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Glucose's Impact on Lac Operon exam Flashcards

Glucose's Impact on Lac Operon exam
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  • What is the preferred energy source for prokaryotes?
    Glucose
  • cAMP
    Cyclic AMP, a molecule that increases when glucose levels are low and enhances lac operon transcription.
  • How does high glucose concentration affect cAMP levels?
    High glucose concentration results in low cAMP levels.
  • CRP
    Cyclic AMP receptor protein, an activator protein that stimulates lac operon transcription when bound to cAMP.
  • What happens to lac operon transcription when glucose is present?
    Lac operon transcription is low or turned off.
  • Positive control mechanism
    A regulatory mechanism where cAMP and CRP enhance lac operon transcription when glucose is scarce.
  • What is the relationship between glucose and cAMP levels?
    Inverse relationship; when glucose is high, cAMP is low, and vice versa.
  • CRP binding site
    A region of DNA upstream of the lac promoter where active CRP binds to stimulate transcription.
  • What role does cAMP play in lac operon transcription?
    cAMP binds to CRP, activating it to enhance lac operon transcription.
  • Activator protein
    A regulatory protein that stimulates transcription, such as CRP when bound to cAMP.
  • What happens to lac operon transcription when glucose is low?
    Lac operon transcription is high.
  • Lac operon
    A set of genes involved in lactose metabolism, regulated by glucose and cAMP levels.
  • How does low glucose concentration affect CRP?
    Low glucose concentration leads to high cAMP levels, which activate CRP.
  • RNA polymerase
    An enzyme that binds to the promoter to initiate transcription, recruited by active CRP.
  • What ensures lactose is used only when glucose is scarce?
    The positive control mechanism involving cAMP and CRP.
  • Gene expression regulation
    The process by which cells control the transcription and translation of their genes, influenced by glucose and cAMP in the lac operon.
  • What is the effect of high cAMP levels on lac operon transcription?
    High cAMP levels increase lac operon transcription.
  • Environmental nutrient availability
    The presence of nutrients like glucose and lactose in the environment, affecting gene expression in prokaryotes.
  • How does CRP affect RNA polymerase?
    Active CRP helps recruit RNA polymerase to the promoter, enhancing transcription.
  • Lac repressor
    A protein that inhibits lac operon transcription in the absence of lactose.
  • What happens to CRP when cAMP levels are low?
    CRP remains inactive and does not stimulate lac operon transcription.
  • Transcription
    The process of copying a segment of DNA into RNA, regulated by factors like cAMP and CRP in the lac operon.
  • What is the role of the CRP binding site?
    It is where active CRP binds to stimulate lac operon transcription.
  • Adaptive evolution
    The process by which organisms adjust and evolve in response to environmental changes, such as nutrient availability.
  • How does lactose concentration affect the lac operon?
    High lactose concentration inactivates the lac repressor, allowing transcription if glucose is low.
  • Energy source preference
    Prokaryotes prefer glucose over lactose as an energy source.
  • What is the effect of an inactive CRP on lac operon transcription?
    Inactive CRP does not stimulate lac operon transcription.
  • cAMP-CRP complex
    The active form of CRP bound to cAMP, which enhances lac operon transcription.
  • What ensures efficient energy use in prokaryotes?
    The regulation of the lac operon by glucose and cAMP levels.