A-LevelBiologyCell membranes and transport9700/12 · Feb/Mar 2025 · Q341 Mark

A molecule of oxygen diffuses from the air in an alveolus to haemoglobin in a red blood cell. Assuming that the molecule crosses cellular layers by passing through cells, rather than between cells, what is the minimum number of phospholipid layers that the molecule of oxygen must pass through?

D10

✓ Correct answer

D: 10

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Topic: Cell membranes and transport, A-Level Biology (syllabus 9700). Multiple choice, 1 mark.
Source: A-Level Biology, Feb/Mar 2025 Paper 1 Variant 2, question 34.

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