Biology – Movement into and out of cells | e-Consult

Experimental Setup:

1. Prepare agar plates with a known concentration of sucrose solution. The sucrose solution will be the hypotonic solution.
2. Cut uniform discs from potato using a cork borer.
3. Place the potato discs into separate wells on the agar plates.
4. Use different concentrations of sucrose solution (e.g., 0%, 10%, 20%, 30%, 40%) as the external solution.
5. Allow the discs to equilibrate in the sucrose solution for a set time (e.g., 30 minutes).
6. Measure the mass of each potato disc before and after the equilibration period.

Variables:

• Independent Variable: Concentration of sucrose solution (e.g., 0%, 10%, 20%, 30%, 40%).
• Dependent Variable: Change in mass of the potato disc (mass after - mass before).
• Controlled Variables:

  • Size and type of potato used.
  • Temperature of the sucrose solution.
  • Equilibration time.
  • Volume of sucrose solution.

Analysis: The change in mass of the potato disc will be plotted against the concentration of sucrose solution. The expected trend is that the mass of the potato disc will increase as the concentration of sucrose solution increases. This is because water will move into the potato cells by osmosis, increasing their mass. At very high concentrations of sucrose, the rate of osmosis will slow down as the water potential gradient between the inside of the potato cell and the external solution becomes smaller. The data can be presented in a graph, with sucrose concentration on the x-axis and change in mass on the y-axis. A scatter graph would be appropriate.