The function of the cell membrane, also known as the plasma membrane, is to act as a selective barrier that separates the interior of the cell from the external environment. It regulates the transport of materials entering and exiting the cell, allowing essential nutrients in and waste products out while keeping harmful substances out. This selective permeability helps maintain a stable internal environment, or homeostasis, within the cell

. Key functions of the cell membrane include:

• Providing protection and structural support to the cell.
• Regulating the movement of ions, organic molecules, and other substances through passive or active transport mechanisms.
• Facilitating communication and interaction between cells via membrane proteins such as glycoproteins and lipid proteins.
• Anchoring the cytoskeleton to maintain cell shape and attaching to the extracellular matrix and other cells to form tissues.
• Enabling cell signaling and adhesion processes through embedded proteins and carbohydrates

The membrane is primarily composed of a lipid bilayer with embedded proteins, cholesterol, and carbohydrates, which together form a fluid mosaic structure that is semipermeable and dynamic in function

. In summary, the cell membrane functions as a protective, regulatory interface that controls the internal environment of the cell by selectively allowing substances to pass in and out, supporting cellular communication, structure, and overall cell survival