A-LevelBiologyGas exchange9700/12 · Oct/Nov 2021 · Q361 Mark
Which flow diagram correctly describes the effect of tar entering the lungs? [Four flow diagrams (A, B, C, D) describing a sequence of events]
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
Acarcinogens come into contact with DNA → mutation occurs → uncontrolled cell division
Bgoblet cells secrete more mucus → mucus accumulates causing infection → phagocytes attracted by inflammation
Cmucus accumulates causing infection → phagocytes attracted by inflammation → elastase destroys the alveolar walls
Dmutation occurs → phagocytes attracted by inflammation → causes irritation and coughing
✓ Correct answer
A: carcinogens come into contact with DNA → mutation occurs → uncontrolled cell division
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