In attenuation, transcription is initiated but terminates prematurely. When tryptophan levels are low, the ribosome stalls at the tryptophan codons and transcription continues. When tryptophan levels are high, the ribosome does not stall at the tryptophan codons, and the 5' UTR adopts a secondary structure that terminates transcription before the structural genes can be copied into RNA (attenuation).
-Attenuation results when which regions of the 5' UTR pair?
A) 1 and 3
B) 2 and 3
C) 2 and 4
D) 3 and 4

Question

Quizplus · Accepted Answer

When tryptophan levels are high, regions 3 and 4 of the 5' UTR pair to form a terminator structure, causing premature termination of transcription.

In Attenuation, Transcription Is Initiated but Terminates Prematurely