GENETICS AND EVOLUTION
MOLECULAR BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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to bind with repressor protein
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To initiate the transcription
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To synthesize structural genes
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All of the above
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Detailed explanation-1: -Lactose acts as an inducer in Lac operon by binding to the repressor protein, the repressor protein is produced by the inhibitory gene (LacI) present upstream to the operon gene.
Detailed explanation-2: -In lac operon, lactose acts as an inducer. If lactose is provided in the medium for the bacteria, the regulatory gene is activated. The inducer will bind to the repressor protein and render it inactive which allows transcription of the operon. Thus, the lac operon is negatively regulated in this case.
Detailed explanation-3: -The lactose ("lac") repressor controls the expression of bacterial enzymes involved in the metabolism of of the sugar lactose. When the lac repressor binds lactose, it changes to an inactive conformation that cannot repress the production of these enzymes.
Detailed explanation-4: -When lactose is present, the lac repressor loses its DNA-binding ability. This clears the way for RNA polymerase to bind to the promoter and transcribe the lac operon.
Detailed explanation-5: -The Lac repressor protein, LacI, prevents the transcription of genes involved in lactose utilization (lac genes) in E. coli. Like many other repressors, LacI utilizes multiple operators to increase the efficiency of repression.