NUCLEOSIDE

Nitrogenous base	Nucleoside	Deoxynucleoside
Chemical structure of adenine Adenine	Chemical structure of adenosine Adenosine A	Chemical structure of deoxyadenosine Deoxyadenosine dA
Chemical structure of guanine Guanine	Chemical structure of guanosine Guanosine G	Chemical structure of deoxyguanosine Deoxyguanosine dG
Chemical structure of thymine Thymine	Chemical structure of 5-methyluridine 5-Methyluridine m5U	Chemical structure of thymidine Deoxythymidine dT
Chemical structure of uracil Uracil	Chemical structure of uridine Uridine U	Chemical structure of deoxyuridine Deoxyuridine dU
Chemical structure of cytosine Cytosine	Chemical structure of cytidine Cytidine C	Chemical structure of deoxycytidine Deoxycytidine dC

'Nucleosides' are glycosylamines made by attaching a nucleobase (often referred to simply as bases) to a ribose or deoxyribose ring. Examples of these include cytidine, uridine, adenosine, guanosine, thymidine and inosine. In short, a nucleoside is a base linked to sugar.
Nucleosides can be phosphorylated by specific kinases in the cell, producing nucleotides, which are the molecular building blocks of DNA and RNA.
Nucleosides are produced as the second step in nucleic acid digestion, whereby nucleotidases break down ''nucleotides'' (such as the thymine nucleotide) into ''nucleosides'' (such as thymidine) and phosphate. The nucleosides, in turn, are subsequently broken down

★ in the lumen of the digestive system by nucleosidases into nitrogenous bases and ribose (or deoxyribose), and

★ inside the cell by nucleoside phosphorylases into nitrogenous bases, and ribose-1-phosphate (or deoxyribose-1-phosphate).
Nucleosides can be produced by combining nucleobases with deoxyribose rings as well.
Nucleosides differ from nucleotides by having a hydroxyl group attached to carbon number 5 (the one that isn't in the ring) of the ribose, rather than one or more phosphate groups.

Contents

See also

See also

★ Nucleobase

★ Nucleotide

★ RNA

★ Adenosine triphosphate (ATP)