Practical questions
You will complete eight compulsory practical activity groups if you are studying GCSE Biology and sixteen if you are studying GCSE Combined Science. You could be asked questions about the methods, safety precautions you might take, results and conclusions of these experiments.
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
Sample question 1 - Foundation
Question
A student is investigating the process of mitosis with a microscope.
The hazard warning label on the chromosome stain they use states:
- May cause skin irritation.
- May cause eye irritation.
- May be harmful if swallowed.
- Non-flammable.
Suggest three safety precautions they should take. [3 marks]
- They should avoid contact with hands/skin. They could also wear gloves.
- They should wear safety googles.
- They should wash their hands after handling the bottle or slide, or (of course!) not drink the stain.
Sample question 2 - Foundation
Question
Describe how you could compare the number of stomata on the top and bottom of a leaf using nail varnish. [4 marks]
- Paint the surface of the leaf with clear nail varnish.
- Allow to dry.
- Peel off the nail varnish with forceps.
- Place on a dry microscope slide and examine.
Sample question 3 - Higher
Question
A student investigated the effects of osmosis in potato tissue by placing potato cylinders in different concentrations of sugar solution.
After each experiment they measured the change in mass of the potato cylinders.
Their results are shown below.
| Sugar solution | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| Low concentration | +4% | +5% | +4% | +6% | +5% | +6% | +5% | +6% | +6% |
| High concentration | -12% | -13% | -15% | -11% | -16% | -2% | -15% | -17% | -15% |
| Low concentration | |
|---|---|
| 1 | +4% |
| 2 | +5% |
| 3 | +4% |
| 4 | +6% |
| 5 | +5% |
| 6 | +6% |
| 7 | +5% |
| 8 | +6% |
| 9 | +6% |
| High concentration | |
|---|---|
| 1 | -12% |
| 2 | -13% |
| 3 | -15% |
| 4 | -11% |
| 5 | -16% |
| 6 | -2% |
| 7 | -15% |
| 8 | -17% |
| 9 | -15% |
Identify the anomalous result. [1 mark]
Experiment 6 - high concentration of sugar
Question
Calculate the mean change in mass for each concentration. Do not include the anomalous result from Experiment 6 in your calculations.
Give your answer to one decimal place. [2 marks]
Low concentration 5.2
High concentration –14.3
Question
Explain why the student expressed change in mass as a percentage. [3 marks]
- The mass of the potato cylinders would be different.
- Because of this, the results of the experiments for cylinders in low and high concentrations could not be compared.
- Apparent differences in mass could be as much the result of differences in the initial masses as the effects of osmosis.
Sample question 4 - Higher
Question
Describe what a potometer is and how it works. [2 marks]
A simple potometer is a piece of capillary tubing to which a plant has been connected. The water uptake is measured by recording the time taken for a bubble in the tube to move a set distance.
A potometer works due to the cohesion between water molecules - so as the water is lost through transpiration, a continuous column of water moves up the stem/xylem causing the bubble to move with it.
