AP BIOLOGY

Detailed explanation-1: -A concentration gradient occurs when the concentration of particles is higher in one area than another. In passive transport, particles will diffuse down a concentration gradient, from areas of higher concentration to areas of lower concentration, until they are evenly spaced.

Detailed explanation-2: -Diffusion is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration. For cell transport, diffusion is the movement of small molecules across the cell membrane.

Detailed explanation-3: -Diffusion: Diffusion is the movement of particles from an area of higher concentration to lower concentration. The overall effect is to equalize concentration throughout the medium.

Detailed explanation-4: -Difference in concentration affects the rate of diffusion. The greater the concentration gradient, the quicker diffusion takes place. For example, if there is a very high concentration of oxygen in the alveoli, and a very low concentration in the blood, diffusion will take place very quickly.

Detailed explanation-5: -A hypertonic solution has a higher concentration of dissolved particles than a cell. A cell in a hypertonic solution will shrivel. A hypotonic solution has a lower concentration of dissolved particles than a cell. A cell in a hypotonic solution will swell.