Biology 3221A Biochemistry Final Exam Q&A- Rush University

Biology 3221A Biochemistry Final Exam Q&A- Rush University Which of the following single-base DNA gene coding changes is least likely to significantly affect the function of resulting protein? (Harper pages 361-363) A. Missence mutation resulting to histidine-to-glutamic acid change B. Silent mutations in the third codon base C. Frameshift mutation D. Nonsense mutation 2. Which of the following is a property of enhancer elements? (Harper pages 384-385) A. They do not work located downstream of the promoter. B. They could work when located long distances from the promoter. C. Upon activation, they could repress transcriptional rate. D. They are proteins binding to DNA sequences. 3. Which of the following is considered as a transcriptional regulation control? (Harper pages 383) A. Chromatin remodelling B. Alternative splicing C. RNA editing D. Capping of the mRNA 4. Which of the following is true of biological membrane structure? (Harper pages 415-421) A. Saturated fatty acids increase fluidity. B. Cholesterol is an amphipathic molecule. C. The inner and outer sheets are symmetrical to each other. D. They contain transport proteins, which are mainly peripheral. 5. Which of the following defines the specificity of hormone activity in a cell? (Harper page 435) A. The synthesis of the hormone in the target cell B. The presence of the hormone receptor C. The upregulation of the hormone receptor in a cell D. Absence of other target cells adjacent to hormone-producing cells 6. Which of the following is true of hormones? (Harper pages 437-38) A. Hormones with intracellular receptors are usually hydrophilic. B. Lipophilic hormones need transport proteins. C. Cathecholamines and steroid hormones act via a plasma membrane receptor. D. Steroid hormones are derivatives of amino acids. 1 7. Which vitamin is essential for one-carbon metabolism? (Harper page 494) A. Thiamine B. Riboflavin C. Niacine D. Folic acid 8. Which of the following correctly characterize a component of the extracellular matrix? (Harper 535-541) A. Collagen type IV, a component of the basement membrane, form compact bundles. B. Elastin is essential for cell-cell communication. C. Fibronectin is involved mainly in cell adhesion and signaling. D. Laminin acts intracellularly as a major component of the cytoskeleton. 9. Which of the following is NOT correctly paired? (Harper page 593) A. IgA: found in secretions B. IgM: transplacental passage C. IgG: opsonization D. IgE: allergic responses 10. Which of the following statements characterizes ATP? (Harper page 84) A. It is used in the synthesis of DNA. B. It contains 3 phosphate bonds for energy storage. C. It is used to drive thermodynamically unfavorable reactions. D. It is produced mainly by substrate level phosphorylation. 11. Enzymes, as biological catalysts accelerate velocity of reactions by: A. lowering the free energy of activation of reactions B. increasing transition state of reactants and products C. lowering the net energy change between initial and final states of the reaction D. increasing the equilibrium constant (Keq) of the reaction 12. A general class of enzymes that join molecules by creating a new chemical bond at the expense of ATP hydrolysis A. lyase B. isomerase C. ligase D. hydrolase 13. An enzyme catalyzing the reaction: lecithin + cholesterol -- fatty acid cholesterol ester + lysolecithin is classified as: A. oxidoreductase B. lipase C. transferase D. hydrolase 14. The Michaelis Menten constant is equal to substrate concentration when: initial velocity is ½ Vmax Vmax is doubled Km= ½ substrate concentration Km/Vmax = 1 2 15. The kinetic parameter that reflects the affinity of the enzyme for its substrate is called: A. Vmax B. Q10 C. Km D. Kcat 16. Double reciprocal plot of the Michaelis Menten equation is called: A. Hanes-Wolf B. Eadie Hofstee C. Lineweaver Burk D. Briggs-Haldane 17. In the Lineweaver Burk plot, the slope of the line is equal to: A. -1/Km B. Km/Vmax C. 1/Vmax D. 1/S 18. Which statement is true about competitive inhibition? A. Inhibitor binds to the allosteric site of the enzyme B. Km is constant while Vmax decreases C. Usually the inhibitor structurally resembles the normal substrate D. Both the Km and Vmax decrease 19. Serum enzymes are elevated following tissue injury and death due to: A. enzyme induction secondary to stimulation of protein synthesizing machinery of the cell B. allosteric enzyme activation by positive activators C. increased cell membrane permeability and leakage of enzymes into blood D. proteolytic activation of proenzymes or zymogens 20. Which of the following coenzymes is not appropriately paired with the enzymatic reaction it is associated with? E. tetrahydrofolate- transamination F. biocytin-carboxylation G. NAD- dehydrogenation H. Coenzyme A- transacylation 21. The active form of Vitamin B12 coenzyme: A. 5’-deoxyadenosylcobalamin B. hydrocobalamin C. aquocobalamin D. cobamide 22. In Bioenergetics, the amount of energy available for the performance of useful work is termed: A. entropy B. free energy C. enthalpy D. equilibrium energy 3 23. During biological oxidations, reduced coenzymes such as NADH and FADH2 generate energy when oxidized thru the: A. Krebs Cycle B. Electron Transport Chain C. Cytochrome P450 system D. Embden Meyerhof Pathway 24. The final acceptor of electrons in