DNA is fundamental to the biology of all life on Earth, but how many of us actually know what it is or what it's made of?

This diagram depicts the chemical structure of pyrimidine, a six-membered aromatic ring with two nitrogen atoms at positions 1 and 3 ... can then be further processed to form the pyrimidine bases ...

This image illustrates the chemical structure of a purine molecule, highlighting the numbering of the carbon and nitrogen atoms ... In DNA and RNA, purines pair with their complementary pyrimidine ...