If such bonds are broken the protein may be denatured. Typically the flow of genetic information moves from DNA to RNA to protein. However, certain exceptions to this rule exist in the microbial world. For example, retroviruses possess RNA as their genetic instructions and reverse transcribe it into a DNA form. Prion agents possess no known nucleic acid at all, yet seemingly have the ability to replicate.
Nitrogenous bases are either pyrimidines or purines.
Pyrimidines include thymine and cytosine. Purines include adenine and guanine. DNA consists of 2 strands of nucleotides wound in a double helix in antiparallel array.