Cellular Transport

1. Cellular Transport How do cells move nutrients, products and wastes in and out of the cell? Why is this traffic across the membrane so important?

2. Cells are filled and surrounded by watery fluid. This fluid helps solids move around inside, outside the cell and cross the cell membrane.

3. Cell Membrane The cell membrane controls what moves in and out of the cell.

4. Semi-permeable membrane Cell membranes only allow some solutes (solids) to move across it. Movement across the membrane depends on size and type of the solute (solid).

5. Membranes are just so beautiful!!!!!

6. Types of Transport Down the concentration gradient Low concentration High concentration Up the concentration gradient High concentration Low concentration

7. Passive Transport Molecules move from area of high concentration to area of low concentration Movement is down the concentration gradient No energy needed Small molecules such as H2O, O2 and CO2 Active Transport Molecules move from area of low concentration to area of high concentration Movement is up the concentration gradient Energy is required (ATP) Large molecules, ions Summary: Types of Transport

8. Diffusion – molecules move from area of high concentration to area of low concentration.

9. Osmosis – water moves across membranes (diffuses) to where there is less water.

10. Concentrations affect Osmosis Water moves out of the cell Water moves across membrane (in/out) at equal rates. Water moves into the cell

11. Red Blood Cells in Hypertonic solution (video)

12. Plants and OsmosisHypertonic solution (video)

13. Concentrations affect osmosis equal amount of solute in and out of cells higher amount of solute outside cells lower amount of solute outside cells

14. Solution is made of solutes dissolved in a liquid or gas. Hypertonic Solution = high amount of solutes Hypotonic Solution = low amount of solutes Isotonic Solution = equal amount of solutes Dynamic Equilibrium is reached when solutes and water move across a membrane at equal rates because concentrations are equal (isotonic). Homeostasis = all living systems need to maintain perfect concentrations inside each cell Let’s Review

16. Test your knowledge On your left side, number 1-14 (short answer) 15 and 16 Extended answers required

17. 1. Which side is hypertonic? 2. Why? 3. Can the solutes fit across the membrane? 4. How can you describe the membrane since it is very selective about what can move across? 5. How can both sides reach equilibrium? Lower concentration of solute (sugar) Higher concentration of sugar Same concentration of sugar Selectively permeable mem- brane: sugar mole- cules cannot pass through pores, but water molecules can Water molecules cluster around sugar molecules More free water molecules (higher concentration) Fewer free water molecules (lower concentration)  Water moves from an area of higher free water concentration to an area of lower free water concentration A B A B Osmosis

18. ENVIRONMENT NaCL (salt is ionic, cannot pass through membrane without energy) 10% NaCL90% H2O ? CELL 10% NaCL 90% H2O • What is the direction of water movement?_________ • Describe the solution outside the cell. ________ • Describe the solution inside the cell. __________

19. 10% NaCL90% H2O ? CELL 20% NaCL 80% H2O 9. What is the direction of water movement?________ 10. Describe the solution outside the cell. ________ 11.Describe the solution inside the cell. __________

20. 15% NaCl85% H2O ? CELL 5% NaCl 95% H2O 12. What is the direction of water movement?_______ 13. Describe the solution outside the cell. ________ 14. Describe the solution inside the cell. __________

21. How do cell move nutrients, products and wastes in and out of the cell? • Why is this traffic across the membrane so important?

22. Demo Lab Materials Celery sticks in different salt solutions??? Iodine solution / starch solution??? Potato cores in different salt solutions??? Procedure