Question 22N.1A.HL.TZ0.27
| Date | November 2022 | Marks available | [Maximum mark: 1] | Reference code | 22N.1A.HL.TZ0.27 |
| Level | HL | Paper | 1A | Time zone | TZ0 |
| Command term | Question number | 27 | Adapted from | N/A |
The diagram illustrates some of the processes involved in DNA replication.
[Source: Rohrmann, G., 2019. AcMNPV DNA replication. [diagram online] Available at:
https://www.ncbi.nlm.nih.gov/books/NBK543453/figure/ch05.F1/ [Accessed 26 October 2021].]
What is shown in the diagram?
A. DNA polymerase bonding nucleotides in a 3’ to 5’ direction
B. Single-stranded DNA-binding proteins on the old strands
C. Gyrase reforming the double helix
D. DNA ligase joining Okazaki fragments in the leading strand
[1]
B
Despite the problems with question 25, many questions performed very well. Question 27 is an example. Candidates had to study a complex diagram of DNA replication and then decide which of four statements about replication was correct. Half of the candidates were successful and the discrimination index at 0.73 was exceptionally high, showing that the question was a very effective test.
