What is the primary function of the cell membrane?

The primary function of the cell membrane is to protect the cell and regulate the movement of substances in and out of the cell. The cell membrane acts as a selective barrier, allowing certain molecules to pass while keeping others out. This selective permeability is crucial for maintaining homeostasis within the cell, as it helps control the internal environment by regulating factors such as ion concentration, nutrient uptake, and waste removal.

Additionally, the cell membrane is involved in communication with other cells and the external environment through various proteins embedded within it, further assisting in the regulation of cellular activities. By this means, the cell membrane plays a vital role in maintaining the integrity and functionality of the cell.