2. I. Homeostasis A. Homeostasis is a balance of substances within the cell. B. Brownian Motion—All objects are in constant, random motion. This is how particles move through the cell membrane.

3. The Cell Membrane— also known as Plasma membrane II. The Cell Membrane— also known as Plasma membrane A. It is vitally important in maintaining homeostasis within a cell.

4. protein-lipid bilayer B. It is a protein-lipid bilayer. Made up of: 1. 2 layers of lipids (called phospholipids) 2. proteins 3. cholesterol

6. fluid mosaic model C. Structure of the membrane described as fluid mosaic model, which means it is made of similar molecules (lipids) which freely move within the membrane.

7. D. Functions of Cell Membrane: 1. Separates the cell from its external environment 2. Selectively permeable (semi- permeable) permeable)-- Controls what enters and exits the cell

8. Protein functions E. Protein functions: a. Protein markers--Allow the cell to communicate with other cells b. Transport proteins--Allow big substances or certain ions to move through the membrane

9. F. Cholesterol—Very rigid molecules Function: Strengthens the membrane

10. G. Model of the cell membrane Hydrophyllic heads Hydrophobic tails

11. III. Types of Transport Systems A. Passive Transport 1. Simple Diffusion *Other Terms: a. With the gradient b. Against the gradient c. Dynamic equilibrium

12. (A. Passive Transport—continued) 2. Osmosis a. Three Kinds of Solutions: 1. isotonic—ex: medicine in shot 2. hypotonic—ex: freshwater 3. hypertonic—ex: saltwater

13. (2. Osmosis continued) b. Terms related to osmosis: 1. turgor pressure 2. cytolysis 3. contractile vacuole (found in some protists such as paramecium) 4. plasmolysis

14. Look for the contractile vacuole in the video clip. Click here: http://www.daviddarling.info/encyclopedia/C/contractile_vacuole.html

15. Egg Lab video

16. (A. Passive Transport—continued) 3. Facilitated Diffusion a. Transport proteins— 2 types: channel, carrier b. Facilitated diffusion occurs by random action. No energy is used.

17. Channel Proteins vs. Carrier Proteins

18. Carrier Protein— The Sodium-Potassium Pump

19. Active Transport B. Active Transport 1. Ion pumps—(Ex: sodium- potassium pump)—are carrier proteins that move ions through membrane Sodium-potassium PumpSodium-potassium Pump—animation

20. 2. Endocytosis 2 Types of Endocytosis: a. phagocytosis b. pinocytosis 3. Exocytosis

21. Endocytosis (inside cell) Exocytosis ( inside cell)

22. Quiz Time Match the structure/ process to the letter: 1. Phospholipid bilayer 2. Osmosis 3. Simple Diffusion 4. Facilitated Diffusion 5. Channel protein

23. 6. This cell would be in a [ hypertonic / hypotonic / isotonic ] solution. 7. All of the processes in the image are examples of [ active / passive ] transport. 8. The cell membrane can be described as [semi-permeable / impermeable ]