Smithsonian Institution - United States National Museum - Bulletin 240 / Contributions From the Museum of History and Technology / Papers 34-44 on Science and Technology

by Museum of History and Technology

Purine	Pyrimidine
(reduced) Adenine	+	(oxidized) Thymine
(oxidized) Guanine	+	(reduced) Cytosine

Pyrimidine

Purine

Adenine

Guanine