Date | May 2019 | Marks available | 1 | Reference code | 19M.1.HL.TZ1.2 |
Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
Command term | Distinguish | Question number | 2 | Adapted from | N/A |
Question
The image shows a phagocytic white blood cell as seen with a transmission electron microscope.
[Source: http://www.wikidoc.org/index.php/File:Monocyte_TEM_0002.jpg, by Cafer Zorkun is licensed
under the Creative Commons Attribution/Share-Alike License]
Which features can be found both within this cell and in a photosynthetic bacterium?
A. Chloroplasts
B. Multiple nuclei
C. 70S ribosomes
D. Lysosomes
Markscheme
C
Examiners report
There were two types of critical comment from teachers – that there was no correct answer and that the micrograph did not help in answering the question. The inclusion of the micrograph was an attempt to place the question within the context of a specific cell type, but it is true to say that it was not a vital element. Answer C was certainly correct – eukaryotic cells have 70S ribosomes in their mitochondria. A larger number of candidates chose answer D, but a photosynthetic bacterium does not contain lysosomes. Answers A and B were more obviously incorrect and were more rarely chosen. All in all, this was not an effective question as it was too hard and the discrimination index was poor.