DP Biology (last assessment 2024)
Question 23M.1.SL.TZ2.14
| Date | May 2023 | Marks available | [Maximum mark: 1] | Reference code | 23M.1.SL.TZ2.14 |
| Level | SL | Paper | 1 | Time zone | TZ2 |
| Command term | Question number | 14 | Adapted from | N/A |
14.
[Maximum mark: 1]
23M.1.SL.TZ2.14
What change causes sickle cell anemia?
A. One amino acid less in a polypeptide of hemoglobin
B. A mutation leading to an extra codon in the genome
C. Thymine replacing adenine in DNA
D. Failure of tRNA to correctly transcribe the sequence of codons from mRNA
[1]
Markscheme
C
Examiners report
It was pointed out in the G2 forms that thymine replaces adenine in only one position in a DNA molecule and this would have been better wording for the correct response.