1. The Cell Membrane

2. The Plasma Membrane Double-layered membrane
(Phospholipid Bilayer)
Flexible boundary between cell and environment.
Allows nutrients to enter cell and chemical wastes to leave.
Maintains cell homeostasis by maintaining a balance in the cells environment.
Hydrophilic Head-water loving
Hydrophobic Tail- water fearing

5. Maintaining Homeostasis
The plasma membrane is selectively permeable.
Allows some molecules to pass through while keeping others out.
Small molecules easily pass through, while large molecules cannot.
Ex: Proteins and Starch cannot pass until they are digested.
*Like a window screen!
Cell Membrane Transport

6. Fluid Mosaic Model
The currently accepted model to describe the plasma membrane.
1. Phospholipids move within the membrane and slide past each other.
2. Transport proteins move molecules across the membrane into or out of the cell.
3. Receptor proteins are along the top of the membrane and create a mosaic, or pattern, on the membrane surface.

7. Proteins in the Plasma Membrane
Transport proteins
Receptor proteins

10. Oil and Water Experiment
Barriers
Oil and Water Experiment