individualnucleotide

An individual nucleotide is the basic unit of nucleic acids such as DNA and RNA. It comprises three components: a five‑carbon sugar (deoxyribose in DNA or ribose in RNA), a nitrogenous base, and a phosphate group. The sugar provides the backbone of the molecule, the base carries the genetic information, and the phosphate group links nucleotides together through phosphodiester bonds. In DNA and RNA, the sugar is connected to a single nitrogenous base, and the phosphate attaches to the 5’ carbon of the sugar.

The nitrogenous bases fall into two categories: purines, which include adenine and guanine, and pyrimidines, which include cytosine, thymine (in DNA), and uracil (in RNA). In DNA, adenine pairs with thymine and cytosine pairs with guanine through hydrogen bonds; in RNA, adenine pairs with uracil, while cytosine still pairs with guanine. These base-pairing rules enable the double-helix structure of DNA and the transcription of genetic information into RNA.

Beyond serving as monomers for nucleic acids, individual nucleotides also function in cellular metabolism. Triphosphate forms such as ATP and GTP store and transfer energy and act as signaling molecules. Other nucleotide-derived cofactors, including NAD+, FAD, and CoA, participate in a wide range of enzymatic reactions. Free nucleotides and nucleotide salvage pathways maintain the supply of monomers needed for nucleic acid synthesis and cellular function.