igcse2010 -osmosis & diffusion

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Osmosis & diffusion. IGCSE

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  • 1. How substancesget in and out of cells Mainly based on the exercises from http://www.biology-resources.com/biology-questions.html IGCSE Revision Questions http://biodeluna.wordpress.com

2. 3. Which one of the following is the best definition ofosmosis ?

  • (i) The movement of water from a concentrated solution to a dilute solution across a
  • partially permeable membrane. .
  • (ii) The movement of a dissolved substance from a concentrated solution to a dilute
  • solution across a partially permeable membrane.
  • (iii) The movement of water from a dilute solution to a concentrated solution across a partially
  • permeable membrane.
  • (iv) The uptake of water by a living cell.

4. Which one of the following is the best definition ofosmosis ?

  • (i) The movement of water from a concentrated solution to a dilute solution across a
  • partially permeable membrane. .
  • (ii) The movement of a dissolved substance from a concentrated solution to a dilute
  • solution across a partially permeable membrane.
  • (iii) The movement of water from a dilute solution to a concentrated solution across a partially
  • permeable membrane.
  • (iv) The uptake of water by a living cell.

5. Which of the statements is an acceptable description ofdiffusion ? (i) The movement of water from a concentrated solution to a dilute solution across apartially permeable membrane. .(ii) The movement of a dissolved substance from a concentrated solution to a dilutesolution across a partially permeable membrane.(iii) The movement of water from a dilute solution to a concentrated solution across a partiallypermeable membrane.(iv) The uptake of water by a living cell. 6. Which of the statements is an acceptable description ofdiffusion ? (i) The movement of water from a concentrated solution to a dilute solution across apartially permeable membrane. .(ii) The movement of a dissolved substance from a concentrated solution to a dilutesolution across a partially permeable membrane.(iii) The movement of water from a dilute solution to a concentrated solution across a partiallypermeable membrane.(iv) The uptake of water by a living cell. 7. Definition ofosmosis 8. Definition ofosmosis

  • The movement ofwater
  • from aconcentratedsolution to adilutesolution across apartially permeable membrane'.

9. Description ofdiffusion 10. Description ofdiffusion

  • The movement of asubstance
  • from aconcentratedsolution to adilutesolution'

11. Active transport 12. Active transport

  • Movement of materials across the cell membrane requiring the use ofenergy .
  • It moves a soluteagainst aconcentration gradient
  • http://media.pearsoncmg.com/bc/bc_campbell_biology_7/media/interactivemedia/activities/load.html?7&F

13.

  • http://www.bio.miami.edu/~cmallery/150/memb/membranes.htm

14.

  • The diagram shows a vessel which contains a concentrated and a dilute solution separatedby apartially permeable membrane.Draw a similar diagram to show the liquid levels after an hour or two.

concentratedsolution dilutesolution 15.

  • The diagram shows a vessel which contains a concentrated and a dilute solution separatedby apartially permeable membrane.Draw a similar diagram to show the liquid levels after an hour or two.

concentratedsolution dilutesolution 16.

  • Make two drawings to show how this cell would appear if it were to be immersed for a few minutes in a solution with...

(a) a lower osmotic potential (water potential) than its own cytoplasm(b) a higher osmotic potential (water potential) than its own cytoplasm. 17. (a) a lower osmotic potential (water potential) than its own cytoplasmPlasmolysis (b) a higher osmotic potential (water potential) than its own cytoplasm. 18.

  • plasmolysis-loss of cytoplasmic structure due to water loss
  • turgidity -swollen cells due to water gain

19. When meat is salted, bacteria cannot grow on it. Suggest a reason for this. 20. When a cell is respiringaerobically, which two gases are likely to bediffusing in and out of the cell, and in which direction will they be diffusing? 21.

  • The graphs (a) to (d) represent the concentration of certain substances as measured inside and outside a cell. Match the following descriptions to the most appropriate graph.
  • (i) A substance which the cell is producing and is expelled by active transport.
  • (ii) A substance which the cell is using and is taken up by active transport.
  • (iii) A substance which the cell is using and can diffuse freely through the cell membrane.
  • (iv) A substance which the cell is producing and is free to diffuse across the cell membrane.

22.

  • The graphs (a) to (d) represent the concentration of certain substances as measured inside and outside a cell. Match the following descriptions to the most appropriate graph.
  • (i) A substance which the cell is producing and is expelled by active transport.
  • (ii) A substance which the cell is using and is taken up by active transport.
  • (iii) A substance which the cell is using and can diffuse freely through the cell membrane.
  • (iv) A substance which the cell is producing and is free to diffuse across the cell membrane.

(i)(ii) (iii)(iv) 23. Flashcards to review IGCSE

  • http://www.proprofs.com/flashcards/story.php?title=igcse-biology-all-topics

24. water and iodine starch and glucose solutions A piece of dialysis (Visking) tubing is knotted at one endwater and iodine and filled with a 2 % starch solution mixed with a 10% glucose solution. The tube is immersed in.a test-tube of water to which iodine has been added. (a )Predict what you will see after 30 minutes(i) in the starch and glucose solutions dialysis tube,(ii) in the test-tube,(iii) when you boil theliquid from the test-tube with Benedict's solution. (b)Give an explanation of these results. 25. Keys:

  • Lugol'siodine solutionsolution (which is actually IKI) is a brown solution which turns black in the presence ofstarches .
  • Benedict'ssolution is used to detect the presence of simple sugars such asglucose . When a simple sugar is mixed in Benedict's solution and heated for a short period of time in a test tube, it goes through a variety of color changes, eventually ending as an orange-red or brick red color.
  • Starch is not dissolvedin cold water

http://answers.yahoo.com/question/index?qid=20070425200251AAx4Alk http://biology.arizona.edu/sciconn/lessons/mccandless/reading.html