Here's how it works:
* Operons are groups of genes that are transcribed together as a single unit in prokaryotes.
* Repressors are proteins that bind to the operator region of an operon, blocking RNA polymerase from binding and initiating transcription.
* Inducers are molecules that bind to the repressor protein, causing a conformational change that prevents the repressor from binding to the operator. This allows RNA polymerase to bind and transcribe the genes in the operon.
Example:
In the lac operon, lactose acts as the inducer.
1. When lactose is absent, the repressor protein binds to the operator, blocking transcription of the genes needed for lactose metabolism.
2. When lactose is present, it binds to the repressor, causing a conformational change that releases the repressor from the operator.
3. With the repressor gone, RNA polymerase can bind to the promoter and transcribe the genes for lactose metabolism.
In summary, the inducer is the molecule that triggers transcription of an operon by binding to the repressor protein and causing it to detach from the operator.
