Wisconsin Esthetics State Board Practice Test

What is the primary function of the cell membrane?

1. Regulate cellular metabolism

2. Protect the genetic material

3. Act as an outer surface of the cell

4. Store nutrients and waste

The correct answer is: Act as an outer surface of the cell

The primary function of the cell membrane is to act as an outer surface of the cell. It serves as a protective barrier that separates the interior of the cell from its external environment. This membrane is selectively permeable, meaning it controls the movement of substances in and out of the cell, thereby helping to maintain homeostasis. The fluid mosaic model describes the cell membrane's structure, which consists of a lipid bilayer with embedded proteins that facilitate various functions including transport and communication. While regulating cellular metabolism, protecting genetic material, and storing nutrients and waste are important cellular functions, these processes are more related to the functions of organelles and the cells' internal systems rather than the primary role of the cell membrane itself. The cell membrane's main function is to define the boundary of the cell and mediate interactions with the external environment.