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Describe three differences between the processes of mitosis and meiosis - AQA - GCSE Biology - Question 5 - 2020 - Paper 1
Question 5
Describe three differences between the processes of mitosis and meiosis. 1. Mitosis produces two daughter cells, while meiosis produces four daughter cells. 2. Mit... show full transcript
Worked Solution & Example Answer:Describe three differences between the processes of mitosis and meiosis - AQA - GCSE Biology - Question 5 - 2020 - Paper 1
Step 1
Describe three differences between the processes of mitosis and meiosis.
Answer
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Number of Daughter Cells: Mitosis results in two daughter cells, while meiosis results in four.
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Cell Divisions: Mitosis occurs through one round of division, while meiosis consists of two rounds of division, known as meiosis I and meiosis II.
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Genetic Variation: Mitosis produces genetically identical cells, whereas meiosis introduces genetic diversity through processes such as crossing over and independent assortment.
Step 2
Step 3
Give the genotype of person 1. Explain your answer.
Answer
Person 1 is likely to have the genotype Dd. This is because they have Dupuytren's, which is determined by a dominant allele (D). Since person 1 has at least one affected offspring (person 3), it indicates they possess the dominant allele.
Step 4
What is the probability of the child having Dupuytren's?
Answer
To determine the probability of Person 7 and Person 8's child having Dupuytren's, we can perform a Punnett square.
Let's denote:
- Person 7’s genotype: Dd (heterozygous, affected)
- Person 8’s genotype: dd (homozygous recessive, unaffected)
Punnett Square:
| D | d | |
|---|---|---|
| d | Dd | dd |
| d | Dd | dd |
From this, the possible offspring would be:
- 50% Dd (will have Dupuytren's)
- 50% dd (will not have Dupuytren's)
Thus, the probability of their child having Dupuytren's is 50%.
Step 5
Explain how Figure 6 shows the allele for Dupuytren's is not on the Y chromosome.
Answer
Figure 6 shows that both males and females in the family can inherit Dupuytren's, indicating that the allele responsible for the condition is not located on the Y chromosome. If it were on the Y chromosome, only males would inherit the condition from their fathers, which is not the case here.