E. coli has five genes that code for enzymes that make tryptophan. These genes are regulated by a single promoter and transcribed as one long gene. The presence of tryptophan shut down the production of tryptophan by the cell by binding to the repressor. This changes the repressors shape allowing it to bind to DNA operator, blocking RNA polymerase and cutting off the production of tryptophan. a. Describe what would happen to the operon if some of the cells had a mutation on the repressor, not allowing it to bind with tryptophan. The repressor is described as an allosteric protein. What does this mean? b. Does the tryptophan model demonstrate an inducible or repressible operon? What is your evidence?*

E. coli has five genes that code for enzymes that make tryptophan. These genes are regulated by a single promoter and transcribed as one long gene. The presence of tryptophan shut down the production of tryptophan by the cell by binding to the repressor. This changes the repressors shape allowing it to bind to DNA operator, blocking RNA polymerase and cutting off the production of tryptophan. a. Describe what would happen to the operon if some of the cells had a mutation on the repressor, not allowing it to bind with tryptophan. The repressor is described as an allosteric protein. What does this mean? b. Does the tryptophan model demonstrate an inducible or repressible operon? What is your evidence?*

Biology (MindTap Course List)

11th Edition

ISBN:9781337392938

Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Publisher:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg

Chapter14: Gene Regulation

Section: Chapter Questions

Problem 8TYU: Through alternative splicing, eukaryotes (a) reinforce gene inactivation (b) prevent transcription...

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E. coli has five genes that code for enzymes that make tryptophan. These genes are regulated by a single promoter and transcribed as one long gene. The presence of tryptophan shut down the production of tryptophan by the cell by binding to the repressor. This changes the repressors shape allowing it to bind to DNA operator, blocking RNA polymerase and cutting off the production of tryptophan. a. Describe what would happen to the operon if some of the cells had a mutation on the repressor, not allowing it to bind with tryptophan. The repressor is described as an allosteric protein. What does this mean? b. Does the tryptophan model demonstrate an inducible or repressible operon? What is your evidence?*
. In the tryptophan operon of E. coli, what happens when tryptophan levels get too high? tryptophan is removed from its co-repressor, causing it to detach from the operator tryptophan is removed from its co-repressor, causing it to attach to the operator tryptophan is bound to its co-repressor, causing it to detach from the operator tryptophan is bound to its co-repressor, causing it to attach to the operator all of the above occur at equal rates when tryptophan levels get too high
a. What is the function of operons in bacterial gene regulation? b. Describe how a bacterial operon can be regulated by repressible proteins (such as the tryptophan operon). Include in your description both the “on” and “off” states of the operon. Key elements of your diagram should include: Co-repressor, Genes, mRNA, Operator, Operon, Promoter, Repressor, RNA polymerase.
Compare and contrast the activities of an activator protein anda repressor protein.
If the lacl gene is mutated so that the repressor protein no longer binds to lactose, what will be the effect on the expression of B-galactosidase in lactose's presence and absence? Explain. If the promoter for lacl is mutated so that the expression of the repressor increases, what will be the effect on the expression of B-galactosidase in the presence and absence of lactose? Explain. D. (Extremely tricky question!) Describe the behavior of the lac operon assuming that the lacl gene has been mutated so that the repressor now binds to DNA in the presence of lactose but cannot bind to DNA in the absence of lactose.
siRNAs are used to “knockdown” gene expression in research. Imagine you are a scientist who hopes to study several genes related to cancer. Select all the scenarios you will be able to successfully use RNA interference with the use of siRNAs (select all that apply): Group of answer choices Regulate transcript levels by targeting the siRNA to core promoter regions (e.g. TATA box) of tumor suppressor genes Regulate transcript levels by targeting the siRNA to the regulatory promoter regions (e.g. enhancers) of tumor suppressor genes Regulate transcript levels by targeting the siRNA to any region of the processed mRNA Regulate transcript levels by targeting the siRNA to the 5’ UTR of the processed mRNA Regulate transcript levels by targeting the siRNA to the 3’ UTR of the processed mRNA Regulate transcript levels by targeting the siRNA to sites where the histone acetyl transferase will acetylate the histones Regulate transcript levels by targeting the siRNA to where the start…
in a fat cell what is the result of activation of genes by PPAR gamma/activator proteins binding? what is the result of inactivation of genes when PPAR gamma and repressor are bound ?
What role does an operator sequence serve in bacterial gene expression regulation? Describe one change in bacterial cells that can cause a repressor protein to go from inactive to active or from active to inactive.
E. coli are grown on a medium containing lactose. Once glucose is added to the medium, the bacteria stop fermenting lactose. Which of the following BEST explains the observed effect? A. Cellular levels of cAMP are lowB.Glucose is bound to the promoter C. Repressor protein is bound to the operator D. Repressor protein is bound to the promoter
You are growing E. coli in a laboratory in order to study their operons. The growth media you are using contains lactose, no glucose and no tryptophan. Using your knowledge of operons and their regulation a.Which operons would be functional under these conditions? b.What repressors would be made? (NOTE: name the repressors using their gene names) c.Which repressor(s) would be made in the inactive form? d.Which repressor(s) would be made in the active form? e.Which repressor(s) under these conditions can bind the operator sequence? f.Which repressor(s)under these conditions cannot bind the operator sequence?
Wilms tumor 1, or nephroblastoma, is caused by mutations in the WT1 gene, which encodes a transcription factor. You have identified a novel variant in WT1: Arg422Pro. You have control cells and cells that have been engineered to carry the homozygous WT1 p.Arg422Pro mutation. You want to assess effects of this mutation on a variety of endpoints. For each endpoint listed below, choose the one technique is best suited to answer the question. Choose from: array CGH, qRT-PCR, qPCR, RNA-seq, FISH, in situ hybridization, western blot, immunostaining, WT1 ChIP-seq, WT1 ChIP-PCR, ATAC-seq, 3C Endpoint Technique? WT1 protein amount (quantitative) Western blot WT1 protein binding to all enhancers, genome-wide Chip-seq WT1 mRNA amount (quantitative) WT1 protein subcellular localization Quantitative assessment of all mRNAs in these cells (genome-wide) RNAseq Chromatin interactions between a specific WT1 chromatin binding site (identified above)…
We have studied Ras signal transduction pathway. In an experiment, two different mutations were produced using different chemicals. The proteins with mutation are listed below. State what will be the effect of each mutation and explain whether it will result in cell proliferation or not. GEF protein GTPase