11 mark
Which of the following are mutagenic agents?
X-rays, benzo(a)pyrene, radio waves
X-rays, microwaves, radio waves
X-rays, benzo(a)pyrene, gamma rays
X-rays, benzo(a)pyrene, microwaves
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Syllabus Edition
First teaching 2023
First exams 2025
|
Mutations & Gene Editing (HL IB Biology)
Topic Questions
1
1 mark
1 markThe nucleotide base sequence and the associated sequence of four amino acids can be seen below:
AGG ACA CCT GGA
Serine Tyrosine Glycine Proline
The table shows the mRNA codons and their associated amino acids.
A single mutation occurred in the original base sequence of the DNA which resulted in only one amino acid from the sequence being produced.
Which of the following would represent the correct nucleotide base sequence which was found in the DNA after the mutation occurred?
AGT ACA CCT GGA
AGG ACT CCT GGA
AGG ACC CCT GGA
AGG ACA UGA GGA
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11 mark
A base substitution mutation has caused a single change to the mRNA transcript of a section of a gene, as shown below.
|
Original sequence |
AUGGAAAUACCGCCAGGA |
|
Mutated sequence |
AUGGAAAUACUGCCAGGA |
Using the table above, what is the change in amino acid sequence caused by this mutation?
Pro → Leu
Met → Glu
Pro → Gln
No change
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21 mark
Which of the following statements, correctly describes the impact of the substitution mutation shown below?
The codon encoding an amino acid was changed to a stop codon, truncating the polypeptide
The sequence of amino acids may code for a different protein structure
The resulting polypeptide chain will be elongated
There will be no change in the polypeptide chain
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31 mark
The risk of developing a cancerous tumour is increased by exposure to which of the following?
| Ultraviolet light | Benzo[a]pyrene | Carbon monoxide | X-rays | |
| A. | ✓ | ✓ | ✗ | ✓ |
| B. | ✓ | ✗ | ✗ | ✓ |
| C. | ✗ | ✓ | ✓ | ✗ |
| D. | ✓ | ✗ | ✓ | ✗ |
Key: ✓ = increases risk, ✗ = does not increase risk
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41 mark
Sickle cell anaemia is caused by the following mutation in the gene that codes for haemoglobin:
Which of the following correctly explains how this mutation causes sickle cell anaemia?
It causes valine to be replaced by glutamic acid, altering the structure of the haemoglobin protein.
It produces an allele known as HbA.
It causes glutamic acid to be replaced by valine, altering the structure of the final haemoglobin protein.
It causes an amino acid substitution at the 8th position in the polypeptide.
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