A-LevelBiologyGas exchangeOct/Nov 2021Paper 1 Q321 Mark

What explains how the maximum volume of oxygen is taken up as blood passes through the capillaries of the lungs?

Q: What topic does this question test?

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

AEach haemoglobin molecule can temporarily bind to four oxygen atoms.

BThe dissociation of carbon dioxide from carboxyhaemoglobin allows more haemoglobin to be available for binding oxygen.

CThe binding of the first oxygen molecule to haemoglobin decreases the affinity of haemoglobin for binding other oxygen molecules.

DOxyhaemoglobin formation increases the ability of red blood cells to transport oxygen.

✓ Correct Answer

The correct answer is D: Oxyhaemoglobin formation increases the ability of red blood cells to transport oxygen.

📋 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 Gas exchange in A-Level Biology (syllabus code 9700). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Biology Oct/Nov 2021 examination, Paper 1 Variant 2.

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