What is the function of the plasma membrane?

The plasma membrane functions primarily to regulate the movement of substances in and out of the cell, a role crucial for maintaining the internal environment and overall homeostasis of the cell. It is composed of a phospholipid bilayer interspersed with proteins, cholesterol, and carbohydrates, which contribute to its fluidity and functionality.

This membrane acts as a selectively permeable barrier, allowing essential molecules such as nutrients and oxygen to enter while retaining waste products and preventing harmful substances from entering. The presence of specific proteins embedded within the membrane facilitates the transport of materials through various mechanisms, such as passive diffusion, facilitated diffusion, and active transport.

By selectively controlling what enters and exits the cell, the plasma membrane ensures that the internal conditions remain stable, which is vital for cellular processes and the survival of the cell as a whole.