Facilitated diffusion across a biological membrane requires and moves a substance its concentration gradient.

Question

Quizplus · Accepted Answer

Facilitated diffusion moves a substance down its concentration gradient, meaning it moves from an area of higher concentration to an area of lower concentration. Transport proteins are required for facilitated diffusion to occur, but no energy input is required. Choice A is incorrect because moving a substance against its concentration gradient would require energy input, which is not the case in facilitated diffusion. Choice C is incorrect because energy input is not required for facilitated diffusion. Choice D is incorrect because although transport proteins are required for facilitated diffusion, energy input is not.

Facilitated Diffusion Across a Biological Membrane Requires and Moves a Substance