Biochemical substances are the molecules that make up living organisms and are essential for life. They include proteins, carbohydrates, lipids, and nucleic acids, each playing a crucial role in biological processes. For example, proteins help build and repair tissues, while carbohydrates provide energy. These substances are involved in various metabolic pathways, enabling cells to function properly. Enzymes, a type of protein, act as catalysts to speed up chemical reactions, while DNA and RNA are vital for storing and transmitting genetic information. Understanding these biochemical substances is fundamental to fields like biochemistry and molecular biology.