Question

Enzymes increase the rate of a reaction by __________? (A) Contributing water to the reaction. (B) Contributing electrons to the reaction. (C) Changing the pH of the substrates. (D) Decreasing activation energy. (E) Increasing the temperature of the substrates.

Answer 1

E. Increasing the temperature of the substrates 

The reaction rate increases as the temperature is raised. The increased temperature comes from an increase in kinetic energy. Enzymes are efficient catalysts for reactions, and due to the shape of the molecules in an enzyme, they are selective as to which reactions they catalyze. 

Answer 2

D, enzymes are catalysts and catalysts work by decreasing activation energy required and therefore increasing rate of reaction.