6 (a) A karyogram is a picture of the chromosomes found in the nucleus of a single cell - Edexcel - GCSE Biology - Question 6 - 2019 - Paper 1
Question 6
6 (a) A karyogram is a picture of the chromosomes found in the nucleus of a single cell. Figure 8 shows a human karyogram.
(i) State two reasons why this karyogram ... show full transcript
Worked Solution & Example Answer:6 (a) A karyogram is a picture of the chromosomes found in the nucleus of a single cell - Edexcel - GCSE Biology - Question 6 - 2019 - Paper 1
Step 1
State two reasons why this karyogram cannot be from a gamete (sex cell).
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Answer
A karyogram from a gamete would display only 23 chromosomes, but this karyogram contains 46 chromosomes.
Gametes are haploid, while this karyogram represents a diploid cell.
Step 2
State the gender shown by this karyogram.
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Answer
The gender shown by this karyogram is male, as it has an X and a Y chromosome.
Step 3
Complete the Punnett square to show how gender is inherited.
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To complete the Punnett square:
| X | Y |
------|-----|-----|
X | XX | XY |
------|-----|-----|
X | XX | XY |
This shows that there is a 50% chance of a female (XX) and a 50% chance of a male (XY).
Step 4
State the probability that a child will be male.
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Answer
The probability that a child will be male is 50%.
Step 5
Name structure Z.
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Structure Z is an acrosome.
Step 6
Explain why sperm B will be more likely to fertilise an egg than sperm A if they were both released at the same time.
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Sperm B has a larger middle section, which provides it with more energy reserves. This increased energy allows sperm B to swim faster and reach the egg more efficiently than sperm A, increasing its chances of fertilisation.
