BIOMOLECULES

Life, despite its astounding diversity, is fundamentally chemistry. The atoms that compose living things—carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur—are identical to those in non-living matter. Yet life arranges these atoms into structures and combinations producing emergent properties absent in non-living chemistry. A protein is "simply" carbon, hydrogen, oxygen, nitrogen, and sulfur arranged in a specific sequence. Yet this arrangement enables an enzyme to catalyze reactions, an antibody to recognize pathogens, or a motor protein to generate movement.

Biomolecules are organic compounds synthesized by living organisms. The main categories—carbohydrates, lipids, proteins, and nucleic acids—are known as macromolecules because of their large size. Understanding biomolecular structure explains biological function; understanding biological function requires understanding molecular structure.