Cell Membrane
The cell membrane, also known as the plasma membrane, is a biological membrane that separates the interior of all cells from the outside environment. It consists of a lipid bilayer with embedded proteins that regulate the passage of molecules in and out of the cell. The cell membrane plays a crucial role in maintaining the cell's internal environment and is involved in various cellular processes such as cell signaling, cell adhesion, and transport of nutrients. It is selectively permeable, allowing only certain substances to pass through while blocking others.