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Figure 9 shows a photomicrograph of two stomata in a leaf - Edexcel - GCSE Biology Combined Science - Question 6 - 2023 - Paper 2
Question 6
Figure 9 shows a photomicrograph of two stomata in a leaf. (a) (i) The length of one guard cell in this image is 6mm. Convert the length of this guard cell into mic... show full transcript
Worked Solution & Example Answer:Figure 9 shows a photomicrograph of two stomata in a leaf - Edexcel - GCSE Biology Combined Science - Question 6 - 2023 - Paper 2
Step 1
Step 2
Calculate the actual size of the guard cell.
Answer
To find the actual size of the guard cell, we need to divide the measured length by the magnification. Given that the length of the guard cell is 6 mm and the magnification is 150x:
ext{Actual Size} = rac{ ext{Length}}{ ext{Magnification}} ightarrow rac{6 ext{ mm}}{150} = 0.04 ext{ mm}To express this in standard form:
Step 3
Explain the role of denitrifying bacteria in the nitrogen cycle
Answer
Denitrifying bacteria play a critical role in the nitrogen cycle by converting nitrates (NO₃) and nitrites (NO₂) back into nitrogen gas (N₂), which is then released into the atmosphere. This process is essential for maintaining the balance of nitrogen in ecosystems. It helps to reduce excess nitrates in the soil, preventing nutrient pollution and promoting a healthy environment.