Final answer:
It is false that all three lac operon operators are bound simultaneously by the Lac repressor. The lac operon's regulation involves one main operator site bound by the repressor and inducers such as allolactose that can derepress the system to enable gene transcription.
Step-by-step explanation:
The statement 'All three lac operon operators are bound simultaneously by the Lac repressor to repress the expression of the operon' is false. The lac operon includes the I gene, which produces a repressor protein. This repressor can bind to the operator region to prevent transcription; however, there are three operator sites: O1, O2, and O3. Only the O1 operator is bound tightly by the repressor. Changes in O2 or O3 alone don't significantly impact the repression but mutations in both can reduce repressor binding.
When lactose is present, it's converted to allolactose within the cell. Allolactose then binds to the repressor, leading to its dissociation from the operator site, allowing RNA polymerase to transcribe the operon's genes. Additionally, when glucose is scarce, cAMP levels increase, which in turn lead to the binding of the cAMP-CAP complex to the promoter, further enhancing the transcription of the lac operon.
Therefore, the repression of the lac operon is complex and involves multiple regulatory mechanisms, including but not exclusive to the binding of the repressor protein to the operator sites.