A medically important example of active transport is that of drug ________ proteins powered by the hydrogen ion gradient.
A) efflux
B) porin
C) membrane-permeant
D) diffusion
E) lysis

Question

Quizplus · Accepted Answer

Active transport is the movement of molecules across a membrane against their concentration gradient and requires energy input. Efflux proteins are a type of active transporter that pump drugs and other molecules out of cells, often as a defense mechanism against toxins or antibiotics. The energy for this transport is provided by the hydrogen ion gradient, which is maintained by the action of other membrane proteins such as ATPases or proton pumps. Therefore, choice A is the correct answer. Porins are passive channels that allow the diffusion of molecules across the membrane, and membrane-permeant molecules can cross the membrane without any assistance. Diffusion is a passive transport process that does not require energy input, and lysis refers to the breaking down of cells, which is not related to transport mechanisms.

A Medically Important Example of Active Transport Is That of Drug