What is the primary function of the cell membrane?

The primary function of the cell membrane is to permit soluble substances to enter and leave the cell. The cell membrane, also known as the plasma membrane, acts as a selective barrier that controls the movement of ions, nutrients, and waste products in and out of the cell. This selective permeability is crucial for maintaining homeostasis within the cell, allowing it to regulate its internal environment.

The cell membrane is composed of a phospholipid bilayer that has embedded proteins which facilitate the transport of substances. This functional characteristic ensures that essential molecules can enter the cell while potentially harmful substances and waste products can be excluded or expelled.

Other functions, such as those related to genetic information storage, protection of the nucleus, or providing energy, do not pertain to the role of the cell membrane. Genetic information storage is the primary role of the nucleus, while energy provision is generally attributed to the mitochondria. The cell membrane’s main focus lies in its role as a control barrier for substance exchange, underscoring its vital function for cellular survival and integrity.