In most cells, there are electrochemical gradients of many ions across the plasma membrane even though there are usually only one or two electrogenic pumps present in the membrane. The gradients of the other ions are most likely accounted for by
A) cotransport proteins.
B) ion channels.
C) carrier proteins.
D) passive diffusion across the plasma membrane.
E) cellular metabolic reactions that create or destroy ions.

Question

Quizplus · Accepted Answer

Cotransport proteins can use the energy stored in the electrochemical gradient of one ion to drive the transport of another ion/molecule against its concentration gradient. This mechanism can account for the gradient of other ions without the need for additional electrogenic pumps.

In Most Cells, There Are Electrochemical Gradients of Many Ions