| Date | May 2021 | Marks available | 1 | Reference code | 21M.1.SL.TZ2.13 |
| Level | Standard level | Paper | Paper 1 | Time zone | Time zone 2 |
| Command term | Question number | 13 | Adapted from | N/A |
Question
The electron micrograph shows a section through a plant cell.
[Source: Photo © E. Newcomb.]
In which structure(s) is the genome of the cell contained?
A. Z only
B. X, Y and Z only
C. W and X only
D. X and Y only
Markscheme
B
Examiners report
This question was difficult and did not discriminate well with most candidates opting for A, the nucleus alone rather than response B which included the chloroplast and mitochondrion. Section 3.1 (Genes) in the guide defines the genome as "the whole of the genetic information of an organism". Section 1.5 (The origin of cells) requires the candidates to have reviewed the evidence for the endosymbiotic theory so knowledge that some organelles also carry genetic material would be expected.
