Practical questions
You will complete ten required practical activities if you are studying GCSE Biology and twenty-one 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.
In the exchange and transport in animals section there is one required practical activity:
Investigate the rate of respiration in living organisms
Edexcel questions courtesy of Pearson Education Ltd.
Sample question 1 - Higher
Question
This figure shows the equipment used for measuring respiration in peas.
- respirometer A contains germinating peas
- respirometer B contains peas that are not germinating
- respirometer C contains glass beads
All three respirometers are placed in a water bath at 25掳C for 30 minutes.
The reduction in oxygen levels in each respirometer is measured using a data logger.
Explain why the respirometers are placed in a water bath at 25掳C. [2 marks]
Same temperature to act as control
To provide the optimum temperature for enzyme action in the peas
Sample question 2 - Higher
Question
Explain why respirometer A has the highest rate of oxygen consumption. [2 marks]
Any one improvement from:
- the peas in respirometer A are germinating so using up oxygen
- during the process of respiration to release energy for growth