Pyrimidines are a type of nitrogenous base found in nucleic acids, which are essential for storing and transmitting genetic information. They are one of the two categories of bases in DNA and RNA, the other being purines. The three main pyrimidines are cytosine, thymine, and uracil. These compounds are characterized by a single six-membered ring structure containing nitrogen atoms. Pyrimidines play a crucial role in the formation of nucleotides, the building blocks of DNA and RNA. Their specific pairing with purines ensures the stability and integrity of the genetic code.