DNA contains the sugar deoxyribose, while RNA contains the sugar ribose. The nitrogen bases for DNA are adenine, uracil, guanine, thymine, and cytosine. RNA and DNA have three identical bases such as a adenine, cytosine and guanine. The fourth base for RNA is uracil in DNA it is thymine. Uracil lacks a methyl group. Adenine and Guanine are purines, Cytosine, Thiamine, and Uracil are pyrimidines, which are smaller.