what are the four nitrogen bases that make up dna
Nucleotides in DNA contain four different nitrogenous bases: Thymine, Cytosine, Adenine, or Guanine. There are two groups of bases: Pyrimidines: Cytosine and Thymine each have a single six-member ring. Purines: Guanine and Adenine each have a double ring made up of a five-atom ring attached by one side to a six-atom ring. The order of nucleotides along DNA polymers encode the genetic information carried by DNA.