The figure given below shows the conversion of a substrate into product by an enzyme. In which one of the four options (1 – 4) the components of reaction labelled as A, B, C and D are identified correctly? [figure]
- array|l|l|l|l| A & B & C & D \ Potential energy & Transition state & Activation energy & Activation energy without enzyme \ array
- array|l|l|l|l| A & B & C & D \ Transition state & Potential energy & Activation energy without enzyme & Activation energy with enzyme \ array
- array|l|l|l|l| A & B & C & D \ Potential energy & Transition state & Activation energy with enzyme & Activation energy without enzyme \ array
- array|l|l|l|l| A & B & C & D \ Activation energy with enzyme & Transition state & Activation energy without enzyme & Potential energy \ array
Answer
(2) array|l|l|l|l| A & B & C & D \ Transition state & Potential energy & Activation energy without enzyme & Activation energy with enzyme \ array
Solution
As per NCERT, the substrate has to pass through a much higher energy state, the transition state, before it changes into product; the difference in energy between the substrate and the transition state is the activation energy, and an enzyme lowers this energy barrier.
⇒ A (the highest point of the curve) = transition state.
⇒ B (the y-axis, energy level of substrate) = potential energy.
⇒ C (the larger energy gap, upper curve) = activation energy without enzyme.
⇒ D (the smaller energy gap, lower curve) = activation energy with enzyme.
Answer: (2)