Gene Regulation Proks Flashcards
Gene Regulation
The level of gene expression can vary under different conditions
Gene regulation is important for:
Protein products needed at the right time
What are the two types of regulatory proteins?
Repressors and Activators
What do effector molecules do?
Bind to regulatory proteins but not DNA
What binds to the promoter?
RNA polymerase
Where does the lac repressor protein bind?
Operator
What is the CAP site?
Where the CAP binds
What are the three structural genes for the lac operon?
Lac Z, Lac Y, Lac A
What does Lac Z encode?
Beta-galactosidase
What does Lac Y encode?
Lactose permease
What does Lac A encode?
Galactosidase transacetylaste
What is the organization of the lac operon?
CAP site, Promoter, Operator, Lac Z, Lac Y, Lac A, Lac terminator
What is the lac operon regulated by?
A repressor protein
Is allolactose an inducer?
yes
When is the lac operon repressed?
When there is no lactose present. This is because there is nothing to be metabolized
What happens when lactose is present?
Allolactose binds to the repressor protein, changing the shape and preventing it from binding to the operator, RNA polymerase can transcribe the protein.
What happens if lac repressor cannot bind to the operator?
No repressor made, operon is always on.
What is the term that described the process of cAMP-CAP complex binding near the cap site and increasing transcription?
Catabolite repression
How many structural genes are involved in the trp Opeorn?
5 (ABCDE)
Which genes are involved in Regulation of the trp Operon?
trpR and trpL
What is the organization of the trp operon?
Promoter, Operator, trpL, trpE, trpD, trpC, trpB, trpA
What happens when there are high levels of tryptophan?
Repression occurs. Tryptophan binds to the trp repressor protein, which binds to the operator site, blocking transcription
How are genes regulated translationally?
- Binding next to the Shine-Dalgarno sequence and/or the start codon 2. Binding outside the Shine-Dalgarno/ start codon region 3. Antisense RNA
What happens when Osmolarity is low?
The ompF protein is produced
How can the function of proteins be controlled?
The covalent modification of their structure
