A New Pedagogy for the Lac-Operon - IB-Biology
... About the bacterial strains that are being used. A great number of different ones are available. Below are given several that have historical significance. They are all derivatives of E.coli K-12 (remember the girl in the early 1920's who sat in row K seat 12 in the class that was taken over by a gr ...
... About the bacterial strains that are being used. A great number of different ones are available. Below are given several that have historical significance. They are all derivatives of E.coli K-12 (remember the girl in the early 1920's who sat in row K seat 12 in the class that was taken over by a gr ...
Problem Set 8 ——– Answer Key - University of California, Berkeley
... If mRNA is 5’ UAU 3’, then anticodon will be 3’ AUA 5’ If mRNA or 5’ UAC3’, then anticodon will be 3’AUG 5’ (f) What is special about the amino acid methionine? Methionine is the first amino acid on the polypeptide chain. Its codon, AUG, serves as the start codon. 2. Regulation of Gene Expression Mu ...
... If mRNA is 5’ UAU 3’, then anticodon will be 3’ AUA 5’ If mRNA or 5’ UAC3’, then anticodon will be 3’AUG 5’ (f) What is special about the amino acid methionine? Methionine is the first amino acid on the polypeptide chain. Its codon, AUG, serves as the start codon. 2. Regulation of Gene Expression Mu ...
Derived copy of Bis2A 14.1 Bacterial Gene
... The third type of gene regulation in prokaryotic cells occurs through inducible operons, which have proteins that bind to activate or repress transcription depending on the local environment and the needs of the cell. The lac operon is a typical inducible operon. As mentioned previously, E. coli is ...
... The third type of gene regulation in prokaryotic cells occurs through inducible operons, which have proteins that bind to activate or repress transcription depending on the local environment and the needs of the cell. The lac operon is a typical inducible operon. As mentioned previously, E. coli is ...
Why genes are regulated?
... What affects the repressor binding to the operator: genome size, specificity of the repressor, the amount of the repressor existed/required 1. Repressors have a high affinity for a specific DNA sequence and also have a low affinity for other DNA sequences. 2. Hence, the large number of low-affinity ...
... What affects the repressor binding to the operator: genome size, specificity of the repressor, the amount of the repressor existed/required 1. Repressors have a high affinity for a specific DNA sequence and also have a low affinity for other DNA sequences. 2. Hence, the large number of low-affinity ...
Gene regulation I Biochemistry 302
... Gene regulation II Biochemistry 302 Bob Kelm February 28, 2005 ...
... Gene regulation II Biochemistry 302 Bob Kelm February 28, 2005 ...
Eukaryotic Gene Regulation
... polymerase binds and then begins transcription. The other region is the operator (O). E. coli cells contain several copies of a DNA-binding protein known as the lac repressor, which can bind to the O region. As the figure below shows, when the lac repressor binds to the O region, RNA polymerase is p ...
... polymerase binds and then begins transcription. The other region is the operator (O). E. coli cells contain several copies of a DNA-binding protein known as the lac repressor, which can bind to the O region. As the figure below shows, when the lac repressor binds to the O region, RNA polymerase is p ...
DNA binding
... Bacteria (such as E. coli) usually rely on glucose as their source of carbon and energy, even when other sugars are available. However, when glucose is scarce, E. coli can use lactose as their carbon source. ...
... Bacteria (such as E. coli) usually rely on glucose as their source of carbon and energy, even when other sugars are available. However, when glucose is scarce, E. coli can use lactose as their carbon source. ...
C1. A constitutive gene is unregulated, which means that its
... The λ repressor will first bind to OR1 and then OR2. The binding of the λ repressor to OR1 and OR2 inhibits transcription from PR and thereby switches off the lytic cycle. Early in the lysogenic cycle, the λ repressor protein concentration may become so high that it will occupy OR3. Later, when the ...
... The λ repressor will first bind to OR1 and then OR2. The binding of the λ repressor to OR1 and OR2 inhibits transcription from PR and thereby switches off the lytic cycle. Early in the lysogenic cycle, the λ repressor protein concentration may become so high that it will occupy OR3. Later, when the ...
Document
... The λ repressor will first bind to OR1 and then OR2. The binding of the λ repressor to OR1 and OR2 inhibits transcription from PR and thereby switches off the lytic cycle. Early in the lysogenic cycle, the λ repressor protein concentration may become so high that it will occupy OR3. Later, when the ...
... The λ repressor will first bind to OR1 and then OR2. The binding of the λ repressor to OR1 and OR2 inhibits transcription from PR and thereby switches off the lytic cycle. Early in the lysogenic cycle, the λ repressor protein concentration may become so high that it will occupy OR3. Later, when the ...
hypothesize that AraC can exist in 2 states, P1 and P2
... -since glucose is the preferred carbon source of E. coli, CAP ensures that other carbon utilization pathways are not expressed in the presence of glucose CATABOLITE REPRESSION -accordingly, CAP functions as a transcription activator of genes involved in metabolism of alternative carbon sources whe ...
... -since glucose is the preferred carbon source of E. coli, CAP ensures that other carbon utilization pathways are not expressed in the presence of glucose CATABOLITE REPRESSION -accordingly, CAP functions as a transcription activator of genes involved in metabolism of alternative carbon sources whe ...
Positive Control and Catabolite Repression
... • lacI+lacO+Z−/lacI+lacOclacZ+ produce fully functional β-galactosidase constitutively. ...
