A-LevelBiologyGas exchangeMay/June 2021Paper 1 Q331 Mark
In some cases where a person has lung disease, the partial pressure of oxygen in the pulmonary veins is less than the partial pressure of oxygen in the alveoli. What could explain the difference in partial pressure of oxygen? 1 A high proportion of alveoli are collapsed and do not have enough alveolar capillaries. 2 The partial pressure of oxygen in the pulmonary arteries is lower than the in the alveolar air. 3 The rate of diffusion of oxygen from the alveolar air to the surrounding alveolar capillaries is too slow.
A1, 2 and 3
B1 and 2 only
C1 and 3 only
D2 and 3 only
✓ Correct Answer
The correct answer is C. This question tests the candidate's understanding of gas exchange within the Biologysyllabus. The examiner's mark scheme requires...
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
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