18 Questions
What is the function of the σ subunit in RNA polymerase?
To recognize specific promoter sites on DNA
What is the name of the consensus sequence found at position –10 in the promoter region?
Pribnow box
What is the composition of the RNA polymerase holoenzyme in E. coli?
α2ββ’ωσ
During which phase of transcription does RNA polymerase recognize a specific site on the DNA?
Initiation
What is the size of the promoter region in prokaryotes?
40–60 bp
What is the function of the core enzyme in transcription?
To synthesize RNA during elongation
What is the consensus sequence of the –35 promoter region?
TTGACA
What is released from the transcriptional complex during the elongation phase?
The σ factor
What is the direction of RNA synthesis by RNA polymerase?
5’ → 3’
What is the region of unwound DNA called that is undergoing transcription?
Transcription bubble
What is the complex of RNA polymerase, DNA template, and new RNA transcript called?
Ternary complex
What is the first nucleotide in the RNA transcript usually?
pppG or pppA
Which strand of DNA is used as a template during elongation?
Antisense (-) strand
In what direction is mRNA synthesized during elongation?
5′ to 3′ direction
What is the function of the promoter site in transcription?
To identify the correct strand for transcription
What is the common feature of termination sequences?
GC-rich region followed by an AT-rich sequence
What happens when the RNA polymerase encounters a termination signal?
It stops transcription and releases the RNA transcript
What is required for termination at some termination sites?
The presence of rho protein
This quiz covers the process of transcription in prokaryotic organisms, including the three phases of initiation, elongation, and termination, and the roles of RNA polymerase and its subunits.
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