In biology the roles of transition metal ions can be broadly

In biology, the roles of transition metal ions can be broadly grouped into two classifications: redox chemistry (catalysis, electron transfer, etc.) and acid-base chemistry (catalysis, structural, etc.).

(a) List three metal ions that commonly participate in biological redox chemistry, and give examples of how they participate.

(b) Compare this list to metal ions commonly participating in acid-base chemistry. Discuss the overlap of these two groups of metal ions. (e.g., why are some used for one of these functions and not for the other?)

(c) List some common biological ligands of these metal ions. Can you see patterns that would allow you to group these ligands into sets with common properties, or that bind common metals?

(d) Why are trace metals used for these biological functions, and not other more-abundant elements like C, N, O, etc?

Solution

(d) the trace elements Ike carbon, nitrogen, oxygen etc have filled orbital due to which the exchange of eletrons between them and enzyme does not take place resulting in not binding with enzymes whereas in transition elements they have empty d-orbitals which help in exchange of electrons and making bond..

(a) zinc, iron, cadmium, arsenic, copper, manganese etc are the transition metals used.

(c) arsenic are used in gluthaione peroxidase which kills the superoxide, hydrogen peroxide etc. Iron binds with hemoglobin which helps in transportation of blood..!!