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Lac Codes Transcription Operon Regulatory Structural Lactose Binding

The lac operon in bacteria comprises structural genes (lacZ, lacY, lacA) encoding enzymes for lactose metabolism, and control sites (promoter P, operator O) where a regulatory gene (lacI) product binds to regulate transcription.

The lac operon in bacteria comprises structural genes (lacZ, lacY, lacA) encoding enzymes for lactose metabolism, and control sites (promoter P, operator O) where a regulatory gene (lacI) product binds to regulate transcription.

Front Draw and label a diagram to show the lac operon and its associated regulatory gene.
Back
Lac operon:



Structural genes:
  • lacZ - codes for beta galactosidase (hydrolyses lactose)
  • lacY - codes for lactose permease (facilitates passage of lactose into cell)
  • lacA - codes for transacetylase (not fullly understood)
Control sites:
  • Promoter - RNA polymerase binding site to allow transcription
  • Operator - transcription factor binding site, switches structural genes on/off
Regulatory gene: (lacI)
  • Not part of the operon
  • Codes for transcription factor (repressor protein)




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