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A nucleoside is a unit made up of a [[Deoxyribose sugar|deoxyribose sugar]] and a [[Base|base]] bonded together. If the base is a [[Purine|purine]], then it is attached to the sugar's C-1 by N-9 or if the base is a [[Pyrimidine|pyrimidine]] then it is attached to the sugar's C-1 by N-1.  
A nucleoside is a unit made up of a [[Pentose|pentose]] [[Sugar|sugar]] (ribose or deoxyribose) and a nitrogenous [[Base|base]] (purine or pyrimidine), which are attatched by a ß N-[[Glycosidic bond|glycosidic linkage]] (the base is above the plane of the sugar). The sugar will be either [[Ribose|ribose]] (for [[RNA|RNA]] nucleosides) or [[Deoxyribose|deoxyribose]] (for [[DNA|DNA]] nucleosides). If the base is a [[Purine|purine]], then it is attached to C-1' by N-9, and if the base is a [[Pyrimidine|pyrimidine]] then it is attached to C-1' by N-1.  


There are four [[Nucleoside|nucleoside]] units in [[RNA|RNA]]&nbsp;and they are known as [[Adenosine|adenosine]], [[Guanosine|guanosine]], [[Cytidine|cytidine]]&nbsp;and [[Uridine|uridine]]. The four [[nucleoside|nucleoside]] units in [[DNA|DNA]] are called [[Deoxyadenosine|deoxyadenosine]], [[Deoxyguanosine|deoxyguanosine]], [[Deoxycytidine|deoxycytidine]]&nbsp;and [[Thymidine|thymidine]]. When a [[Nucloside|nucloside]] has a [[Phosphate|phosphate]] group attached to the C5 of its [[Deoxyribose sugar|deoxyribose sugar]], it is then called a [[Nucleotide|nucleotide]], which is a&nbsp;[[Monomer|monomer]] of [[Nucleic acid|nucleic acid]]&nbsp;<ref>Berg et al, Biochemistry, 6th Edition, New York: W.H. Freeman and Company, 2007</ref><br>  
There are four nucleoside units in [[RNA|RNA]] - [[Adenosine|adenosine]], [[Guanosine|guanosine]], [[Cytidine|cytidine]] and [[Uridine|uridine]]. The four nucleoside units in [[DNA|DNA]] are called [[Deoxyadenosine|deoxyadenosine]], [[Deoxyguanosine|deoxyguanosine]], [[Deoxycytidine|deoxycytidine]] and [[Thymidine|thymidine]]. A nucleoside can have a [[Phosphate|phosphate]] group attached to the C-5' through a [[Condensation reaction|condensation reaction]], producing a [[Nucleotide|nucleotide]], a [[Monomer|monomer]] of [[Nucleic acid|nucleic acid]]<ref>Berg et al, Biochemistry, 6th Edition, New York: W.H. Freeman and Company, 2007</ref><ref>Berg JM, Tymoczko JL and Stryer L, 2012, Biochemistry 7th edition, NY, W. H Freeman and Company, page 115</ref>.


=== References<br> ===
=== References  ===


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Latest revision as of 00:40, 10 December 2018

A nucleoside is a unit made up of a pentose sugar (ribose or deoxyribose) and a nitrogenous base (purine or pyrimidine), which are attatched by a ß N-glycosidic linkage (the base is above the plane of the sugar). The sugar will be either ribose (for RNA nucleosides) or deoxyribose (for DNA nucleosides). If the base is a purine, then it is attached to C-1' by N-9, and if the base is a pyrimidine then it is attached to C-1' by N-1.

There are four nucleoside units in RNA - adenosine, guanosine, cytidine and uridine. The four nucleoside units in DNA are called deoxyadenosine, deoxyguanosine, deoxycytidine and thymidine. A nucleoside can have a phosphate group attached to the C-5' through a condensation reaction, producing a nucleotide, a monomer of nucleic acid[1][2].

References

  1. Berg et al, Biochemistry, 6th Edition, New York: W.H. Freeman and Company, 2007
  2. Berg JM, Tymoczko JL and Stryer L, 2012, Biochemistry 7th edition, NY, W. H Freeman and Company, page 115