Step 1: Define a chiral center.A chiral center, also known as an asymmetric carbon, is a carbon atom bonded to four distinct atoms or groups of atoms.
Step 2: Examine the basic amino acid structure.Amino acids consist of a central \(\alpha\)-carbon atom bonded to an amino group (-NH\(_2\)), a carboxyl group (-COOH), a hydrogen atom (-H), and a variable R group.
Step 3: Analyze chirality requirements.The \(\alpha\)-carbon is chiral only if all four attached groups are different. Thus, the R group must differ from -H, -NH\(_2\), and -COOH.
Step 4: Identify the exception to chirality.In Glycine, the R group is a hydrogen atom (-H). Consequently, the \(\alpha\)-carbon in glycine is attached to two identical hydrogen atoms. This makes glycine's \(\alpha\)-carbon achiral, and glycine itself is an achiral molecule. All other standard amino acids have dissimilar R groups, rendering their \(\alpha\)-carbons chiral.