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Transcription and translation are stages in the synthesis of proteins - Edexcel - GCSE Biology - Question 9 - 2019 - Paper 1
Question 9
Transcription and translation are stages in the synthesis of proteins. (a) (i) Which enzyme is involved in the process of transcription? A DNA ligase B lysozyme C ... show full transcript
Worked Solution & Example Answer:Transcription and translation are stages in the synthesis of proteins - Edexcel - GCSE Biology - Question 9 - 2019 - Paper 1
Step 1
Step 2
Describe how a mutation in the non-coding region of the DNA can prevent a gene being transcribed.
Answer
A mutation in the non-coding region of the DNA can disrupt regulatory elements, such as promoters or enhancers, which are crucial for the initiation of transcription. If these elements are altered, RNA polymerase may not be able to bind effectively, leading to reduced or absent transcription of the corresponding gene.
Step 3
Explain how the mutation in allele 2 could affect the functioning of this protein.
Answer
The mutation in allele 2 alters one of the codons in the mRNA sequence. If this change leads to the production of a different amino acid, the structure and function of the protein may be affected. For example, if the mutation results in a stop codon, the protein synthesis will terminate prematurely, producing a non-functional protein.
Step 4
Explore how this child is blood group O.
Answer
To determine how a child with blood group A and a mother with blood group B can be blood group O, we can set up a Punnett square. The potential genotypes from these parents can be A (IAi) and B (IBi). The Punnett square shows the following combinations:
| IA | i | |
|---|---|---|
| IB | IAIB | IBi |
| i | IAi | ii |
The possible blood types are AB, B, A, and O. The child could inherit the recessive i allele from both parents, resulting in blood group O (ii).