Biologically active molecules are compounds that have an effect on living organisms. These molecules can influence biological processes, such as metabolism, cell signaling, and immune responses. Examples include hormones, enzymes, and neurotransmitters, which play crucial roles in maintaining health and regulating bodily functions. Many biologically active molecules are found in nature, such as those derived from plants, like alkaloids and flavonoids. These compounds can have therapeutic effects and are often studied for their potential in medicine. Understanding these molecules helps researchers develop new drugs and treatments for various diseases.