Nucleobases are nitrogen-containing biological compounds (nitrogenous bases) found linked to a sugar within nucleosides—the basic building blocks of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Often simply called bases in genetics, their ability to form base pairs and to stack upon one another lead directly to the helical structure of DNA and RNA.

Nucleobases are nitrogen-containing biological compounds (nitrogenous bases) found linked to a sugar within nucleosides—the basic building blocks of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Often simply called bases in genetics, their ability to form base pairs and to stack upon one another lead directly to the helical structure of DNA and RNA.