Explain5 marksStandard
Explain why an enzyme usually catalyses only one specific reaction. In your answer, refer to the structure of the active site, the formation of the enzyme–substrate complex, and the lock-and-key and induced-fit models.
CAIE A Level Biology 9700 · Enzymes
Enzymes: explain question
How this question is marked
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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