Proteins are the workhorses of the cell and, as might be anticipated, possess a wide variety of structures and functions. Select all of the factors below that help explain this rich diversity in protein structure and function. Proteins can have one or more polypeptide chains. Polypeptide chains vary widely in length. Proteins are composed of sequences of 20 different amino acids that vary in their order in a polypeptide chain. Proteins are composed of amino acids that all have a central a carbon