Practice Questions

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#Question id: 18981

The pL promoter is controlled by the cl repressor protein of bacteriophage A. In practice, a temperature-sensitive mutant of the cl repressor, cl857, is generally used to regulate pL-directed transcription. Cells carrying the temperature-sensitive cl repressor are first grown at 30°C, and 42°C

#Unit 13. Methods in Biology

at 30°C the cl repressor prevents transcription directed by the pL promoter
at 42°C the thermosensitive cl repressor is inactivated and transcription can proceed.
at 30° the thermosensitive cl repressor is inactivated and transcription can proceed.
at 42°C the cl repressor prevents transcription directed by the pL promoter