A-LevelBiologyEnzymesOct/Nov 2022Paper 1 Q141 Mark

The Michaelis–Menten constant, Km, is the substrate concentration at which an enzyme works at half its maximum rate. What is correct when the Km value is low?

Q: What topic does this question test?

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

AThe enzyme has a low affinity for the substrate and the quicker the reaction will proceed to its maximum rate.

BThe enzyme has a low affinity for the substrate and the slower the reaction will proceed to its maximum rate.

CThe enzyme has a high affinity for the substrate and the quicker the reaction will proceed to its maximum rate.

DThe enzyme has a high affinity for the substrate and the slower the reaction will proceed to its maximum rate.

✓ Correct Answer

The correct answer is C: The enzyme has a high affinity for the substrate and the quicker the reaction will proceed to its maximum rate.

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

Source

This question appeared in the Cambridge A-Level Biology Oct/Nov 2022 examination, Paper 1 Variant 2.

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