Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows; thus, a crossword puzzle was developed to connect some of the fundamental properties of the standard amino acids (composition of the side chains) with some of the latter, metabolic properties. (Contains 1 note and 2 figures.)