Tryptophan regulates the trp operon by doing what?

What is the likely effect of each of the following mutations of the trpL region on attenuation control of trp operon gene transcription? Explain your reasoning.

The start (AUG) codon of the trpL polypeptide is deleted.

The function of tRNA synthetases is to attach amino acids to tRNAs. Suppose the tRNA synthetase responsible for attaching tryptophan to tRNA is mutated in a bacterial strain, with the result that the tRNA synthetase functions at about 15% of the efficiency of the wild-type tRNA synthetase. Would formation of the 3–4 stem-loop structure in mRNA be more frequent or less frequent in the mutant strain than in the wild-type strain? Why?

The function of tRNA synthetases is to attach amino acids to tRNAs. Suppose the tRNA synthetase responsible for attaching tryptophan to tRNA is mutated in a bacterial strain, with the result that the tRNA synthetase functions at about 15% of the efficiency of the wild-type tRNA synthetase.

How would this mutation affect attenuation of the tryptophan operon? Explain your answer.

Attenuation uses what molecule to regulate the trp operon?

What is the name of the sequence responsible for regulating the trp operon through attenuation?

If tryptophan levels are low, attenuation does what to the trp operon?

How do we know that the trp operon is a repressible control system, in contrast to the lac operon, which is an inducible control system?