Regulation of Transcription
... – The transcribed sequence begins at the Transcription start site (TSS) and finishes at the Transcription Termination site (TES) ; – The sequence of DNA that is translated into the amino acid sequences is knows as the CDS (coding sequence) ...
... – The transcribed sequence begins at the Transcription start site (TSS) and finishes at the Transcription Termination site (TES) ; – The sequence of DNA that is translated into the amino acid sequences is knows as the CDS (coding sequence) ...
Lac Operon
... initiation of transcription of the lac operon through their effects on the lac repressor protein and CAP. Lactose addition increases the concentration of allolactose, which binds to the repressor protein and removes it from the DNA. Glucose addition decreases the concentration of cyclic AMP; because ...
... initiation of transcription of the lac operon through their effects on the lac repressor protein and CAP. Lactose addition increases the concentration of allolactose, which binds to the repressor protein and removes it from the DNA. Glucose addition decreases the concentration of cyclic AMP; because ...
Gene Expression/Mutations
... - proto-oncogene: normal form of oncogene that controls cells growth and proliferation - mutation in proto oncongene causes uncontrolled growth leading to cancer (becomes an oncogene) ...
... - proto-oncogene: normal form of oncogene that controls cells growth and proliferation - mutation in proto oncongene causes uncontrolled growth leading to cancer (becomes an oncogene) ...
IB104 - Lecture 15
... A. TRANSCRIPTIONAL - usually having to do with promoters and interactions at the DNA level. This is perhaps the most important level of gene regulation and the only one we will consider. ...
... A. TRANSCRIPTIONAL - usually having to do with promoters and interactions at the DNA level. This is perhaps the most important level of gene regulation and the only one we will consider. ...
31. The Control of Gene Expression in Prokaryotes
... the bacteria Vibrio fischerili that live symbioBcally within these organs. These bacteria become luminescent when they reach an appropriately high density. The density is sensed by the circuit shown on the ...
... the bacteria Vibrio fischerili that live symbioBcally within these organs. These bacteria become luminescent when they reach an appropriately high density. The density is sensed by the circuit shown on the ...
Lecture 14 Gene Regulation
... • b. The CAP-cAMP level drops, and is insufficient to maintain high transcription of the lac genes. • c. Even when allolactose has removed the repressor protein from the operator, lac gene transcription is at very low levels without CAPcAMP complex bound to the CAP-site. • d. Experimental evidence s ...
... • b. The CAP-cAMP level drops, and is insufficient to maintain high transcription of the lac genes. • c. Even when allolactose has removed the repressor protein from the operator, lac gene transcription is at very low levels without CAPcAMP complex bound to the CAP-site. • d. Experimental evidence s ...
Chap 18.1 - Wild about Bio
... • The “switch” is a segment of DNA called an operator usually positioned within the promoter • An operon is the entire stretch of DNA that includes the operator, the promoter, and the genes that they control © 2011 Pearson Education, Inc. ...
... • The “switch” is a segment of DNA called an operator usually positioned within the promoter • An operon is the entire stretch of DNA that includes the operator, the promoter, and the genes that they control © 2011 Pearson Education, Inc. ...
Exam Review 4B - Iowa State University
... 4. Which of the following components of the lac operon forms a trans-acting product a. LacA b. LacI c. LacP d. LacO 5. All of the following are structural genes except a. LacZ b. LacA c. LacO d. LacY 6. If lacO is mutated to lacOc, what is the result a. The structural genes are not expressed b. The ...
... 4. Which of the following components of the lac operon forms a trans-acting product a. LacA b. LacI c. LacP d. LacO 5. All of the following are structural genes except a. LacZ b. LacA c. LacO d. LacY 6. If lacO is mutated to lacOc, what is the result a. The structural genes are not expressed b. The ...
BioH Control over Genes Ch14
... enzymes to be produced by allowing the repressor protein to bind at the operator site, preventing RNA polymerase from binding. • High lactose concentration allows some lactose molecules to bind to the repressor proteins, keeping them from binding to the operator. This allows RNA polymerase to bind t ...
... enzymes to be produced by allowing the repressor protein to bind at the operator site, preventing RNA polymerase from binding. • High lactose concentration allows some lactose molecules to bind to the repressor proteins, keeping them from binding to the operator. This allows RNA polymerase to bind t ...
Chapter 13 - Microbial Genetics
... D) The lac operon will be induced only when both glucose and lactose are present E) The lac operon will be induced only when glucose is present and lactose is absent ...
... D) The lac operon will be induced only when both glucose and lactose are present E) The lac operon will be induced only when glucose is present and lactose is absent ...
Lecture#6 - Further regulation of the lac operon
... I- is a mutation that affects the DNA binding region and therefore there is no repressor binding and thus transcription occurs even without an inducer. ...
... I- is a mutation that affects the DNA binding region and therefore there is no repressor binding and thus transcription occurs even without an inducer. ...
