A mutation occurs in the trp operon DNA of E. coli and results in the change to the two UGG tryptophan codons in the 5′ UTR of t
he RNA to UAG stop codons. What effect will this mutation be expected to have on the regulation of this mutant trp operon compared to a wild-type operon? A) In the presence of tryptophan, transcription of the structural genes will be reduced compared with a wild-type operon.
B) In the absence of tryptophan, transcription of the structural genes will be reduced compared with a wild-type operon.
C) In the presence of tryptophan, the repressor will bind to the operator/promoter region with the mutant operon more strongly than with a wild-type operon.
D) In the absence of tryptophan, RNA polymerase will not bind to the operator/promoter region with the mutant operon.
E) In the presence of tryptophan, transcription of the structural genes will be enhanced compared with a wild-type operon.
E) In the presence of tryptophan, transcription of the structural genes will be enhanced compared with a wild-type operon.
Explanation:
A mutation can be described as any changes which occur in the DNA of an organism. Some mutations can be useful whereas others have devastating effects.
A stop codon is required to stop the transcription of a gene. If this code becomes mutated, then the process of transcription will continue to happen unless a new stop codon is recognized.
Hence, when tryptophan will be present, the mutations will cause more transcription of the structural genes.
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