These pairs are : adenine (purine) with thymine (pyrimidine ... we devised our structure, which rests mainly though not entirely on published experimental data and stereo-chemical arguments.

Both uracil and thymine pair with adenine, but they differ in their chemical structure. Thymine has an additional methyl group (-CH3) attached to its pyrimidine ring, while uracil lacks this group.

This image depicts the chemical structure of cytosine. It shows a hexagonal ring with ... For example, a point mutation where cytosine is replaced by thymine (C-to-T transition) is a common cause of ...