How do enzymes catalyze a reaction?

• A. By lowering the $E$_a of the reaction
• B. By providing additional reactants
• C. By changing the equilibrium position of the reaction
• D. By increasing the temperature of the reaction

Answer: (A)

Verified step by step guidance

1. Understand that enzymes are biological catalysts that speed up chemical reactions without being consumed in the process.
2. Recognize that enzymes work by lowering the activation energy of a reaction, which is the energy barrier that must be overcome for a reaction to proceed.
3. Visualize the energy profile of a reaction with and without an enzyme. The presence of an enzyme lowers the peak of the energy barrier, making it easier for reactants to be converted into products.
4. Note that enzymes do not change the equilibrium position of a reaction; they only speed up the rate at which equilibrium is reached.
5. Remember that enzymes do not provide additional reactants or increase the temperature of the reaction. Their primary role is to lower the activation energy, facilitating the reaction under physiological conditions.