Lac operon
- Created by: vezting
- Created on: 19-04-16 16:05
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- lac operon and proteins
- protein synthesis
- can be controlled at a genetic level
- by stopping an starting genes by switching them on or off
- operons: genetically control the protein in prokaryotes
- an operon is a section of DNA that control structural genes, control elements and sometimes a regulatory gene
- factors that start transcription are called activators and those that stop it are called repressors
- can be controlled at a genetic level
- E.coli lac operon
- e.coli is a bacterium that respires using glucose but can use lactose if glucose isnt present
- the genes that produce the enzymes needed to respire lactose are found on the lac operon
- lactose not present
- 1:regulatory gene produces the lac repressor
- 2: repressor binds to operator site blocking the promotor site
- 3: RNA polymerase cant bind to this site, meaning no transcription
- lactose present
- 1: lactose binds to a site on the repressor, which is in the operator binding site
- 2: this causes repressor to chnage shape and dissociate with the operator region
- 3: promotor region is unblocked
- 4: RNA polymerase binds to operator site and transcription of genes Z and Y can start
- 5: these genes are transcribed into Beta Galactisodase and lactose permease.
- 6: lactose permease takes up the lactose and converts to glucose uning B Galac.
- protein synthesis
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