Lac operon Flashcards
Lac operon is an example of genetic response to environmental change. What happens when glucose is absent and lactose available?
Lac operon is activated to switch to lactose metabolism.
Low glucose leads to increased adenylyl cyclase activity –> cAMP is generated leading to activation of catabolite activator protein (CAP).
CAP binds to the lac operon and induces transcription.
When lactose is available allolactose binds to repressor protein allowing RNA polymerase to bind and LAc genes are strongly expressed.
If lactose is not available the repressor binds to the Operator region inhibiting transcription.
Organization of a eukaryote gene: Promoter region
Where RNA polymerase II and other transcription factors bind to the DNA upstream from the gene.
is an AT rich area - TATA or CAAT boxes.
if mutated leads to decrease in gene expression
Enhancer/silencer region
Lies upstream to gene and alters gene expression through binding of transcription factors.
