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CELLS Revision Questions on diffusion Write down your answer before pressing the mouse to find the correct answer. W. McConnell 2004 Kinross High School 1. Give the definition of diffusion. Answer: The natural movement of particles from an area of high particle concentration to an area of low particle concentration. W. McConnell 2004 Kinross High School 2. Which of the examples below show diffusion? •The smell of air freshener spreading through a room This is diffusion •Air being pumped into a tyre •Smoke rising upwards in a nonsmoky room •Leaking gas spreading through the air in a lab This is diffusion •Disappearing vapour trail from a This is diffusion jet aircraft W. McConnell 2004 Kinross High School 3. List 3 substances which are able to diffuse into a cell. ? Answer •Glucose •Amino acids •Oxygen W. McConnell 2004 Kinross High School 4. What substances can diffuse out of a cell. Answer •Carbon dioxide •Water •Urea W. McConnell 2004 Kinross High School 5. Give the definition of osmosis. 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. W. McConnell 2004 Kinross High School 6.6. If plant cells are placed in a 100% water solution, in what direction will the water move by osmosis? 100% water plant cell W. McConnell 2004 Kinross High School water moves into the cell by osmosis 7. What name is given to describe a plant cell which is full of water that has entered by osmosis? Answer: Turgid cell membrane W. McConnell 2004 Kinross High School cell wall 8. What happens to red blood cells if they are placed in distilled water? Answer: They burst ! W. McConnell 2004 Kinross High School 9. Why will a plant cell not burst if it is placed in distilled water? Answer: Because it has a rigid cell wall. 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 vacuole cell membrane cell wall W. McConnell 2004 Kinross High School 10. Describe the appearance of a potato cell after 30 minutes in strong sucrose solution. Answer: Vacuole is small Membrane has pulled away from cell wall. W. McConnell 2004 Kinross High School 11. Look at the diagram below. Do the substances below move into or out of the cell? oxygen carbon dioxide W. McConnell 2004 Kinross High School 12. Look at the diagram below. visking tubing water glucose and starch solution After 15 minutes, what has happened to the: They pass out of the visking • glucose molecules ? tubing into the water They remain in the visking • starch molecules ? tubing W. McConnell 2004 Kinross High School 13. Why did the glucose molecules pass through the visking tubing? Glucose molecules are small enough to diffuse through the membrane. Why did the starch molecules not pass through the visking tubing? Starch molecules are too large to diffuse through the visking tubing membrane. W. McConnell 2004 Kinross High School Multicellular organisms need special 14. organs for diffusion of gases into and out of their bodies. Where does this exchange of gases take place in mammals? Air sacs of the lungs. W. McConnell 2004 Kinross High School 15. The inner wall of the air sac is lined with a layer of …………… moisture . This is to allow the gases to dissolve ………….… and allow easier diffusion …………….. W. McConnell 2004 Kinross High School 16. 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. Answer: Stomata W. McConnell 2004 Kinross High School 17. To investigate osmosis in plant cells the experiment below was set up. A B strong salt solution water potato potato In which apparatus will the water enter the cell ? Apparatus B W. McConnell 2004 Kinross High School 18. Why did the water enter the potato? A B strong salt solution water potato potato In osmosis water moves from a high concentration (the water) to a low concentration (in the potato cells). W. McConnell 2004 Kinross High School 20. What do we call a membrane which only allows certain substances to pass through? Selectively permeable. W. McConnell 2004 Kinross High School This is the end of the revision questions on diffusion These revision questions will automatically run again. If you want to return to the list of revision topics click on the back browser button on your toolbar. W. McConnell 2004 Kinross High School