Discovery of ribozymes (ribonucleic acid enzymes). Cech discovered that RNA itself could cut strands of RNA, suggesting that life might have started as RNA. "In the 1970s, Cech had been studying the splicing of RNA in the unicellular organism Tetrahymena thermophila when he discovered that an unprocessed RNA molecule could splice itself. In 1982, Cech became the first to show that RNA molecules are not restricted to being passive carriers of genetic information – they can have catalytic functions and can participate in cellular reactions. RNA-processing reactions and protein synthesis on ribosomes in particular are catalysed by RNA. RNA enzymes are known as ribozymes and have provided a new tool for gene technology. They also have the potential to provide new therapeutic agents – for example, they have the ability to destroy and cleave invading, viral RNAs" (Wikipedia article on Thomas Cech, accessed 7-22).

In 1989 Cech shared the Nobel Prize in Chemistry with Sidney Altman "for their discovery of catalytic properties of RNA."