Which of the following describes the role of enzymes in biochemical reactions?

• A. They increase the activation energy
• B. They slow down the reaction rate
• C. They act as catalysts
• D. They provide energy for reactions

Answer: (C)

Enzymes are biological catalysts that speed up biochemical reactions by lowering the activation energy required for the reaction to proceed. This allows the reaction to occur more rapidly and efficiently. By providing an alternative reaction pathway with a lower energy threshold, enzymes enhance the rate at which reactants are converted into products without being consumed in the process. This catalytic function is essential for maintaining life, as many biochemical reactions would occur too slowly to support cellular functions if not for the presence of enzymes.

In contrast, the other options inaccurately describe enzyme function. Enzymes do not increase activation energy; instead, they decrease it. They also do not slow down reaction rates but rather accelerate them, and they do not provide energy for reactions; instead, they facilitate the reactions that release or use energy stored in the reactants.