A-LevelBiologyCell structureMay/June 2019Paper 1 Q31 Mark
Two different types of cell, P and Q, were broken up using ultrasound and their contents analysed. Both types of cell contained small circular DNA. The circular DNA from P all carried the same base sequence, but those from Q were of two types, with different base sequences. What may be concluded about the identity of cell types P and Q?
AP: heart muscle fibres, Q: root cortical cells
BP: lymphocytes, Q: mature red blood cells contaminated by bacteria
CP: mature red blood cells, Q: phloem sieve tube element
DP: root cortical cells, Q: leaf mesophyll cells
✓ Correct Answer
The correct answer is D: P: root cortical cells, Q: leaf mesophyll cells
📋 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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