One of the basic classes of substances studied in biochemistry.
Nucleic acid, so called because of its prevalence in cellular nuclei, is the generic name of family of biopolymers. The monomers are called nucleotides, and each consists of three components: a nitrogenous heterocyclic base (either a purine or a pyrimidine), a pentose sugar, and a phosphate group. Different nucleic acid types differ in the specific sugar found in their chain (e.g. DNA or deoxyribonucleic acid contains 2'-deoxyriboses). The sugars and phosphates in nucleic acids are connected to each other in an alternating chain:
through shared oxygens (forming a phosphodiester functional group) Using the conventional nomenclature, the carbons to which the phosphate groups are attached are the 3' and the 5' carbons.
The bases are pendant from a glycosidic linkage to the 1' carbon of the pentose ring.