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Bio Q !!!!

Discussion in 'DAT Discussions' started by lintydent, Aug 4, 2006.

  1. lintydent

    lintydent member
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    .....This is from topscore:

    Which of the following best describes gene regulation and expressoin in a repressible system?

    A. The respressor binds to the operator, forming a barrier that prevents genes from being transcribed.
    B. The repressor is inactive until it combines with the corepressor allowing genes to be transcribed.
    C. The repressor-corepressor binds to the operator and represses enzyme synthesis.
    D. In a constant state of transcipription without a corepressor.
    E. C&D


    What's the answer? I'm not sure if I agree with topscore....they say E. I say A. Am i going crazy? Or stupid?
     
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  3. ConfusedOne

    ConfusedOne Member
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    I believe 'a' describes an inducible system (eg lac operon) while 'e' describes a repressible system. In a repressible system, the repressor must be activated by a corepressor
     
  4. dat_student

    dat_student Junior Member
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    With repressible systems, the binding of the effector molecule to the repressor greatly increases the affinity of repressor for the operator and the repressor binds and stops transcription. I'd pick E
     
  5. electron

    electron Newbie
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    There are two different systems when it comes to Gene Regulation

    Inducible System (eg. lac operon) - which has an active repressor which stops the expression of genes unless an inducer is available.

    Repressible System - has an inactive repressor allowing gene expression unless a corepressor is available.

    You were thinking of an inducible system
     
  6. lintydent

    lintydent member
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    alright....just gave myself a big whack in the forehead.

    anyone care to do seconds....
     

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