CAIE A Level Biology 9700 · Enzymes
The enzyme urease catalyses the hydrolysis of urea into ammonia and carbon dioxide. Describe the mechanism by which urease lowers the activation energy for this reaction. In your description, include the roles of the active site and the formation of the enzyme-substrate complex, and compare the lock-and-key hypothesis with the induced-fit hypothesis.
6 marks, so the mark scheme is looking for about 6 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.