1. Plasma Membrane

2. Function Allows nutrients to pass into and out of the cell.
Maintains homeostasis.

3. Structure
Composed of a phospholipid bilayer called the fluid mosaic model.

4. Structure Structure of phospholipid bilayer:
Each phospholipid contains a glycerol backbone, 2 fatty acid chains, and a phosphate group.
A phosphate is formed by replacing one fatty acid in a lipid with a phosphate group.

5. Structure Structure of phospholipid bilayer:
Each phosphate group has two fatty acid tails that are nonpolar and one head containing a polar phosphate group.
The nonpolar tails stop water-soluble molecules form moving through the membrane.
The polar head interacts with the watery environment inside and outside the cell.

6. Structure The phospholipid bilayer also contains: Cholesterol
Transport Proteins
Proteins
Carbohydrates

7. Structure Function of cholesterol: Function of transport proteins:
Stabilizes the membrane by preventing the fatty acid tails from sticking together.
Function of transport proteins:
Span the entire membrane to move substances through the plasma membrane.

8. Structure Function of carbohydrates:
Stick out of the surface of the cell along with proteins in order to identify chemical signals.
Function of proteins at inner surface:
Attach the plasma membrane to the internal support structure of the cell.
Give flexibility.