Dr. Bustamante begins his talk by explaining why one would wish to study biochemical reactions at the level of a single molecule. He explains that many processes within the cell are carried out by very few molecules. By studying single molecules, it is possible to obtain details about the mechanism of a reaction that cannot be ascertained by studying a population of molecules. Bustamante goes on to describe the technique of optical tweezers and how it can be used to manipulate single molecules. His lab has successfully used this method to follow DNA transcription one molecule at a time and RNA translation one codon at a time. In both cases, single molecule studies provided detailed information about complex biochemical processes.