A student compared the number of stomata on the upper and lower surfaces of a leaf - Edexcel - GCSE Biology - Question 3 - 2018 - Paper 1
Question 3
A student compared the number of stomata on the upper and lower surfaces of a leaf.
She completed a leaf peel as shown in Figure 5.
Figure 5
The layer of nail varn... show full transcript
Worked Solution & Example Answer:A student compared the number of stomata on the upper and lower surfaces of a leaf - Edexcel - GCSE Biology - Question 3 - 2018 - Paper 1
Step 1
State why a cover slip is placed on top of the leaf peel.
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Answer
A cover slip is placed on top of the leaf peel to keep the leaf peel flat and prevent drying out.
Step 2
Explain why the leaf peel rather than the whole leaf was viewed with a microscope.
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Answer
The leaf peel is viewed rather than the whole leaf because it is thinner, allowing light to pass through it, which is essential for the observation of stomata and cells under the microscope.
Step 3
How many stomata were counted?
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Answer
3 / three
Step 4
Describe how guard cells take in water.
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Answer
Guard cells take in water by osmosis. They become turgid as they absorb water and change shape, causing the stomata to open.
Step 5
Explain why stomata are found on the lower surface of the leaf.
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Answer
Stomata are found on the lower surface of the leaf to reduce water loss through transpiration, as this surface is less exposed to direct sunlight and wind.
