Which of the following statements is true regarding enzyme effects on chemical reactions?

• A. Enzymes decrease the activation energy of reactions
• B. Enzymes consume substrate during the reaction
• C. Enzymes alter the equilibrium position of reactions
• D. Enzymes always increase the final product yield

Answer: (A)

Enzymes are biological catalysts that play a crucial role in facilitating biochemical reactions by lowering the activation energy required for those reactions to occur. This decrease in activation energy allows the reactions to proceed more quickly and efficiently, enhancing the rate at which products are formed from substrates.

The process works by stabilizing the transition state of the reaction, making it easier for reactants to convert into products. This catalytic action does not alter the overall energy change of the reaction (the difference between products and reactants) or change the inherent equilibrium position of the reaction itself. Instead, enzymes simply allow the reaction to reach equilibrium faster without affecting the equilibrium concentrations of reactants or products.

Understanding this fundamental property of enzymes is crucial in biochemistry, as it highlights how they function to regulate metabolic pathways without being consumed or permanently altered in the process. Therefore, the statement that enzymes decrease the activation energy of reactions is indeed true and reflects the core role of enzymes in biological systems.