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IPSCs are nearly identical to human embryonic stem cells in terms of gene expression, but there may be other ways in which they are not equivalent. For example, the telomeres of IPSCs often vary in length, with many IPSCs cells having telomeres shorter than those of embryonic. How might shortened telomeres affect the life-span of IPSCs or of differentiated cells derived from them?
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Chapter 31 Solutions
MindTap Biology, 1 term (6 months) Printed Access Card for Starr/Taggart/Evers/Starr's Biology: The Unity and Diversity of Life (MindTap Course List)
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- . Early in development, most human cells turn off expression of an essential component of telomerase, the enzyme responsible for addition of telomere repeat sequences (5’-TTAGGG) to the ends of chromosomes. Thus, as our cells proliferate their telomeres get shorter and shorter, but are normally not lost over the course of a lifetime. If cells are removed from the body and grown in culture, however they ultimately enter a state of replicative senescence and stop dividing when their telomeres get too short. By contrast, most human tumor cells express active telomerase, allowing them to maintain their telomeres and grow beyond the normal limit imposed by senescence - good for them, bad for us. Anticipating a universal cure for cancer, you set up a company to screen chemical ‘libraries’ for telomerase inhibitors. The company share price takes a dive, however, when a rival group generates a strain of telomerase-knockout mice. These mice breed happily for several generations, but…arrow_forwardThe human body contains many distinct cell types yet almost all human cells contain the same genome with 21,000 genes. The distinct cell types are primarily due to differences in gene expression. Assume that one set of 1000 genes is expressed in all cell types and that the remaining 20,000 genes can be divided into sets of 1000 genes that are either all expressed or all not expressed in a given cell type. How many different cell types are possible if each cell type expresses 10 sets of these genes? Note that the number of combinations of n objects into m sets is given by n !/ (m!(n-m)!) where n! = 1*2*…*(n 2 1)*n.arrow_forwardIn a mutant mouse, it was discovered that a gene "W" is moved from its original chromosomal locus to the telomere region, where chromatin is packed into heterochromatin. Given what we have learned about eukaryotic gene regulation, can you speculate how the expression of gene W in the new mouse line would be changed as compare to the normal mouse? Question 18 options: elevated in the mutant mouse than in the wild-type mouse. cannot be determined. reduced in the mutant mouse than in the wild-type mouse. no change in the mutant mouse as compared to the wild-type mouse.arrow_forward
- You are interested in studying a novel gene that appears to be involved in cancer. There is no information about the function of this gene. What would you do to obtain the cDNA for this gene? How would you express this gene and what expression systems might you utilize to study its function and why? How would determine the subcellular localization of this gene in eukaryotic cells? What are alternative methods in case one doesn't work? How would you purify and determine the 3-dimensional structure of this protein?arrow_forwardWhich of the following does NOT pertain to the myoblast-determining gene 1?*a. It is a master gene.b. It is a silencing gene.c. It produces a transactivating protein.d. It activates its own gene. Gene silencing involves which type of histone modification?* a. acetylation of histone 4 b. dimethylation of histone 3 c. trimethylation of histone 4 d. trimethylation of histone 3 Given the required environment, the totipotency of the nucleus can allow which of the following?* a. a committed cell to undergo dedifferentiation b. a committed cell to undergo terminal differentiation c. a terminally differentiated cell to produce a complete organism d. a terminally differentiated cell to produce specific types of tissues An induced pluripotent cell is described by which of the following?* a. It is a committed cell that undergoes redifferentiation. b. It is a committed cell that undergoes dedifferentiation. c. It is a terminally…arrow_forwardA genon wide analyst of human genome indicated that approximately 1500 genes encoded transcription factors that are important for sequence specific gene expression. based on this information approximately what percentage of the protein coding genes in human belong to the transcription factors? A. 15% B. 5% C. 7.5% D.1.5%arrow_forward
- DNA sequencing has provided data to indicate that cancer cells may contain tens of thousands of somatic mutations, only some of which confer a growth advantage to a cancer cell. How do scientists describe and categorize these recently discovered populations of mutations in cancer cells?arrow_forwardThe rb gene encodes a protein that inhibits E2F, a transcriptionfactor that activates several genes involved in cell division.Mutations in rb are associated with certain forms of cancer,such as retinoblastoma. Under each of the following conditions,would you expect the cancer to occur?A. One copy of rb is defective; both copies of E2F are functional.B. Both copies of rb are defective; both copies of E2F arefunctional.C. Both copies of rb are defective; one copy of E2F is defective.D. Both copies of rb and E2F are defective.arrow_forwardIn times of nutrient stress, the cellular slime mold Dictyostelium discoideum develops one of two cell types: pre-stalk and pre-spore. Scientists studying this development discovered that the pH of individual cells regulates the type of cell that is formed. Which of the following claims could scientists make about how environmental cues affect the gene expression of Dictyostelium discoideum? A - A response to nutrient deprivation leads to a change in pH that causes mutation in the cells, forming the different cell types. B - A response to nutrient deprivation leads to a change in pH that disrupts the cells, forcing them to develop into certain cell types. C - A response to environmental stress leads to a change in pH that triggers transcription factors to differentiate the cell type that will be formed. D - A response to environmental stress leads to a change in pH and a decrease in transcription factors that differentiate the cell type that will be formed.arrow_forward
- Some cancers are consistently associated with the deletion of a particularpart of a chromosome. Does the deleted region contain an oncogene or atumor-suppressor gene? Explain.arrow_forwardIn 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_forwardEukaryotes have a multitude of ways of regulating gene expression. Why are all these regulatory mechanisms necessary to the functioning of a eukaryotic organism?arrow_forward
- Biology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage Learning