In λ phage, which protein, the product of the cI gene, blocks the transcription required to initiate the lytic cycle?
A)cro
B)repressor
C)enhancer
D)integrase
E)operator

Question

Quizplus · Accepted Answer

The product of the cI gene in λ phage is the repressor protein, which binds to the operator site and prevents RNA polymerase from transcribing genes required for the lytic cycle. The cro protein (choice A) is produced during the lytic cycle and acts as a repressor of the repressor, allowing the lytic cycle to proceed. Enhancer (choice C), integrase (choice D), and operator (choice E) are all important components of gene regulation, but do not directly block transcription in the same way that the repressor protein does.

In λ Phage, Which Protein, the Product of the CI