Which of the following general structures represents the type of amino acid obtained by the complete hydrolysis of naturally occurring proteins?

Step-by-step solution

Proteins are natural polymers of -amino acids linked by peptide bonds. Upon complete hydrolysis, they yield -amino acids. In an -amino acid, both the amino group ( - NH ₂ ) and the carboxyl group ( - COOH ) are attached to the same carbon atom (the -carbon). Among the given options, R - CH ( NH ₂)- COOH has both functional groups on the same carbon, representing an -amino acid. The other structures represent a -amino acid, a -amino acid, and an amide, respectively. Answer: R - CH ( NH ₂)- COOH