A-LevelBiologyCell membranes and transportMay/June 2023Paper 1 Q171 Mark
The three main factors that affect the rate of diffusion across a membrane can be expressed by the relationship shown. rate of diffusion is proportional to surface area × concentration difference / thickness of membrane Which changes in the factors would result in the rate of diffusion doubling? 1 Surface area has doubled. 2 Concentration difference has halved. 3 Thickness of membrane has doubled. 4 Thickness of membrane has halved.
A1, 2 and 4
B1 and 3
C1 and 4 only
D2 and 3
✓ Correct Answer
The correct answer is C: 1 and 4 only
📋 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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