If you made a mutation in the operator region of the lac promoter such that LacI can no longer bind to it, what would be the effect on lac operon expression?
Q: A mutation in the lac operator that prevents binding of the lac repressor to the operator
A: Lac operon The lac operon is a group of genes with a single promoter. It consists of three genes…
Q: In the lac operon system, do the inducers act at the transcription or translation level? Explain why…
A: The lactose operon (lac operon) consists of a regulatory gene (i-gene) and three structural genes -…
Q: What role does the I gene product play in regulation of the Lac operon
A: The operon plays an important role in bacteria. The lac operon is an essential operon useful for…
Q: In E. coli, induction in the lac operon and repression in the trp operon are both examples of a.…
A: Transcription, translation, post-transcription and post-translation. The process in which the gene…
Q: If an abnormal repressor protein could still bind allolactose but the binding of allolactose did not…
A: Operon acts as a single regulated unit having one or more structural genes, promoter gene, a…
Q: Which of the following molecules is an inducer of the lac operon:a. Galactose d. Isothiocyanateb.…
A: The structural genes lac z, lac y, and lac in the lac operon code for beta-galactosidase (converts…
Q: A mutation in the operator region of the trp operon can prevent the trp repressor from binding to…
A: Operons are the functional unit of transcription and regulation of genes in almost all bacteria and…
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 elements of the lac operon and its associated regulatory factors function in…
A: One of many types of functional regulatory elements are cis-regulatory modules. Regulatory elements…
Q: What is the function of the Z gene of the Lac operon?
A: The lactose is cleaved into glucose and galactose by the enzyme β-galactosidase which is coded by…
Q: Which of the following is false when the genes of the Lac operon are being tran- scribed in high…
A: Lac operon is a set of genes used by E.coli to metabolize lactose when glucose is not available for…
Q: Which of the following statements can be made concerning the role of the lac repressor (Lac R) in…
A: The lac repressor is a protein that binds to the promoter sequence of the lac operon and inhibits…
Q: In the lac operon, how would gene expression be affected if each one of the following segments was…
A: The lac operon is basically a group of genes with a single promoter whose genes encode proteins that…
Q: Why is the TRP operon considered a repressible operon, while the LAC operon is considered an…
A: Operons are areas of DNA which are composed of cluster of related genes which are controlled by…
Q: A mutation in the lac I gene that prevents production of the lac repressor choose an answer below:…
A: lac operon also known as lactose operon was discovered by F. Jacob and J. Monod, for that, they…
Q: Which enzyme will be produced in a cell where a nonsense mutation is present in the lac operon?
A: In genetics, the mutation in which a sense codon that corresponds to one of the twenty amino acids…
Q: A mutation prevents the catabolite activator protein (CAP) from binding to the promoter in the lac…
A: Mutation means sudden changes occur in DNA sequences. The mutation occurs randomly. It also occurs…
Q: How do we know that the trp operon is a repressible controlsystem, in contrast to the lac operon,…
A: Introduction The process by which the information contained in a gene is used to drive the assembly…
Q: Why it is essential to the positive stimulation of transcription of the lac operon ?
A: Lac operon includes the genes that code for the enzymes involved in lactose catabolism.
