Final answer:
The cI gene encodes the λ repressor protein in E. coli cells. The false statement is PRE is activated by the λ repressor. Therefore, the false statement is B. PRE is activated by the λ repressor.
Step-by-step explanation:
The cI gene encodes the λ repressor protein in E. coli cells. It has two promoters, PRE and PRM. The statements mentioned are:
A. PRE is activated by the cII protein: This statement is true. The cII protein can activate the PRE promoter, leading to the production of the λ repressor protein.
B. PRE is activated by the λ repressor: This statement is false. The λ repressor does not activate the PRE promoter. It binds to the operator's DNA to prevent transcription.
C. PRM is turned on after PRE: This statement is true. PRM is the promoter for the production of repressor protein, and it is turned on after PRE is activated.
D. PRM is needed to maintain the lysogenic cycle: This statement is false. PRM is not needed to maintain the lysogenic cycle. It is involved in producing the repressor protein.
Therefore, the false statement is B. PRE is activated by the λ repressor.