Final answer:
Amino acids possess unique properties predominantly determined by their side chains, with glycine having a neutral side chain, cysteine being able to form disulfide bonds, and histidine, lysine, and arginine considered basic due to their charged side chains.
Step-by-step explanation:
The chemical nature of the side chain significantly influences the properties of amino acids. For instance, glycine (G) is unique as it is the only proteinogenic amino acid that lacks a chiral center due to its hydrogen atom R-group, making it neutral. Cysteine (C), known for its ability to form disulfide bonds through the oxidation of its sulfhydryl (SH) group, is generally nonpolar and hydrophobic.
Meanwhile, histidine (H), lysine (K), and arginine (R) have side chains that are positively charged at physiological pH, classifying them as basic amino acids with hydrophilic properties.
All amino acids share a general structure, each containing an amino group and a carboxyl group, allowing them to function as buffers in the body's acid-base balance. The distinctive features of amino acids are attributed to their unique side chains or R-groups, which can range in size, charge, and polarity. These differences dictate how amino acids interact with each other and contribute to the structure and function of proteins.