Six strains of E. coli (mutants 1-6) that had one of the following mutations affecting the lac operon were isolated. a. deletion of lacY b. lacO mutation c. missense mutation in lacZ d. inversion of the lac operon (but not an inversion of the lacl gene) e. superrepressor mutation f. inversion of lacZ, Y, and A but not lacl, P, O The entire lac operon (including the lacI gene and its promoter) from each of the six E. coli strains was cloned into a plasmid vector containing an ampicillin resistance gene. Each recombinant plasmid was transformed into each of the six strains to create merodiploids, and each was plated on ampicillin media in which lactose is the only carbon source. (Ampicillin was included to ensure maintenance of the plasmid.) Growth of the transformants is scored here (a “+" sign = growth, a "-" sign = no growth). Synthesis of ß-galactosidase and permease are required for growth on this medium. Results of this merodiploid analysis are shown on the table given above. Which mutant bacterial strain contained each of the alterations listed previously? Justify your answers. It is given that mutation 1 was found to be a deletion of the lacY gene. 2. 1. 2. 3.

Six strains of E. coli (mutants 1-6) that had one of the following mutations affecting the lac operon were isolated. a. deletion of lacY b. lacO mutation c. missense mutation in lacZ d. inversion of the lac operon (but not an inversion of the lacl gene) e. superrepressor mutation f. inversion of lacZ, Y, and A but not lacl, P, O The entire lac operon (including the lacI gene and its promoter) from each of the six E. coli strains was cloned into a plasmid vector containing an ampicillin resistance gene. Each recombinant plasmid was transformed into each of the six strains to create merodiploids, and each was plated on ampicillin media in which lactose is the only carbon source. (Ampicillin was included to ensure maintenance of the plasmid.) Growth of the transformants is scored here (a “+" sign = growth, a "-" sign = no growth). Synthesis of ß-galactosidase and permease are required for growth on this medium. Results of this merodiploid analysis are shown on the table given above. Which mutant bacterial strain contained each of the alterations listed previously? Justify your answers. It is given that mutation 1 was found to be a deletion of the lacY gene. 2. 1. 2. 3.

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Give the levels of Beta-galactosidase activity (high or low or zero) expected for the following partial diploids for the lac operon strains.
Mutants were isolated in which the constitutive phenotype of a missense lacl mutation was suppressed. That is, the operon was now inducible. These suppressor mutations mapped to the operon, not to the lacl gene. What could these mutations be?
The organization and function of the lac operon in E. coli is shown in the following figures: XXI Transcription Repressor mRNA Translation RNA polymerase M M Flask ZYA XXXX Active M-repressor protein Repressor active, operon off. The repressor protein binds with the operator, preventing transcription from the operon. (a) An inducible operon Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Allolactose (inducer) Carbon/Energy Source 0 Z MInactive repressor protein (a) An inducible operon Transcription Translation XXX Permease B-Galactosidase Transacetylase Operon mRNA 3 Repressor inactive, operon on. When the inducer allolactose binds to the repressor protein, the inactivated repressor can no longer block transcription. The structural genes are transcribed, ultimately resulting in the production of the enzymes needed for lactose catabolism. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Suppose you inoculate three flasks of minimal…
Which of the following statements is true regarding transcriptional attenuation of the trp operon? a. The leader peptide encodes a protein that binds to the operator site b. Translation of the leader peptide stalls when tryptophan levels are high c. Stalling of the ribosome in region 1 of the leader peptide inhibits formation of the transcriptional terminator sequence d. This kind of mechanism can only occur in prokaryotes e. Both c. and d. are true
Explain how the lac operon is regulated under the following conditions. Include the following terms in your answers: Repressor, Operator, RNA polymerase, CAP site, CAP protein, Promoter A. Lactose and glucose are both present. B. Lactose and glucose are both absent. C. Lactose is present and glucose is absent.
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?
1) A. What is the difference between a repressible vs, an inducible operon? B. Using diagrams and words, describe how the Lac Operon is regulated by different levels of lactose and glucose. Be sure to show what’s happening at the molecular level, including the roles of lactose, glucose the repressor protein, cAMP and CAP.
. Listed in parts a through g are some mutations that were found in the 5′ UTR of the trp operon of E. coli. What will the most likely effect of each of these mutations be on the transcription of the trp structural genes? Q. A mutation that prevents the binding of the ribosome to the 5′ end of the mRNA 5′ UTR
There is Hyaluronic acid synthesis occuring in Group X Strep and it is controlled by an operon with 3 genes, called hasXYZ. Based on the 3-line diagram model, a. How many ribosome binding sites are there for the protein? b. How many promoters are there for the genes? c. How many start codons are there for the protein? d. How many RNA Polymerase binding locations are there for the genes? e. How many proteins will be fully functional? f. How many mRNA strands are made?