nukleot

Nukleot is a term used in some languages to refer to a nucleotide, the fundamental building block of nucleic acids such as DNA and RNA. Each nukleot consists of three components: a five‑carbon sugar (deoxyribose in DNA, ribose in RNA), a phosphate group, and a nitrogenous base (adenine, cytosine, guanine, and thymine in DNA; adenine, cytosine, guanine, and uracil in RNA).

Nukleot forms polymers by linking the sugar of one unit to the phosphate of the next via phosphodiester bonds, creating the backbone of nucleic acids. In DNA and RNA, sequences of nukleot encode genetic information. The two strands in DNA are complementary, with A pairing with T and G with C; in RNA, A pairs with U and G with C. The sugar, base, and phosphate composition also allows the existence of nucleotides in mono-, di-, or triphosphate forms, the latter providing energy for synthesis and other cellular processes (as in ATP and GTP).

Beyond information storage, certain nukleot play roles in cellular signaling and metabolism. Cyclic nucleotides such as cyclic AMP and cyclic GMP act as second messengers; nucleotide triphosphates serve as energy carriers; many cofactors are built from nucleotide subunits, including NAD+, FAD, and coenzyme A derivatives.

Cells synthesize nukleot via de novo pathways or salvage pathways that recycle bases and nucleosides from degraded nucleic acids. Abnormalities in nukleot metabolism can affect DNA replication, RNA transcription, and energy balance, with implications for growth and disease.