Micro Final 3 Flashcards
What is an operon?
Groups of genes that occur one after another and put onto the same messenger RNA. It has a promoter which helps transcription and an operator which makes the enzyme “go”
What are the two types of proteins that affect regulation?
Repression and Activators
What is repression the repression protein?
A repressor protein would be inhibiting the transcription. This binds to the operator.
What is induction for the repression protein?
It causes the gene to turn on. The inductor turns off the repressor. The inducer binds the allosteric site which changes the shape. The repressor therefore cannot bind and transcription can occur
What is corepression?
a corepressor binds to the allosteric site of the repressor, activating it to bind the operator
What is the activation protein?
It is a protein that promotes transcription. There is a binding site for the activator just ahead of the promoter. this will assist the sigma factors and polymerase binding the DNA.
What is induction for the activation protein?
Activators that need inducers will be the wrong shape to bind the binding site until the inducer comes along to bind the activator which changes it binding site to fit.
What is repression of an activator?
Allosteric inhibitor binds the activator which turns it off. This prevents transcription
What is the Lac Operon? (LacZ, Lac Y, LacA, LacI)
The Lac Operon has 3 genes: lac Z, lac Y, and lac A. Lac Z encodes for beta galactosidase. This cuts lactose into 2 products of glucose and galactose. Lac Y is the permease. It permits lactose into the cell. Lac A aids in the transport of lactose. LacI is the inhibitor
What is the structure of the lac operon?
PROG
CAP site –> lac promoter –> operator –> lacZ –> lacY –> lacA –> lac terminator
What are small or noncoding RNA’s
They will never make proteins and are antisense RNA’s. These small RNA’s can base pair with mRNA’s creating double stranded RNA. This creates RNA interference. This targets the message for destruction.
What is Quorum Sensing?
Bacteria can detect how many other cells are nearby. Autoinducers are used to communicate and diffuse through the membrane easily. Gm negative cells produce AHL and Gm positive cells produce short peptides. All cells make it and there is monitoring of the levels.
Where are resistance mechanisms normally found?
On plasmids because they are expensive to maintain, so the bacteria will only hold on to them if they are being used
