The single-celled organism Thiomargarita namibiensis measures 700 µm in diameter and is enclosed in a cell wall. The genetic material of T. namibiensis is located free in the cytoplasm where it occurs as thousands of copies of circular DNA. Most of the cell is taken up by a large vacuole, which stores essential chemicals for metabolism. Which statement is correct?
✓ Correct Answer
The correct answer is D: It must be a prokaryote because its DNA is circular and located in the cytoplasm.
📋 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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