As I've stated in another post, we have this odd first semester course that is a hybrid between a sophomore descriptive inorganic chemistry course and general chemistry. Since this course is the ONLY inorganic course that our biochemistry majors are exposed to, I want to give them a flavor of why inorganic chemistry is important to their field. Some of the topics that I have typically taught with bioinorganic applications include: acidity of metal ions and bioavailability, HSAB, types of ligands and the chelate effect, and hemoglobin as a case study in coordination chemistry. I've sometimes done some redox applications as well. Anyone have any particularly fun bioinorganic chemistry applications that are accessible to approximately a sophomore level course (perhaps with an appropriate article for the students to read)? --Hilary