AP BIOLOGY

Detailed explanation-1: -The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. The basic function of the cell membrane is to protect the cell from its surroundings. It consists of the phospholipid bilayer with embedded proteins.

Detailed explanation-2: -Just as the outer layer of your skin separates your body from its environment, the cell membrane (also known as the plasma membrane) separates the inner contents of a cell from its exterior environment. This cell membrane provides a protective barrier around the cell and regulates which materials can pass in or out.

Detailed explanation-3: -Only the smallest molecules like water, carbon dioxide, and oxygen can freely diffuse across cell membranes. Larger molecules or charged molecules often require an input of energy to be transported into the cell.

Detailed explanation-4: -This membrane not only surrounds the cellular organelles but also acts as a barrier between the internal and the external environment. A cell membrane that is selectively permeable acts as a boundary or fence of the cell. It allows the molecules to pass through active or passive transport.

Detailed explanation-5: -Some proteins in the plasma membrane form open pores, called membrane channels, which allow the free diffusion of ions into and out of the cell. Others bind to specific molecules on one side of a membrane and transport the molecules to the other side.