Carbon: The Backbone of Life
Carbon is the star player in biological chemistry. Any compound containing carbon is an organic compound, and these form the four major classes of biological molecules: carbohydrates, lipids, proteins, and nucleic acids. Carbon's unique bonding properties allow it to form an enormous variety of molecules.
Hydrocarbons, made only of carbon and hydrogen, serve as energy-rich molecules in organisms. Carbon's versatility allows different arrangements of the same atoms to form isomers - compounds with identical molecular formulas but different structures and properties. Structural isomers differ in how their atoms are connected, creating diverse molecules with different functions.
The properties of carbon-containing molecules are largely determined by their functional groups - specific configurations of atoms that behave predictably in chemical reactions. Key functional groups include hydroxyl −OH, carboxyl −COOH, amino −NH2, and carbonyl C=O groups. Each gives unique properties to the molecules containing them.
⚡ ATP (adenosine triphosphate) is the energy currency of cells. When its bonds break during hydrolysis, they release energy that powers nearly all cellular work!
Biological molecules are often polymers - large molecules built from smaller, similar building blocks called monomers. These monomers join through dehydration reactions, which release water molecules. The reverse process, hydrolysis, breaks polymers back into monomers by adding water, making biological molecules both buildable and recyclable.