What should be the answer of this one?
Ans. Option D) is correct: X= uncatalysed reaction, Y = Catalysed reaction and Z = Overall energy change
All enzymes are catalysts. As a catalyst, these lower the activation energy of the reaction, as it acts on the transition state and binds with the transition state.
The energy released in the binding of catalyst with transition state, supplies a part of activation energy and thus, reduces the overall activation energy required for a particular reaction.