Attenuation is dependent upon all of the following EXCEPT
A) direct physical interaction between the ribosome and RNA polymerase.
B) pausing of a ribosome in the leader peptide due to low levels of an operon-specific charged tRNA.
C) no proteins other than those in ribosomes and RNA polymerase.
D) the formation of a stem loop structure in the nascent mRNA strand that acts as a transcriptional terminator.

Question

Quizplus · Accepted Answer

Attenuation does not depend on direct physical interaction between the ribosome and RNA polymerase. The other choices are all factors that can affect attenuation. Choice B refers to the presence or absence of charged tRNAs that correspond to particular codons in the nascent mRNA strand. If a charged tRNA is not available for a particular codon, the ribosome may slow down or stall, which can trigger attenuation. Choice C emphasizes that attenuation is a process that involves only the ribosome and RNA polymerase, and no additional factors. Choice D refers to the formation of a stem loop structure in the nascent mRNA that can interfere with transcription, an important factor in regulating attenuation.

Attenuation Is Dependent Upon All of the Following EXCEPT