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Figure 9 shows a sperm cell - Edexcel - GCSE Biology Combined Science - Question 6 - 2021 - Paper 1
Question 6
Figure 9 shows a sperm cell. (a) Describe how structure A and structure B enable fertilisation. (2) (b) Figure 10 shows a human egg cell, magnified ×700. Calcula... show full transcript
Worked Solution & Example Answer: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 to digest the outer layers of the egg cell, allowing the sperm to penetrate and fertilise the egg. Structure B, the flagellum, provides movement to the sperm, enabling it to reach the egg cell for fertilisation.
Step 2
Calculate the actual width of the region indicated by the line on Figure 10.
Answer
The magnification of Figure 10 is ×700. If we assume that the width indicated by the line on the image is approximately 1 cm (10 mm), we can calculate the actual width using the formula:
ext{Actual Width} = rac{ ext{Width in Image}}{ ext{Magnification}} = rac{10 ext{ mm}}{700} = 0.0142857 ext{ mm}
In standard form, this is approximately:
Step 3
Evaluate the results of this experiment.
Answer
From the data in Figure 11, it can be observed that the mass of the eggs in different solutions varied after 24 hours. For instance, the eggs in tap water increased in mass, indicating water entered the eggs due to osmosis. In contrast, the eggs in 10% salt solution decreased in mass, indicating that water exited the eggs due to the higher concentration of solute outside the eggs, leading to a hypertonic environment. These results demonstrate the principle of osmosis, where water moves from an area of lower solute concentration to an area of higher concentration.