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What is Part B? In Figure 8 the structure of DNA shows four different bases - AQA - GCSE Biology - Question 7 - 2018 - Paper 1
Question 7
What is Part B? In Figure 8 the structure of DNA shows four different bases. There are four different bases and they always pair up in the same pairs. Which b... show full transcript
Worked Solution & Example Answer:What is Part B? In Figure 8 the structure of DNA shows four different bases - AQA - GCSE Biology - Question 7 - 2018 - Paper 1
Step 2
Step 3
Explain how the mutation could cause the enzyme not to work.
Answer
The mutation changes the DNA sequence from C to T. This alteration results in a change in the triplet code, which affects the corresponding amino acid in the sequence. Consequently, the structure of the protein can change, leading to a different tertiary structure. This change may result in the enzyme no longer fitting its substrate or carbohydrate, rendering it ineffective.
Step 4
Draw a Punnett square diagram to determine the probability of the child having syndrome H.
Answer
To determine the probability, a Punnett square can be drawn using the alleles from the heterozygous woman (Aa) and the homozygous recessive man (aa). The Punnett square will show possible combinations:
A | a
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a | Aa | aa
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a | Aa | aa
From this, we can see that there is a 50% chance of having a child with syndrome H (aa).
Step 5