The Operon Means to operate. Discovered by Jacob, Lwoff, and Monad. Operons are mostly found in prokaryotic cells, like bacteria. Led to other terms like regulons, modulus, and stimulus.
Parts of an Operon
Lac Operon Breaks down lactose in E. coli. Bacteria in our stomach must break down the food we eat. When lactose is moving around, one molecule with move into the repressor, changing its shape. As a result, it opens a region where the RNA polymerase can begin transcription to break down the lactose. Once the lactose is removed, the repressor will become active again.
Trp Operon The trp operon makes the amino acid tryptophan when it’s not present. When tryptophan is present, it will change the repressor’s shape so it fits into the operator. Thus, the repressor stays on to prevent transcription.
When tryptophan is absent, the repressor changes shape and detaches from the operator. Thus, transcription can begin to produce more tryptophan.
Regulatory Sequence A regulatory sequence produces a repressor for the operon.