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Date November 2020 Marks available 1 Reference code 20N.1.SL.TZ0.11
Level Standard level Paper Paper 1 Time zone TZ0 / no time zone
Command term Question number 11 Adapted from N/A

Question

The diagram shows a respirometer.

[Source: Courtesy The Royal Society of Biology.]

 

What solution should be in the bottom of each tube and in which direction will the manometer fluid move?

Markscheme

B

Examiners report

This was another poorly answered question, but a reasonable discriminator. It was based on one of the prescribed practicals, so was not unfair. The even spread of answers reveals two gaps in understanding: that an alkali rather than an acid is needed to absorb carbon dioxide and also that the fluid in the manometer moves in the direction of the tube with the organisms, because oxygen is used up.

Syllabus sections

Core » Topic 2: Molecular biology » 2.8 Cell respiration
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