Question

It is thought that the glucose transporter switches between two conformational states in a completely random fashion. How is it possible for such a system to move glucose across the membrane efficiently in a single direction?

a) Uniport
b) Symport
c) Antiport
d) Facilitated diffusion

Answer 1

The glucose transporter moves glucose efficiently across the membrane using facilitated diffusion, specifically as a symporter in secondary active transport, coupling glucose movement with ions like sodium.

Correct option is d. Facilitated diffusion.

Step-by-step explanation:

The glucose transporter can efficiently move glucose across the membrane in a single direction by utilizing a mechanism known as facilitated diffusion. Although the glucose transporter randomly switches between conformations, it only allows glucose to move down its concentration gradient, from areas of high concentration to areas of low concentration. This is a form of passive transport that does not require energy.

When the glucose transporter works as a symporter, it couples the movement of glucose with another ion, such as sodium, enhancing glucose uptake into the cell against its concentration gradient through secondary active transport.

Correct option is d. Facilitated diffusion.