Lac-Operon-Modell, Regulation?
Hallo,
was genau ist die biologische Bedeutung der doppelten Kontrolle der Synthese der lactoseabbauenden Enzyme durch Glucose und Lactose? Wir haben das im Unterricht behandelt und ich komme bisher auf keine Lösung.
LG und danke im voraus!
Quite simply: austerity principle.
The synthesis of enzymes for lactose degradation requires energy and resources. Double control suppresses the expression of these enzymes when glucose is present and at the same time lactose is missing. This saves energy that would otherwise be used for the synthesis of unnecessary enzymes.
Thank you very much!!!!
prokaryotic
Lac-Operon: Promoter, Operator, Gene
Operator lies between promoter and genes
Lactose and glucose deficiency strengthen gene expression
Lactose binds to Regulator protein and inactivates it
RNA polymerase can then bind to promoter with open operator
Glucose-concentration affects cAMP constant
CAP binds near the promoter and increases RNA polymerase activity
Energy/ATP is saved by this mechanism
Transcription:
moving the RNA polymerase along the DNA needs ATP
Translation:
Connecting amino acids to one another by ribosomes requires ATP