6D * Recognize that a gene expression is a regulated process.
... In 10 sec, discuss the following with your partner: What is being controlled when the gene expression is regulated? ...
... In 10 sec, discuss the following with your partner: What is being controlled when the gene expression is regulated? ...
Genetics Guided Notes Use Chapter 12
... Lac genes are _____________ by _________________ and _______________by ________________________________ Define Operator: ...
... Lac genes are _____________ by _________________ and _______________by ________________________________ Define Operator: ...
Operons - Haiku Learning
... IV. Control of metabolic pathways A. Two ways 1. Vary the activity of the enzymes (inhibit them or promote their ability) – feedback inhibition pathways 2. Vary the # of enzymes present – regulate enzyme production at the gene expression level ...
... IV. Control of metabolic pathways A. Two ways 1. Vary the activity of the enzymes (inhibit them or promote their ability) – feedback inhibition pathways 2. Vary the # of enzymes present – regulate enzyme production at the gene expression level ...
Negative regulation
... B. lactose present: release of repressor/ inducer complex - allows transcription RNA polymerase binds ...
... B. lactose present: release of repressor/ inducer complex - allows transcription RNA polymerase binds ...
DNA, and in some cases RNA, is the primary source of heritable
... molecule called an inducer inactivates the repressor to turn the lac operon on. When there is no lactose present there is not need for the enzymes that break it down. Inducible enzymes usually function in catabolic pathways; like digestion; their syntesis is induced by a chemical signal (the item th ...
... molecule called an inducer inactivates the repressor to turn the lac operon on. When there is no lactose present there is not need for the enzymes that break it down. Inducible enzymes usually function in catabolic pathways; like digestion; their syntesis is induced by a chemical signal (the item th ...
31_operons
... (b) Lactose present, repressor inactive, operon on. Allolactose, an isomer of lactose, derepresses the operon by inactivating the repressor. In this way, the enzymes for lactose utilization are induced. ...
... (b) Lactose present, repressor inactive, operon on. Allolactose, an isomer of lactose, derepresses the operon by inactivating the repressor. In this way, the enzymes for lactose utilization are induced. ...
Chapter 15 / Lecture Outline 36
... 1. The presence of lactose induces expression of the genes required for lactose utilization 2. Analysis of the lactose induction system was a wise choice for the study of gene regulation B. Experiments analyzing the behavior of lactose-utilization mutants reveal the coordinate repression and inducti ...
... 1. The presence of lactose induces expression of the genes required for lactose utilization 2. Analysis of the lactose induction system was a wise choice for the study of gene regulation B. Experiments analyzing the behavior of lactose-utilization mutants reveal the coordinate repression and inducti ...
Regulation
... II. Regulation of transcription (induction and repression): A. Some enzymes are always made at the same levels. 1. This is called: __________________ expression 2. The enzyme is always present regardless of nutrients available to the organism. 3. The control of mRNA levels is governed by: ...
... II. Regulation of transcription (induction and repression): A. Some enzymes are always made at the same levels. 1. This is called: __________________ expression 2. The enzyme is always present regardless of nutrients available to the organism. 3. The control of mRNA levels is governed by: ...
Gene Expression Notes
... c) When lactose is added to the medium: (1) E. coli increases the number of m-RNA molecules coding for galactosidase (2) These molecules are quickly translated into thousands of galactosidase molecules d) Lactose metabolism is programmed by the ______________. 3. ___________________ - has a single ...
... c) When lactose is added to the medium: (1) E. coli increases the number of m-RNA molecules coding for galactosidase (2) These molecules are quickly translated into thousands of galactosidase molecules d) Lactose metabolism is programmed by the ______________. 3. ___________________ - has a single ...
Bio 102 Practice Problems
... 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 ...
Slide 1
... Transcription is activated because the lactose molecule has bound to the repressor protein. This causes the repressor protein to release from the operator site, which then permits RNA polymerase to transcribe the structural genes. ...
... Transcription is activated because the lactose molecule has bound to the repressor protein. This causes the repressor protein to release from the operator site, which then permits RNA polymerase to transcribe the structural genes. ...
Document
... lactose as the sole carbon source converts lactose into allolactose. ◦ i. Repressor bound with allolactose changes shape (allosteric shift) and dissociates from the lac operator. Free repressor– allolactose complexes are unable to bind the operator. ◦ ii. Allolactose induces expression of the lac op ...
... lactose as the sole carbon source converts lactose into allolactose. ◦ i. Repressor bound with allolactose changes shape (allosteric shift) and dissociates from the lac operator. Free repressor– allolactose complexes are unable to bind the operator. ◦ ii. Allolactose induces expression of the lac op ...
Chapter 9 homework due 3/31/08 1a. Will lacZ be transcribed and
... What factors will be bound to the lacO and lacP sites these conditions? Repressor will be bound at O. c. Will lacZ be transcribed and translated if E. coli are grown in media with both lactose and glucose as sugar sources? NO What factors will be bound to the lacO and lacP sites these conditions and ...
