cýtósín

Cytosine is one of the four main bases found in DNA and RNA. Its chemical formula is C4H5N3O. Cytosine is a pyrimidine derivative, meaning it has a two-ring structure. In DNA, cytosine always pairs with guanine through three hydrogen bonds, forming a complementary base pair. This pairing is crucial for the stability and replication of genetic material. In RNA, cytosine also pairs with guanine. Cytosine is synthesized from carbamoyl phosphate and aspartate. It is a fundamental component of the genetic code, carrying information from one generation to the next. Modifications to cytosine, such as methylation, play a significant role in gene regulation and epigenetics. These modifications can affect gene expression without altering the underlying DNA sequence. Cytosine's presence and interactions are essential for the processes of transcription and translation, which are central to protein synthesis. It is found in all living organisms and is a universal building block of nucleic acids.