Match each of the following mechanisms with how it can change the levels of gene products--whether on different operons or within the same operon. Different promoters might have different DNA sequences Translation initiation 1. Differences in mRNA levels BETWEEN operons sequences can cause different open reading frames to be translated differently. 2. Differences in protein levels
Q: All of the following statements about the repressor of the lac operon of E. coli are true EXCEPT…
A: The lac operon is a clustered group of related genes that are transcribed as a single unit. These…
Q: The TRP operon functions by attenuation. Briefly explain how attenuation works and why it is…
A: Trp operon or the tryptophan operon is a group of genes that are responsible for tryptophan enzymes.…
Q: 5g. A mutation has occurred rendering the regulatory protein unable to recognize the operator…
A: Operons are groups of genes involved in regulating a process and are transcribed as a single mRNA.…
Q: In the lac and trp operons, the repressors are said to be “allosteric molecules” because…
A: Operons are basically the cluster of genes that can be transcribed together to give a messenger RNA…
Q: What is the difference between negative and positive regulation in operon? Explain it with the help…
A: BASIC INFORMATION OPERON MODEL This model of gene regulation was put forward by Francis Jacob and…
Q: A mutation at the operator prevents the regulator protein from binding. What effect will this…
A: An operon includes a group of genes that have a common promoter, regulator, and would be transcribes…
Q: Describe the regulation of the lac operon when lactose is present and glucose is present Your…
A: The operon consists of a series of structural gene like Z, Y and A. a segment of DNA called an…
Q: Which of the following statements about the trp operon is false?
A: From above question the statement If a mutation in region 2 prevents the formation of the 2 + 3…
Q: E. coli has five genes that code for enzymes that make tryptophan. These genes are regulated by a…
A: When a group of related genes exist under the control of a single promoter, it is referred to as an…
Q: Which of the following conditions is most likely to result in an increase rate of transcription of…
A: Lactose in bacteria is called beta-galactoside which is used as energy and as a carbon source.…
Q: Regulation of the E. coli trp operon by attenuation requires the trp repressor protein. prevents…
A: An operon is a function unit of DNA containing a set of genes including structural gene, a…
Q: A mutation that inactivates transcription and translation from the regulatory gene of an inducible…
A: An operon is a functional unit of genomic DNA that comprises a collection of genes that are all…
Q: The polycistronic Histidine Operon in E. coli encodes all of the proteins necessary for the…
A: An operon is a gene unit of bacterial system whose transcription is positively and negatively…
Q: You are growing E. coli in a laboratory in order to study their operons. The growth media you are…
A: 1. What effect does lactose have on the bacterial cell’s lac operon? Answer:- It induces the operon,…
Q: Which of the following mutations would result in the highest level of lac operon transcription in…
A:
Q: Explain how the following conditions will affect the regulation of the operon. Low cAMP levels; E.…
A: Operon is a sequence of DNA that consists of a set of genes which are involved in a particular…
Q: A novel operon is controlled by two regulatory systems that function in a hierarchy. The first is…
A: An operon can be defined as the cluster of coordinately controlled and regulated genes. It is…
Q: Choose the best options, by dragging and dropping the colour coded text boxes below, that fill in…
A: Operon is transcription unit of prokaryotic genome with consist of many contiguous structural genes…
Q: I need help with answer 2 and 3
A: Ans. 2 promoter sequence
Q: Which of the following describes the lac operon in E. coli when lactose and glucose is present in…
A: The lac repressor acts as a lactose sensor. It normally blocks transcription of the operon, but…
Q: Which of the following arabinose operon regulatory sites is exclusively involved in the repression…
A: Answer - Option B - ara O2
Q: Operons encoding catabolic enzymes are often _______, while those encoding anabolic enzymes are…
A: Answer - Option B - Activated by their enzymatic substrate; inhibited by the presence of their…
Q: One way that regulation is often studied is by examining the effects of mute ons. For example,…
A: There are two types of lac mutations occurring in lac operon: 1. uninducible - operon can't be…
