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Prokaryotic Gene Regulation via Operons quiz #1 Flashcards

Prokaryotic Gene Regulation via Operons quiz #1
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  • What is an operon in prokaryotic gene regulation?
    An operon is a set of related prokaryotic genes controlled by a single promoter.
  • What role does the promoter play in an operon?
    The promoter is a DNA sequence where RNA polymerase binds to initiate transcription.
  • What is the function of the operator in an operon?
    The operator is a DNA region where regulatory proteins bind to control RNA polymerase binding.
  • How do repressor proteins affect transcription in an operon?
    Repressor proteins bind to the operator and block RNA polymerase, preventing transcription.
  • What is the role of activator proteins in an operon?
    Activator proteins bind to the operator and promote RNA polymerase binding, stimulating transcription.
  • What is an inducible operon?
    An inducible operon is normally turned off but can be turned on in the presence of an inducer.
  • How does an inducer molecule affect an inducible operon?
    The inducer molecule inactivates the repressor protein, allowing transcription to proceed.
  • What is a repressible operon?
    A repressible operon is normally turned on but can be turned off in the presence of a corepressor.
  • How does a corepressor molecule affect a repressible operon?
    The corepressor molecule activates the repressor protein, which then binds to the operator to block transcription.
  • What is the lac operon and its function?
    The lac operon is an inducible operon that encodes enzymes for lactose metabolism.
  • Under what conditions is the lac operon turned on?
    The lac operon is turned on in the presence of lactose and absence of glucose.
  • What are the three genes encoded by the lac operon?
    The three genes are lacZ, lacY, and lacA, which are involved in lactose metabolism.
  • What is the role of the lacI gene in the lac operon?
    The lacI gene encodes the repressor protein that binds to the operator to repress transcription.
  • How does the presence of lactose affect the lac operon?
    Lactose binds to the repressor protein, inactivating it and allowing transcription to proceed.
  • What is the significance of the operator in the lac operon?
    The operator is the binding site for the repressor protein, which controls the transcription of the lac operon genes.
  • can you match terms related to operons to their definitions?
    Operons: Groups of related genes controlled by a single promoter. Promoter: DNA sequence where RNA polymerase binds to initiate transcription. Operator: DNA region where regulatory proteins bind to influence transcription. Inducible operon: Normally off, can be activated by an inducer that inactivates a repressor. Repressible operon: Normally on, can be turned off by a corepressor activating a repressor.
  • according to the animation, where on the dna strand does a repressor bind?
    A repressor binds to the operator region on the DNA strand, which is a small DNA sequence within the operon.