Enzymes are biocatalysts made up mostly of protein that facilitate chemical reactions by lowering the activation energy required for the reactions to occur. Living organisms require these facilitators because they cannot provide the high amount of activation energy needed by themselves.
The name "enzyme" comes from the observation that yeast introduced into fruit sap converted it into alcohol. This action of enzymes allows biological reactions to proceed rapidly at relatively low temperatures and pressures that are tolerable for living organisms.
