Which of the following statements about enzymes are correct ?
(i) Enzymes do not alter the overall change in free energy for a reaction.
(ii) Enzymes are proteins whose three dimensional energy.
(iii) Enzymes speed up reactions by lowering activation energy.
(iv) Enzymes are highly specific for reactions.
(v) The energy input needed to start a chemical reaction is called activation energy.

Options

A. (i) and (iv)
B. (i) and (iii)
C. (ii), (iii) and (iv)
D. (i)

Answer

C

Explanation

Enzymes can react with a substrate through its active site. These active sites contain a reactive nucleophilic group that attacks the substrate through covalent forces. For example, if an enzyme contains a nucleophilic group X, then
`A-B + X : to A - X + B overset(H_2 O)to A + X : + B`