Genetics: From Genes to Genomes, 5th edition
5th Edition
ISBN: 9780073525310
Author: Leland H. Hartwell, Michael L. Goldberg, Janice A. Fischer, Leroy Hood, Charles F. Aquadro
Publisher: McGraw-Hill Education
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Chapter 15, Problem 28P
Many genes whose expression is turned on by DNA damage have been isolated. Loss-of-function mutations in the lexA gene lead to the expression of many of these genes, even when there has been no DNA damage. Would you hypothesize that LexA protein is a positive or a negative regulator? Why?
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Chapter 15 Solutions
Genetics: From Genes to Genomes, 5th edition
Ch. 15 - For each of the terms in the left column, choose...Ch. 15 - The following statement occurs early in this...Ch. 15 - One of the main lessons of this chapter is that...Ch. 15 - All mutations that abolish function of the Rho...Ch. 15 - The promoter of an operon is the site to which RNA...Ch. 15 - You are studying an operon containing three genes...Ch. 15 - Prob. 7PCh. 15 - You have isolated two different mutants reg1 and...Ch. 15 - Bacteriophage , after infecting a cell, can...Ch. 15 - Mutants were isolated in which the constitutive...
Ch. 15 - For each of the E. coli strains containing the lac...Ch. 15 - For each of the growth conditions listed, what...Ch. 15 - For each of the following mutant E. coli strains,...Ch. 15 - Maltose utilization in E. coli requires the...Ch. 15 - Seven E. coli mutants were isolated. The activity...Ch. 15 - Prob. 16PCh. 15 - Six strains of E.coli mutants 16 that had one of...Ch. 15 - a. The original constitutive operator mutations in...Ch. 15 - Prob. 19PCh. 15 - Figure 15.16 on p. 525 shows that in the lac...Ch. 15 - Why is the trp attenuation mechanism unique to...Ch. 15 - a. How many ribosomes are required at a minimum...Ch. 15 - The following is a sequence of the leader region...Ch. 15 - For each of the E. coli strains that follow,...Ch. 15 - One mechanism by which antisense RNAs act as...Ch. 15 - For each element in the list that follows,...Ch. 15 - Great variation exists in the mechanisms by which...Ch. 15 - Many genes whose expression is turned on by DNA...Ch. 15 - Prob. 29PCh. 15 - The E.coli MalT protein is a positive regulator of...Ch. 15 - Prob. 31PCh. 15 - To find genes that are turned on or off in...Ch. 15 - Prob. 33PCh. 15 - Prob. 34PCh. 15 - Prob. 35PCh. 15 - The researchers who investigated bioluminescence...Ch. 15 - Prob. 37PCh. 15 - Quorum sensing controls the expression of...
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- Understanding why these receptors are present when they are not supposed to be is important in finding new treatments for Cushing's syndrome. When the sequences for the promoters for the receptor genes were analyzed there was no common sequences found. This led to the theory that the loss of methylation of cytosine in the promoters of these genes was leading to their inappropriate expression. How could the loss of cytosine methylation lead to overexpression of the receptor genes? O a. Increased histone acetyltransferase activity O b. Decreased histone deacetylase activity Oc Decreased histone acetyltransferase activity O d. Increased histone deacetylase activityarrow_forwardWhat is a second messenger? What are two second messengers that are involved in signaling pathways downstream of GPCRs and explain how they are produced? long answer: If you wanted to compare a cardiac muscle cell with a skeletal muscle, how could you use RNA sequencing to identify genes that are differentially expressed? In your answer, explain this technique and describe what type of information you can learn from it. If RNA sequencing led to the identification of two genes, gene X and gene Y, what are two experiments you could do to study the functions of these two genes?arrow_forwardYou have isolated a protein that binds to DNA in the region upstream of the promoter sequence of a gene sys. If this protein is a positive regulator, which of the following would be true (multiple selection possible)? Loss-of-function mutations in the gene encoding the DNA-binding protein would cause constitutive expression of sys. Loss-of-function mutations in the gene encoding the DNA-binding protein would result in little or no expression of sys.arrow_forward
- CD3 is a signaling protein that is typically found only in the plasma membrane of immune system T lymphocytes. CD3 is composed of several different polypeptides, including a gamma chain, CD3γ. Scientists analyzed the promoter of the CD3γ chain gene for regulatory sequences that might have positive or negative effects on expression of the gene. The scientists cloned fragments of the CD3γ gene that included the first transcribed nucleotides plus up to 789 nucleotides of upstream regulatory sequences into plasmids in which the gene for the firefly enzyme luciferase immediately follows the fragments. The plasmids were then introduced into a line of T lymphocytes (Figure 1), and the cells were allowed to grow for a short while. Because the regulatory sequences of the CD3γ gene immediately precede the luciferase gene in the plasmids, the activity, either positive or negative, of the regulatory sequences affected the amount of luciferase gene expression by the T lymphocytes. Luciferase…arrow_forwardsiRNAs are used to “knockdown” gene expression in research. Imagine you are a scientist who hopes to study several genes related to cancer. Select all the scenarios you will be able to successfully use RNA interference with the use of siRNAs (select all that apply): Group of answer choices Regulate transcript levels by targeting the siRNA to core promoter regions (e.g. TATA box) of tumor suppressor genes Regulate transcript levels by targeting the siRNA to the regulatory promoter regions (e.g. enhancers) of tumor suppressor genes Regulate transcript levels by targeting the siRNA to any region of the processed mRNA Regulate transcript levels by targeting the siRNA to the 5’ UTR of the processed mRNA Regulate transcript levels by targeting the siRNA to the 3’ UTR of the processed mRNA Regulate transcript levels by targeting the siRNA to sites where the histone acetyl transferase will acetylate the histones Regulate transcript levels by targeting the siRNA to where the start…arrow_forwardWhich mechanisms for regulating gene expression may be applied for the treatment of such diseases? Propose a method of treatment. Explain how it might work. Reference: https://link.springer.com/article/10.1186/ar3317arrow_forward
- Given the following schematic for a gene and its associated regulatory regions, answer the following questions by placing the correct letter in the provided blanks please put in the correct letter for the questions What region would provide cell type-specific expression of genes? region What site would significantly increase gene expression rates? = region What region or regions of this gene’s coding sequence are expressed as amino acids = regionarrow_forwardYou have isolated different mutants (reg1 and reg2) causing constitutive expression of the emu operon (which has genes emu1 and 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?arrow_forwardLysR regulators like llvY repress transcription from their own promoters. This is called a negative feedback loop. Why might negative feedback be a good way to control expression of a transcriptional repressor? This type of negative feedback loop ensures that ilvC transcription will always be repressed when llvY levels are low, and ilvC will be transcribed highly when llvY levels are high. This type of negative feedback regulation ensures that ilvY is never transcribed. Since llvY is a transcriptional repressor, it will slow down cell growth by blocking transcription. So, llvY represses it's own transcription so that no llvY can ever be made, and the cell can grow. This type of negative feedback loop ensures that there is always a moderate amount of llvY. When IlvY levels fall too low, transcription from the promoter will increase since IlvY won't be able to repress it's own promoter. This negative feedback also ensures that IlVY levels don't rise too high - when llvY levels are high,…arrow_forward
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