Date : 2012. 12. 6, 5:00 PM Place : Mogam Hall, Bldg.500 -Abstract- Over the last 40 years as a chemist, I dealt with various chemical species present in simple and complex systems at 10 part per million level. As a graduate student at Chicago, I studied an extremely well defined quantum mechanical system, at the uncertainty limit, of Nd2+ ions imbedded in LaCl3 crystal at about 10 ppm level. As a postdoc at MIT, I lived with amino acyl-tRNA synthetase present at 10 ppm level in E. coli cells. Then as a senior chemist at a U.S. federal laboratory at Natick, Massachusetts, I invented an internationally accepted method for analysis of sulfite ion present at 10 ppm level in foods. Finally at SNU, I have been studying changes in proteins present at 10 ppm level in plant and animal cells. This breadth of experience gave me an appreciation of the central place of chemistry in science and a new pedagogy of teaching chemistry as a center piece in understanding life in the universe.