This document, titled "AMINO ACIDS" and intended for the BCH201/211 course, provides a comprehensive and detailed overview of amino acids, which are the fundamental building blocks of proteins. It systematically covers their basic chemical structure, stereochemistry, and diverse classification based on the properties of their side chains (R-groups). The document emphasizes the zwitterionic nature of amino acids, explaining how they exist as dipolar ions at physiological pH.

A significant portion of the content is dedicated to the acid-base properties of amino acids, detailing their amphoteric behavior, the concept of pKa values for their ionizable groups, and the crucial role of the isoelectric point (pI). It includes clear explanations of titration curves and the methods for calculating pI for different types of amino acids. Furthermore, the document describes the formation of peptide bonds, the covalent linkages that connect amino acids into polypeptide chains, highlighting the directionality of these chains.

The document also explores various chemical reactions characteristic of amino acids, categorizing them by the functional group involved (alpha-amino, alpha-carboxyl, and R-groups), many of which are utilized in analytical techniques. It differentiates between essential and non-essential amino acids, providing examples and a mnemonic for the essential ones. Finally, it touches upon important amino acid derivatives and outlines common qualitative and quantitative methods used for amino acid analysis, such as chromatography and the ninhydrin reaction, making it a complete resource for understanding the chemistry and biological significance of amino acids.