MCB Exam 3 Clicker Questions With Correct Marking Scheme

MCB Exam 3 Clicker Questions With Correct Marking Scheme /.In cells, NADH serves as a carrier of which of the following? - Answer-electrons /.In cells, biotin serves as a carrier of which of the following? - Answer-Carboxyl groups /.which of the following serves as the primary direct donor of activated methyl groups in biosynthetic pathways? - Answer-S-adenosylmethionine /.which of the following best describes the biochemical role of coenzyme A? - Answer-it activates acyl groups for group transfer /.which of the following are reasons that glucose is a common metabolic fuel used by living organisms? - Answer-it has a stable ring structure & it is unlikely to glycosylate proteins /.which of the following glycolytic reactions constitutes major thermodynamic driving force for glycolysis in vivo? - Answer-phosphoenolpyruvate + ADP -- pyruvate + ATP /.which of the following is NOT an intermediate of the glycolytic pathway by which glucose is oxidized by pyruvate? - Answer-glucose 1 phosphate /.why can't cells use the breakdown of glucose to pyruvate to generate energy without further conversion of pyruvate via fermentation or respiration? - Answer-the electron acceptor reduced during glycolysis must be regenerated /.what is substrate level phosphorylation? - Answer-ATP synthesis when the phosphate donor is a substrate with high phosphoryl transfer potential /.the synthesis of glucose from pyruvate by gluconeogenesis: - Answer-requires the participation of biotin /.which one of the following is a common intermediate in the conversion of glycerol and lactate to glucose? - Answer-glucose 6 phosphate /.which of the following is most likely to occur in a normal individual after ingesting a high carbohydrate meal? - Answer-only insulin levels increase /.which of the following is unique to gluconeogenesis? - Answer-oxaloacetate to phosphoenolpyruvate /.which of the following would be expected to occur after acute alcohol ingestion? - Answer-lactic acidosis /.a hereditary deficiency in aldolase B leads to which of these conditions? - Answer-hypoglycemia, hyperuricemia, liver failure /.why does G6PD deficiency result in a propensity for hemolytic anemia? - Answer-NADPH production is compromised resulting in an inability to maintain the cytoplasm in a reducing state /.which vitamin gives rise to the cofactor in transketolase? - Answer-vitamin B1 thiamine /.which of the following reactions is not part of pentose phosphate pathway? - Answer-C5 + C6 -- C2 + C9 transketolase /.In the non-oxidative stage of pentose PO4 pathway, intermediates of __________ are produced. - Answer-glycolysis /.a 36 year old man with viral pneumonia has an episode of hemolysis. Over the next week, he has an increased rate of reticulocytosis. Which of the following compounds serves as a precursor to heme in the reticulocytes? - Answer-succinyl-CoA /.Coenzyme A is an acyl group carrier. The acyl group is linked to coenzyme A via the: - Answer-thioester bond /.a 50 year old chronic alcoholic presents with dementia paralysis of lateral gaze, and difficulty walking. The vitamin deficient in this patient requires another cofactor for which of the following enzymes? - Answer-pyruvate dehydrogenase /.In the citric acid cycle, succinate thiokinase (succinyl CoA synthetase) catalyzes the cleavage of the succinyl-CoA thioester bond with formation of a high-energy compound. This compound can then be used by the body in which of the following biochemical pathways? - Answer-elongation of the polypeptide chain /.A 34-year-old woman presents to her physician complaining of oral ulcers. A careful history reveals that she is a strict vegetarian and does not eat meat, fish, poultry, eggs, or dairy products. She is found to have a severe riboflavin deficiency. The function of which enzymes in the TCA cycle would be most directly affected by the riboflavin deficiency? - Answer-succinate dehydrogenase /.Mammalian pyruvate dehydrogenase complex (PDC) is inactivated by pyruvate dehydrogenase kinase in the presence of : - Answer-High NADH /.A teenager, concerned about his weight, attempts to maintain a fat-free diet for a period of several weeks. If his ability to synthesize various lipids were examined, he would be found to be most deficient in his ability to synthesize: - Answer-prostaglandins /.long chain fatty acids are shuttled into the mitochondrion bound to what molecule? - Answer-carnitine /.A 7-year-old girl is brought to the emergency department by her parents with a complaint of severe polyuria. Laboratory examination reveals ketones in her urine. Which of the following is the most likely source of the ketones? - Answer-free fatty acid breakdown /.A 30-year-old man has been fasting for religious reasons for several days. His blood glucose level is now about 60% of its normal value, but he does not feel lightheaded because his brain has reduced its need for serum glucose by using which of the following substances as an alternate energy source? - Answer-Beta-hydroxybutyrate /.A 57-year-old man with type 1 diabetes mellitus has progressive retinopathy. Ophthalmoscopic examination reveals macular edema and retinal thickening with hard exudates of yellow-white lipid deposits. Which of the following contributes to hyperlipidemia in type 1 diabetes, and thus the risk for lipid deposition in the retina? - Answer-overactive hormone-sensitive lipase /.the oxidation of fatty acids is best described by which of the following sets of reactions? - Answer-oxidation, hydration, oxidation, carbon carbon bond breaking /.In which one of the following periods will fatty acids be the major source of fuel for the tissues of the body? - Answer-while running the last mile of a marathon /.