... • lacI+lacO+Z−/lacI+lacOclacZ+ produce fully functional β-galactosidase constitutively. ...
Ch 18
... • The phenomenon of inhibition of gene expression by RNA molecules is called RNA interference (RNAi) • RNAi is caused by small interfering RNAs (siRNAs) • siRNAs and miRNAs are similar but form from different RNA precursors • In some yeasts siRNAs play a role in heterochromatin formation and can bl ...
... • The phenomenon of inhibition of gene expression by RNA molecules is called RNA interference (RNAi) • RNAi is caused by small interfering RNAs (siRNAs) • siRNAs and miRNAs are similar but form from different RNA precursors • In some yeasts siRNAs play a role in heterochromatin formation and can bl ...
Test 2 - HCC Learning Web
... 19. What is the chemical reaction mechanism by which cells make polymers from monomers? 20. The bonding of two amino acid molecules to form a larger molecule requires ...
... 19. What is the chemical reaction mechanism by which cells make polymers from monomers? 20. The bonding of two amino acid molecules to form a larger molecule requires ...
Jacques Monod and the Advent of the Age of Operons
... Around this time two major advances occurred in the genetics of Escherichia coli through the pathbreaking work of Joshua Lederberg, William Hayes, Francois Jacob and Elie Woolman. The first was the discovery of bacterial conjugation which involved the transfer of parts of the chromosome from a donor ...
... Around this time two major advances occurred in the genetics of Escherichia coli through the pathbreaking work of Joshua Lederberg, William Hayes, Francois Jacob and Elie Woolman. The first was the discovery of bacterial conjugation which involved the transfer of parts of the chromosome from a donor ...
Gene Regulation
... presence of lactose), the trp Operon is repressed when high levels of tryptophan are present. In this case, the effector is the level of tryptophan Tryptophan is an amino acid that is used by E coli cells for the production of protein E coli cells located on the intestinal lining of a mammal c ...
... presence of lactose), the trp Operon is repressed when high levels of tryptophan are present. In this case, the effector is the level of tryptophan Tryptophan is an amino acid that is used by E coli cells for the production of protein E coli cells located on the intestinal lining of a mammal c ...
Argumentation activity: Gene expression regulation in bacteria You
... (a natural component of the human gut flora), the small molecule lactose (a sugar found in milk) controls expression of the genes whose protein products are responsible for metabolizing lactose (turning the lactose into energy). Q2: What protein product(s) is (are) being is being made in this case? ...
... (a natural component of the human gut flora), the small molecule lactose (a sugar found in milk) controls expression of the genes whose protein products are responsible for metabolizing lactose (turning the lactose into energy). Q2: What protein product(s) is (are) being is being made in this case? ...
Document
... The trp operon is a biosynthetic operon - it codes for the enzymes that make the amino acid tryptophan. This pathway should be kept in the “off” state when tryptophan is present. When tryptophan is absent, the bacteria need to make it from scratch. Now the pathway needs to be turned on. ...
... The trp operon is a biosynthetic operon - it codes for the enzymes that make the amino acid tryptophan. This pathway should be kept in the “off” state when tryptophan is present. When tryptophan is absent, the bacteria need to make it from scratch. Now the pathway needs to be turned on. ...
Ch 18
... Allolactose, an isomer of lactose, derepresses the operon by inactivating the repressor. In this way, the enzymes for lactose utilization are induced. lac operon ...
... Allolactose, an isomer of lactose, derepresses the operon by inactivating the repressor. In this way, the enzymes for lactose utilization are induced. lac operon ...
Jigsaw handout - the Biology Scholars Program Wiki
... repressor. Lac repressor is a DNA binding protein that binds to a site on the DNA called the operator. The operator partially overlaps with the promoter, which is the site where RNA polymerase binds to initiate transcription. When lac repressor binds to the operator site, RNA polymerase cannot bind ...
... repressor. Lac repressor is a DNA binding protein that binds to a site on the DNA called the operator. The operator partially overlaps with the promoter, which is the site where RNA polymerase binds to initiate transcription. When lac repressor binds to the operator site, RNA polymerase cannot bind ...
PowerPoint
... 11.1 Proteins interacting with DNA turn prokaryotic genes on or off in response to environmental changes • Early understanding of gene control ...
... 11.1 Proteins interacting with DNA turn prokaryotic genes on or off in response to environmental changes • Early understanding of gene control ...
High Frequency of Recombination (Hfr)
... Therefore, transcriptional initiation is usually the major control point. Most prokaryotic genes are regulated in units called operons (Jacob and Monod, 1960) Operon: a coordinated unit of gene expression consisting of one or more related genes and the operator and promoter sequences that regulate t ...
... Therefore, transcriptional initiation is usually the major control point. Most prokaryotic genes are regulated in units called operons (Jacob and Monod, 1960) Operon: a coordinated unit of gene expression consisting of one or more related genes and the operator and promoter sequences that regulate t ...
Gene Regulation - Marblehead High School
... and are occasionally responsible for costly product recalls. The harmless strains are part of the normal flora of the gut, and can benefit their hosts by producing vitamin K2, or by preventing the establishment of pathogenic bacteria within the intestine. ...
... and are occasionally responsible for costly product recalls. The harmless strains are part of the normal flora of the gut, and can benefit their hosts by producing vitamin K2, or by preventing the establishment of pathogenic bacteria within the intestine. ...
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.