Final answer:
Enzymes accelerate chemical reactions by lowering the activation energy, which increases the reaction rate without changing the reactants or final products. They operate by forming an enzyme-substrate complex, providing an optimal environment, and in some cases, participating directly in the reaction.
Step-by-step explanation:
Enzymes are biological catalysts that significantly speed up the rate of chemical reactions by lowering the activation energy required for the reaction to proceed. They accomplish this by forming an enzyme-substrate complex that reduces the activation energy barrier that would otherwise need to be overcome. This process is facilitated by the unique structure of the enzyme's active site, which binds the substrate molecules in an optimal orientation, creates an ideal chemical environment for the reaction, and may even participate directly in the chemical reaction.
Enzymes do not change the reactants or the final products of a reaction, but they do enable reactions to occur more quickly and under less extreme conditions than would otherwise be required. This is critical for sustaining life, as it allows biological processes to occur at speeds that are compatible with life.