This chapter focuses on the chemistry of the transition metals. These metals play a large role in our day to day lives, but they also play a large role in biology. With a few exceptions, transition metals form the core of many enzymes and other proteins in organisms, while non-transition metals, like Ca, Na, K, perform signaling and structural roles. For discussion this week go out and find examples of transition metals roles in biological systems. Focus on the elements Fe, Ni, Zn, Mn, Cu, and Co.