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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. lyso... 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
(a) (ii) 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 can affect the binding of transcription factors or RNA polymerase to the DNA. If the mutation alters essential regulatory sequences, such as promoters or enhancers, the transcription machinery may not be able to recognize or bind to the DNA, thus inhibiting the transcription of the gene.
Step 3
(b) Explain how the mutation in allele 2 could affect the functioning of this protein.
Answer
The mutation in allele 2 changes the codon sequence from CAG (which codes for the amino acid Gln) to GAG (which codes for the amino acid Glu). This alteration may affect the protein's structure and function because the amino acid sequence determines the folding and, ultimately, the function of the protein. If Glu is functionally different from Gln in the context of the protein, this could lead to altered enzymatic activity or stability, impacting the protein's role in the cell.
Step 4
(c) Explain how this child is blood group O.
Answer
The child's blood group O results from inheriting one O allele from each parent. The mother, being blood group A, can either possess AA or AO genotypes, while the father, being blood group B, can possess either BB or BO genotypes. A Punnett square illustrates the potential combinations of alleles:
| A | O | |
|---|---|---|
| B | AB | BO |
| O | AO | OO |
From this, there is a possibility of producing an OO genotype, which corresponds to blood group O. Therefore, the child can have blood group O as a result of receiving an O allele from each parent.