Which property of enzymes allows them to increase reaction rates?

• A. Their ability to absorb heat
• B. Their catalytic action
• C. Their structural complexity
• D. Their ability to change the pH

Answer: (B)

Enzymes are specialized biological catalysts that increase the rates of chemical reactions without being consumed in the process. Their catalytic action is fundamental to their function. Enzymes lower the activation energy required for a reaction to occur, which allows reactants to convert into products more quickly. This is accomplished through various mechanisms, such as stabilizing the transition state or providing an optimal environment for the reaction to take place.

While structural complexity may contribute to the specificity and efficiency of an enzyme, it is not the primary reason for their ability to speed up reactions. Additionally, enzymes do not absorb heat to enhance reaction rates; rather, they function optimally at specific temperatures and conditions. Lastly, changing the pH can affect the activity of an enzyme, but it is not a mechanism by which enzymes themselves increase reaction rates. Instead, each enzyme has an optimal pH at which it is most active. Thus, the catalytic action is the direct property that enables enzymes to effectively speed up reactions.