5. Why is it important that an adolescent with a history of hypertrophic cardiomyopathy (HCM) in the family have an echocardiogram before playing high-intensity sports? a. HCM is transmitted as an autosomal dominant trait and can cause sudden cardiac death during exercise.b. HCM is transmitted as an autosomal dominant trait, and it is most likely to cause a problem during swimming.c. Teens with HCM are counseled to play only pickup games of basketball.d. Having HCM in the family makes it more likely that one will have Ehlers-Danlos syndrome. 6. The mitochondrial disease MELAS results in strokelike episodes in addition to encephalopathy and lactic acidosis. It is transmitted from a mother to her children but is not transmitted by an affected father. Why is this so?
7. How does factor V Leiden increase the likelihood of stroke? Summary (chapter 12)All cancers arise from normal cells that have mutations in either suppressor genes or oncogenes. These mutations result in loss of the strict control of mitosis that normal cells have. Although all cancer is “genetic,” only 5% to 15% of cancers are inherited. Whether a person develops cancer is related to his or her age, exposure to carcinogenic substances or events, the degree of efficient immune function, and genetic composition and predisposition.GENE GEMS• Cancer cells arise from normal cells.• Suppressor gene products limit cell division by controlling the expression of oncogenes so that mitosis occurs only when and to the extent it is needed.• Oncogenes are normal genes, and their products are promitotic.• Benign tumors grow by simple, nonessential expansion.• The transformation of a normal cell into a cancer cell is caused by genetic mutations.• Whenever oncogenes are overexpressed after normal growth and development are complete, the person is at risk for cancer development.• Tissues that retain mitotic ability are far more likely to undergo carcinogenesis than those that do not continue to replace dead or damaged cells through mitosis.• Malignant tumors have physical, biochemical, and metabolic advantages that allow them to survive and invade other tissues (metastasis).
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