Regulation of Gene Expression II Flashcards
The structure of an operon:
Multiple genes under the control of one regulatory region
When an operon with three genes is expressed, how many different mRNAs are produced?
One
When an operon with three genes is expressed, how many different proteins are produced?
Three
How many start and stop codons are present in each mRNA?
Three start and three stop codons
(Positive Transcriptional Regulation)
In positive transcriptional regulation, RNA polymerase can bind to the promoter only if …
An activator protein (positive transcription factor) is bound to the DNA near the promoter
(Positive Transcriptional Regulation)
In positive transcriptional regulation, if the activator protein is not bound to the DNA, RNA polymerase …
Cannot bind to the promoter so transcription does not occur
(Positive Transcriptional Regulation)
‘Default’ expression is …
OFF (due to the need for the activator)
Another name for an activator is:
Positive transcription factor
(Positive Transcriptional Regulation)
The DNA sequence that the activator binds to in an operon:
Activator binding site
(Negative Transcriptional Regulation)
In negative transcriptional regulation, RNA polymerase can bind to the promoter …
Without any other proteins needing to be present
(Negative Transcriptional Regulation)
In negative transcriptional regulation, if the repressor protein is bound to the DNA, RNA polymerase …
Is not recruited to the promoter sequence so transcription does not occur
(Negative Transcriptional Regulation)
‘Default’ expression is …
ON
(Negative Transcriptional Regulation)
Another name for a repressor is:
Negative transcription factor
(Negative Transcriptional Regulation)
The DNA sequence that the repressor binds to in an operon:
Operator
trpO:
the operator of the trp operon
