucose diffusion.