adenine NH Bases in dna H pure Adenine(a) purines 9 Guanine) cytosine NH yrimidine Cytosine(C)∵ H H pyrimidines thymine Thymine(t) 004 Pearson Education, Inc, publishing as benjarBases in DNA purines pyrimidines Adenine (A) Guanine (G) Cytosine (C) Thymine (T) N9 N1