AP BIOLOGY

Detailed explanation-1: -Cell membranes protect and organize cells. All cells have an outer plasma membrane that regulates not only what enters the cell, but also how much of any given substance comes in.

Detailed explanation-2: -In its role as gatekeeper, the cell membrane regulates molecular traffic into and out of the cell via specialized membrane proteins.

Detailed explanation-3: -Protein machineries embedded in the membranes of our cells act as ‘gatekeepers’ controlling everything transported in and out of every cell in our bodies. Because these machineries, called membrane embedded proteins, are vital to the way our bodies function they are the target of at least 40% of drugs.

Detailed explanation-4: -The Cellular Membrane The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells.

Detailed explanation-5: -It protects and supports the cell and also controls everything that enters and leaves the cell. It allows only certain substances to pass through, while keeping others in or out. The ability to allow only certain molecules in or out of the cell is referred to as selective permeability or semipermeability.