What is the main function of the cell membrane?

The main function of the cell membrane is to regulate the entry and exit of substances. This is crucial for maintaining homeostasis within the cell, as the membrane selectively allows certain molecules to pass while keeping others out. The structure of the cell membrane, composed of a phospholipid bilayer with embedded proteins, enables this selective permeability. By controlling what enters and exits the cell, the membrane plays a vital role in processes such as nutrient uptake, waste removal, and signaling with the external environment.

While the cell membrane does contribute to structural support by providing a boundary for the cell, this is not its primary function. Storing genetic information is the role of the nucleus, and protein synthesis occurs mainly in the ribosomes and the endoplasmic reticulum, not directly at the membrane. Understanding the function of the cell membrane helps clarify its importance in cellular processes and overall cell health.