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The Trp Operon quiz #2 Flashcards

The Trp Operon quiz #2
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  • What is the determining factor for the transcription of structural genes of the trp operon?
    The determining factor is the presence or absence of tryptophan, which acts as a corepressor to activate the TRP repressor protein.
  • What role does tryptophan play in the regulation of the trp operon?
    Tryptophan acts as a corepressor that binds to the TRP repressor protein, activating it to bind to the operator and repress transcription.
  • How does the trp operon behave in the absence of tryptophan?
    In the absence of tryptophan, the TRP repressor remains inactive, allowing transcription to proceed and enabling the cell to synthesize tryptophan.
  • What happens to the trp operon when tryptophan levels are high?
    When tryptophan levels are high, it binds to the TRP repressor, activating it to bind to the operator and repress transcription of the trp operon.
  • What is the function of the TRP repressor protein?
    The TRP repressor protein binds to the operator to repress transcription of the trp operon when activated by tryptophan.
  • What is the role of the TRP operator in the trp operon?
    The TRP operator is the site where the TRP repressor protein binds to inhibit transcription of the trp operon.
  • How is the TRP repressor protein initially expressed?
    The TRP repressor protein is initially expressed in an inactive form and requires tryptophan to become active.
  • What is the relationship between tryptophan and the TRP repressor protein?
    Tryptophan acts as a corepressor that binds to the TRP repressor protein, activating it to repress the trp operon.
  • What happens to the trp operon when tryptophan is absent?
    When tryptophan is absent, the TRP repressor remains inactive, allowing transcription of the trp operon to proceed.
  • What is the function of the genes within the trp operon?
    The genes within the trp operon encode enzymes necessary for the synthesis of tryptophan.
  • How does the presence of tryptophan regulate the activity of the trp operon in bacteria?
    When tryptophan is abundant, it acts as a corepressor by binding to the trp repressor protein, activating it. The active repressor then binds to the operator region of the trp operon, blocking transcription and preventing the synthesis of tryptophan.
  • What is the function of the five genes within the trp operon?
    The five genes within the trp operon encode enzymes that are required for the biosynthesis of tryptophan from scratch.
  • What role does the trp repressor protein play in the regulation of the trp operon?
    The trp repressor protein, encoded by the trpR gene, binds to the operator region of the trp operon when activated by tryptophan, thereby blocking transcription of the operon's genes.