In the presence of excess tryptophan, a repressor protein binds the operator of the trp operon and prevents the operon from being transcribed. In the absence of lactose, the lacR repressor protein binds the lac operon. In the presence of the sugar arabinose, an activator protein binds the promoter of the genes responsible for processing arabinose and induces their transcription.

In the presence of excess tryptophan, a repressor protein binds the operator of the trp operon and prevents the operon from being transcribed. In the absence of lactose, the lacR repressor protein binds the lac operon. In the presence of the sugar arabinose, an activator protein binds the promoter of the genes responsible for processing arabinose and induces their transcription.

Name: Ⓒ Macmillan LearningClassify the given examples of prokaryotic gene e
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Description: Ⓒ Macmillan LearningClassify the given examples of prokaryotic gene expression as positive or negative gene regulation.54$RIn the presence of excess tryptophan, a repressor protein binds the operator of the trp operon and prevents the operon from be

Biology 2e

2nd Edition

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:Matthew Douglas, Jung Choi, Mary Ann Clark

Chapter16: Gene Expression

Section: Chapter Questions

Problem 14RQ: A scientist compares the promoter regions of two genes. Gene A’s core promoter plus proximal...

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Q1. Bioluminescence is emitted by the marine bacterium Vibrio fischeri in response to the concentration of a chemical signal. The luxCDABEG genes form part of an operon that encodes all of the structural components necessary for light production. At high cell density, the concentration of the inducer increases and can bind to LuxR protein which then activates transcription of the operon. What kind of operon is the Lux operon? [Positive Inducible, Positive Repressible, Negative Inducible, Negative Repressible?] Q2. A population of bacteria has a Lux operon that produces bioluminesence via an autoinducer that activates a transcription factor. You grow a flask of cells that have a loss-of-function mutation in the gene that encodes the enzyme that produces an autoinducer. What is the predicted bioluminesence in this population at high and low density?
1. Please tell me: What's a mutation in moleculer terms? 2. When a mutation deletes a base in genomic DNA, how does it affect the expression product production and reading frame? 3. How does induction control enzyme synthesis using lactose operon?
10. Think about the situation where there is an increased concentration of both glucose and allolactose in the media. Does this situation lead to the lac operon activation or not? Justify your answer? 11. Draw the structure of lac operon and its action when the following conditions are prevailing in the media: increased glucose, low glucose, higher c-AMP, low c-AMP, higher glucose, and high c-AMP, low glucose and High c-AMP, Higher glucose and higher allolactose? please assist with the above two questions
A scientist compares the promoter regions of two genes. Gene A’s core promoter plus proximal promoter elements encompasses 70bp. Gene B’s core promoter plus proximal promoter elements encompasses 250bp. Which of the scientist’s hypotheses is most likely to be correct? More transcripts will be made from Gene B Transcription of Gene A involves fewer transcription factors Enhancers control Gene B’s transcription Transcription of Gene A is more controlled than transcription of Gene B.
INTERPRET DATA Develop a simple hypothesis that would explain the behavior of each of the following types of mutants in E. coli. Mutant a: The map position of this mutation is in the trp operon. The mutant cells are constitutive; that is, they produce all the enzymes coded for by the trp operon, even if large amounts of tryptophan are present in the growth medium. Mutant b: The map position of this mutation is in the trp operon. The mutant cells do not produce any enzymes coded for by the trp operon under any conditions. Mutant c: The map position of this mutation is some distance from the trp operon. The mutant cells are constitutive; that is, they produce all the enzymes coded for by the trp operon, even if the growth medium contains large amounts of tryptophan.
For the E. coli lac operon, when lactose is present: a. and glucose is absent, cAMP binds and activates catabolicactivator protein (CAP). b. and glucose is absent, the level of cAMP decreases. c. activated CAP binds the repressor protein to remove it from the operator gene. d. the cell prefers lactose over glucose. e. RNA polymerase cannot bind to the promoter.
4) Suppose you have an E. coli in which the gene that codes for the lac repressor protein has been mutated in such a way that the protein produced can bind to both lactose and DNA (at its specific binding site in the lac operon promoter) simultaneously. What effect, if any, would this have on regulation of expression of the lac operon? Briefly (1 sentence) explain why you would predict the effect or lack of effect this mutation would have.
1. How does induction control enzyme synthesis using lactose operon? 2. Describe how level of a key metabolite [tryptophane] controls the gene function using tryptophane operon
1. Describe which enzymes are required for lactose and tryptophan metabolism inbacteria when lactose and tryptophan, respectively, are (a) present and (b)absent. 2. Contrast positive versus negative regulation of gene expression. Describe therole of the repressor in an inducible system and in a repressible system.
How does the 4 feature of transcription factors namely the structural motifs of DNA binding protein, activation domains, multiple transcription factors and enhancers help in the design of a building block tool. U can use the SrY gene as ur building block tool. Pls explain in details using those features of the transcription factors. In 400 words
1. A)Explain the mechanism by which the lac operon is sensitive to glucose levels (presence and absence of glucose). B)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?
4. Which or which (can select more than one alternative) of the control methods of genetic expression in eukaryotes NOT USED in prokaryotic cells?to. control how often a gene is expressedb. control how an mRNA is processedc. control which mRNA is exported from the nucleus to the cytosold. control which mRNA is translated to proteins in the ribosomeand. control how quickly proteins are destroyed once synthesized 5. Unlike DNA that usually forms a helical structure, different RNA molecules assume bends in a wide variety of 3D shapes. This is due to :to. RNA contains uracil and ribose as sugarb. the bases in the RNA cannot form hydrogen bonds with each otherc. nucleotides in RNA have a different chemical structure than they have in DNAd. Although RNA is single-stranded, complementary bases can pair with each other. 6. Viruses consist of a layer of protein that surrounds your genetic material. the genetic material in the HIV virus is:to. Double-stranded DNA (dsDNA)b. Single-stranded DNA…