Which of the following statements uses the term homologous correctly?A. The two X chromosomes in female mammalian cells are homologousto each other.B. The α-tubulin gene in Saccharomyces cerevisiae is homologousto the α-tubulin gene in Arabidopsis thaliana.C. The promoter of the lac operon is homologous to the promoterof the trp operon.D. The lacY genes of E. coli and K. pneumoniae are approximately60% homologous to each other.

Which of the following statements uses the term homologous correctly?A. The two X chromosomes in female mammalian cells are homologousto each other.B. The α-tubulin gene in Saccharomyces cerevisiae is homologousto the α-tubulin gene in Arabidopsis thaliana.C. The promoter of the lac operon is homologous to the promoterof the trp operon.D. The lacY genes of E. coli and K. pneumoniae are approximately60% homologous to each other.

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 9TYU: A mutation that inactivates the repressor gene of the lac operon results in (a) the continuous...

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When iron is scarce, some bacteria can stop synthesis of all enzymes that require iron (Fe3+), such as superoxide dismutase (SOD). Which of the following accurately describes a mechanism for this regulation? Mark all that apply. A. Regulation occurs by an inducible operon B. When absent, the lack of iron causes the repressor to deactivate and block the promoter region for these genes C. Regulation occurs by a repressible operon D. When present, iron binds and activates the repressor protein
Geneticists isolated six trains of E. coli (strains 1-6) whose lac operons had one of the following mutations (a-f): a. deletion of lacY b. oº mutation c. missense mutation in lacz d. inversion of the lac operon (which does not include the lacl gene) e. superrepressor mutation f. inversion of lacZ, Y, and Z, but not lacl, P, o Focusing on the mutation in B: a. what is the state of the lac operon (on, off, inducible, or constitutive)? b. Provide an explanation using repressor, RNA pol, transcription, and the appropriate regulatory region of the operon. c. If a pDNA of another lac operon is inserted into the bacteria with a wild type/normal copy of the DNA, how would this impact the transcription of the original mutant in B?
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…
Geneticists isolated six trains of E. coli (strains 1-6) whose lac operons had one of the following mutations (a-f): a. deletion of lacY b. oº mutation c. missense mutation in lacz d. inversion of the lac operon (which does not include the lacl gene) e. superrepressor mutation f. inversion of lacZ, Y, and Z, but not lacl, P, o Which of these mutations above would prevent cells from utilizing lactose?
Consider the lac operon of E. coli. Specifically, explain the following: a. Describe the overall chromosomal structure/organization of the operon, indicating the location and function of the regulatory regions and the structural genes. b. Is lac a catabolic or anabolic pathway? Explain. Is the operon inducible or repressible? Explain. c. Describe the mechanisms involved in negative control & positive control
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
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.
A mutation that inactivates the repressor gene of the lac operon results in (a) the continuous transcription of the structural genes (b) no transcription of the structural genes (c) the binding of the repressor to the operator (d) no production of RNA polymerase (e) no difference in the rate of transcription
Match the key complex or product to its related process of regulating gene expression. a. Constitutive genes b. Operons c. The lac operon d. An operator e. A repressor f. The trp operon g. Tryptophan h. A promoter 65. is induced by the presence of lactose in the environment. 66. is a repressed by the presence of tryptophan in the environment. 67. are regions of clustered genes under the control of one promoter.
IPTG (isopropylthiogalactoside) is commonly used to induce protein expression in Lac operon-regulated gene in E. Coli, because IPTG a. is a repressor to Lac operon. O b. is an enhancer binding compound. O C. O d. unwinds DNA, leading to DNA duplication and transcription. is a mimetic of allolactose, that binds to repressor, causing it release from the operator of the lac operon, leading to transcription.
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.
If the above gene is one of the three structural genes of the lac operon that codes for the protein/ enzyme responsible for breaking lactose into two molecules of simple sugars, what triggers the activation of this gene? a. Absence of Inhibitory protein b. Presence of lactose c. Absence of lactose d. Presence of Inhibitory protein e. Absence of Regulatory protein