Midterm 2-4 Flashcards
(18 cards)
Why not express genes all the time
Regulation makes sure that competing genes do not get activated at the same time. Biochemistry disruption and rapid destruction of the cell
What is microbial adaption based on
Altered gene expression, inducing the production of protein needed to respond to a specific change in conditions
What is transcription regulation
Control of gene expression at the chromosome involves the regulation of RNA polymerase binding and transcriptional activation. This regulation responds to changing cellular conditions and changing environmental conditions
Why is sugar needed in cells
Cells metabolize them into energy in the form of ATP. Glucose brakdown goes down the glycolysis pathway
What happens when glucose is not available
This means they cannot import glucose so they have to turn to other molecules to convert to energy. This requires an enzyme that are expressed only when glucose is not available
What does the beta galactosidase mutants do
It give the inability of beta galactosidase to cleave lactose or even onpg.
Called lac Z
What do the galactosidase permeate mutants do
This mediates transport of lactose in the cell so that lactose only enters when glucose is gone, without it, the lactose cannot enter the cell
What does the constitutive mutants do
When there is a loss of regulatory expression so in the case of lactose, the beta galactosidase will always be produced. LacI
What is repression
The stop of gene expression, loss of this function will result in abnormal activity
What is an operon
A group of genes with a similar function
What does the lac I do
This is under the control of its own promoter. It regulated gene expression from the lactose operon (lacZ,Y,A)
How does the promoter in the operon work
It activates all the lac operon genes and it is only activated under specific conditions
What is positive control
When something must bind the promoter to activate expression
What is negative control
When something binds to the promoter that blocks expression of the operon
What is a repressor
A regulatory molecule (lacI) that is a negative regulator for the lactose operon
What does constitutive mean
When the expression of the operon is always on
What are the three central hypotheses to the Jacob monad model of lac operon
Expression of the three genes is coordinately operated- the lac operon
LacI represses transcription of the lac operon genes by binding to the operator motif within the promoter of the operon
Lactose is an inducer I. This system, binding to the repressor protein and blocking the ability to bind to the operator
What does the lac operon show
Repressor based regulation
