Question

Transcription termination in E. coli occurs when:

A. TFIID is released from the DNA
B. a stem-loop structure forms on the RNA transcript and signals the polymerase to come off the DNA
C. a stop codon is encountered on the RNA molecule
D. a stem-loop structure forms on the DNA and creates a physical barrier
E. the telomere repeat is encountered by the polymerase

Answer 1

In E. coli, transcription termination happens when a stem-loop structure forms in the RNA, causing RNA polymerase to stall and release the mRNA transcript.

Step-by-step explanation:

In Escherichia coli (E. coli), transcription termination is a crucial process regulated by the formation of a stem-loop structure on the RNA transcript. This mechanism involves specific DNA sequences that prompt the development of a stable hairpin structure within the mRNA, referred to as a terminator or terminator stem. The terminator structure induces the RNA polymerase to stall during transcription.

As the polymerase encounters a region abundant in adenine-thymine (A-T) nucleotides, with weak interactions with the mRNA transcript, it releases the newly synthesized mRNA. This event signifies the termination of transcription, preventing further elongation of the RNA chain. The termination process in E. coli is a finely tuned molecular event, ensuring precise control over gene expression and the production of functional RNA molecules.