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Question 19M.3.SL.TZ2.2b

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.3.SL.TZ2.2b
Level SL Paper 3 Time zone TZ2
Command term Determine Question number b Adapted from N/A
b.
[Maximum mark: 2]
19M.3.SL.TZ2.2b

Cairns’ technique was used in an experiment to measure the length of DNA in the Chinese hamster (Cricetulus griseus). Fibroblast cells were grown with radioactive nucleotides. The DNA autoradiogram obtained is shown.

[Source: © Joel A. Huberman and Arthur D. Riggs]

(b)

Determine, with a reason, the nucleotide base that was marked with radioactivity.

Base:

Reason:

 

 

[2]

Markscheme

a. thymine / T ✔

b. because only in DNA / not in RNA ✔

Examiners report

Few were able to name thymine as the base or give a reason it was used in the experiment.

Syllabus sections