Q: How does exposing an E. coli cell to glucose affect the regulation of the lac operon via CAP? a.…
A: Catabolite activator protein (CAP) impacts the expression of the lac operon based on the catabolites…
Q: What is the difference between positive regulation of the lac operon and negative regulation of the…
A: The lac operon is a set of three bacterial genes under the control of a single promoter which is…
Q: In E. coli, the trp operon is on by default, while the lac operon is off. Why do you think that this…
A:
Q: A low level of expression of lac operon occurs at all the time.can you explain the logic behid this…
A: The operon is the group of genes controlled by shared protein. Operons have multiple genes with…
Q: The transcription of many bacterial genes relies on functional groups called operons, such as the…
A: Turning/switching genes on and off is referred to as gene regulation. Cells start to take on…
Q: In a bacterial operon, the active repressor bind to the A. promoter. B. terminator. C.…
A: The operon concept can be defined as a DNA containing a set of genes that are transcribed basically…
Q: Why do eukaryotic cells not have a lac operon? A. Eukaryotic cells cannot transcribe multiple genes…
A: Lac operon is a gene regulating unit present in prokaryotes. It consists of a promoter, repressor,…
Q: If you make a large deletion in the lac operon to remove the operator region, will the structural…
A: Lac operpon Is an operon or a group of genes with a single promoter that encode genes for the…
Q: In the lac operon, regulation of gene expression by CAP-CAMP is a type of O a. positive repressible…
A: Lac operon can be defined as the set of constitutive genes with a single promoter that encodes for…
Q: when tryptophan is present, what would happen to trp operon regulation
A: Introduction:- The trp operon is a collection of genes identified in E. coli bacteria that code for…
Q: Under which of the following conditions will transcription of the lac operon occur?a) Lactose…
A: Introduction All the gene expressions are under high regulation and this is necessary to avoid…
Q: For some time it was not clear whether lac repressor inhibits lac operon transcription by inhibiting…
A: Lac operon is a transcriptional regulation of lactose metabolism seen in prokaryotes. It was…
Q: You have E. coli growing in HIGH lactose and HIGH glucose. You measure the amounts of protein and…
A: The E.coli is growing in a medium rich in lactose and Glucose both. There are two regulatory…
Q: For some time, it was not clear whether lac repressor inhibits lac operon transcription by…
A: The binding of the lac repressor to the RNA(ribonucleic acid) polymerase of the lac transcription…
Q: Select all of the cis-acting regulatory elements of the lac operon. Operator CAP+cAMP CAP+cAMP…
A: lac operon: - Inducible system - Both positive and negative regulation - Involved in lactose…
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 will be bound to the Lac Operon in an environment with lactose and glucose? A) both repressor…
A: The bacteria comprise many operons and one of the important operons is lac operon. Lac operon is…
Q: The lac operon produces enzymes that allow the bacteria E. coli to metabolize lactose, it is in an…
A: Operon is a bacterial and viral genetic regulation mechanism in which genes coding for functionally…
Q: There is a mutation in sequence of the lac operator that prevents the lac repressor from being able…
A: Gene expression is regulated at the level of transcription by operon systems. In prokaryotes,…
Q: ill the Lac Operon be turned off or on if the allolactoase is
A:
Q: Which reaction normally happens in the regulation of the trp operon when high levels of tryptophan…
A: The trp repressor controls the trp operon. When coupled to tryptophan, the trp repressor prevents…
Q: The blob operon produces enzymes that convert compound A into compound B. The operon is controlled…
A: Operon is a term used for the functional unit of the DNA that contains the cluster of genes which…
Q: What does the lac operon consist of? How is the operator switch turned on and off in the expression…
A: Lac operon is the operon or machinery for the transport and metabolism of lactose in Escherichia…
Q: What is the difference between the role of the operator and the role of the promoter in an operon
A: According to Jacob and monod concept, operon is a group of contiguous structural genes showing…
Gene Interactions
When the expression of a single trait is influenced by two or more different non-allelic genes, it is termed as genetic interaction. According to Mendel's law of inheritance, each gene functions in its own way and does not depend on the function of another gene, i.e., a single gene controls each of seven characteristics considered, but the complex contribution of many different genes determine many traits of an organism.
Gene Expression
Gene expression is a process by which the instructions present in deoxyribonucleic acid (DNA) are converted into useful molecules such as proteins, and functional messenger ribonucleic (mRNA) molecules in the case of non-protein-coding genes.
If you made a mutation in the operator region of the lac promoter such that LacI can no longer bind to it, what would be the effect on lac operon expression?
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- What would happen if the operator sequence of the lac operon contained a mutation that prevented the repressor protein from binding the operator? (Explain what would happen both in the presence and absence of lactose)You identify a mutant that affects lac operon expression. You decide to investigate this mutant further by adding a construct into the mutant's cells that contains a wild type version of the full lac operon as well as lacl. When haploid, the lac operon is constitutive. When the wild type construct is added to make a merodiploid, the lac operon is still constitutive. Based on the mutant phenotypes we learned about in class, indicate which of the following might be mutated in the mutant (if there is more than one possibility, then list them all). O The operator is mutated. O The lac repressor ligand-binding domain is mutated. The lac repressor tetramerization/dimerization domain is mutated. O The lac repressor DNA-binding domain is mutated. O The lac repressor is deleted in the mutant.You identify a mutant that affects lac operon expression. You decide to investigate this mutant further by adding a construct into the mutant's cells that contains a wild type version of the full lac operon as well as lacl. When haploid, the lac operon is uninducible. When the wild type construct is added to make a merodiploid, the lac operon is still uninducible. Based on the mutant phenotypes we learned about in class, indicate which of the following might be mutated in the mutant (if there is more than one possibility, then list them all). O The lac repressor tetramerization/dimerization domain is mutated. The lac repressor ligand-binding domain is mutated. The operator is mutated. The lac repressor DNA-binding domain is mutated. O The lac repressor is deleted in the mutant.
