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Arabinose Operon quiz

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  • What is the main function of the arabinose operon?
    The arabinose operon encodes genes that control the breakdown of arabinose, a sugar.
  • What sugar does the arabinose operon help break down?
    It helps break down arabinose.
  • What happens to the arabinose operon when arabinose is present?
    The operon is activated to break down arabinose.
  • Which protein binds to the ARAI (initiator) site to initiate transcription?
    The AraC protein binds to the ARAI site to initiate transcription.
  • What additional complex is required for transcription initiation of the arabinose operon?
    The cAMP-CAP complex is also required for transcription initiation.
  • Where does the cAMP-CAP complex bind in relation to the arabinose operon?
    It binds to an adjacent site near the operon to help activate transcription.
  • What happens to the arabinose operon when arabinose is absent?
    The operon is repressed and transcription does not occur.
  • How does AraC protein repress transcription in the absence of arabinose?
    AraC binds both the ARAI and ARAO sites, creating a DNA loop that prevents RNA polymerase from binding.
  • What is the effect of the DNA loop formed by AraC protein?
    The DNA loop prevents RNA polymerase from binding, thus repressing transcription.
  • What determines whether the arabinose operon is activated or repressed?
    The presence or absence of arabinose determines whether AraC binds one site (activating) or both sites (repressing).
  • What are the two regulatory regions involved in arabinose operon control?
    The two regions are ARAI (initiator) and ARAO.
  • What happens if AraC binds only the ARAI site?
    Transcription is initiated, and the operon is activated.
  • What happens if AraC binds both the ARAI and ARAO sites?
    A DNA loop forms, repressing transcription of the operon.
  • Why does the cell repress the arabinose operon when arabinose is not present?
    To avoid wasting energy producing unnecessary proteins.
  • What is the role of the cAMP-CAP complex in the arabinose operon?
    It helps activate the operon by binding to a site near the operon, facilitating transcription initiation.