Acidic amino acids are -
Proline is a unique amino acid and has an immino group (=NH) instead of an amino (NH2) group found in other amino acid. Methionine & Cysteine are sulfur containing aminoacids. The propey of photochromicity (i.e. absorbance of ultraviolet light at 250-290nm esp 280nm) is seen with aromatic amino acid (tryptophan > tyrosine > phenylalanine). Hydrophobic (non polar) aminoacids have no charge on their R group or side chain. Aliphatic (eg methyl, methylene, thioether & imino) side chains and aromatic side chains are nonpolar. So methyl (CH3) side chain of alanine; propyl (C3H7) side chain of valine; butyl (C4H9) side chain of leuicine & isoleucine; thioether side chain of methionine; and imino group/ pyrrolidine containing side chain of proline are nonpolar. Methyl (CH3) side chain of alanine is nonpolar. Serine, threonine, tyrosine containing hydroxyl group and cysteine containing sulfhydryl group, are polar aminoacids with neutral/uncharged/nonionic side chain. Positively charged basic amino (NH 3+)group side chain of histidine, arginine and lysine ; and negatively acidic carboxyl (COO-) side chain of aspaic acid and glutamic acid is polar.
Asparagine
Arginine
None
Lysine