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6 (a) Figure 9 shows a sperm cell - Edexcel - GCSE Biology: Combined Science - Question 6 - 2021 - Paper 1
Question 6
6 (a) Figure 9 shows a sperm cell. Describe how structure A and structure B enable fertilisation. (2) (b) Figure 10 shows a human egg cell, magnified ×700. Calcu... show full transcript
Worked Solution & Example Answer:6 (a) Figure 9 shows a sperm cell - Edexcel - GCSE Biology: Combined Science - Question 6 - 2021 - Paper 1
Step 1
Describe how structure A and structure B enable fertilisation.
Answer
Structure A, the acrosome, contains enzymes that help the sperm penetrate the outer layers of the egg, allowing for fertilization. Structure B, the flagellum, propels the sperm towards the egg, increasing the likelihood of successful fertilization.
Step 2
Calculate the actual width of the region indicated by the line on Figure 10.
Answer
To find the actual width, we can use the magnification scale. If the line measures X mm on the image, then the actual width can be calculated as:
ext{Actual Width} = rac{ ext{Measured Width}}{ ext{Magnification}}
For example, if the line measures 5 mm: ext{Actual Width} = rac{5 ext{ mm}}{700} = 0.00714 ext{ mm} = 7.14 imes 10^{-3} ext{ mm}
Step 3
Evaluate the results of this investigation.
Answer
After placing the eggs in different solutions, there was a notable change in mass.
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Tap Water: The mass increased, indicating that water moved into the eggs by osmosis.
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5% Salt Solution: There was no change in mass, suggesting the solution was isotonic with the egg contents.
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10% Salt Solution: The mass decreased, indicating water left the eggs due to osmosis.
This investigation demonstrates how the osmotic pressure varies with different solute concentrations.