Required practical (transport in cells)

• Required Practical: Osmosis in plant tissue

  1. Cut 6 equal pieces of potato

  2. Measure the mass and volume of the potato pieces

  3. Prepare different concentrations of sugar solution

  4. Place potato pieces in the solutions

  5. Remove potato pieces after 12-24 hours, dry and measure mass

  6. Calculate percentage change in mass for each concentration
• Scientists investigate the effects of osmosis on living cells by either observing cells under a microscope in different solutions or measuring changes in cylinders/discs of fresh potato or beetroot
• Potato cylinders will have a larger mass than discs, so scientists will have larger measurements to work with
• The experiment investigates the effect of different concentrations of sucrose (a disaccharide made from glucose) on plant tissue
• Sodium chloride solution could also be used instead of sucrose to investigate the effect of a range of solutes on plant tissue
• The method involves cutting 6 equal pieces of potato, measuring their mass and volume, preparing different concentrations of sugar solution, placing the potato pieces in the solutions for 12-24 hours, then removing, drying and re-measuring the mass of the potato pieces
• Repeating the experiment with several potato cylinders allows the results to be more repeatable and accurate, excluding any anomalies
• A graph should be plotted showing the change in mass of the plant tissue against the concentration of sugar
• This experiment shows the effect of osmosis on plant tissue - the potato cylinders will decrease or increase in mass depending on the concentration of the sugar solution
• Variables


  • Independent = concentration of sugar solution
  • Dependent = mass of plant tissue at the end
  • Control = volume and surface area of plant tissue, length of time in solution, temperature
• The percentage change in mass for each cylinder is calculated using the formula: (final mass - initial mass) / initial mass x 100