Glycine is the exception. The R group in glycine is a lone hydrogen thus the central carbon in glycine is not attached to four unique groups and glycine is achiral. The R group of some amino acids like alanine and valine are simple alkyl groups. Phenylalanine and tyrosine contain benzene rings. Tryptophan and proline contain even more R complex structures.
Some amino acids are polar and some are neutral.
As these amino acids are connected together at the ribosome, they interact according to their properties to form uniquely shaped proteins. Amino acids are connected together at the ribosome with amide and disulfide bonds. This primary linkage forms the backbone of the protein and its primary structure. The secondary structure of proteins involves conformations in localized groups of amino acids. The right-handed alpha helix is a common, naturally occurring secondary structure.