Now in this lecture we're going to focus on a type of opera that is used by bacterial cells in anabolic processes. Now an anabolic process is simply a process in which we synthesize some type of molecule that is needed by the cell, by the bacterial cell. And the type of Operon we're going to focus on is a repressible opera. Now a specific example of a repressible Operon used by bacterial cells is a tryptophan Operon. So what exactly is a repressible Operon? Well, a repressible Operon is the most common type of Operon used by bacterial cells in anabolic processes.