the Respiratory Chain is: A. cytochrome oxidase B. coenzyme Q C. iron sulfur center D. oxygen 25. Substrate level phosphorylation differs from oxidative phosphorylation in that: A. oxidative phosphorylation synthesizes ATP via the Electron Transport Chain B. substrate level phosphorylation only takes place in the cytosol C. oxidative phosphorylation is coupled to a direct transfer of high energy ~Pi from a high energy compound to ADP D. Substrate level phosphorylation is more energy efficient per molecule of substrate oxidized 26. Which of the following affects biological oxidation by dissociating mitochondrial respiration from phosphorylation? A. 2,4 dinitrophenol B. B. rotenone C. C. antimycin D. cyanide 27. Which of the following statements is correct regarding digestion of carbohydrates? A. Digestion of dietary polysaccharides takes place to a significant extent in the stomach due to acid hydrolysis. B. Digestion initially takes place in the mouth through the action of - amylase. C. Pancreatic amylase hydrolyzes -1,4 glycosidic linkages in cellulose. D. The final end products of digestion are all glucose molecules from dietary carbohydrates 28. In man, glucose from dietary cellulose could not be available for energy because: A. cellulose is made up of very long polysaccharide chain made up of  1,4 and  1,6 glycosidic bonds B. human diet does not have a significant amount of cellulose C. man inherently lacks enzyme to hydrolyze cellulose D. cellulose is not made up of glucose units 29. A 3 month old infant develops diarrhea and abdominal discomfort a following a milk formula. However feeding history revealed that he was able to tolerate breast feeding and the same milk formula at birth. The most likely condition is A. Primary - galactosidase deficiency B. Milk allergy C. Lactose malabsorption D. Secondary lactose intolerance 4 30. The major pathway of glucose metabolism that exists in all cells is the: A. Pentose Phosphate Pathway B. Citric Acid Cycle C. Uronic Acid Pathway D. Embden Meyerhof Pathway 31. Hexokinase differs from glucokinase in which aspect? A. Glukokinase has a higher affinity to glucose B. Hexokinase is induced by insulin C. Glucokinase phosphorylates glucose to glucose 6 phosphate D. Hexokinase is inhibited by glucose 6 phosphate 32. The end product of glycolysis in exercising muscle and red blood cells is: A. pyruvic acid B. acetic acid C. lactic acid D. acetoacetic acid 33. The most important positive regulator of the committed step of glycolysis is the availability of A. fructose 1,6 bisphosphate B. ATP C. Citrate D. fructose 2,6 bisphosphate 34. True of the The Malate Aspartate Shuttle A. can be considered as an anaplerotic reaction B. less energetically efficient than the  glycerophoshate shuttle C. transports NADH from the cytosol into the mitochondria for oxidative phosphorylation D. provides reducing equivalents for reductive biosynthesis of fats 35. The initial step in the TCA Cycle is catalyzed by: A. pyruvate dehydrogenase B. lactate dehydrogenase C. citrate synthase D. -keto-glutarate dehydrogenase 36. The Hexose Monophosphate Shunt is metabolically significant to nucleic acid metabolism because it: A. provides NADPH B. furnishes pentose phosphates C. is an alternative pathway for glycolysis D. stabilizes structure of DNA 37. The rate limiting step in the Pentose Phosphate Pathway is catalyzed by: A. hexokinase B. glucose-6 phosphate dehydrogenase C. 6- phosphogluconolactonase D. transketolase 38. Which of the following enzymatic reaction is common to both glycolysis and gluconeogenesis? A. hexokinase B. pyruvate carboxylase C. phosphofructokinase 1 D. phosphotriose isomerase 5 39. The inherent absence of this enzyme prevents muscle glycogenolysis to maintain glucose homeostasis: A. glycogen phosphorylase B. glucose- 1- phosphatase C. glucose-6-phosphatase D. UDP-Glucose pyrophosphorylase 40. Glycogen synthesis is activated while glycogenolysis is inhibited when: A. glucagon/ insulin ratio is elevated B. glycogen synthase is covalently modified by phosphorylation C. cyclic AMP dependent protein kinase is activated D. glycogen synthase I predominates over glycogen synthase D 41. Mannose and Fructose enter the mainstream of carbohydrate metabolism via: A. Citric Acid Cycle B. Embden Meyerhoff Pathway C. Hexose Monophosphate Shunt D. Glyoxylic Acid Cycle 42. Fatty acids enter the mitochondrial matrix for oxidation in what form? A. acyl-CoAs through active transport B. as free fatty acids C. following conversion to carnitine D. complexed with carnitine as acyl-carnitine 43. The number of reduced electron carriers generated when one mole of palmitate is subjected to oxidation: A. 2 FADH2 and 3 NADH + H+ B. 3 FADH2 and 2 NADH + H+ C. 7 FADH2 and 7 NADH + H+ D. 5 FADH2 and 5 NADH + H+ 44. Majority of the reducing equivalents necessary for fatty acid biosynthesis are generated during conversion of: A. 1,3 bisphosphoglycerate to 3 phosphoglycerate B. pyruvate to malate C. glucose 6-phosphate to 6 phosphogluconate D. 6 phosphogluconate to ribulose 5-phosphate 45. How many moles of NADPH + H+ can be derived from the pathway utilized in the transport of acetyl CoA out of the mitochondria? A. 8 moles B. 10 moles C. 12 moles D. 14 moles 46. The site of action of the NSAIDS is: A. thromboxan synthase B. prostaglandin cyclooxygenase C. lipoxygenase D. prostacyclin synthase . . . . . . . .