Nucleic acids are the polymers of nucleotides and they are joined together by a phosphodiester linkage. Nucleotides are the structural units of nucleic acids and are composed of a nitrogenous base, pentose i.e.,five carbon sugar either ribose or 2′-deoxyribose and a phosphate group.
Chemical composition of nucleic acid
When DNA (or RNA) is completely hydrolyzed, it produces phosphoric acid, a pentose sugar, and a nitrogenous base.
The sugar moiety in DNA molecules is -D-2-deoxyribose, whereas it is -D-ribose in RNA molecules.