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Prokaryotic Gene Regulation via Operons quiz #1 Flashcards

Prokaryotic Gene Regulation via Operons quiz #1
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  • Which regions of a bacterial promoter are essential for promoting transcription?
    The promoter region, located just ahead of the gene, is essential for promoting transcription because it is the DNA sequence where RNA polymerase binds to initiate transcription.
  • Which type of regulatory protein binds to the operator of a bacterial gene?
    Regulatory proteins such as repressors or activators bind to the operator of a bacterial gene to control transcription by either blocking or promoting RNA polymerase binding.
  • What is the function of the operator region in a prokaryotic operon?
    The operator is a DNA sequence where regulatory proteins bind to control the ability of RNA polymerase to initiate transcription of the operon’s genes.
  • How do activator proteins influence transcription in operons?
    Activator proteins bind to the operator and promote RNA polymerase binding to the promoter, thereby stimulating transcription.
  • What role does the regulatory gene play in operon function?
    The regulatory gene encodes the regulatory protein, such as a repressor or activator, which binds to the operator to control transcription.
  • How does an inducer molecule affect an inducible operon?
    An inducer molecule binds to the repressor protein, inactivating it and allowing transcription to proceed by freeing the operator.
  • What is the normal state of a repressible operon and how is it turned off?
    A repressible operon is normally turned on, but it can be turned off when a corepressor binds to the repressor protein, activating it to block transcription.
  • What is the effect of a corepressor on the repressor protein in repressible operons?
    A corepressor binds to the inactive repressor protein, activating it so it can bind to the operator and inhibit transcription.
  • Which operon is an example of an inducible operon and what molecule acts as its inducer?
    The lac operon is an example of an inducible operon, and lactose acts as its inducer by inactivating the repressor.
  • Which operon is an example of a repressible operon and what molecule acts as its corepressor?
    The trp operon is a repressible operon, and tryptophan acts as its corepressor by activating the repressor protein.