1. Fluidity:
* Lipid bilayer: The cell membrane is primarily composed of a phospholipid bilayer. These phospholipids can move laterally within the plane of the membrane, like a fluid.
* Cholesterol: Cholesterol is embedded within the membrane and helps regulate its fluidity. It prevents the phospholipids from packing too tightly at low temperatures, maintaining flexibility.
* Membrane proteins: Proteins are also embedded within the membrane and can move laterally. This fluidity allows the membrane to be dynamic and adapt to changing conditions.
2. Mosaic:
* Diverse components: The cell membrane isn't just a uniform layer of phospholipids. It's a complex mosaic of different components.
* Proteins: Proteins embedded within the membrane have a variety of functions, including transport, communication, and enzymatic activity. These proteins can be integral (spanning the entire membrane) or peripheral (attached to the surface).
* Carbohydrates: Carbohydrates attached to lipids (glycolipids) or proteins (glycoproteins) can act as recognition sites and play a role in cell-cell interactions.
In summary: The cell membrane is "fluid" because its components can move laterally, and it's "mosaic" because it's composed of a variety of diverse components that work together to perform essential cellular functions.
