1. The Plasma Membrane 7.2

2. Function of Plasma Membrane  Homeostasis needs to be obtained  Thin, flexible boundary between the cell and its environment.  Allows nutrients into cell  Allows waste to exit cell  All prokaryotic and eukaryotic cells have a plasma membrane

3. Selective permeability  A membrane allows some substances to pass through while keeping others out.  Fish net analogy

4. Structures of P. Membrane  Phospholipid Bilayer-two layers of phospholipids composing the P. Membrane.  Arranged tail-to-tail  Allows existance in H2O

5. Other Components  Cholesterol  Contributes to fluidity of acid tails  Carbohydrates  Define cell characteristics and fight infection  Transport Proteins  Tunnels in membrane that allow substances to enter/leave the cell