A scientist is trying to increase the number of cells grown in the lab. After giving 3 different treatments, she obtained the results presented in the table below. Percent survival of cell cultures Cell Type Treatment A Treatment B Treatment C HeLa* 79% 25% 54% Stem 56% 18% 81% Kidney 18% 9% 2% T cells 22% 22% 22% *HeLa cells come from an immortal human cancer cell line. They were taken from a patient, Ms. Henrietta Lacks, in 1951 and have been continuously grown for research to this day. Ms. Lacks' cells have been credited with helping find a cure for polio as well as becoming an effective model to study (and hopefully cure) cancer. What one of the following represents possible dependent and independent variables for the investigation in this scenario? ODV = treatment; IV = percent survival of cell cultures ODV = percent survival of cell cultures; IV = treatment DV treatment; IV = cell type ? DV = cell type; IV = treatment ODV = cell type; IV = percent survival of cell cultures
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Scientists Discover the "Longevity Gene." Researchers working at the University of California, Berkeley have discovered a key gene in cell longevity. When they turn off the gene in special lab cells called HeLa cells, the cells die after only a few divisions. When the gene stays on, the cells divide quickly and eternally. Once they find a way to turn on the same gene in all our cells, people should be able to live forever - or at least much longer than we do today. Based on your understanding of cell division and cell death, do you agree with the journalist's conclusion at the end of the excerpt posted above? Select the one answer that best explains why the journalist's conclusion makes sense or does not make sense: No. In a healthy person, cells should not divide quickly or eternally, as these traits characterize cancer cells. Yes. Cell death has no benefit to an organism. Finding ways to overcome it will help us to live longer. Yes. A multicellular organism begins to die when too many of its cells are nearing the end of their lives; so preserving cell life will also preserve organism life. Studying cells in the laboratory is unlikely to provide any useful conclusions about how life works outside of the lab.
Marlyn J.
A friend of yours who works at a biotechnology start up company has computationally designed three new proteins that she thinks might be able to prevent and possibly reverse cancers if they could be expressed in the right place in cells. If this works, the company will be worth billions and everyone who works there will be rich. The plan is to use a genetically modified virus to deliver the DNA genes for these three proteins. This should result in the transcription of mRNA and translation of the three proteins. The trick is getting the proteins to go to the right places in the cells so they can interact with the right cellular pathways. One protein is a transcription factor that binds to DNA and should shuts down transcription of cancer promoting genes by binding to their promoters. The second is a protein that interacts with electron transport chain proteins to reduce the output of reactive free radicals in mitochondria. The third is a cell surface protein that inhibits incoming growth factor signals. Based on your talents in cell biology, your friend offers you a job on her research and development team. Your goal is to genetically modify each of these designer proteins so that when they are transcribed and translated in a human cell, they will be transported by cellular machinery to the correct location in the cell for their specific functions. How would you do this? Give a description of what you would add to each of the three proteins to get them transported to the right place and how the relevant transport system works.
Dominador T.
Multiple myeloma or blood plasma cancer is characterized by increased blood vessel formulation in the bone marrow that is a prognostic factor in survival. One treatment approach used for multiple myeloma is stem cell transplantation with the patient’s own stem cells. The following data represent the bone marrow microvessel density for a sample of 7 patients who had a complete response to a stem cell transplant as measured by blood and urine tests. Two measurements were taken: the first immediately prior to the stem cell transplant, and the second at the time of the complete response. Patient 1 2 3 4 5 6 7 Before 158 189 202 353 416 426 441 After 284 214 101 227 290 176 290 A. If we wish to determine if the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant, the null hypothesis would be ? B. If we are interested in determining if the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant, the alternative hypothesis would be ? C. Perform an appropriate test of hypothesis to determine if there is evidence, at the .05 level of significance, to support the claim that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant? What is the value of the sample test statistic? D. What is the p-value associated with the test of hypothesis you conducted? E. At the .05 level of significance, is there sufficient evidence to conclude that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant?
Supreeta N.
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