Cell transportation

• What is diffusion?


  A process in which particles at high concentration travel to a low concentration, across a semi-permeable membrane
• What is osmosis?


  When water molecules go from a high concentration to a low concentration across a permeable membrane
• What is active transport?

  When particles go from a low concentration to a high concentration across a semi-permeable membrane. This also need energy because it is going against the concentration gradient
• Osmosis practical

  1. Label boiling tubes 0M, 0.5M, 1M with sticky label
  2. Measure 20ml of each salt solution using a measuring cylinder and pour into each corresponding boiling tube
  3. Use cork borer to cut 3 long cylinders of potato so they are equal width
  4. Ensure each potato piece was 3cm long and did not have any potato skin by using a knife
  5. Use balance to check weight of each piece and note it as its initial mass before placing all of them in their tubes
  6. Leave them in the solution for 20 minutes
  7. Pour away the solution, dry and re-weigh your potatoes to find their change in mass