1. SWBAT describe membrane structure

2. Cell Membranes
Structure

3. Functions of the cell membrane
Separates living cell from surrounding environment

4. Functions of the cell membrane
Controls what can enter and exit cell
Selectively permeable
allows some substances to cross more easily than others

5. Functions of the cell membrane
Communicate with other cells
Send and receive messages—like cortisol

6. Key to membrane function is its structure
Made of phospholipids, proteins & other macromolecules

7. What is a phospholipid? Phospho = phosphate “head”
Lipid = fatty acid “tail”

8. What is a phospholipid? Phosphate head hydrophilic: loves water
Fatty acid tail hydrophobic: hates water
So phospholipids arrange as a bilayer
Keeps outside liquid out and inside liquid in!

9. Membrane structure
Membrane has other molecules embedded in phospholipid bilayer
-Carbohydrates
-***Proteins!

10. Membrane Proteins
1. Gatekeepers: determine what particles can pass through the membrane.
2. Enzymes (speed up reactions).
3. Cell recognition and signaling (the immune system).

11. Fluid mosaic model
Fluid: phospholipids and other molecules move within bilayer
Mosaic: made of different pieces