Basic Vocabulary
Normally ON (the cell needs it by default).
Turned OFF when a specific molecule (usually the product) is abundant.
Typically controls anabolic pathways (biosynthesis pathways, which build something).
What is a repressible operon?
Name one of the 5 structural genes.
trpE, trpD, trpC, trpB, and trpA,
This environmental condition turns the operon ON?
What is “the lack of trp”?
This is the regulatory mechanism in the trp operon that causes transcription to terminate prematurely when tryptophan levels in the cell are too high.
What is “Attenuation”?
What type of feedback is the trp operon?
What is negative feedback?
Is the trp operon normally ON or OFF?
What is “ON”?
What is the operator?
a DNA sequence adjacent to the promoter.
The cell stops producing tryptophan when there is a(n) ____________ of it.
What is “high concentration / abundance”
What molecule acts as a corepressor, binding to the repressor protein and causing it to block transcription of the trp operon once levels are too high?
What is “tryptophan”?
Tryptophan does this to inhibit its own synthesis?
What is Negative Feedback loop?
This molecule acts as the corepressor in the trp operon?
What is “tryptophan”?
This gene codes for the repressor protein?
What is Regulatory Gene?
These are the conditions for producing tryptophan?
What is “low tryptophan”?
What is there a lack of, causing the ribosome to stall (not make polypeptides) when tryptophan is low?
What is “tRNA-trp”?
What things are saved by turning the operon OFF?
What is energy and resources
A _________ is a molecule that binds to an otherwise inactive repressor protein and activates it.
What is a co-repressor?
Where does RNA polymerase bind?
What is the operator?
This molecule goes into the slot of the repressor in order to deactivate it?
What is “tryptophan”?
Which mRNA hairpin allows transcription to continue?
What is the “2-3 hairpin”?
Is the following information a description of negative gene regulation, a corepressor, or an inducible operon
If tryptophan is scarce, the cell must MAKE it -> turns the operon ON
If tryptophan is abundant, the cell should NOT waste energy -> turns the operon OFF
What is negative gene regulation
The repressor does this when activated?
What is “creating tryptophan (trp)”?
This happens when the operator is deleted
What is “forced trp synthesis"?
A repressible system that is normally on, but is turned off when adequate levels of the amino acid tryptophan are present in the cell?
What is the “trp operon”?
A _______ prevents the leader peptide from being translated.
What is a “mutation”
This process uses negative feedback, a repressible operon, and attenuation to prevent the overproduction of tryptophan
What is the “trp operon regulatory process?”