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A student compared the number of stomata on the upper and lower surfaces of a leaf - Edexcel - GCSE Biology - Question 9 - 2018 - Paper 1
Question 9
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 22. The layer of nail varnish shows... 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 9 - 2018 - Paper 1
Step 1
Step 2
Explain why the leaf peel rather than the whole leaf was viewed with a microscope.
Answer
The leaf peel is used rather than the whole leaf because it is thin, allowing light to pass through. If the whole leaf were used, it would be too thick and would not permit sufficient light to shine through, making it difficult to identify the stomata and cells.
Step 4
Step 5
Use Figure 24 to help you describe how water and sucrose move through a plant.
Answer
Water moves through the plant via the xylem, which consists of dead cells that are structured to form narrow, hollow tubes. These tubes transport water and minerals from the roots to the leaves, driven by the process of transpiration where water evaporates from the leaves.
Sucrose, on the other hand, is transported through the phloem, which is made of living cells equipped with sieve tubes. The phloem carries sucrose, which is produced in the leaves during photosynthesis, down to the roots and to flowering buds through a process called translocation. This transport involves loading sucrose into the phloem by active transport.