Final answer:
Enzymes reduce the activation energy necessary for a reaction, facilitating the creation of a transition state intermediate and allowing reactions to occur more quickly and under mild conditions.
Step-by-step explanation:
Enzymes catalyze a chemical reaction by lowering the activation energy because they provide conditions favorable for the formation of a transient intermediate called the transition state.
By binding to substrates at the active site, enzymes bring about the required orientation and provide an alternative pathway with lower activation energy, enabling reactions to proceed more quickly and efficiently under physiological conditions. The induced fit model explains that enzymes can make slight adjustments to fit their substrates, which enhances catalysis.