Nobel Prize-winning chemist Thomas Cech will speak June 19 at this year's commencement ceremony for the Division of Biological Sciences at UC Davis. His speech is titled "Commence to Educate." A professor at the University of Colorado, Boulder, Cech discovered that the genetic material RNA -- a non-protein molecule that "reads" the genetic blueprint contained in DNA -- can catalyze changes in its own structure. This research provided the first example of catalytic activity in a molecule other than protein and earned Cech the 1989 Nobel Prize in Chemistry, which he shared with Canadian Sydney Altman of Yale University. Approximately 600 students are expected to graduate at the commencement, scheduled for 2:30 p.m. in Recreation Hall at UC Davis.