AP BIOLOGY

Detailed explanation-1: -Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism.

Detailed explanation-2: -Diffusion is the net movement of a substance from a region of its higher concentration to a region of its lower as a result of the random movement of its individual molecules; or, in other terms, down a concentration gradient. The greater (steeper) the concentration gradient, the faster the movement.

Detailed explanation-3: -Secretion is a fundamental cellular process involving the regulated release of intracellular products from cells. Physiological functions such as neurotransmission, or the release of hormones and digestive enzymes, are all governed by cell secretion.

Detailed explanation-4: -Diffusion is the movement of substances through the membrane from an area of higher concentration to an area of lower concentration. Molecules that are small, uncharged, and/or non-polar can pass right through the membrane by simple diffusion which occurs following the concentration gradient (high to low).

Detailed explanation-5: -Cells use exocytosis to secrete molecules too large to pass through the cell membrane by any other mechanism.