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A-LevelBiologyEnzymesFeb/Mar 2024Paper 1 Q131 Mark

A scientist investigated the progress of two enzyme-catalysed reactions in separate test-tubes, X and Y. Both reactions result in colour changes that can be detected using colorimetry. 0.5 cm³ samples were taken from each test-tube at the start of the investigation and at regular intervals for the next 5 minutes. Copper ions were added to each sample as soon as the sample was collected to inactivate the enzymes and stop the reactions from progressing further. The absorbance of each sample was measured using a colorimeter. The graph shows the results of this investigation. [Figure 13.1]

AThe substrate in test-tube X has a higher absorbance than the product.
BThe product in test-tube Y has a lower absorbance than the substrate.
CThe rate of the reaction in test-tube X increased with time.
DThe rate of the reaction in test-tube Y increased with time.

✓ Correct Answer

The correct answer is B. This question tests the candidate's understanding of enzymes within the Biologysyllabus. The examiner's mark scheme requires...

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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...

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About This A-Level Biology Question

This multiple-choice question appeared in the Cambridge A-Level Biology (9700) Feb/Mar 2024 examination, Paper 1 Variant 2. It tests the topic of Enzymes and is worth 1 mark.

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