A-LevelBiologyTransport in mammalsFeb/Mar 2021Paper 1 Q321 Mark

The graph shows the oxygen dissociation curves for adult haemoglobin at two carbon dioxide concentrations. [Graph showing two oxygen dissociation curves P and Q, with points S and R indicated] Which letters show measurements taken in the capillaries of the lungs and in the capillaries of active muscle?

Q: What is the correct answer to this A-Level Biology question?

The correct answer is A: lungs: P active muscle: R.

Q: What topic does this question test?

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

Alungs: P active muscle: R

Blungs: P active muscle: S

Clungs: Q active muscle: R

Dlungs: Q active muscle: S

✓ Correct Answer

The correct answer is A: lungs: P active muscle: R

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

Source

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

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