Activation energy is defined as the energy barrier that must be overcome for a reaction to proceed. How do enzymes affect this barrier?

• A. Activation energy is the energy barrier that must be overcome for a reaction to proceed; enzymes lower activation energy by stabilizing transition states and bringing substrates together.
• B. Activation energy is the energy barrier that must be overcome for a reaction to proceed; enzymes increase activation energy to speed up reactions.
• C. Activation energy is the energy released during a reaction.
• D. Activation energy is not relevant to enzyme-catalyzed reactions.

Answer: (A)