Old_Exam_3__2007 Fall_

Old_Exam_3__2007 Fall_ - BCH 4024 INTRODUCTION TO...

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Unformatted text preview: BCH 4024 INTRODUCTION TO BIOCHEMISTRY AND MOLECULAR BIOLOGY DR. R. D. ALLISON THIRD EXAMINATION: NOV. 15, 2007 Please PRINT your last name neatly on the answer sheet, followed by your initials. Fill in your UFID Number legibly and accurately. You must be careful in doing this. If you are unsure of how to properly encode your number and name onto the answer sheet, ask a proctor for assistance. If the answer sheet is filled in incorrectly, your sheet will be lost in cyber—space! Mark the most-nearly—correct-answer on the sheet by completely filling in the appropriate box with the correct type of pencil. If you do not have the correct type of pencil, one can be provided for you. Each question is worth two points. You have two hours to work on the examination. At the end of that time, all answer sheets will be collected. If you need assistance, RAISE YOUR HAND AND WAIT IN YOUR SEAT FOR A PROCTOR. AT NO TIME SHOULD YOU RAISE YOUR EXAMINATION OR YOUR ANSWER SHEET OFF YOUR DESK! Before the start of the examination, remove all notes, books, etc., from your desk. Please have at least one seat between you and any fellow student. DO NOT OPEN THE EXAMINATION UNTIL YOU ARE TOLD TO DO SO BY THE PROCTOR. Take a breath, relax, and do your best. 1. Which of the following is a saturated fatty acid? A) oleic acid B) palmitoleic acid C) elaidic acid D) arachidic acid E) none of the above 2. Saponification (that is, reacticn with sodium hydroxide) of which of the following, produces only one mole of fatty acid per mole oflipid? A) phosphatidylcholine B) phosphatidylglycerol C) cardiolipin D) sphingomyelin E) none of the above 3. Regarding lipids, what is the aggregation number? A) the maximum number of micromoles of lipid that can dissolve in water at pH 7. B) the average number of lipid molecules per micelle. C) the concentration of lipid that will form micelles. D) the average number of cholesterol molecules found in a lipid bilayer. E) the number of bile acids that will break up massive lipid aggregation. 4. Which of the following statements is TRUE concerning biological membranes? A) The amount and types of lipids found in the inner mitochondria of a liver cell are more similar to the plasma membrane of that cell than the membrane of a ' bacterial cell. B) The polar head groups are on one side of the lipid bilayer and not the other. C) The phospholipids on one surface of the membrane freely flip through the membrane to the other surface. D) The phospholipids in the membrane bilayer can move laterally within the membrane. E) The fluidity of a biomembrane at room temperature can be increased by the introduction of phospholipids having more saturated fatty acids. 5. Bile salts, used to solubilize fats in the diet, are synthesized from: A) triacylglycerol B) prostaglandin H; C) cholesterol D) linoleic acid E) bilirubin 6. The physiological activity of lipase is stimulated by: A) ATP B) glucagon C) phosphatidylcholine D) NADH E) insulin 7. Transport of fatty acids into the mitochondria require: A) a syrnport system B) two distinct pools of coenzyme A. C) the formation of an anhydride with camosine D) formation of an acyl—adenylate inside the mitochondria B) All of the above are false 8. What is the net number of ATP molecules that can be formed from the complete oxidation of a twenty—eight—carbon, straight—chain, saturated fatty acid (CH3(CH2)25COO)? A) 219 B) 231 C) 233 D) 244 E) 246 9. The third enzyme-catalyzed reaction of fi-oxidation in the mitochondrial matrix results in the formation of : O O u H. A) fi—CHZ a C ~ CH2” C e SCoA O H raj/$012 : CH(OH>CH2 ~ C — SCOA O c) xél~CH2 *CH : CH * 'c' ~ 560A 0 P) AD~CH :(‘H' [#2 ACE ’“ SCO/l 0 19am; at CH2 (2 a ram 10. The conversion of methylmalonyl-CoA to succinyl-CoA requires: A) a-oxidation in order to oxidize branched-chain fatty acids. B) the release of mevalonate to form the methylmalonyl-COA. C) decarboxylation of malonyl-CoA. D) the presence of NAD+ E) the presence of cobalamin (Vitamin Biz). 