DP Biology (first assessment 2025)

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Question 19M.1A.SL.TZ1.2

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.1A.SL.TZ1.2
Level SL Paper 1A Time zone TZ1
Command term Distinguish Question number 2 Adapted from N/A
2.
[Maximum mark: 1]
19M.1A.SL.TZ1.2

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

[1]

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. 

Syllabus sections