A-LevelBiologyCell structureMay/June 2025Paper 1 Q21 Mark

Which statement about a light microscope is correct?

Q: What topic does this question test?

This question tests Cell structure in A-Level Biology (syllabus code 9700). It is worth 1 mark.

AAs the distance to see two points as separate points decreases, the resolution also decreases.

Bbacterium 0.2 µm in diameter will not be visible if the resolution is 220 nm.

CTwo membranes that are less than 300 nm apart will be visible as two separate membranes if the wavelength of light is 600 nm.

DThe resolution will improve with visible light of a longer wavelength, such as red light.

✓ Correct Answer

The correct answer is B: bacterium 0.2 µm in diameter will not be visible if the resolution is 220 nm.

📋 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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About This A-Level Biology Question

Topic

This multiple-choice question tests Cell structure in A-Level Biology (syllabus code 9700). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Biology May/June 2025 examination, Paper 1 Variant 2.

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