Q: As diagrammed below, some amino acid biosynthetic operons have stem loop structures in the mRNA.…
A: Option A is incorrect as without the formation of heparin the process of translation can not be…
Q: Mutations may have an effect on the expression of the lac operon and the trp operon. Would the…
A: Mutations are defined as the change in the sequence of DNA of an organism due to any environmental…
Q: The lac operon in E. coli bacteria codes for proteins that break down (digest) the disaccharide…
A: The lac operon is expressed at its highest levels when there is lactose but no glucose (Option C is…
Q: The diagram below represents the tryptophan operon with the trp leader mRNA transcript enlarged to…
A: The trp operon is operated in most bacteria including E. coli which is a repressible operon. This…
Q: Let’s suppose you have isolated a mutant strain of E. coli in which the lac operon is constitutively…
A: Escherichia coli contains genes present in the lac operon that are activated in the absence of…
Q: The tryptophan operon is regulated by two methods. Describe in detail the regulation of the operon…
A: Genes are the functional unit of heredity. Operons are a group of genes under a single promoter. The…
Q: A researcher was trying to determine whether two molecules (A and B) were corepressors or inducers…
A: Gene expression is predominantly regulated at the transcriptional level, owing to protein binding to…
Q: Say you have an operon called the CAKE operon, it contains genes for the enzymes require to convert…
A: An operon consists of a set of genes regulated by a single promoter. The products of these genes are…
Q: You are growing E. coli in a laboratory in order to study their operons. The growth media you are…
A: According to our guideline we can answer only the first question up to first three subparts. So,…
Q: One of the main lessons of this chapter is that several bacterial genes are often transcribed from a…
A: As given: Several bacterial genes are often transcribed from a single promoter into a large…
Q: regulation of the lac operon by cAMP-CAP complex is an example of positive regulation. what in…
A: They are transcription, translation, post-transcription and post-translation. Genes which code for…
Q: What is the role of catabolite activator protein (CAP) in the lactose operon of E. coli? it…
A: Catabolite activator protein is a transcriptional activator. It binds RNA polymerase and activates…
Q: Which of the following diagrams best models the regulation of the trp operon when tryptophan is…
A: An operon is a polycistronic gene regulated by a common promoter and regulatory sequences. Operons…
Q: Mutations in the genes of an operon could affect the expression of its genes. For each statement,…
A: Introduction: Mutation can be defined as any change in DNA. This is any heritable and genetic change…
Q: Consider the following scenario: A bacteria cell is surrounded by lactose, but there is no glucose…
A: Lac operon is an operon model takes place in E coli bacteria . It consists of :- A)Promoter B )…
Q: Which of the following is true about the Lac operon? Group of answer choices An operon with a…
A: Operon is the cluster of genes found in DNA. It consists os regulatory gene, structural gene,…
Q: What is the role of catabolite activator protein (CAP) in the lactose operon of E. coli?
A: Lac operon Lac operon is a group of protein that code for enzyme β-galactosidase. The function of…
Q: Decide which operon each of the following characteristics applies to. Note: a description may apply…
A: Introduction "In E.coli And Other Bacteria, The Lac Operon Is An Operon Or A Set Of Genes With A…
Q: A mutation occurs in the 5′ UTR of the trp operon that reduces the ability of region 2 to pair with…
A: In the absence of tryptophan, the trp operon would be expressed maximum as the trp repressor would…
Q: Which of the following statements about the lactose operon in E. coli is TRUE? ) It contains the…
A: An operon is a functional unit of DNA (Deoxyribonucleic acid) containing a cluster of genes under…
Q: A mutation at the operator prevents the regulator protein from binding.What effect will this…
A: An operon is defined as a group of genes that have a common promoter and regulator and also…
Q: The promoter of an operon is the site to which RNA polymerase binds to begin transcription. Certain…
A: Promoter is a binding site for the RNA polymerase in the gene. The RNA polymerase is involved in the…
Q: Which statement does NOT explain why the lac operon would not be effectively regulated by an…
A: Lac operon is composed of a regulatory gene, promoter, operator, and structural genes. Lac operon is…
