Test #3- Gene Expression Flashcards
What is Gene Expression?
where information from a gene is used in the synthesis of a functional gene product
What is Differential expression?
Both of these cells contain the same genome, but express different RNAs and proteins
What 2 things can Genes be?
constitutive genes- expressed at a fixed rate irrespective of a cell condition
controllable genes- expressed only as needed (more complex)
What is positive regulation?
expression of gene is increased by a specific regulatory element
What is negative regulation?
Expression is diminished by the presence of a specific regulatory element
What is bacteria metabolism?
Needs to respond quickly to their environment
- -either stop production
- -or utilize new source
What does a operon do?
genes grouped together with related functions
What does a promotor do?
RN polymerase binding site single promoter controls transcription of all genes on operon (one mRNA is made)
What does the repressor protein do?
binds to DNA at operator site- blocking RNA polymerase
What happens when tryptophan is present?
it binds to the trp repressor protein which turns the operon off
What if there isn’t enough trp in the environment?
it makes its own
What are the 3 lac__ in lac-operon?
lac Y-encodes lactose permease–transports lactose into the cell
lac Z-encodes Beta galactosidase- enzyme that catalyses the reaction of lactose (glucose and galactose)
lac A-Encodes enzyme lactose transacetylase-biological function unclear
What happens if there is no lactose?
NO TRANSCRIPTION
Does the operator have to be active or inactive in lac-operon?
INACTIVE
Is lactose a monosaccharide or a disaccharide?
disaccharide
What does the Inducible operon do?
It enhances the reaction
–wants glucose over lactose
What happens if glucose runs out in inducible operon?
when lactose runs out, cAMP starts increasing and binds to CAP to activate it to bind to the promoter to make it faster–This is a secondary process
