1. W. McConnell 2004 Kinross High School CELLS Revision Questions on diffusion Write down your answer before pressing the mouse to find the correct answer.

2. W. McConnell 2004 Kinross High School Answer: The natural movement of particles from an area of high particle concentration to an area of low particle concentration. Give the definition of diffusion. 1.

3. W. McConnell 2004 Kinross High School The smell of air freshener spreading through a room Air being pumped into a tyre Smoke rising upwards in a non- smoky room Leaking gas spreading through the air in a lab Disappearing vapour trail from a jet aircraft Which of the examples below show diffusion? 2.2. This is diffusion

4. W. McConnell 2004 Kinross High School Answer Glucose Amino acids Oxygen ? List 3 substances which are able to diffuse into a cell. 3.

5. W. McConnell 2004 Kinross High School 4. What substances can diffuse out of a cell. Answer Carbon dioxide Water Urea

6. W. McConnell 2004 Kinross High School Answer The movement of water molecules from an area of high water molecule concentration to an area of low water molecule concentration across a selectively permeable membrane. 5.5. Give the definition of osmosis.

7. W. McConnell 2004 Kinross High School6. If plant cells are placed in a 100% water solution, in what direction will the water move by osmosis? plant cell 100% water water moves into the cell by osmosis

8. W. McConnell 2004 Kinross High School 7. Answer: What name is given to describe a plant cell which is full of water that has entered by osmosis? Turgid cell wall cell membrane

9. W. McConnell 2004 Kinross High School 8. Answer: They burst ! What happens to red blood cells if they are placed in distilled water?

10. W. McConnell 2004 Kinross High School 9. Answer: Why will a plant cell not burst if it is placed in distilled water? Because it has a rigid cell wall.

11. W. McConnell 2004 Kinross High School 9. What name is given to describe a plant cell which has lost a lot of water by osmosis? Answer: Flaccid cell wall cell membrane vacuole

12. W. McConnell 2004 Kinross High School 10. Answer: Vacuole is small Membrane has pulled away from cell wall. Describe the appearance of a potato cell after 30 minutes in strong sucrose solution.

13. W. McConnell 2004 Kinross High School 11. Look at the diagram below. Do the substances below move into or out of the cell? glucose carbon dioxide oxygen

14. W. McConnell 2004 Kinross High School 12. glucose and starch solution water visking tubing After 15 minutes, what has happened to the: glucose molecules ? starch molecules ? They pass out of the visking tubing into the water They remain in the visking tubing Look at the diagram below.

15. W. McConnell 2004 Kinross High School 13. Why did the glucose molecules pass through the visking tubing? Why did the starch molecules not pass through the visking tubing? Glucose molecules are small enough to diffuse through the membrane. Starch molecules are too large to diffuse through the visking tubing membrane.

16. W. McConnell 2004 Kinross High School 14. Where does this exchange of gases take place in mammals? Multicellular organisms need special organs for diffusion of gases into and out of their bodies. Air sacs of the lungs.

17. W. McConnell 2004 Kinross High School 15. The inner wall of the air sac is lined with a layer of ……………. This is to allow the gases to ………….… and allow easier …………….. moisture dissolve diffusion

18. W. McConnell 2004 Kinross High School 16. Answer: Gases are exchanged between the cells of the leaves and the air by diffusion. Name the structures in the leaf through which the gases pass. Stomata

19. W. McConnell 2004 Kinross High School 17. To investigate osmosis in plant cells the experiment below was set up. water strong salt solution potato AB In which apparatus will the water enter the cell ? Apparatus B

20. W. McConnell 2004 Kinross High School 18. water strong salt solution potato AB In osmosis water moves from a high concentration (the water) to a low concentration (in the potato cells). Why did the water enter the potato?

21. W. McConnell 2004 Kinross High School 20. What do we call a membrane which only allows certain substances to pass through? Selectively permeable.

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