What is the main function of enzymes in biological reactions?

Enzymes primarily function to decrease the activation energy required for biological reactions. This is significant because activation energy is the energy barrier that must be overcome for a reaction to proceed. By lowering this barrier, enzymes allow reactions to occur more readily and efficiently, facilitating metabolic processes within living organisms.

When the activation energy is decreased, the reaction can occur at a much faster rate and under milder conditions than would otherwise be possible. This is crucial for sustaining life, as many biochemical reactions need to happen quickly and at temperatures that are compatible with cellular functions. Enzymes achieve this by binding to substrates and stabilizing the transition states, thus making it easier for the transformation to occur.

While increasing substrate concentration can enhance the rate of reactions, it is not the primary role of enzymes. They are not reactants themselves nor do they provide energy for reactions; rather, they function as catalysts that remain unchanged after the reaction is completed, ready to facilitate further reactions. This distinction highlights the unique and essential role that enzymes play in biological systems.