Here's a breakdown:
* Lac operon: This is a group of genes in bacteria that are responsible for breaking down lactose.
* Lac repressor: This is a protein that binds to the lac operator and prevents the transcription of the lac operon genes.
* Lac operator: This is a specific DNA sequence located near the beginning of the lac operon.
When the lac repressor is bound to the lac operator, it physically blocks RNA polymerase from attaching to the DNA and transcribing the genes. This effectively turns off the expression of the lac operon.
In summary: The lac repressor turns off the genes by physically blocking the transcription process at the lac operator.
