macromolecules
Functional Groups Functional groups are groups of atoms that occur within molecules and confer specific chemical properties to those molecules. They are found along the carbon backbone of macromolecules. This carbon backbone is formed by chains and/or rings of carbon atoms with the occasional substitution of an element such as nitrogen or oxygen. Molecules with other elements in their carbon backbone are substituted hydrocarbons. The functional groups in a macromolecule are usually attached to the carbon backbone at one or several different places along its chain and/or ring structure. Each of the four types of macromoleculesproteins, lipids, carbohydrates, and nucleic acidshas its own characteristic set of functional groups that contributes greatly to its differing chemical properties and its function in living organisms.