Which of the following is NOT correct regarding tryptophan operon:()
A. Ribosome are involved in transcription termination
B. Attenuator is a key regulatory element
C. When Trp is deficient, transcription termination will be initiated in advance
D. Coupled transcription and translation is the molecular basis of transcription regulation
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Which of the following descriptions regarding tryptophan operon in E.coli is correct:()
A. it contains regulations in both transcription level and translation level
B. It contains regulations in both initiation step of transcription as well as termination step of transcription.
C. It contains both positive regulation and negative regulation.
D. It contains regulations for enzyme induction as well as enzyme repression.
Besides the negative regulation of repressor protein, what’s the unique regulation of tryptophan operon:()
A. Repression
B. Induction
C. Attenuation
D. Catabolite repression
E. Anti-termination
Which of the following conditions lead to the highest expression of tryptophan operon:()
A. High concentration of Trp while low concentration of other amino acids.
B. High concentration of other amino acids while low concentration of Trp.
C. Both Trp and other amino acids are high concentration.
D. Both Trp and other amino acids are low concentration.
Tryptophan operon belongs to:()
A. negative regulation-induction system
B. negative regulation-repression system
C. positive regulation-induction system
D. positive regulation-repression system
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