We have an excess of these tryptophan molecules floating around in the cell. Some of these tryptophan molecules will act as a co repressor. They will bind onto the allosteric side of that inactive repressor protein and that will activate the protein by changing its three dimensional shape. And now the active form of this repressor protein will go on and bind onto the operator section, the green section of the opera and once down that will basically inhibit that will block RNA polymerase from actually transcribing these five genes. And so in this case when we have a high concentration of tryptophan inside the cell we're not going to produce any mRNA molecules and so we will not synthesize these enzymes and will not synthesize the tryptophan. And that makes sense because if inside the cells we have a lot of tryptophan that bacterial cell wants to conserve as much energy as possible.