Diffusion and Osmosis in Cells Prac Write Up

PROCEDURE  
(Molecule size and diffusion)
  Open dialysis tubing and tie one end with rubber band then     fill tubing with distilled water.
      Place in beaker with open end leaning against lip of beaker.     Fold end of dialysis tubing over beaker and secure with rubber     band.
      Add 100ml distilled water, 500ml starch and 50ml glucose     solution to beaker. Mark level of water in beaker.
      Leave beaker and tube for 30 min. After, note level of water     in beaker, and then test for presence of glucose and starch     inside tube.
    (Affect of time and chemical concentration on diffusion)
  Cut 15 potato cubes into 1x1cm.
      In each of the 3 cups, place 5 cubes.
        Remove one cube from each cup every 5 minutes, cut cube in half     and measure depth of the KMn04 has diffused into the cube.     (Record results in table, analyse and write short report)
    RESULTS
(Molecule size and diffusion)
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_(Affect of time and chemical concentration on diffusion)
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DISCUSSIO*N
CONCLUSION
This experiment was extremely significant as the aim was achieved. A model of cell membrane using dialysis tubing was constructed and the effect of diffusion and osmosis through this membrane was observed. The direction of movement of sugar and starch was determined. The presence of glucose was found inside and outside the cell membrane, while the presence of starch was only outside the cell membrane. Lastly, the effect of time and concentration on the diffusion of potassium permanganate into starch cubes was also determined. The 5% KMn04 solution diffused the quickest, in the shortest time. The hypothesis was proved correct.