Biology 5090 · Question 1[9 marks]
Enzymes are essential biological catalysts present in all living organisms.
(a)[2]
Define the term biological catalyst.
(b)[5]
(i)[3]
Describe how an enzyme catalyses the breakdown of a specific substrate molecule with reference to the lock-and-key hypothesis.
(ii)[2]
Explain why a high temperature above 60 °C prevents the lock-and-key mechanism from functioning.
(c)[2]
Figure 5.1 shows energy profile curves and for a metabolic reaction. Identify which curve represents the enzyme-catalysed pathway and explain how the enzyme alters the activation energy of the reaction.