ESSENTIALS OF GENETICS-MODIFIED ACCESS
9th Edition
ISBN: 9780134190006
Author: KLUG
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 15, Problem 16PDQ
A marine bacterium is isolated and is shown to contain an inducible operon whose genetic products
In an attempt to understand how the operon functions, a constitutive mutant strain and several partial diploid strains were isolated and tested with the results shown here:
| Host Chromosome | F' Factor | |
| wild type | none | inducible |
| wild type | reg gene from mutant strain | inducible |
| wild type | operon from mutant strain | constitutive |
| mutant strain | reg gene from wild type | constitutive |
Draw all possible conclusions about the mutation as well as the nature of regulation of the operon. Is the constitutive mutation in the trans-acting reg element or in the cis-acting o operator element?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
In addition to observing similarities to the lac operon, you also notice that this gene is regulated via attenuation, similar to the trp operon. Based on this similarity to this model operon, you could state that ___________.
Group of answer choices
If a terminator loop forms in the DNA, the expression of the structural genes is halted.
The formation of the terminator hairpin followed by a series of Uracil (UUUUUUU) functions similar to Rho-Independent termination to result in the stopping of transcription.
The transcription of a leader sequence affects the translation of the structural genes.
Never mind – all of these statements are true!
Attenuation will be the primary means of transcriptional regulation, with a repressor used as a back up option.
For the following questions, describe the expression levels of the structural genes in the Trp operon under the conditions described.
In the absence of tryptophan, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"]
In the presence of tryptophan, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"]
In the absence of tryptophan and the promoter sequence was mutated such that the RNA polymerase can no longer bind, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"]
In the presence of tryptophan and the promoter sequence was mutated such that the RNA polymerase can no longer bind, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"]
In the absence of tryptophan and the trpR repressor gene is mutated such that the…
For the following questions, describe the expression levels of the structural genes in the Trp operon under the conditions described.
In the absence of tryptophan, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"]
In the presence of tryptophan, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"]
In the absence of tryptophan and the promoter sequence was mutated such that the RNA polymerase can no longer bind, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"]
Chapter 15 Solutions
ESSENTIALS OF GENETICS-MODIFIED ACCESS
Ch. 15 -
CASE STUDY | A mysterious muscular dystrophy
A...Ch. 15 -
CASE STUDY |A mysterious muscular dystrophy
A...Ch. 15 -
CASE STUDY |A mysterious muscular dystrophy
A...Ch. 15 -
HOW DO WE KNOW?
1. In this chapter, we have...Ch. 15 -
2. Review the Chapter Concepts list on p. 280....Ch. 15 - Describe which enzymes are required for lactose...Ch. 15 - Contrast positive versus negative regulation of...Ch. 15 -
