Metabolites are small molecules produced during the process of metabolism, which is how living organisms convert food into energy and other necessary substances. They can be categorized into primary metabolites, essential for growth and development, and secondary metabolites, which often play roles in defense or signaling. These compounds are crucial for various biological functions and can be found in all forms of life, from plants to animals. Examples of metabolites include amino acids, lipids, and carbohydrates. Scientists study metabolites to understand health, disease, and the effects of different substances on living organisms.