... What factors will be bound to the lacO and lacP sites these conditions? Repressor will be bound at O. c. Will lacZ be transcribed and translated if E. coli are grown in media with both lactose and glucose as sugar sources? NO What factors will be bound to the lacO and lacP sites these conditions and ...
Slides PPT
... Repressor with allolactose bound is now off the operator and the CAP with cAMP bound is on the DNA in a region upstream from the promoter. The RNA pol can bind to the promoter and the CAP:cAMP can act positively to enhance the frequency of transcription initiation. Brake off accelerator on ...
... Repressor with allolactose bound is now off the operator and the CAP with cAMP bound is on the DNA in a region upstream from the promoter. The RNA pol can bind to the promoter and the CAP:cAMP can act positively to enhance the frequency of transcription initiation. Brake off accelerator on ...
Transcription Regulation Background: Lactose Background: How
... Transcription Regulation The Lac Operon – a paradigm for all transcription regulation ...
... Transcription Regulation The Lac Operon – a paradigm for all transcription regulation ...
Operons: The Basic Concept
... – Involves the negative control of genes, because the operons are switched off by the active form of the repressor protein ...
... – Involves the negative control of genes, because the operons are switched off by the active form of the repressor protein ...
Wednesday, September 5
... because the Ffactor is integrated into the chromosome •Transferred genes can then recombind with recipent’s genes ...
... because the Ffactor is integrated into the chromosome •Transferred genes can then recombind with recipent’s genes ...
INDUCTION OF ß-GALACTOSIDASE IN E.COLI
... The structure genes of the lac operon encode the information of three proteins (ß-galactosidase, transacetylase and lactose permease) necessary to be synthesized by the cells utilizing lactose as energy source. ß-galactosidase catalyzes the hydrolysis of lactose into glucose and galactose. Besides t ...
... The structure genes of the lac operon encode the information of three proteins (ß-galactosidase, transacetylase and lactose permease) necessary to be synthesized by the cells utilizing lactose as energy source. ß-galactosidase catalyzes the hydrolysis of lactose into glucose and galactose. Besides t ...
Chapter 12.5
... • THE PROMOTER REGION IS WHERE RNA POLYMERASE CAN ATTACH AND START TRANSCRIPTION. • THERE IS ANOTHER REGION CALLED THE OPERATOR. THIS CONTAINS A PROTEINS CALLED A LAC REPRESSOR. IF THE LAC REPRESSOR IS ATTACHED TO THE DNA THE GENE IS TURNED OFF. • THE REPRESSOR WILL BE ON DNA UNLESS LACTOSE IS PRESE ...
... • THE PROMOTER REGION IS WHERE RNA POLYMERASE CAN ATTACH AND START TRANSCRIPTION. • THERE IS ANOTHER REGION CALLED THE OPERATOR. THIS CONTAINS A PROTEINS CALLED A LAC REPRESSOR. IF THE LAC REPRESSOR IS ATTACHED TO THE DNA THE GENE IS TURNED OFF. • THE REPRESSOR WILL BE ON DNA UNLESS LACTOSE IS PRESE ...
Lecture 2
... 5.4 Catabolite repression A diauxic growth curve results when two sugars are present –e.g. Glucose is used first followed by other sugars such as lactose or xylose. Glucose has been shown to block the expression of a number of operons controlling the catabolism of particular sugars such as lact ...
... 5.4 Catabolite repression A diauxic growth curve results when two sugars are present –e.g. Glucose is used first followed by other sugars such as lactose or xylose. Glucose has been shown to block the expression of a number of operons controlling the catabolism of particular sugars such as lact ...
Lecture 28
... during DNA replication when the repressor is temporarily “off” the operator. This escape synthesis is necessary, as β-galactosidase is needed to convert lactose into allolactose (the inducer) and lac permease is needed to transport lactose into the cell. d) The operon system was elucidated through t ...
... during DNA replication when the repressor is temporarily “off” the operator. This escape synthesis is necessary, as β-galactosidase is needed to convert lactose into allolactose (the inducer) and lac permease is needed to transport lactose into the cell. d) The operon system was elucidated through t ...
Genes
... the transcription level. If lactose is added to the medium, the synthesis of both molecules is induced. ...
... the transcription level. If lactose is added to the medium, the synthesis of both molecules is induced. ...
Solutions for Practice Problems for Molecular Biology, Session 5
... Dark blue colonies Mutants 8-10 White colonies White colonies Dark blue colonies Dark blue colonies d) A loss-of-function mutation in which component or components (I, Pi, CAP binding site, Plac, O, lacZ) could produce the constitutive phenotype seen in these mutants? I, Pi, O e) You introduce a pie ...
... Dark blue colonies Mutants 8-10 White colonies White colonies Dark blue colonies Dark blue colonies d) A loss-of-function mutation in which component or components (I, Pi, CAP binding site, Plac, O, lacZ) could produce the constitutive phenotype seen in these mutants? I, Pi, O e) You introduce a pie ...
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.