BIOS 251 EXAM 1 PRACTICE QUESTIONS 2023 | BIOS 251 ANATOMY AND PHYSIOLOGY

BIOS 251 EXAM 1 PRACTICE QUESTIONS 2023 | BIOS 251 ANATOMY AND PHYSIOLOGY. Each of the following medical problems involves a disorder in the function of an organelle or other cellular structure. In each case, identify the organelle or structure involved and indicate whether it is likely to be underactive or overactive. a) A smoker develops lung cancer and is told that the problem is a population of cells in her lungs that are undergoing mitosis at a much greater rate than normal. Cell division is controlled very carefully during the cell cycle. The nucleus is responsible for control during mitosis (M phase of the cell cycle), and since the rate of mitosis is higher than normal, the nucleus is likely overactive. b) A girl inadvertently consumes cyanide and dies almost immediately because ATP production ceases. The cessation of ATP production mostly likely would be due to a problem involving cellular respiration. The complete lack of ATP points towards a problem in the first step, glycolysis, which occurs in the cytoplasm, since there is a net of two ATP during glycolysis. There could be an issue with a competitive or non-competitive inhibitor affecting one of the enzymes in the investment phase of glycolysis. However, the bulk of ATP made during cellular respiration is produced in the mitochondria during the Krebs cycle and electron transport chain. Since ATP production has ceased, the mitochondria are likely underactive. 3. You discover a new unicellular organism and cleverly name it Cellus biologicus. Your initial studies reveal that this organism has a distinct nucleus, ER, golgi and ribosomes – all components of a normal eukaryotic cell. You also discover a novel cellular component that appears to be an “organelle. ” You hypothesize that this “organelle ” originated via endosymbiosis, and do experiments to test this hypothesis. Your data reveal the following information: a) Do the above data support the endosymbiont hypothesis? A “yes” or “no” answer will suffice. No. b) Provide a 5 – 6 sentence explanation for your Yes/No choice. The “organelle” is not likely to have originated via endosymbiosis. Although it is similar in size to bacteria, there is no DNA and the membrane is only a single membrane. If the bacteria were engulfed by the unicellular organism, there should be an inner bacterial membrane surrounded by an outter eukaryotic plasma membrane. However, this is not the case. The composition of the “organelle” membrance is identical to that of the eukaryotic unicellular organism. According to the data, it is highly unlikely that this “organelle” originated via endosymbiosis.