Q: In the presence of arabinose sugar and absence of glucose, which of the following conditions may be…
A: Arabinose could also be a five-carbon sugar that happens naturally and can be used as a result of…
Q: Discuss the regulation of the tryptophan operon. How does this story change under the two…
A: Introduction: The trp operon is a collection of genes found in E. coli bacteria that code for…
Q: f. Complete the diagrams below to reflect the proteins and any relevant cofactors (e.g. - inducer/…
A: Given:
Q: An E. coli cell as the following genotype for the lac operon system: I- OC Z+ / F’ I+. Which term…
A: The presence I+ repressor is dominant to the absence of a repressor I-. Oc mutants:- these are the…
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- . In an effort to determine the location of an operator sitefor a negatively regulated gene, you have made a seriesof deletions within the regulatory region. The extent ofeach deletion is shown by the line underneath the sequence, and the resulting expression from the operon(i = inducible; c = constitutive; − = no expression) isalso indicated.... GGAT C T T AGCCGGCTAACATGATAAATATAA......C C T AGAATCGGCCGA TTGTA C T A TTT ATAT T ...1 i2 –3 c4 –5 ca. What can you conclude from these data about thelocation of the operator site?b. Why do you think deletions 2 and 4 show no expression of the gene?One of the main lessons of this chapter is that severalbacterial genes are often transcribed from a singlepromoter into a large multigene (polycistronic) transcript. The region of DNA containing the set of genesthat are cotranscribed, along with all of the regulatoryelements that control the expression of these genes, iscalled an operon.a. Which of the mechanisms in the following listcould explain differences in the levels of themRNAs for different operons?b. Which of the mechanisms in the following listcould explain differences in the levels of theprotein products of different genes in the sameoperon?i. Different promoters might have different DNAsequences.ii. Different promoters might be recognized bydifferent types of RNA polymerase.iii. The secondary structures of mRNAs might differ so as to influence the rate at which they aredegraded by ribonucleases.PROBLEMSProblems 575a. Why did the mating with a nonlysogenic recipientresult in phage growth and release, but the infectionof a…You are studying an operon containing three genesthat are cotranscribed in the order hupF, hupH, andhupG. Diagram the mRNA for this operon, showingthe location of the 5′ and 3′ ends, all open readingframes, translational start sites, stop codons, transcription termination signals, and any regions thatmight be in the mRNA but do not serve any of thesefunctions.
- The promoter of an operon is the site to which RNApolymerase binds to begin transcription. Certain basechanges in the promoter result in a mutant site towhich RNA polymerase cannot bind. Would you expect mutations in the promoter that prevent binding ofRNA polymerase to act in trans on another copy ofthe operon on a plasmid in the cell, or only in cis onthe copy immediately adjacent to the mutated site?The activator (V protein) that is present in the bacterial cell is normally phosphorylated, but only binds to the A site in the operon when it is not phosphorylated. What operon-independent mechanism can regulate the binding of (and also ultimately regulates the removal of) protein V to the A site? Describe this binding/removal mechanism in detail – useappropriateterminologythatwasdiscussedinlecture. Aspartofyouransweraboutthisactivatorproteinbindingto (and then detaching from) the A site of the operon, be sure to address what are the results of this type of control in terms of function of the operon.You have isolated two different mutants (reg1 andreg2) causing constitutive expression of the emu operon (emu1 emu2). One mutant contains a defect in aDNA-binding site, and the other has a loss-of-functiondefect in the gene encoding a protein that binds tothe site.a. Is the DNA-binding protein a positive or negativeregulator of gene expression?b. To determine which mutant has a defect in the siteand which one has a mutation in the binding protein, you decide to do an analysis using F′ plasmids. Assuming you can assay levels of the Emu1and Emu2 proteins, what results do you predict forthe two strains (i and ii; see descriptions below) ifreg2 encodes the regulatory protein and reg1 is theregulatory site?i. F′ (reg1−reg2+emu1−emu2+)/reg1+reg2+emu1+emu2−ii. F′ (reg1+reg2−emu1−emu2+)/reg1+reg2+emu1+emu2−c. What results do you predict for the two strains(i and ii) if reg1 encodes the regulatory proteinand reg2 is the regulatory site?
