Photo AI
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 ly... 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 DNA may disrupt the binding sites for transcription factors or RNA polymerase. If these proteins cannot bind effectively, the transcription of the corresponding gene may be inhibited, leading to reduced or absent gene expression.
Step 3
Explain how the mutation in allele 2 could affect the functioning of this protein.
Answer
The mutation in allele 2 results in a codon change that alters the sequence of amino acids in the polypeptide chain. For instance, the codon GAG (glutamic acid) might be changed to another amino acid, potentially affecting the protein's overall structure and function. This change can result in a loss of activity or a malfunction, depending on the protein's role.
Step 4
Use the Punnett square and probability in your answer.
Answer
To determine the possible blood groups of the child with a mother of blood group O (genotype OO) and a father of blood group B (genotype either IBIB or IBi), we can set up a Punnett square:
| O | O | |
|---|---|---|
| IB | IBO | IBO |
| i | iO | iO |
From this, the potential genotypes for the child can be:
- IBi (blood group AB)
- iO (blood group A)
- OO (blood group O)
Thus, there is a possibility for the child to be of blood type A or AB but not O. This child cannot be blood group O since one parent contributes an O allele and the other contributes either B (IB) or O (i). The only possibility for the child to be blood type O is if the father had contributed an O allele.