Function of the cell membrane?

• A. To protect the cell and regulate what enters and exits
• B. To store genetic information
• C. To produce energy
• D. To synthesize proteins

Answer: (A)

The cell membrane’s main function is to protect the cell and regulate what enters and leaves. It forms a selective barrier made of a phospholipid bilayer with embedded proteins, which allow nutrients to come in, waste to exit, and ions to move in a controlled way. This keeps the internal environment stable—a state called homeostasis—and enables the cell to respond to signals from its surroundings through receptors on the membrane.

Storing genetic information is the job of the nucleus and DNA, not the membrane. Energy production occurs mainly in mitochondria through respiration, and protein synthesis happens at ribosomes, not at the membrane.