Question 1 (2 marks)
Knowledge
What two features distinguish a typical plant cell from an animal cell in microscope images?
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Cell wall (1); large permanent vacuole or chloroplasts in photosynthetic plant cells (1).
Required Practical 01: Microscopy | AQA GCSE Science | The Science Department
About this practical and its aim
Aim
How to use a microscope
Introduction
In this practical, you will learn how to use a light microscope correctly. You will be able to label all of the parts and explain what they do. You need to be able to prepare a plant and animal cell slide and describe this method. You will have an opportunity to make accurate scientific drawings of the cells that you see including labels. You should also take measurements that will allow you to calculate sizes using the combines magnification of the two lenses.
The science behind the practical
How magnification works
Key things to remember
Real and image size
Equipment and apparatus
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Light microscope
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prepared plant and animal slides
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glass slides and coverslips
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forceps
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dropper
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suitable stain
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ruler
Method: How to carry out the experiment
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Carefully collect your microscope and return it to your bench, ensure that you carry it with both hands.
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Select the lowest magnification lens, apply the slide and move it so that it is close to the lens.
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Focus the slide by moving the platform/slide AWAY from the lens until it is in focus.
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Identify and draw and label features seen and carefully note down the magnification of the lenses to allow you to calculate image size later.
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Repeat for other slides at other magnifications.
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NOTE: You may be permitted to create your own slide of a thin layer of onion which needs to be stained. If you collect cheek cells, it is very important that you follow your teacher's instructions carefully.
Variables and fair testing
| Type of variable | What is measured or controlled? |
|---|---|
| Independent variable | Magnification |
| Dependent variable | Observed cell structures and apparent image size |
| Control variables | Same microscope settings and preparation method when comparing samples |
Safety and managing risks
Follow your teacher's instructions and your school's risk assessment. This page is not a substitute for a formal risk assessment.
| Hazard | Risk | Precaution |
|---|---|---|
Glass slides and coverslips |
Cuts from broken glass |
Handle by edges and report breakages; use the school glass-disposal procedure. |
Stains and biological specimens |
Irritation or contamination |
Follow stain guidance; wash hands; use teacher-approved sample collection. |
Results, calculations and analysis
Recording, presenting and interpreting results
Record labelled biological drawings, magnification, and an appropriate scale.
Calculations
Magnification = image size ÷ actual size. Convert mm to µm using 1 mm = 1000 µm.
Conclusions, accuracy and evaluation
Drawing a conclusion
Higher magnification reveals more detail but a smaller field of view.
Evaluating the investigation
Thin specimens and suitable stains improve visibility; drawings should show what is observed, not imagined.
More to learn
Scientific drawings
Use a sharp pencil, a large clear outline, straight ruled labels and a scale or magnification. Do not shade.
Common exam mistake
Eyepiece magnification must be multiplied by objective magnification, not added.
GCSE examination practice
Answer each question in full before opening the model answer. Check your work against the marking points and look for scientific key words.
Question 2 (3 marks)
Calculation
An image is 24 mm across and the actual cell is 60 µm across. Calculate magnification.
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Convert 24 mm to 24 000 µm (1); magnification = 24 000 ÷ 60 = ×400 (2).
Question 3 (2 marks)
Method
Describe two rules for a clear scientific biological drawing.
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Draw clear continuous outlines without shading (1); use straight ruled label lines and show scale or magnification (1).
Question 4 (2 marks)
Evaluation
Suggest one improvement to make the investigation more reliable and explain why it helps.
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Repeat measurements and calculate a mean (1), reducing the influence of random variation/anomalies (1). Alternative valid improvement specific to the experiment with explanation can gain both marks.
This page was updated on: 11th October 2026