A-LevelBiologyTransport in mammalsFeb/Mar 2021Paper 1 Q351 Mark
The heart rate of a person at rest was recorded at intervals over two 15-minute periods. During the first five minutes of the second 15-minute period, the person smoked a cigarette. The graph shows the results recorded during the two 15-minute periods. [Graph showing heart rate /beats per min vs time/mins, with lines for 'smoking for first five minutes' and 'not smoking'] What can be concluded from the graph?
ACarbon monoxide affects the heart rate.
BCarbon monoxide binds to haemoglobin increasing the flow of blood.
CNicotine increases the heart rate so is a stimulant.
DThe heart rate increases as a result of smoking.
✓ Correct Answer
The correct answer is D: The heart rate increases as a result of smoking.
📋 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...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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