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The lac repressor in bacteria _______, and when lactose is present, the lac genes ______. Activates transcription of lactose-metabolism genes; are transcribed Activates transcription of lactose-metabolism genes; are NOT transcribed Inhibits transcription of lactose-metabolism genes; are transcribed Inhibits transcription of lactose-metabolism genes; are NOT transcribed

User Prankster
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Answer:

Inhibits transcription of lactose-metabolism genes; are transcribed

Step-by-step explanation:

The lac gene is a structural gene in bacterial cells that encodes the synthesis of lactose-degrading proteins or enzymes in the bacterial cell. However, the expression of this gene is regulated at the transcriptional level. In the absence of lactose sugar in the cell, lac repressor binds to the operator region of the gene and inhibit the transcription of lactose-metabolism genes (Lac A, Y and Z).

However, if LACTOSE sugar is present, the lac repressor protein is inactivated and removed as a result of its binding to allolactose. This allows RNA polymerase to bind to the promoter and transcription of lac genes will go on.

User Sergio Negri
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