What is the primary function of the plasma membrane?

The primary function of the plasma membrane is the regulation of movement of substances. The plasma membrane acts as a selective barrier that controls what enters and exits the cell, thereby maintaining homeostasis. It is composed of a phospholipid bilayer with embedded proteins that facilitate various transport mechanisms, including passive and active transport. This selective permeability is crucial for the cell's ability to obtain necessary nutrients, expel waste, and respond to environmental changes.

In contrast, energy production occurs primarily in organelles like mitochondria, while the storage of genetic material is performed by the cell nucleus. The production of ribosomes takes place in the nucleolus within the nucleus, not the plasma membrane. Understanding the specific roles of these cellular components helps to clarify the importance of the plasma membrane in cellular function.