View source for Polar amino acids

'''&nbsp;Polar amino acids'''<br>There are twenty amino acids, five of which are polar but uncharged. Two of which contain a [[Hydroxyl group|hydroxyl group]] (-OH) attached to [[Aliphatic side chain|aliphatic side chain]] that is ''[[Serine|serine]] ''and ''[[Threonine|threonine]]''. As for the [[Asparagine|''asparagine'']] and [[Glutamine|''glutamine'']] they contain a terminal carboxamide in place of carboxylic acid. The fifth polar amino acid is ''[[Cysteine|cysteine]]'' that is structurally similar to [[Serine|serine]] but contain a [[Sulfhydryl|sulfhydryl]], or [[Thiol|thiol]] (-SH), instead of the [[Hydroxyl|hydroxyl]] (-OH) group&nbsp;<ref>Berg J., Tymoczko J and Stryer L, (2007) Biochemisty, 6th edition, New York: WH freeman.</ref>. &lt;/b&gt; All amino acids in solutions of a neutral pH form dipolar ions called zwitterions, the amine group being positive and the carboxyl group negative. 

'''Polar amino acids''' 

{| border="1" cellspacing="1" cellpadding="1" width="200"
|-
| [[Serine|Serine]] 
| Ser 
| S
|-
| [[Cysteine|Cysteine]] 
| Cys 
| C
|-
| [[Threonine|Threonine]] 
| Thr 
| T
|-
| [[Glutamine|Glutamine]] 
| Gln 
| Q
|-
| [[Asparagine|Asparagine]] 
| Asn 
| N
|}

=== References  ===

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