EBK ESSENTIALS OF GENETICS
9th Edition
ISBN: 8220102741614
Author: Palladino
Publisher: YUZU
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Textbook Question
Chapter 15, Problem 27PDQ
It has been estimated that at least two-thirds of human genes produce alternatively spliced mRNA isoforms. In some cases, incorrectly spliced RNAs lead to human pathologies. Scientists have examined human cancer cells for splice-specific changes and found that many of the changes disrupt tumor-suppressor gene function (Xu and Lee, 2003. Nucl. Acids Res. 31: 5635–5643). In general, what would be the effects of splicing changes on these RNAs and the function of tumor-suppressor gene function? How might loss of splicing specificity be associated with cancer?
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Alternative splicing takes place in more than 95% of the human protein-encoding genes with multiple exons. Researchers have found that how a pre-mRNA is spliced is affected by the pre-mRNA’s promoter sequence (D. Auboeuf et al. 2002. Science 298:416–419). In addition, factors that affect the rate of elongation by the RNA polymerase during transcription affect the type of splicing that takes place. These findings suggest that the process of transcription affects splicing. Propose one or more mechanisms that would explain how transcription might affect alternative splicing.
A mutant strain of Salmonella bacteria carries a mutation of the rho protein that has fully activity at 37°C but is completely inactivated when the mutant strain is grown at 40°C.
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Chapter 15 Solutions
EBK ESSENTIALS OF GENETICS
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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- 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_forwardA. Do you have any mature transcripts that show alternative splicing? If so, give an example by naming two transcripts that differ in this way. If your gene does not have this difference, write "no". B. Do you have any transcripts that have an alternative transcription start sites? If so, give an example by naming two transcripts that differ in this way. If your gene does not have this difference, write "no". C. Do you have any transcripts that have an alternative termination sites? If so, give an example by naming two transcripts that differ in this way. If your gene does not have this difference, write "no".arrow_forwardThree similar proteins are expressed in human tissues: HHT1 is expressed in the liver, HHT2 is expressed in the pancreas, and HHT3 is expressed in the heart. You are given the task of investigating how these 3 similar proteins are produced. After investigation, you conclude that: all answers are correct it is possible that HHT1 and 3 are produced via alternative splicing, and HHT2 is encoded by a different gene it is possible that all 3 proteins are encoded by the same gene and produced via alternative splicing it is possible that each of these proteins are encoded by different genes (3 different genes)arrow_forward
- Debes 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_forwardThe asterisk (*) in the diagram below indicates a single base mutation in the 5' splice site of the second intron of a eukaryotic gene. Due to this mutation, the second intron is now not ‘spliced out’ during the splicing process. What are the most likely consequences of this mutation with respect to the size of the pre-mRNA and the size of the mature mRNA? a. The pre-mRNA will be longer and the mature mRNA will be longer. b. The pre-mRNA will be longer and the size of the mature mRNA will not be affected c. The size of the pre-mRNA will not be affected and the mature mRNA will be longer d. The size of the pre-mRNA will not be affected and the size of the mature mRNA will not be affectedarrow_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_forward
- The yeast gene SER3, whose product has a role in serine biosynthesis, is repressed during growth in nutrient-rich medium, so little transcription takes place, and little SER3 enzyme is produced, under these conditions. In an investigation of the repression of the SER3 gene, a region of DNA upstream of SER3 was found to be heavily transcribed when SER3 is repressed ). Within this upstream region is a promoter that stimulates the transcription of an RNA molecule called SRG1 RNA (for SER3 regulatory gene 1). This RNA molecule has none of the sequences necessary for translation. Mutations in the promoter for SRG1 result in the disappearance of SRG1 RNA, and these mutations remove the repression of SER3. When RNA polymerase binds to the SRG1 promoter, the polymerase travels downstream, transcribing the SGR1 RNA, and passes through and transcribes the promoter for SER3. This activity leads to the repression of SER3. Propose a possible explanation for how the transcription of SGR1 might…arrow_forwardWhat are the functions of transcriptional activator proteins and repressor proteins? Explain how they work at the molecular level.arrow_forwardConsider the Rho-dependent terminator sequence 5’CCCAGCCCGCCUAAUGAGCGGCCUUUUUUUU-3’. What affect would a point mutation at any one of the bolded and underlined nucleotides disrupt termination of transcription? Group of answer choices Mutation in one of these nucleotides would disrupt base pairing, preventing the formation of the hairpin and disrupting termination. Mutation in one of these nucleotides would have no affect on base pairing, so the termination hairpin is formed and termination proceeds. Mutation in one of these nucleotides would not disrupt base pairing, but would prevent the formation of the hairpin and disrupt termination. Mutation in one of these nucleotides would disrupt base pairing, but not affect the formation of the hairpin and termination proceeds.arrow_forward
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