Question

a type of process that moves chemicals through the plasma membrane following their concentration gradient and using a carrier is called ________.
diffusion
active transport
receptor - mediated endocytosis
facilitated diffusion
i dont know yet

Explanation:

1. Analyze each option:

• Diffusion: Movement of substances down the concentration gradient without a carrier. So this is incorrect.
• Active transport: Requires energy and moves substances against the concentration gradient, also may use carriers but the energy and gradient direction rule it out here.
• Receptor - mediated endocytosis: A type of bulk transport, not related to moving substances down concentration gradient with a carrier in the typical membrane transport sense for small molecules.
• Facilitated diffusion: Moves substances down their concentration gradient (following the gradient) and uses a carrier protein to facilitate the movement across the plasma membrane.

Answer:

D. facilitated diffusion