Essentials of Genetics (9th Edition) - Standalone book
9th Edition
ISBN: 9780134145815
Author: KLUG
Publisher: PEARSON
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Chapter 15, Problem 8PDQ
The locations of numerous lacI– and lacIs mutations have been determined within the DNA sequence of the lacI– gene. Among these, lacI– mutations were found to occur in the 5'-upstream region of the gene, while lacIs mutations were found to occur farther downstream in the gene. Are the locations of the two types of mutations within the gene consistent with what is known about the function of the repressor that is the product of the lacI gene?
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What is the function of the repressor encoded by the lacI gene?
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Transcriptional regulation often involves a regulatory protein that binds to a segment of DNA and a small effector molecule that binds to the regulatory protein. Do each of the following terms apply to a regulatory protein, a segment of DNA, or a small effector molecule?
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Chapter 15 Solutions
Essentials of Genetics (9th Edition) - Standalone book
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...
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- 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.arrow_forwardWhat are the functions of transcriptional activator proteins and repressor proteins? Explain how they work at the molecular level.arrow_forwardIf the lacZ protein breaks down lactose, is it worthwhile to make it when there is no lactose around? How does the bacteria use this system to efficiently control the production of the lacZ protein? Does the presence of lactose in the cell alter its ability to repress translation? To what does the lacI protein bind to? What effect does the lacI gene have on transcription of the lacZ and lacY genes?arrow_forward
- In response to potentially toxic substances (e.g., high levels of iron), eukaryotic cells often use translational or posttranslational regulatory mechanisms to prevent cell death, rather than using transcriptional regulatory mechanisms. Explain why.arrow_forwardExplain how the expression of a single gene can be quickly,efficiently,and specifically shut down at the transcriptional,posttranscriptional,and posttranslational stages through thecoordinated expression of a transcriptional repressor, an miRNA,and a ubiquitin ligase.arrow_forwardWhy are regulatory mutations at the mouse Sonic hedgehog gene dominant and viable? Why do coding mutations cause more widespread defects?arrow_forward
- In the sea urchin, early development may occur even in the presence of actinomycin D, which inhibits RNA synthesis. However, if actinomycin D is present early in development but is removed a few hours later, all development stops. In fact, if actinomycin D is present only between the sixth and eleventh hours of development, events that normally occur at the fifteenth hour are arrested. What conclusions can be drawn concerning the role of gene transcription between hours 6 and 15?arrow_forwardHow does the binding of the trp corepressor and the lac inducer to their respective repressor proteins alter repressor function and transcription in each case? What if there was a mutation in the operator region of the lac operon and the active repressor could not bind there? How would this affect the cell’s production of β–galactosidase? In general, Histone acetylation makes DNA ___________________, while DNA methylation makes DNA ________________.arrow_forwardDebes et al recently described how aging in humans, mice, nematodes, and other eukaryotes is associated with an increase in the average speed of transcriptional elongation by RNA polymerase II. Overexpression of some proteins that decreased PolII elongation speed extended lifespan in the fly Drosophila. For each of the following proteins, predict whether overexpression of that protein (assuming all other cellular components are normal) would likely reduce transcriptional speed, and briefly justify your answer. a) Mediator proteinsb) Histone proteinsc) Insulator binding proteinsarrow_forward
- . Another class of suppressor mutations, not describedin the chapter, are mutations that suppress missensemutations.a. Why would bacterial strains carrying such missense suppressor mutations generally grow moreslowly than strains carrying nonsense suppressormutations?b. What other kinds of mutations can you imagine ingenes encoding components needed for gene expression that would suppress a missense mutationin a protein-coding gene?arrow_forwardGenes in both prokaryotes and eukaryotes are regulated by activators and repressors.a. Compare and contrast the mechanism of functionof a prokaryotic repressor (for example, Lac repressor) with a typical eukaryotic repressor protein(a direct repressor).b. Compare and contrast the mechanism of functionof a prokaryotic activator (for example, CAP) witha typical eukaryotic activator protein.arrow_forwardWhat experimental results would indicate that the mutation lacISlacIS is dominant to lacI+lacI+? In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in a repressed state in the absence of lactose. In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in a constitutive state in the absence of the repressor. In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in an activated state in the presence of lactose. In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in a repressed state in the absence of the repressor. In lacISlacIS/lacI+lacI+ partial diploids, the lac operon is in a repressed state in the presence of lactose.arrow_forward
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