Biology 303 EXAM III
... present, the glucose will be metabolized first and the lactose will be used when the stores of glucose have been depleted. How does the bacterial cell recognize the fact that glucose is present and turn off the transcription even when lactose is present? 1. The lac promoter binds glucose and shuts d ...
... present, the glucose will be metabolized first and the lactose will be used when the stores of glucose have been depleted. How does the bacterial cell recognize the fact that glucose is present and turn off the transcription even when lactose is present? 1. The lac promoter binds glucose and shuts d ...
Exam301ANS
... are present, the glucose will be metabolized first and the lactose will be used when the stores of glucose have been depleted. How does the bacterial cell recognize the fact that glucose is present and turn off the transcription even when lactose is present? ...
... are present, the glucose will be metabolized first and the lactose will be used when the stores of glucose have been depleted. How does the bacterial cell recognize the fact that glucose is present and turn off the transcription even when lactose is present? ...
Prokaryotic Gene Expression (Learning Objectives)
... • Biochemical pathways are either biosynthetic or breakdown pathways • Cellular feedback inhibition enables cells/organisms to response to their environment • A protein is produced in a cell if its gene is present and expressed (i.e. transcribed and translated) • A transcription unit (gene) consist ...
... • Biochemical pathways are either biosynthetic or breakdown pathways • Cellular feedback inhibition enables cells/organisms to response to their environment • A protein is produced in a cell if its gene is present and expressed (i.e. transcribed and translated) • A transcription unit (gene) consist ...
Predicted Existence of Messenger RNA: The Operon Model Until
... adjacent on the chromosome (operon), one of these proteins is βgalactosidase which hydrolyzes lactose and other β-galactosides. - When grown on glucose as a energy source- lactose enzymes are very low in bacteria. - When shifted to lactose rich media- these enzymes are highly expressed. Removal of l ...
... adjacent on the chromosome (operon), one of these proteins is βgalactosidase which hydrolyzes lactose and other β-galactosides. - When grown on glucose as a energy source- lactose enzymes are very low in bacteria. - When shifted to lactose rich media- these enzymes are highly expressed. Removal of l ...
LAC OPERON: A CONCEPT TO BE CLEARED What is an
... But until lactose was added to the culture medium, these 3 genes were not expressed completely. (Synthesis of β-galactosidase in the quiescent cell is just as much as to be capable of producing allolactose from lactose.) In the absence of lactose, a repressor protein encoded by the regulatory gene b ...
... But until lactose was added to the culture medium, these 3 genes were not expressed completely. (Synthesis of β-galactosidase in the quiescent cell is just as much as to be capable of producing allolactose from lactose.) In the absence of lactose, a repressor protein encoded by the regulatory gene b ...
10-DNA-TranslationControl
... The lac operon is also regulated by an activator The activator is a protein called CAP It binds to the CAP-binding site and gives the RNA polymerase more access to the promoter However, a “low glucose” signal molecule has to bind to CAP before CAP can bind to the DNA ...
... The lac operon is also regulated by an activator The activator is a protein called CAP It binds to the CAP-binding site and gives the RNA polymerase more access to the promoter However, a “low glucose” signal molecule has to bind to CAP before CAP can bind to the DNA ...
Biology 303 EXAM II 3/14/00 NAME
... specific genes encoding proteins through: A. complex enhancer elements that can associate with multiple activator and repressor proteins B. production of different types of sigma factors C. attenuation D. all of the above ...
... specific genes encoding proteins through: A. complex enhancer elements that can associate with multiple activator and repressor proteins B. production of different types of sigma factors C. attenuation D. all of the above ...
Bio 102 Practice Problems Gene Expression and Regulation
... 1. Testosterone (shown at right) is a hormone that plays important roles in male development and reproduction. Among other things, it stimulates germ cells in the seminiferous tubules of the testes to divide by meiosis and produce sperm. a. Like all hormones, testosterone travels in the blood throug ...
... 1. Testosterone (shown at right) is a hormone that plays important roles in male development and reproduction. Among other things, it stimulates germ cells in the seminiferous tubules of the testes to divide by meiosis and produce sperm. a. Like all hormones, testosterone travels in the blood throug ...
- ISpatula
... RNA polymerase initiates transcription at promoter site polycistronic mRNA(3 sets of start and stop codons) its translation produces 3 proteins for lactose use in energy metabolism ...
... RNA polymerase initiates transcription at promoter site polycistronic mRNA(3 sets of start and stop codons) its translation produces 3 proteins for lactose use in energy metabolism ...
principles of gene control
... Before this work the prevailing model was called the instruction hypothesis that stated that all proteins were present in a cell, but that in the absence of an inducer they were not properly folded and were inactive. Jacob and Monod were awarded the Nobel Prize in 1965 for their work on characterisi ...
... Before this work the prevailing model was called the instruction hypothesis that stated that all proteins were present in a cell, but that in the absence of an inducer they were not properly folded and were inactive. Jacob and Monod were awarded the Nobel Prize in 1965 for their work on characterisi ...
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.