What is the function of the cell membrane?

The function of the cell membrane is primarily to regulate the entry and exit of substances. It acts as a selective barrier, controlling what goes in and out of the cell, maintaining homeostasis within the cellular environment. This regulation is crucial for the survival of the cell, as it allows for the necessary nutrients to enter while keeping harmful substances out. Additionally, the cell membrane facilitates communication and signaling processes, enabling the cell to respond to its environment.

Other functions mentioned in the options are not associated with the cell membrane. While the cell membrane contributes to the overall structure of the cell, its main role is not providing structural support; rather, that function is typically more associated with the cytoskeleton and cell wall in certain organisms. Storing genetic information is primarily the role of the nucleus, where DNA is housed. Similarly, energy production is predominantly carried out in the mitochondria, not the cell membrane. Thus, the primary role of the cell membrane in regulating substance flow makes it a vital component of cellular function.