5. Both attenuation and riboswitches rely on...Ch. 15 - For the lac genotypes shown in the accompanying...Ch. 15 -
7. For the genotypes and conditions (lactose...
Ch. 15 -
8. The locations of numerous lacI– and lacIs...Ch. 15 - Explain why catabolite repression is used in...Ch. 15 - Describe experiments that would confirm whether or...Ch. 15 - Predict the level of genetic activity of the lac...Ch. 15 - Predict the effect on the inducibility of the lac...Ch. 15 -
13. Describe the role of attenuation in the...Ch. 15 -
14. In a theoretical operon, genes A, B, C, and D...Ch. 15 - A bacterial operon is responsible for production...Ch. 15 - A marine bacterium is isolated and is shown to...Ch. 15 -
17. Why is gene regulation more complex in a...Ch. 15 -
18. List and define the levels of eukaryotic gene...Ch. 15 -
19. Distinguish between the cis-acting regulatory...Ch. 15 - Prob. 20PDQCh. 15 - Compare the control of gene regulation in...Ch. 15 - Many eukaryotic promoter regions contain CAAT...Ch. 15 -
23. What is RNA-induced gene silencing in...Ch. 15 - Although it is customary to consider...Ch. 15 - DNA methylation is commonly associated with a...Ch. 15 - The interphase nucleus appears to be a highly...Ch. 15 - It has been estimated that at least two-thirds of...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- 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?arrow_forwardFor the following questions, describe the expression levels of the structural genes in the Lac operon under the conditions described. In the absence of lactose, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"] In the presence of lactose, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"] In the absence of lactose and the promoter sequence was mutated such that the RNA polymerase can no longer bind, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"] In the presence of lactose and the promoter sequence was mutated such that the RNA polymerase can no longer bind, the structural genes will:[ Select ] ["No longer be expressed", "Be constantly expressed", "Be deleted from the operon"] In the absence of lactose and the lacI repressor gene is mutated such that the repressor protein…arrow_forward. Mutants were isolated in which the constitutive phenotype of a missense lacI mutation was suppressed.That is, the operon was now inducible. These suppressor mutations mapped to the operon, not to the lacIgene. What could these mutations be?arrow_forward
- When referring to attenuation in the regulation of the trp operon it would be safe to say that, when there are high levels of tryptophan available to the organism, ________. tryptophan inactivates the repressor protein translation termination of the trp operon is likely the trp operon is transcribed at relatively high levels the ribosomes stall during translation of the attenuator region transcription termination at the attenuator region is likelyarrow_forwardMutants 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?arrow_forwardIf 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?arrow_forward
- 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?arrow_forwardIn the lac operon, the lacZ gene codes for an enzyme called ____________, which catalyze the breakdown of the sugar __________ into monosaccharides. This enzyme can also hydrolyze the sugar analog ____________, which produces blue pigments following its breakdown. Since the lac operon is not always on the bacterial cells, we add the chemical ________ which prevents the lac depressor from binding to the operators, leading to constitutive expression of the operon.arrow_forwardThe molecules indicated below can be used experimentally due to their roles in relation to the expression of the lac operon. Drag the listed molecules to their corresponding bin. Reset Help ONPG IPTG X-Gal allolactose Dragable beta-galactosidase cleaves this molecule to form a visible yellow product. beta-galactosidase cleaves this molecule which then dimerizes to form a visible blue product. This molecule induces the transcription of the lac operon by inactivating the lac repressor.arrow_forward
- An E. coli cell acquires a mutation in the gene that encodes CAP. The mutation affects the DNA-binding domain of CAP and ablates the ability of CAP to bind to the CAP site. Under which condition will the genes of the lac operon be transcribed at high levels? Glucose absent, lactose absent Glucose absent, lactose present Glucose present, lactose absent Glucose present, lactose present Under any of these conditions, the lac operon will not be transcribed at high levelsarrow_forwardYou have isolated two different mutants (reg1 and reg2) causing constitutive expression of the emu operon (emu1 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. Is the DNA-binding protein a positive or negative regulator of gene expression? Explain. To determine which mutant has a defect in the site and which one has a mutation in the binding protein, you decide to do an analysis using F′ plasmids. Assuming you can assay levels of the Emu1 and Emu2 proteins, what results do you predict for the two strains (i and ii; see descriptions below) if reg2 encodes the regulatory protein and reg1 is the regulatory site? Explain. F′ (reg1− reg2+ emu1− emu2+)/reg1+ reg2+ emu1+ emu2− F′ (reg1+ reg2− emu1− emu2+)/reg1+ reg2+ emu1+ emu2−arrow_forwardUnder what conditions would you expect to see high levels of expression of the structural genes in the lac operon? Group of answer choices Lactose is absent and glucose is absent Lactose is absent and glucose is present Lactose is present and glucose is present None of these Lactose is present and glucose is absentarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSON
Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax
Anatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & Company
Laboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:PEARSON
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Anatomy & Physiology
Biology
ISBN:9781259398629
Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:9780815344322
Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:W. W. Norton & Company
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:9781260159363
Author:Martin, Terry R., Prentice-craver, Cynthia
Publisher:McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)
Biology
ISBN:9781260231700
Author:Sylvia S. Mader, Michael Windelspecht
Publisher:McGraw Hill Education
Bacterial Genomics and Metagenomics; Author: Quadram Institute;https://www.youtube.com/watch?v=_6IdVTAFXoU;License: Standard youtube license