Question

Enzymes increase the rate of chemical reactions by a. increasing the body temperature. b. decreasing the blood $\mathrm{pH}$. c. increasing the affinity of reactant molecules for each other. d. decreasing the activation energy of the reactants.

Short answer

Enzymes increase the rate of chemical reactions by: d. decreasing the activation energy of the reactants.

Step-by-step solution

Option A

Enzymes do not work by increasing the body temperature. They actually function optimally in certain specific temperature ranges. So option (a) is incorrect.

Option B

Enzymes do not work by decreasing the blood pH. They have their optimal functioning in specific pH ranges, which can be either more or less than the blood pH depending on the enzyme. So option (b) is incorrect.

Option C

Enzymes might allow reactant molecules to interact more efficiently, but this is not the primary way they increase the rate of chemical reactions. So option (c) is not the best answer.

Option D

Enzymes work by lowering the activation energy required for a reaction to take place. By doing so, they allow more reactant molecules to overcome the activation energy barrier, increasing the rate of the reaction. Therefore, option (d) is the correct answer. In conclusion, enzymes increase the rate of chemical reactions by: d. decreasing the activation energy of the reactants.