Gene Regulation Flashcards
Why is it important for genes to be regulated
It allows cells to react quicky to changes in the environment, it also increases the versatility pf an organism
How does a cell make sure that processes that requiring many enzymes have all the enzymes activated and transcribed at the same time?
p: the enzymes are collected in the same location and they are turned on and off together as a single unit
e: the enzymes are at different locations but they use the same transcription mechanism at different sites to turn them on at once
What do operons do
They carry lots of proteins in bacteria and collect all needed genes together
Importance of the lac operon
Used to break down lactose when glucose is not present and has negative (lacl) and positive (cap) regulation
How is the lac operon regulated
- It can only be turned on in the absence of glucose. the CAP (protein) binds and helps RNA polymerase to bind on to DNA
- Second protein also regulates the operon. Lacl binds on to the operatopr and inhibits transcription. When lactose is present, lacl is removed and transcription starts
Why is the lac Operon said to be both positive a negative regulation
b/c the cap is positive since it turns on transcription and the lacl is negative since it turns off transcription
What do lacz and lacy do
lacz: cuts lactose into monosaccharides
lacy: transports lactose
Explain the processes of 3 scenarios
- No lactose
- lots of lacts
2a. lactose getting used up
- lacl will bind to operator restrictiong rna pol from binding to the promoter region so no transcription
- lots of lactose so they bind on to lacl which changes its shape so it does not interact with the operator and transcription happens
- lactose is being used up so it unbinds from lacl, lacl goes back to origonal shape that interacts with operator region and restricts rna
Where is an example of post-translational transcription in the operon process?
lactose binds on to the lacl repressor
Epignetic regulation
packing dna into high order structures such as chromatin
negative control because it restriucts access to genes
Gene regulation eukaryotes
- chromatin can be loosened or tightened to access DNA
- genes are not kept togetehr but there is one transcription factor to turn them all on
Types of transcription factors
Activators: they bind on to sites called enhancers and speed up transcription
Repressors: bind onto sites known as silincers and slow down transcription
Basal transcription factors: get info from activators and then they position RNA polymerase and initiate transcription
Coactivators: coordinate signals from activators and repressors
What type of cpontrol do transcription factors have on gene expression
positive and negative
