Science
Cell membrane.
Definition
The cell membrane is a thin, flexible barrier made of a phospholipid bilayer that surrounds every cell. It controls what enters and exits the cell, maintaining homeostasis through selective permeability.
Examples
Real-world.
- 1 The cell membrane allows oxygen and carbon dioxide to pass through freely by diffusion
- 2 Receptor proteins on the membrane surface let hormones like insulin communicate with the cell
- 3 White blood cells use their membranes to engulf bacteria through phagocytosis
Key Fact
The fluid mosaic model describes the membrane as a dynamic structure of phospholipids, proteins, cholesterol, and carbohydrates.