What are heterocyclic organic carbon compounds? Explain with examples.

(N/A) Heterocyclic compounds are organic compounds that contain at least one atom other than carbon (such as nitrogen,oxygen,or sulfur) within their ring structure.
In living organisms,many important biomolecules contain heterocyclic rings. Nitrogenous bases are classic examples of such compounds.
Nitrogenous bases include purines (e.g.,Adenine,Guanine) and pyrimidines (e.g.,Cytosine,Uracil,Thymine).
When a nitrogenous base is attached to a sugar molecule,it forms a nucleoside (e.g.,Adenosine,Guanosine,Thymidine,Uridine,Cytidine).
When a phosphate group is also esterified to the sugar of a nucleoside,it forms a nucleotide (e.g.,Adenylic acid,Thymidylic acid,Guanylic acid,Uridylic acid,Cytidylic acid).
Nucleic acids like $DNA$ and $RNA$ are polymers of nucleotides and serve as the genetic material in living organisms.