Now that Bill has lactose, I can do my job as activation is back on! Hi, I am a unit of DNA called the lac operon. Operons control protein synthesis. I get involved with the operator, promoter, structural genes, the regulator gene, in order to make sure everything goes smoothly in gene expression.
These are structural genes which encode for lactose-controlling enzymes
Regulatory genes (green) transmit repressor proteins to the operator (pink) so that RNA polymerase cannot bind to the promoter (blue) and start transcription!