Editing Nucleotide (section)

{{Short description|Biological molecules constituting nucleic acids}}
{{Distinguish|nucleoside|nucleobase}}
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[[File:DAMP chemical structure.svg|thumb|275px|class=skin-invert-image|This nucleotide contains the five-carbon sugar [[deoxyribose]] (at center), a [[nucleobase]] called [[adenine]] (upper right), and one [[phosphate]] group (left). The deoxyribose sugar joined only to the nitrogenous base forms a <u title="Nucleotide">[[Deoxyribonucleoside]]</u>  called [[deoxyadenosine]], whereas the whole structure along with the phosphate group is a <u title="Deoxyadenosine monophosphate" href="deoxyadenosine monophosphate">nucleotide</u>, a constituent of DNA with the name [[deoxyadenosine monophosphate]].]]

'''Nucleotides''' are [[Organic compound|organic molecules]] composed of a nitrogenous base, a [[pentose]] sugar and a [[phosphate]]. They serve as [[monomer]]ic units of the [[nucleic acid]] [[polymers]] – [[deoxyribonucleic acid]] (DNA) and [[ribonucleic acid]] (RNA),  both of which are essential [[biomolecules]] within all [[Life|life-forms]] on Earth. Nucleotides are obtained in the diet and are also synthesized from common [[Nutrient|nutrients]] by the [[liver]].<ref name="easy-peasy" />

Nucleotides are composed of three subunit molecules: a [[nucleobase]], a [[pentose|five-carbon sugar]] ([[ribose]] or [[deoxyribose]]), and a phosphate group consisting of one to three [[phosphate]]s.  The four nucleobases in DNA are [[guanine]], [[adenine]], [[cytosine]], and [[thymine]]; in RNA, [[uracil]] is used in place of thymine.

Nucleotides also play a central role in [[metabolism]] at a fundamental, cellular level. They provide chemical energy—in the form of the [[nucleoside triphosphate]]s, [[adenosine triphosphate]] (ATP), [[guanosine triphosphate]] (GTP), [[cytidine triphosphate]] (CTP), and [[uridine triphosphate]] (UTP)—throughout the cell for the many cellular functions that demand energy, including: [[amino acid]], [[protein]] and [[cell membrane]] synthesis, moving the cell and cell parts (both internally and intercellularly), cell division, etc..<ref name=Alberts>Alberts B, Johnson A, Lewis J, Raff M, Roberts K & Walter P (2002). ''Molecular Biology of the Cell'' (4th ed.). Garland Science. {{ISBN|0-8153-3218-1}}. pp. 120–121.</ref> In addition, nucleotides participate in [[cell signaling]] ([[cyclic guanosine monophosphate]] or cGMP and [[cyclic adenosine monophosphate]] or cAMP) and are incorporated into important [[Cofactor (biochemistry)|cofactors]] of enzymatic reactions (e.g., [[coenzyme A]], [[flavin adenine dinucleotide|FAD]], [[flavin mononucleotide|FMN]], [[nicotinamide adenine dinucleotide|NAD]], and [[NADP+|NADP<sup>+</sup>]]).

In experimental [[biochemistry]], nucleotides can be [[radiolabeled]] using [[radionuclide]]s to yield radionucleotides.

'''5-nucleotides''' are also used in [[flavour enhancer]]s as [[food additive]] to enhance the [[umami]] taste, often in the form of a yeast extract.<ref name="nucleotides-flavour-2017">{{Cite journal | vauthors = Abd El-Aleem FS, Taher MS, Lotfy SN, El-Massry KF, Fadel HH |date=2017-12-18 |title=Influence of extracted 5-nucleotides on aroma compounds and flavour acceptability of real beef soup |journal=International Journal of Food Properties |volume=20 |issue=sup1 |pages=S1182–S1194 |doi=10.1080/10942912.2017.1286506|s2cid=100497537 |doi-access=free }}</ref>