Lac operon -gene regulation in prokaryotes : Molecular basis of inheritance

Lac operon -gene regulation in prokaryotes : Molecular basis of inheritance


Welcome guys in this video tutorial I will be talking about lactose operon if you want to like my videos then click the like button Subscribe my YouTube channel click on the bell icon to get notification and watch on YouTube it is given by Jacob and Monad in 1961 now what is operon? operon is a coordinate unit of genetic expression in Bacteria? it is a group of genes that are functioning together, but What is lactose operon? regulation of the lactose Metabolism in Bacteria Like E-Coli So it is popularly known as lac operon Now in this video. I will be talking about structure of Lac Operon repression and Activation that is derepression of Lac Operon and regulation of Lac Operon now. We are going to discuss about structure of Lac Operon It contains the regulatory gene that is denoted by I that is inhibitory it also contained it is followed by the Promoter site that is denoted by p where the RNA polymerase is bind promoter site is followed by operator that is where the lac repressor is bind. it contains the Structural gene. it contains the three structural gene the first one that is structural genes z second one that is structural gene y and third one that is structural beam a structural genes encode for the Enzyme Beta galactosidase This beta galactosidase break down the lactose into the glucose and galactose molecule Now the structural gene y that encode for enzyme galactose permease This enzyme that transfers the lactose into cell Now the third one that encoded in for the enzyme galactose acetylase and its function is unknown This structural gene produced the single messenger Rna that is Give rise to the three independent translation in for the synthesis of three different enzymes from the M-RNA to produce the more than one protein so it is known as polycistronic M-RNA now the repression of Lac Operon if you see the regulatory gene that produced the lac repressor in the constitutive or Constant rate this is the Tetrameric form and these regulatory proteins bias to the operator side and block the binding of RNA Polymerase to promoter site when the rNA polymerase cannot bind to promoter it blocks the Transcription of structural genes and Lac Operon each turn off. When Lactose absent so like repressor is a negative regulator of Lac operon Now Derepression of the Lac Operon now when the lactose is present what happens it binds to the Lac repressor and changes Conformation and it is going to be inactivated, so it cannot be bind to operators But rNa polymerase bind to the promoter so transcriptional of this structural gene and Translation and produce the enzyme that is proteins in nature and it is break down the lactose Now, what is gratuitous inducer? It is the structural analoge of lactose that Is induce the Lac Operon but not substrate for Beta galactosidase because only Lactose is a substrate This is the IPTG now if you see the importance of CAP and CAmp protein These are inside and outside of the cell This is the lac Operon now see CAP and Bind with the cMP that is required for the rNa polymerase to bind with promoter it is obtained from the conversion of ATP into CAMP by the Enzyme Adenylate Cyclase, but what happens when the glucose is present? Inside the cell that is intracellular concentration of glucose is high then it blocks the Adenylate cyclase, so CMP level is Fallen down and CMP cannot bind with CAmp and rna polymerase cannot bind to the promoter in lac Operon is off now So it is two conditions required for the left operand to be turned on first condition is glucose is must be absent if there is present it in a CAMP down level down and The second one that is left. lactose must be present Now for the Lac operon there is glucose and lactose level and the operon effect If the glucose is not present and lactose is present then operon is turn on but if the glucose is present And the left off is absent then it will be also turned off now The glucose is present and lactose is present Then Lac Operon is turn off Now the glucose is present and the lactose reception then Lac operon it turn oh so this is all about lake opener if you like my videos then click the like button and thanks for watching my videos and you Can see more videos on my YouTube channel? If you want to like my Facebook page, you can also like my Facebook page And if you want to donate any small amount then you can contact us

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