1. To inhibit the transcription of operon genes, the lacI gene product binds to __________.
a. the inducer
b. the promoter
c. the operator
d. the lacZ gene
e. the repressor
2. A DNA mutation (resulting in a lack of function) in which of the following locations would lead to constitutive expression of the lac operon genes? (Select all that apply.)
a. the lacI promoter
b. the lac operon promoter
c. the lac operon operator
d. the lacZ gene
e. the lacI gene
3. Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If she moves the lacI (repressor) gene, along with its promoter, to a position at some several thousand base pairs away from its normal position, we would expect that:
a. the repressor protein will no longer be made.
b. the repressor protein will no longer bind to the operator in absence of lactose.
c. the repressor protein can no longer bind to the inducer if present.
d. the lac operon will be expressed continuously.
e. there will be no difference in repressor gene or lac operon function.
4. Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If she moves the operator to the far end of the operon, downstream of the transacetylase (lacA) gene, which of the following would likely occur when the cell is exposed to lactose?
a. The inducer will not bind to the repressor.
b. The repressor will not bind to the operator.
c. The operon will not be transcribed.
d. The lacZ, lacY, and lacA genes will be transcribed continuously.
e. The repressor protein will not be produced.