- Maltose utilization in E. coli requires the proteins encoded by genes in three different operons. One operonincludes the genes malE, malF, and malG; the secondincludes malK and lamB; and the genes in the thirdoperon are malP and malQ. The MalT protein is apositive regulator that controls the expression of allthree operons; expression of the malT gene itself iscatabolite sensitive.a. What phenotype would you expect to result from aloss-of-function mutation in the malT gene?b. Do you expect the three maltose operons to containbinding sites for CRP (cAMP receptor protein)?Why or why not?In order to infect E. coli, bacteriophage λ binds to themaltose transport protein LamB (also known as the λreceptor protein) that is found in the outer membraneof the bacterial cell. The synthesis of LamB is induced by maltose in the medium via expression of theMalT protein, as described aboveMaltose utilization in E. coli requires the proteins encoded by genes in three different operons. One operonincludes the genes malE, malF, and malG; the secondincludes malK and lamB; and the genes in the thirdoperon are malP and malQ. The MalT protein is apositive regulator that controls the expression of allthree operons; expression of the malT gene itself iscatabolite sensitive.a. What phenotype would you expect to result from aloss-of-function mutation in the malT gene?b. Do you expect the three maltose operons to containbinding sites for CRP (cAMP receptor protein)?Why or why not?In order to infect E. coli, bacteriophage λ binds to themaltose transport protein LamB (also known as the λreceptor protein) that is found in the outer membraneof the bacterial cell. The synthesis of LamB is induced by maltose in the medium via expression of theMalT protein, as described above.c. List the culture conditions under which wild-typeE. coli cells would be sensitive to infection bybacteriophage…ne of the main lessons of this chapter is that several bacterial genes are often transcribed from a single promoter into a large multigene (polycistronic) transcript. The region of DNA containing the set of genes that are cotranscribed, along with all of the regulatory elements that control the expression of these genes, is called an operon. a. Which of the mechanisms in the following list (i-vi) could explain differences in the levels of the protein products of different genes in the same operon? Different promoters might have different DNA sequences Different promoters might be recognized by different types of RNA polymerase The secondary structures of mRNAs might differ which will influence the rate at which they are degraded by ribonucleases. In an operon, some genes are farther away from the promoter than other genes The translational initiation sequences at the beginning of different open reading frames in an operon might result in different efficiencies of translation Proteins…
- The E. coli MalT protein is a positive regulator ofseveral mal operons, which are induced in the presenceof the sugar maltose. The gene that encodes MalT wasidentified in a screen for mutants causing constitutiveexpression of mal operons; the operons were transcribedeven in the absence of maltose. The screen involved alacZ transcriptional fusion reporter gene in which theregulatory region of a maltose-inducible operon wasfused to the coding sequences of lacZ.a. Bacteria with a lacZ− mutation are transformedwith the reporter gene and spread on petri platescontaining the β-galactosidase substrate X-gal.What color would the colonies be if the plates alsocontained maltose? What if the plates had X-galbut no maltose?b. In the screen, scientists mutagenized the lacZ− bacteria before transforming them with the reportergene, and then spread the transformed bacteria onplates with X-gal and no maltose. All of the colonies were white except for one colony that wasblue. At this stage of the…The figure at the beginning of this chapter showsthe binding of both a Lac repressor tetramer and aCRP-cAMP complex to the regulatory region of thelac operon.a. What is the key feature of a regulatory protein suchas the Lac repressor or CRP that allows it to regulate specifically the genes or operons it is supposedto control?b. On the figure, show the positions of the followingcomponents: (i) A Lac repressor monomer; (ii) a Lacrepressor dimer; (iii) all four DNA binding domains ofthe Lac repressor tetramer; (iv) a single helix-turnhelix motif; (v) the o1 part and either the o2 or o3 partsof the lac operator (assume the operon would be transcribed from right to left on the figure); (vi) themultimerization domains of the four Lac repressormonomers; (vii) an inducer-interacting domain; (viii)the CRP-cAMP complex; and (ix) a DNA loop.c. What is the physical basis for the formation of theDNA loop shown in the figure?d. On the figure, show the position of two axes ofsymmetry in the sequence…Resection of a bacterial chromosome in which genes for the enzymes of of a particular metabolic pathway are clusteredtogether in a functional complex under coordinate control is called operon activator promotor repressor operator