The cell membrane is a thin, flexible envelope that surrounds the cell. It controls what enters and leaves the cell and protects the internal environment of the cell.
The basic structure of a biological membrane, composed of two layers of phospholipids. This structure forms a barrier that helps keep ions, proteins and other molecules where they are needed within cells.
A type of biological or synthetic membrane that will allow certain molecules or ions to pass through it by diffusion and occasionally specialized 'facilitated diffusion'.