- Let’s suppose you have isolated a mutant strain of E. coli in which the lac operon is constitutively expressed. In other words, the operon is turned on in the presence or absence of lactose. One possibility is that the mutation mayblock the transcription of the lacI gene, thereby preventing the synthesis of lac repressor. A second possibility is that the mutation could alter the sequence of the lac operator in a way that prevents lac repressor from binding to the operator. How would you distinguish between these two possibilities?If glucose levels in the cell are high and lactose is available from the environment, what is the status of transcription of the lac operon genes? Explain your answer from both an evolutionary perspective and in terms of negative and positive regulation of the operon?Let’s suppose you have isolated a mutant strain of E. coli in which the lac operon is constitutively expressed. In other words, the operon is turned on in the presence or absence of lactose. One possibility is that the mutation may block the transcription of the lacI gene, thereby preventing the synthesis of lac repressor. A second possibility is that the mutation could alter the sequence of the lac operon in a way that prevents the repressor protein from binding to the operator. How would you distinguish between these two possibilities?
- To study the lac operon, you engineer a strain of E coli to have a lac operon in which the lac Z gene is replaced by the gene for green fluorescent protein (GFP). Expression of GFP generates a green color in the cells that can be easily quantitated with a fluorescence microscope. You test the activity of the operon in the absence of the inducer IPTG, the presence of the inducer IPTG and the presence of an antibiotic the completely inhibits RNA polymerase (i.e. no gene expression). You then use this system to test the effects of various mutation on the activity of the operon. Match the following mutations with the activity (A, B or C) you would expect to observe with the mutation. All experiments are done in the presence of IPTG unless otherwise stated.If glucose is not available, but lactose is available from the environment, what is the status of transcription of the lac operon genes? Explain your answer from both an evolutionary perspective and in terms of negative and positive regulation of the operon?You have isolated different mutants (reg1 and reg2) causing constitutive expression of the emu operon (which has genes emu1 and emu2). One mutant contains a defect in a DNA-binding site, and the other has a loss-of-function defect in the gene encoding a protein that binds to the site Say you don’t know which mutant has a defect in the site and which one has a mutation in the binding protein. To figure it out, you construct the two partial diploid strains (i and ii below), and you then assay the levels of the Emu1 and Emu2 proteins in these two strains. F’ (reg1- reg2+ emu1- emu2+) / reg1+ reg2+ emu1+ emu2- F’ (reg1+ reg2- emu1- emu2+) / reg1+ reg2+ emu1+ emu2- What proteins do you predict will be expressed for strains i and ii if reg2 encodes the regulatory protein and reg1 is the regulatory site?
- What experimental results would indicate that the mutation lacISlacIS is dominant to lacI+lacI+? In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in a repressed state in the absence of lactose. In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in a constitutive state in the absence of the repressor. In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in an activated state in the presence of lactose. In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in a repressed state in the absence of the repressor. In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in a repressed state in the presence of lactose.Tryptophan (Trp) attenuation is an extra mechanism of regulation of trp operon when trp level is too high. Attenuation causes premature transcription termination. b) Predict what will happen if trp repressor lose its allosteric effect.You are doing a genetic engineering experiment. You use restrictions enzymes to cut the regulatory sequences from the lac operon and replace them with the regulatory sequences of the trp operon. Specifically, you will eliminate everything upstream of the beginning of lacZ and replace them with the trp sequences upstream of the beginning of trpE, including trpR. Now, describe the regulation of your ñew constructed gene. What will you do to get expression of the three lac genes? The lac Operon and its Control Elements lacl CAP P lacz lacY lacA genes 5 DNA binding site 3 AUG AUG AUG messenger RNA RNA polymerase blocked from transcribing trp operon Regulatory gene trp operon T PR Ptrp DNA trpR trpE trpD trpC trpB trpA Repressor bound to operator Promoter 5' trpR-MRNA R (a) Tryptophan present, repressor bound to operator, operon repressed. When complexed with tryptophan, the repressor protein produced by the trpR gene binds tightly to the trp operator, thereby preventing RNA polymerase from…