Final answer:
The statement is true; the Lac repressor protein is constitutively expressed, as it is always produced by E. coli and binding is affected by the presence or absence of lactose.
Step-by-step explanation:
The statement "The Lac repressor protein is constitutively expressed." is true.
This means that the repressor protein product of the I gene is always made and present in E. coli cells.
In the absence of lactose, the repressor protein binds to the operator DNA, blocking transcription of the operon.
When lactose is present, it is converted into allolactose, which in turn, binds to the repressor.
This causes the repressor to be released from the operator and allows transcription to proceed, albeit at a slow rate.
An operon encoding proteins that are expressed continuously is described as constitutive.
A mutation in the repressor protein preventing it from binding lactose would lead to its inability to be removed from the operator, thus continuously blocking transcription despite the presence of lactose.