Gene regulation (Part 1) Flashcards
Prokaryotes differ from Eukaryotes in that they lack…
A cell nucleus and specialized membrane-bound organelles.
What is the difference between constitutive and regulate genes?
Constitutive genes: Always on
Regulated genes: Only required under certain conditions
In bacteria, the amount of mRNA dictates protein synthesis and thus amount of protein, controlling its activity. (T/F)
TRUE
Bacterial operons are ____.
Polycistronic
(Meaning: single mRNA encodes for several polypeptide chains
What are the two main types of regulatory proteins in bacteria?
- Negative regulation
- Positive regulation
How does negative regulation regulate transcription in bacteria?
Through repressors which bind to an operator and prevent RNA polymerase initiating transcription
How does positive regulation regulate transcription in bacteria?
Through activators which bind to an operator and allow RNA polymerase to initiate transcription.
In bacteria, a gene cannot use both types of regulation (T/F)
FALSE!!
A gene CAN use both Negative and Positive regulation.
What is the lac operon and what is its role?
Lac Operon: 6000 bp long collection of genes involved in sugar metabolism (Lactose)
- Metabolize the sugar “lactose” if there are no other energy source
How many proteins are coded in the lac operon?
3
What are the proteins coded by the Lac Operon?
Lac Z - Beta-galactosidase
Lac Y - lactose permease
Lac A - Transacetylase
What occurs at the Lac O region of the Lac Operon?
O= Operator; main ‘switch’ - binds repressor protein
What occurs at the Lac P region of the Lac Operon?
P= Promoter; binds to RNA polymerase
What occurs at the Lac I region of the Lac Operon?
Lac Repressor - turns gene off
Regulatory protein
