The Dolan DNA Learning Center at Cold Spring Harbor Laboratory
... 4. What role does the repressor (product of the lacI gene) play in control of transcription of the lac operon? It is inhibits transcription when physically bound to the regulatory region. 5. What effect does the inducer have on the lacI gene product? It has an allosteric effect on the repressor, cha ...
... 4. What role does the repressor (product of the lacI gene) play in control of transcription of the lac operon? It is inhibits transcription when physically bound to the regulatory region. 5. What effect does the inducer have on the lacI gene product? It has an allosteric effect on the repressor, cha ...
Regulation of Gene Expression
... Regulation of Gene Expression (Chapter 7) Reading Guide 1. Why is it important for bacterial cells to be able to regulate gene expression? Provide an example. ...
... Regulation of Gene Expression (Chapter 7) Reading Guide 1. Why is it important for bacterial cells to be able to regulate gene expression? Provide an example. ...
Controlling Gene Expression
... •B-galactosidase: enzyme responsible for the degradation of lactose The lac operon is a cluster of three genes that code for the metabolism of lactose: lacZ codes for B-galactosidase lacY codes for B-galactosidase permease which lets lactose cross the cell membrane lacA codes for transacetylase; unk ...
... •B-galactosidase: enzyme responsible for the degradation of lactose The lac operon is a cluster of three genes that code for the metabolism of lactose: lacZ codes for B-galactosidase lacY codes for B-galactosidase permease which lets lactose cross the cell membrane lacA codes for transacetylase; unk ...
Name: Date: Class Period: Video questions: Video 1: Gene
... Class Period:______________________ Video questions: Video 1: Gene Regulation (Bozeman) What is a regulatory gene? What is an example of a regulatory sequence? What is lactose? What does it mean when a gene is expressed? What is the function of the TATA box? What is the function of an operator seque ...
... Class Period:______________________ Video questions: Video 1: Gene Regulation (Bozeman) What is a regulatory gene? What is an example of a regulatory sequence? What is lactose? What does it mean when a gene is expressed? What is the function of the TATA box? What is the function of an operator seque ...
Discussion Question Set 9
... repressible system. 4. What is the difference between negative control and positive control? 5. Briefly describe the structure of DNA binding proteins. 6. Describe the dual control of the lac operon. 7. If tryptophan were present in the media, how would a trpR mutant act with respect to expression f ...
... repressible system. 4. What is the difference between negative control and positive control? 5. Briefly describe the structure of DNA binding proteins. 6. Describe the dual control of the lac operon. 7. If tryptophan were present in the media, how would a trpR mutant act with respect to expression f ...
Gene Regulation
... (recall the TATA box) and the genes to be expressed Collectively, all three portions are called an operon Specific proteins, called repressors, fit into the operator When there, they block the RNA polymerase from binding ...
... (recall the TATA box) and the genes to be expressed Collectively, all three portions are called an operon Specific proteins, called repressors, fit into the operator When there, they block the RNA polymerase from binding ...
Chem 431C Lecture 10a Test 2 grade distribution Chapter 28
... between promoter and the genes of the operon. A regulatory protein can be a repressor or activator or selectivity factor. Operon contains one or more structural genes transcribed into one polycistronic mRNA: a single mRNA molecule that codes for more than one protein. ...
... between promoter and the genes of the operon. A regulatory protein can be a repressor or activator or selectivity factor. Operon contains one or more structural genes transcribed into one polycistronic mRNA: a single mRNA molecule that codes for more than one protein. ...
Objectives - World of Teaching
... able to regulate itself depending on the environmental conditions it is subjected to. • It codes for 3 genes: Beta-galactosidase, lactose permease and Thiogalactosidase transacetylase. These genes are involved in lactose metabolism. • If lactose is absent, the system is turned off; if lactose is pre ...
... able to regulate itself depending on the environmental conditions it is subjected to. • It codes for 3 genes: Beta-galactosidase, lactose permease and Thiogalactosidase transacetylase. These genes are involved in lactose metabolism. • If lactose is absent, the system is turned off; if lactose is pre ...
Slide 1
... There are positive and negative regulatory elements that make catabolite repression work. cAMP receptor protein (CAP), acting as a homodimer can bind both cAMP and DNA. When glucose is absent (high cAMP state), CAP binds to its positive regulatory element increasing transcription of the lac operon 5 ...
... There are positive and negative regulatory elements that make catabolite repression work. cAMP receptor protein (CAP), acting as a homodimer can bind both cAMP and DNA. When glucose is absent (high cAMP state), CAP binds to its positive regulatory element increasing transcription of the lac operon 5 ...
Lac operon
lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. Although glucose is the preferred carbon source for most bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available. Gene regulation of the lac operon was the first genetic regulatory mechanism to be understood clearly, so it has become a foremost example of prokaryotic gene regulation. It is often discussed in introductory molecular and cellular biology classes at universities for this reason.Bacterial operons are polycistronic transcripts that are able to produce multiple proteins from one mRNA transcript. In this case, when lactose is required as a sugar source for the bacterium, the three genes of the lac operon can be expressed and their subsequent proteins translated: lacZ, lacY, and lacA. The gene product of lacZ is β-galactosidase which cleaves lactose, a disaccharide, into glucose and galactose. LacY encodes lactose permease, a protein which becomes embedded in the cytoplasmic membrane to enable transport of lactose into the cell. Finally, lacA encodes galactoside O-acetyltransferase. Layout of the lac operon.It would be wasteful to produce the enzymes when there is no lactose available or if there is a more preferable energy source available, such as glucose. The lac operon uses a two-part control mechanism to ensure that the cell expends energy producing the enzymes encoded by the lac operon only when necessary. In the absence of lactose, the lac repressor halts production of the enzymes encoded by the lac operon. In the presence of glucose, the catabolite activator protein (CAP), required for production of the enzymes, remains inactive, and EIIAGlc shuts down lactose permease to prevent transport of lactose into the cell. This dual control mechanism causes the sequential utilization of glucose and lactose in two distinct growth phases, known as diauxie.