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In the mechanism of transcription attenuation of the trp operon, the ribosome stalls at the adjacent Trp codons when the levels of tryptophan in the cell are high.

a. true
b. false

1 Answer

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Final answer:

The statement is false; high levels of tryptophan in the cell lead to continuous translation of the leader peptide, facilitation of a terminator loop formation, and termination of transcription in the trp operon mechanism.

Step-by-step explanation:

The statement presented is false. In the mechanism of transcription attenuation of the trp operon, the ribosome does not stall at the adjacent Trp codons when the levels of tryptophan in the cell are high. Instead, it is the presence of tryptophan that allows the ribosome to continue translating the leader peptide, which results in the formation of a terminator loop between regions 3 and 4 of the mRNA, leading to the termination of transcription. When tryptophan is scarce, the ribosome stalls at the tryptophan codons within region 1 of the leader sequence, allowing regions 2 and 3 to form an antiterminator loop, which prevents the formation of the terminator stem-loop, thereby enabling RNA polymerase to continue transcription of the operon's structural genes.

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