AP BIOLOGY

Detailed explanation-1: -In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers. A concentration gradient exists for these molecules, so they have the potential to diffuse into (or out of) the cell by moving down it.

Detailed explanation-2: -Diffusion is the movement of particles down their gradient.

Detailed explanation-3: -Channel proteins, gated channel proteins, and carrier proteins are three types of transport proteins that are involved in facilitated diffusion. A channel protein, a type of transport protein, acts like a pore in the membrane that lets water molecules or small ions through quickly.

Detailed explanation-4: -Diffusion is a random movement of molecules down the pathway called the concentration gradient. Molecules are said to move down the concentration gradient because they move from a region of higher concentration to a region of lower concentration.

Detailed explanation-5: -Both facilitated diffusion and simple diffusion are types of passive transport. They move substances from an area of high concentration to an area of low concentration.