AP BIOLOGY

Detailed explanation-1: -The cell membrane, also called the plasma membrane, is found in all cells and separates the interior of the cell from the outside environment. The cell membrane consists of a lipid bilayer that is semipermeable. The cell membrane regulates the transport of materials entering and exiting the cell.

Detailed explanation-2: -The cell membrane, therefore, has two functions: first, to be a barrier keeping the constituents of the cell in and unwanted substances out and, second, to be a gate allowing transport into the cell of essential nutrients and movement from the cell of waste products.

Detailed explanation-3: -Specialized proteins in the cell membrane regulate the concentration of specific molecules inside the cell. Membrane transport proteins are specific and selective for the molecules they move, and they often use energy to catalyze passage.

Detailed explanation-4: -The most important function of the cell membrane is that it controls the entry and exit of materials from cells. Hence it is also called semipermeable membrane.