A-LevelBiologyCell membranes and transportFeb/Mar 2017Paper 2 Q67 Marks
(a) A student investigated the effect of changing the surface area to volume ratio on diffusion. • Two different-sized blocks of agar, X and Y, were made. • The agar contained Universal Indicator solution. • Universal Indicator solution changes colour when acid is added. • The blocks were placed in dilute hydrochloric acid at the same temperature. • The student timed how long it took for each block to change colour completely. Blocks X and Y are shown in Fig. 6.1. All dimensions are in cm. [Figure 6.1]
📋 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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