For each of the following conditions in the Lac Operon, state whether transcription will occur or not and state why. Include all the major actors including glucose, lactose, cAMP and CAP(CPR). Key + (present) - (absent) 1) Glucose-; Lactose- 2) Glucose+; Lactose- 3) Glucose+; Lactose+ 4) Glucose-; Lactose+
For each of the following conditions in the Lac Operon, state whether transcription will occur or not and state why. Include all the major actors including glucose, lactose, cAMP and CAP(CPR).
Key + (present) - (absent)
1) Glucose-; Lactose-
2) Glucose+; Lactose-
3) Glucose+; Lactose+
4) Glucose-; Lactose+
The lac operon of E. coli contains genes responsible in lactose metabolism. It is expressed only when lactose is present and glucose is absent.
Two regulators turn the operon "on" and "off" in response to lactose and glucose levels: the lac repressor and catabolite activator protein (CAP).
The lac repressor acts as a lactose sensor. It blocks transcription of the operon, but stops acting as a repressor when lactose is present.
Catabolite activator protein (CAP) acts as a glucose sensor. It activates transcription of the operon, but only when glucose levels are low.
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