1. Cell Membrane

2. Function Separates cytoplasm from external environment
Regulates what enters and leaves cell
Cell identification
Cell-cell communication

3. Plasma membrane regulates movement of materials due to its chemical composition: Phospholipids Cholesterol Proteins

4. Phospholipids Phospholipids Bilayer Phospholipids have:
Hydrophilic head
Nonpolar hydrophobic tail
Phospholipids Bilayer

5. Hydrophilic "heads" faces the watery environment inside and outside cell
Hydrophobic tail forced to face inward – away from water.

6. The phospholipids are not bound together – gives the membrane a fluid nature

7. CHOLESTEROL Function: Stabilizes membrane (structural support)
Cell communication (cell-cell and cell- hormone)

8. Some interesting facts
Most common molecule in membrane (>50%)
Due small size and weight – only 20% of membrane mass
Is an amphipathic molecule Homework – find out what this means

9. Proteins
Are embedded in membrane
Serve different functions

10. Functions
1. Channel Proteins - small openings for molecules to diffuse through
2. Carrier Proteins- binding site on protein "grabs” molecules, pulls them into cell
3. Receptor Proteins – act as triggers that set off cell responses (such as release of hormones or opening of channel proteins)
4. Cell Recognition Proteins - ID tags, identify cell to immune system
5. Enzymatic Proteins - carry out metabolic reactions

11. LABEL YOUR DIAGRAM WITH THE FOLLOWING DETAILS

12. Task: Due end of class Read pages 47 -49 in your text
Answer questions 1 – 5 in practice section
Explain the structure and function of glycoproteins.
How are liposomes used in cancer treatment and gene therapy?
What role might receptor proteins have in medical disorders such as Hypertension?