Diffusion and Osmosis Review

1. Discuss three factors that affect diffusion rates.

2. Describe the difference between active and passive transport.

3. What is a selectively permeable membrane?

4. Define diffusion.

5. Explain the process of osmosis.

6. What factor determines the direction in which molecules will move during osmosis?

7. The point at which water molecules enter and leave a cell at the same rate is called .

8. Define isotonic, hypotonic, and hypertonic.

9. What happens to the size of a cell placed in a hypotonic solution?

10. You are fertilizing the lawn one day and spill some fertilizer in one spot. What do expect to observe over the next few days? Explain.

11. How does facilitated diffusion differ from normal diffusion and osmosis? Why is it a benefit to cells?

12. What is meant by the terms turgor pressure and plasmolysis?

13. Why is turgor pressure not used in reference to animal cells?

14. How do the effects of osmosis differ in plant and animal cells?

15. When cells are placed in isotonic solutions, in which direction does water move and what happens to the cells?

16. Water moves mainly in which direction through the pores of a cell placed in a hypertonic solution?

17. Which of the following conditions describe a hypotonic solution that a cell is placed in?
a) a higher solute concentration outside the cell (b) a lower solute concentration outside the cell (c) a equal solute concentration both inside and outside the cell (d) none of the above

18. A ___ barrier allows only certain particles to pass through.

19. Identify whether each of the following is passive or active transport.
a) osmosis (b) exocytosis (c) diffusion (d) phagocytosis (e) active transport (f) endocytosis (g) facilitated diffusion

20. Suppose that the concentration of carbon dioxide in the fluid outside a cell became higher than that on the inside. Predict what would happen. What prevents this from happening normally?

21. A marathon runner collapses after running on a hot day. Although the runner consumed adequate water along the route, blood testing showed that many of his red blood cells had burst. Why was this the case? (hint: on hot days, runners drink fluids that contain sugar and salt.)

22. When gardeners bring in fresh vegetables from the garden, they sometimes soak them in saltwater before rinsing them and soaking them in freshwater. Why would they do this?

23. Explain why it is not a good idea to drink distilled water or saltwater.

24. Grocery stores spray their vegetables with water to preserve their freshness. Explain how this makes the vegetables appear fresh.