Question 23M.1.HL.TZ2.22
| Date | May 2023 | Marks available | [Maximum mark: 1] | Reference code | 23M.1.HL.TZ2.22 |
| Level | HL | Paper | 1 | Time zone | TZ2 |
| Command term | Question number | 22 | Adapted from | N/A |
The image shows an X-ray diffraction photograph produced by Rosalind Franklin.
[Source: Franklin, R.E. and Gosling, R.G., 1953. [image online] Available at: https://scripts.iucr.org/cgi-bin/paper?a00979.
[Accessed 8 March 2022].]
What did Watson and Crick deduce about DNA from this image?
A. DNA carries the genetic code.
B. The DNA molecule is helical in shape.
C. DNA has two strands of nucleotides linked by bases.
D. DNA is composed of an equal number of purines (A and G) and pyrimidines (C and T).
[1]
B
This question showed an X-ray diffraction photograph and asked what Watson and Crick deduced about the structure of DNA from this image. It was suggested that the photograph may have been taken by Gosling but this would not affect the candidate's choice of the correct response.