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: -In facilitated diffusion, substances move into or out of cells down their concentration gradient through protein channels in the cell membrane. Simple diffusion and facilitated diffusion are similar in that both involve movement down the concentration gradient.

Detailed explanation-3: -“Facilitated diffusion is a type of diffusion in which the molecules move from the region of higher concentration to the region of lower concentration assisted by a carrier.”

Detailed explanation-4: -Biological Transport In passive transport, particles (e.g. ions or molecules) are transported along the concentration gradient. This means that the particles move from areas of high concentrations to areas of low concentrations. Because of the passive movement of particles no chemical energy is spent as it takes place.

Detailed explanation-5: -Facilitated diffusion is a form of passive transport and, therefore, the direction of transport is always down a concentration gradient.