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Date May 2022 Marks available 1 Reference code 22M.1.SL.TZ1.11
Level Standard level Paper Paper 1 Time zone Time zone 1
Command term Question number 11 Adapted from N/A

Question

The graph shows the changes in lactate measured in an athlete’s blood during exercise.

 

Which hypothesis provides the most likely explanation for the curve?

A. As exercise intensity increases, lactate is converted back to glucose.

B. Anaerobic exercise results in high levels of lactate.

C. Lactate provides energy for intense exercise.

D. Under anaerobic conditions the body produces less lactate.

Markscheme

B

Examiners report

The wording of the question was slightly awkward as none of the hypotheses offered in the answers fully explained the form of the curve on the graph. The discrimination index for the question was relatively low, probably due to some of the better candidates overthinking the issues, rather than choosing obvious answer that anaerobic exercise results in high levels of lactate.

Syllabus sections

Core » Topic 2: Molecular biology » 2.8 Cell respiration
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