How do enzymes affect biological reactions?

Enzymes are biological catalysts that significantly speed up the rate of chemical reactions in living organisms without undergoing permanent changes themselves. They achieve this by lowering the activation energy required for a reaction to proceed, making it more likely to occur at a given temperature and pressure. This catalytic action is crucial for facilitating various biochemical processes, such as metabolism, cellular respiration, and DNA replication, among others.

The correct assertion that enzymes act as catalysts emphasizes their role in enhancing reaction rates. They do not get consumed in these reactions, meaning they can be used repeatedly. This characteristic makes them incredibly efficient and allows biological systems to regulate and accelerate essential life processes effectively.

Although some of the other options touch on aspects related to enzymes, such as their involvement in the conversion of reactants into products, they do not capture the fundamental role enzymes play in catalytic activity and reaction kinetics. Enzymes do not provide energy for reactions or slow them down; instead, they facilitate the transformation of reactants to products at an accelerated pace.