What are the roles of allolactose in the lac operon and tryptophan in the trp operon?

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anonymous · Answer

allolactose is an inducer in case of lac-operon.

anonymous · Answer

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anonymous · Answer

Allolactose as said above is an inducer in the lac operon which binds to LacI and deactivates it. LacI is the repressor that stops the transcription of the lac operon genes. Tryptophan on the other hand does the reverse effect. It activates the repressor TrpR by binding to it so that the genes for the Trp operon can be repressed and stopped from getting transcribed. One important thing about the Trp operon is that TrpR is not the only way by which the operon gets regulated. It is also regulated by a Leader peptide sequence. That is a story for another day. Let me know if you want to know about it. I hope this helps. :)