Structure Of Dna And Rna

The nitrogenous bases present in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T). Uracil (U) is a nitrogenous base found in RNA, not in DNA. Cyclosine, although sounding similar to cytosine, is not a known nitrogenous base in either RNA or DNA. Thus, Cyclosine is the nitrogen base not present in DNA.