Chirality in Amino Acids
What causes chirality "handedness"?
If an atom such as carbon, silicon, nitrogen, phosphorus or
sulphur forms a tetrahedral structure with four different groups attached
then two non-superimposable mirror images will be formed. The most common
and simplest example of this is with carbon. The diagram below shows that
there is no way that you can put the two molecules on top of one another and
have all the groups lined up. One molecule is the mirror image of the other
one.
This is an example of a molecule with a chiral centre.
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Compare the two amino acids below (glycine and alanine). Which one shows chirality?
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