Food and ecosystems - Practical questions
During the GCSE Biology course you will complete practical activities from eight Practical Activity Groups (PAGs).
The exams will include questions about some of these experiments. You may also be asked to apply what you know to unfamiliar practical contexts, which will draw on your practical knowledge and understanding.
You could be asked to:
- write or identify a hypothesis or prediction that could be tested in an experiment
- name equipment and measuring instruments, and describe what they do and how they are used
- identify factors that must be controlled, and explain why
- describe how to work safely
- process data by doing calculations and representing it graphically
- identify patterns and trends in data
- evaluate the accuracy, repeatability and reproducibility of data, and identify possible errors and anomalous results
- suggest improvements to methods
- interpret data and draw conclusions from it
Practical questions will appear throughout both exam papers (Breadth and Depth), and at both Foundation tier and Higher tier. Practical questions could be multiple-choice or free-response, and could include calculations. A six-mark question could be asked in a practical context, so practice writing in detail about the practical work you have done.
It's important to look back at your lab book or your notes from the practical activities you have done when revising for your exams.
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 investigated the effects of osmosis in potato tissue by placing potato cylinders in different concentrations of sugar solution.
The changes in the mass of the potato cylinders in 9 experiments 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.
Low concentration: 5.2
High concentration: -14.3
Question
Explain why the student expressed change in mass as a percentage. [3 marks]
- The original mass of each potato cylinder may have been different.
- Because of this, the change in mass would vary depending on the original size of the potato cylinders.
- By finding percentage change in mass, any differences are due to how much osmosis occurred, and not on the original size of the cylinders.
Sample question 2 - Foundation
Question
Two students are investigating the effect of temperature on the rate of decay of fresh milk by measuring pH change.
What safety precautions should they take? [2 marks]
Two from:
- They should wear safety googles and tie their hair back if it is long.
- They should work standing up.
- They should wash their hands after the experiment is finished.
- Avoid eating and drinking in the location.
Sample question 3 - Higher
Question
Describe the method you would use determine if there are more species of plant on the school field rather than in woodland. [6 marks]
- Choose a starting point on the school field and use random numbers to generate a set of coordinates to place your first quadrat.
- Count the number of different plant species within this quadrat (the species richness).
- Return to your starting position and repeat steps two and three further times using different random numbers.
- Repeat steps one to four for a woodland.
- Compare your results by calculating a mean for each location.
Sample question 4 - Higher
Question
Two students visited two locations and measured the number of lichens on nine trees in each place. Their results are below.
| Tree 1 | Tree 2 | Tree 3 | Tree 4 | Tree 5 | Tree 6 | Tree 7 | Tree 8 | Tree 9 | |
| London | 4 | 6 | 11 | 13 | 4 | 2 | 6 | 2 | 4 |
| North Wales | 21 | 13 | 18 | 7 | 16 | 2 | 5 | 19 | 15 |
| London | |
|---|---|
| Tree 1 | 4 |
| Tree 2 | 6 |
| Tree 3 | 11 |
| Tree 4 | 13 |
| Tree 5 | 4 |
| Tree 6 | 2 |
| Tree 7 | 6 |
| Tree 8 | 2 |
| Tree 9 | 4 |
| North Wales | |
|---|---|
| Tree 1 | 21 |
| Tree 2 | 13 |
| Tree 3 | 18 |
| Tree 4 | 7 |
| Tree 5 | 16 |
| Tree 6 | 2 |
| Tree 7 | 5 |
| Tree 8 | 19 |
| Tree 9 | 15 |
Calculate the mean for each location. Give your answer to one decimal place. [2 marks]
London 5.8 and North Wales 12.9
Question
One of the students said "This definitely proves that there are more lichens in North Wales than London."
Suggest why the second student might not have been so sure. [2 marks]
The have only looked at nine trees in one location in North Wales and London. They would need to sample many, many more trees in many different locations to prove anything.
More guides on this topic
- What happens during photosynthesis? - OCR 21st Century
- How do producers get the substances they need? - OCR 21st Century
- How do producers transport substances they need? - OCR 21st Century
- How are organisms in an ecosystem interdependent? - OCR 21st Century
- How are levels maintained within an ecosystem? - OCR 21st Century
- How are populations affected by conditions in an ecosystem?
