So this is what an alpha amino acid is. It contains the center carbon, that is an alpha carbon, that is, it is attached to this carbon of this carbonyl group, as shown in the following diagram. Now, alphamino acids usually contain a Chiral carbon and the only exception is Glycine, because in Glycine, this R group is a simple H atom. So let's remember what Chiral groups are. A Chiral carbon is a carbon that contains four different groups attached to that carbon. So in this particular case, one of these groups is the carboxylic acid.