- Definition: The plasma membrane is a thin, semi-permeable barrier surrounding cells.
- Composition: It consists of a lipid bilayer made of phospholipids, proteins, and cholesterol.
- Function: The plasma membrane regulates the passage of substances in and out of the cell, maintaining cell integrity.
- Selective Permeability: It allows some molecules to pass (permeable) while blocking others (impermeable).
- Proteins: Membrane proteins play essential roles in transport, signaling, adhesion, and recognition.
- Fluid Mosaic Model: The plasma membrane is dynamic and flexible, with proteins embedded like a “mosaic” in the lipid “fluid.”
- Endocytosis/Exocytosis: These processes involve the plasma membrane engulfing or releasing materials, respectively.
- Maintains Homeostasis: The plasma membrane helps the cell maintain its internal environment for optimal function