GCSE Biology Required Practical: Osmosis in Plant Tissue

Key Stage 4

Meaning

Investigate the effect of the concentration of sugar solution on the mass of plant tissue.

Experiment

Variables

• Independent Variable - The concentration of sugar solution.
• Dependent Variable - The mass of plant tissue at the end.
• Control Variables - Volume of plant tissue. Surface area of plant tissue. Length of time the plant tissue is left in solution. Temperature of the solution.

Method

A diagram of the equipment needed in this experiment.

1. Cut 6 equal volumes of plant tissue (potato). 2. Dry the plant tissue with paper towel and measure the mass of each piece using an electronic balance or find their volume by measuring length, width and height with ruler and multiplying them together.	3. Use a Measuring Cylinder to measure 10cm3 of 1.0M sugar solution and pour it into a Boiling Tube. 4. Repeat step 3 with 8cm3 of sugar solution and 2cm3 of distilled water to give 0.8M sugar solution, then 6cm3 and 4cm3 of distilled water to give 0.6M sugar solution, repeating this pattern until there is 10cm3 of 0.0M sugar solution.

5. Place one piece of plant tissue into each of the 6 boiling tubes leaving them for 12-24 hours (ensuring it is the same time for all).	6. Remove the pieces of plant tissue, drying them with a paper towel and measure their mass.

7. Plot a graph showing the concentration of sugar solution on the x-axis and the change in mass of plant tissue on the y-axis.