An overview of the structure and function of proteins. Beginning with a discussion of some key research methods for studying proteins, including column chromatography, electrophoresis, and x-ray crystallography, we then discuss the structure of proteins, with a focus on secondary structure, motifs, structural domains, and quaternary structure. The episode concludes with a look at protein function, including protein folding, denaturation, enzymatic function, and allosteric regulation. Recommended pre-requisites are Episode 18: Biochemistry Basics, and Episode 10: The Cell. Episode 32: Light and Optics may also be helpful for the crystallography portion.