This document discusses amino acids and proteins. It explains that in amino acids, the carboxylic acid closest to the amine group is the stronger acid because its conjugate base is more stable due to electron delocalization. Similarly, the amine group closest to the carboxylic acid is the stronger acid because the carboxylic acid withdraws electron density from the amine, making it a weaker base. The document also defines the 10/20/30/40 structure of proteins as involving primary, secondary, tertiary and quaternary levels of structure and describes alpha helices and beta pleated sheets. It compares acid/base hydrolysis to enzyme cleavage in digesting proteins, noting enzyme cleavage is more selective.