The Amino Acids Which Occur in Proteins

Question

The amino acids which occur in proteins
A) are all of the L- form.
B) are all of the D- form.
C) can be either the L- or D- form.
D) do not have L- and D- forms.

Accepted Answer

The amino acids that occur in proteins are all of the L-form, except for glycine which does not have an L or D form because its R group is a hydrogen atom. The D-form of amino acids may occur naturally in some organisms, but they are not typically found in proteins.