Question

Active transport must function continuously because _______. a. plasma membr anes wear out b. cells must be in constant motion c. facilitated transport opposes active tran sport d. diffusion is constantly moving the solutes in the other direction

Short answer

Answer: Active transport must function continuously because diffusion is constantly moving the solutes in the other direction, working against the maintenance of concentration gradients essential for the cell's functions.

Step-by-step solution

Understand Active Transport

Active transport is the movement of molecules or ions against their concentration gradient, from a region of lower concentration to higher concentration. This process requires energy, usually in the form of ATP (Adenosine triphosphate), and involves special carrier proteins. The main purpose of active transport is to maintain concentration gradients, which are crucial for various cellular functions.

Analyze Each Option

a. Plasma membranes wear out: This is incorrect, as active transport does not primarily function continuously because of the wearing out of plasma membranes. b. Cells must be in constant motion: This is also incorrect, as active transport has more to do with maintaining concentration gradients than the movement of cells. c. Facilitated transport opposes active transport: This statement is incorrect, as facilitated transport is another type of membrane transport that moves molecules down their concentration gradient without the need for energy input, and it does not oppose active transport. d. Diffusion is constantly moving the solutes in the other direction: This is the correct option. Active transport must function continuously because diffusion, a passive process, is always happening and tends to even out concentration gradients. Active transport works against diffusion by moving solutes against their concentration gradient, hence maintaining the concentration differences essential for the cell's functions.

Choose the Correct Answer

The correct answer is option d. Active transport must function continuously because diffusion is constantly moving the solutes in the other direction.