How do transporters and channels select which solutes they help move across the membrane?.

Channels discriminate between solutes mainly on the basis of size and electric charge.

Explanation:

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.