Explain the effect of a change in pH on enzyme action? (3 marks)

First step in answering this question is to read it carefully and determine what exactly is being asked:-we are being asked to give the reasons for the effect of 'pH change' only, not any other factors, so our answer must stay on topic and only address the effect of pH not of other factors that can affect enzyme action such as substrate concentration or temperature.-the key command word here is 'explain', so we are being asked to give the reasons why pH change affects enzyme action in a logical series of steps (not just state the effect without scientific explanation). -the question is worth 3 marks so that suggests at least three points should be given in the answer
Suitable answer:A change in pH outside the optimum range for an enzyme can affect its ability to function because the bonds within the enzyme will be altered, changing the shape of the enzyme molecule. This will change the shape of the active site, so the substrate cannot fit into the active site, and cannot bind with the enzyme. So the enzyme is denatured and will not function.