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A-LevelBiologyEnzymesMay/June 2023Paper 1 Q131 Mark

CYP3A4 is an important enzyme in the human digestive system where it is needed to break down a range of different toxins. The activity of CYP3A4 has been shown to be reduced by substances called furanocoumarins. Furanocoumarins are found in some fruits and so dangerous concentrations of toxins may develop in the human digestive system when fruits containing furanocoumarins are eaten. From the information provided, what can be concluded about molecules of the enzyme CYP3A4?

AThey lower the activation energy of the toxin breakdown reactions.
BThey bind specifically through the active site to a substrate found in some fruits.
CThey change permanently when acted upon by furanocoumarin molecules.
DThey resume normal activity when concentrations of furanocoumarins decrease.

✓ Correct Answer

The correct answer is A. 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) May/June 2023 examination, Paper 1 Variant 2. It tests the topic of Enzymes and is worth 1 mark.

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