1. CELLULAR TRANSPORT

2. All materials entering or leaving the cell must pass through which cell organelle?  Cell Membrane A. Function  Provides support and protection  Semipermeable: Allows only certain things (molecules and ions) to enter and exit the cell  Keeps the inside of the cell in a balanced state called homeostasis B. Structure  Flexible, double-layered sheet called a lipid bilayer  Contains proteins and small openings called pores that allow molecules to enter the cell

3. Cell Membrane Movie

4. II. Concentration Definition: measure of how much of a given substance there is mixed with another substance A.What is the concentration of the solution? 20% Sugar solution B.What is the solvent? Water C.What is the solute? Sugar D.How can I make the solution more concentrated? Add more sugar or less water E.Why don’t we call this a 80% water solution?

5. III. Cell Transport Definition: The movement of molecules across the cell membrane A. Passive Transport 1. Diffusion a.The movement of molecules (food, water, O 2, CO 2 ) from areas of high concentration to areas of low concentration b.Does not require energy c.Solute is the substance dissolved in the solution (salt) d.Solvent is what dissolves the solute (water)

6. Passive Transport Movie

7. What is the solute and which way will it flow?

8. 2. Osmosis a.The movement of water through a semipermeable membrane from a place of higher concentration to a place of lower concentration (the diffusion of water) b.Osmosis keeps the cell from drying out. c.Does not require energy Which way will the water flow? H2OH2O H2OH2O H2OH2O

9. Osmosis Movie

10. B. Active Transport 1.Some molecules are pumped across the membrane by special proteins from where they are less concentrated to where they are more concentrated 2.Requires energy

11. 3. Endocytosis a.Surrounding a substance with some of the cell membrane, bringing it into the cell within a vacuole. 1)Phagocytosis - Solids 2)Pinocytosis- Liquids

12. 4. Exocytosis a.The opposite of endocytosis. b.Used to remove wastes from cells.