Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Lac
Document related concepts
Transposable element wikipedia , lookup
Ridge (biology) wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Public health genomics wikipedia , lookup
X-inactivation wikipedia , lookup
Epigenetics in learning and memory wikipedia , lookup
Genomic imprinting wikipedia , lookup
RNA silencing wikipedia , lookup
Epigenetics of neurodegenerative diseases wikipedia , lookup
Copy-number variation wikipedia , lookup
Point mutation wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Neuronal ceroid lipofuscinosis wikipedia , lookup
Epigenetics of diabetes Type 2 wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Genome evolution wikipedia , lookup
Genetic engineering wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Genome editing wikipedia , lookup
History of genetic engineering wikipedia , lookup
Genome (book) wikipedia , lookup
The Selfish Gene wikipedia , lookup
Gene therapy wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Gene expression programming wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Gene desert wikipedia , lookup
Helitron (biology) wikipedia , lookup
Gene expression profiling wikipedia , lookup
Gene nomenclature wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Microevolution wikipedia , lookup
Transcript
Chapter 18 Genetics of Viruses and Bacteria Gene Regulation Gene Regulation Your body needs to make tryptophan. Gene Regulation There are 5 steps to making tryptophan. Gene Regulation Eventually you have enough tryptophan. Gene Regulation High levels of tryptophan inhibits the first enzyme in the process that makes more tryptophan. Gene Regulation This is negative feedback. Gene Regulation This is negative feedback. Making tryptophan Gene Regulation This is negative feedback. Making tryptophan means we have more Gene Regulation This is negative feedback. which inhibits Making tryptophan means we have more Gene Regulation This is negative feedback. which inhibits Making tryptophan means we have more Gene Regulation Negative feedback is also used to regulate the genes that make the five enzymes that make tryptophan. A B C D E Gene Regulation DNA codes for these enzymes. ======================EDCBA===== Gene Regulation RNA polymerase has to attach to the DNA to start transcription of the genes. ======================EDCBA===== Gene Regulation It needs a place to attach. The promoter is a region of DNA that marks the beginning of the gene. ======================EDCBA===== Gene Regulation It needs a place to attach. The promoter is a region of DNA that marks the beginning of the gene. ======================EDCBA===== Gene Regulation It needs a place to attach. The promoter is a region of DNA that marks the beginning of the gene. ======================EDCBA===== Gene Regulation RNA polymerase makes the mRNA for the five enzymes. ======================EDCBA===== EDCBA Gene Regulation The mRNA goes to the ribosomes where the five enzymes are made. ======================EDCBA===== ABCDE Gene Regulation The five enzymes make tryptophan. ======================EDCBA===== Gene Regulation When there is enough tryptophan, the first enzyme is inhibited. ======================EDCBA===== Gene Regulation But the genes could still go on making more enzymes. ======================EDCBA===== Gene Regulation But the genes could still go on making more enzymes. ======================EDCBA===== ABCDE Gene Regulation But the genes could still go on making more enzymes. ======================EDCBA===== ABCDE Gene Regulation But the genes could still go on making more enzymes. ======================EDCBA===== Gene Regulation But the genes could still go on making more enzymes. ======================EDCBA===== ABCDE Gene Regulation But the genes could still go on making more enzymes. ======================EDCBA===== ABCDE Gene Regulation You really don’t need all those enzymes if you’re not using them. ======================EDCBA===== Gene Regulation You want to be able to shut off the gene. Actually, you want to shut off all 5 genes. ======================EDCBA===== Gene Regulation The repressor gene trpR makes a repressor molecule. ==trpR================EDCBA===== Gene Regulation The repressor gene trpR makes a repressor molecule. ==trpR================EDCBA===== Gene Regulation The repressor gene trpR makes a repressor molecule. ==trpR================EDCBA===== Gene Regulation The repressor gene trpR makes a repressor molecule. ==trpR================EDCBA===== trpR Gene Regulation The repressor gene trpR makes a repressor molecule. ==trpR================EDCBA===== trpR Gene Regulation The repressor gene trpR makes a repressor molecule. ==trpR================EDCBA===== trpR Gene Regulation The repressor is inactive. ==trpR================EDCBA===== Gene Regulation It needs tryptophan to be a corepressor in order to activate it. ==trpR================EDCBA===== Gene Regulation When there is a lot of tryptophan, enough repressor is activated to shut down the gene. ==trpR================EDCBA===== Gene Regulation The activated repressor binds to the operator region inside the promoter. ==trpR================EDCBA===== Gene Regulation This prevents RNA polymerase from binding to DNA. ==trpR================EDCBA===== Gene Regulation This prevents RNA polymerase from binding to DNA. ==trpR================EDCBA===== Gene Regulation This prevents RNA polymerase from binding to DNA. ==trpR================EDCBA===== Gene Regulation The operon includes the promoter, operator, and all five genes. ==trpR================EDCBA===== Gene Regulation The regulatory gene is separate. ==trpR================EDCBA===== Gene Regulation The repressor is inactive ==trpR================EDCBA===== Gene Regulation The repressor is inactive until the corepressor binds to it. ==trpR================EDCBA===== Gene Regulation The genes that make tryptophan are repressible genes. ==trpR================EDCBA===== Positive Feedback Positive Feedback E. coli needs three separate enzymes to digest lactose. Positive Feedback Tryptophan was something the cell needed to make, so the trp gene was repressed by tryptophan. Positive Feedback Lactose is something the cell needs to digest, so the lac gene is induced by lactose. Positive Feedback The lac genes are inducible genes. =========== lacL ======ZYA======== Positive Feedback The regulatory gene, lacL, makes an active repressor. =========== lacL ======ZYA======== Positive Feedback The repressor binds to the operator region within the promoter. =========== lacL ======ZYA======== = Positive Feedback RNA polymerase is blocked from transcribing the structural genes. =========== lacL ======ZYA======== Positive Feedback Lactose is an inducer. =========== lacL ======ZYA======== Positive Feedback It inactivates the repressor. =========== lacL ======ZYA======== Positive Feedback It inactivates the repressor. =========== lacL ======ZYA======== Positive Feedback It inactivates the repressor. =========== lacL ======ZYA======== ZYA Positive Feedback It inactivates the repressor. =========== lacL ======ZYA======== ZYA Positive Feedback It inactivates the repressor. =========== lacL ======ZYA======== usable energy Positive Feedback But there’s more… =========== lacL ======ZYA======== Positive Feedback But there’s more… If glucose is available, the cell would rather use that than lactose =========== lacL ======ZYA======== Positive Feedback If there is a shortage of glucose, the cell builds up quantities of cAMP. =========== lacL ======ZYA======== Positive Feedback cAMP is a cofactor for another regulatory protein called CRP. (cAMP receptor protein) =========== lacL ======ZYA======== Positive Feedback cAMP activates CRP. =========== lacL ======ZYA======== Positive Feedback CRP makes the lac genes much more active. =========== lacL ======ZYA======== Positive Feedback So less glucose means more lactose gets digested. =========== lacL ======ZYA======== Positive Feedback More glucose means you don’t need to digest the lactose even if it’s there… =========== lacL ======ZYA======== Positive Feedback More glucose means very little cAMP. =========== lacL ======ZYA======== Positive Feedback Without cAMP, CRP is inactive. =========== lacL ======ZYA======== Positive Feedback Without CRP, the lac genes are less active. =========== lacL ======ZYA======== Positive Feedback Without cAMP, CRP is inactive. =========== lacL ======ZYA========
