DNA, also known as deoxyribonucleic acid, belongs to a class of polymeric organic macromolecules called nucleic acids. The only other member of this class is ribonucleic acid, or RNA. Nucleic acids were first discovered in 1869 by the Swiss scientist Friedrich Miescher.
DNA and RNA play important roles as genetic information carriers in biology, enabling the mechanisms of heredity and protein synthesis. Nucleic acids are polymers of nucleotides, which are composed of a five-carbon sugar, also called a pentose sugar, a nitrogenous base and a phosphate group. The sugar is deoxyribose, in the case of DNA, and ribose, in the case of RNA.