11. Which step of B—oxidation requires the presence of FAD? A) the formation of a trans-enoyl—COA derivative B) the same step that produces hydrogen peroxide C) the step after the enzyme that produces NADH. D) the step that produces acetyl-COA. E) none ofthe above 12. 3—hydroxy-3-rnethylglutaryl~l—CoA plays each of the following roles EXCEPT: A) It is a precursor in the formation of ketone bodies. B) One mole is produced from three moles of acetyl-CoA. C) Reaction with NADPH produces mevalonate. D) It can be produced in the cytosol. E) It regulates the formation of LDL receptors. 13. The acyl—carrier protein contains a covalently attached group that resembles: A) biotin B) folic acid C) coenzyme A D) lipoic acid E) NAD+ 14. The first step of the fatty-acid synthase complex involves the reaction of the acyl—can'ier protein with: A) rnalonyl—CoA B) mevalonate C) NADPI-I D) acetyI-CoA E) none of the above 15. In fatty acid biosynthesis, a trans-AZ—enoyl-[acyl—carrier protein] is produced (i.e., am: CH r 5 s swim/9). It reacts with to produce the next intermediate in the fatty acid biosynthetic pathway. A) water B) a cysteinyl residue of an adj acent protein C) NADPH D) FAD B) (none of the above) 16. Biosynthesis of palmitate occurs in the cytosol. Biosynthesis ofpalmitoleate in mammals is completed: A) in the cytosol. B) nowhere; it is obtained in the diet. C) in the mitochondria. D) E) in the endoplasmic reticulum in the Golgi body. 17. The formation of malonyl—CoA is regulated by a number of methods. These include: A) B) C) D) B) activation by ADP. inhibition by NAD. phosphorylation by a protein kinase resulting in activation of the enzyme that produces malonyl—CoA activation by fatty acids. activation by citrate. 18. CTP is an important nucleotide in the biosynthesis of: A) B) C) D) E) squalene. B—hydroxybutyrate. triacylglycerol. phosphatidylinositol. (none ofthe above) v 19. The biosynthesis of cholesterol results in the formation of famesyl pyrophosphate (a fifteen-carbon compound) as an intermediate. How many NADPH are needed to produce farnesyl pyrophosphate? A) twelve B) thirteen C) eighteen D) nineteen E) none (NADH is needed.) 20. Each of the following statements is true for lipoproteins and their metabolism, EXCEPT: A) B) C) D) E) Lipoproteins are complexes of lipid and protein that are necessary for lipid transport in the blood. High density lipoproteins function to remove cholesterol from peripheral tissues. Low density lipoproteins (LDL) are sometimes referred to as "bad cholesterol". Very low density lipoproteins (VLDL) have one of the highest ratios of lipid to protein of all the lipoproteins Chylomicrons are produced by the liver to deliver triacylglycerols and phospholipids (produced by the liver) to other tissues. 21. Elevated cholesterol levels within a fat or muscle cell will : A) activate the biosynthesis of nievalonate. B) inhibit the production of HDL by the liver, C) inhibit the biosynthesis ofmalonyI-COA D) inhibit the production of LDL receptors. E) none of the above 22. Which of the following pairs of amino acids contains two nutritionally non—essential amino acids for a normal mammal? A) iscleucine and serine B) glutamine and asparagine C) lysine and tyrosine D) threonine and valine E) methionine and proline 23. The daily requirement for is lessened because of the presence of in the diet. A) cysteine, cystinc. B) leucine, lysine. C) threonine, tryptOphan. D) valine, isovaleric acid. E) methionine, cysteine. « 24. Which of the following amino acids is not synthesized by vertebrates but can be absent in the diet for a few weeks? A) arginine B) tyrosine C) histidine D) phenylalanine E) methionine 25. Which ofthe following is a ketimine‘? , Coo a ffHZ—A/z c/‘ _ \COO C)z€—CH:/i/:C”€ 4 A D R“CH2‘WH-&R—H 600’ d£:c#»w—c/H __ ‘COO 26. Which of the following compounds will not undergo an arninotransferase reaction in mammals? A) phenylalanine B) tyrosine. C) asparagine. D) leucine E) lysine 27. Which of the following compounds is, in elevated levels, an inhibitor of mammalian glutamate dehydrogenase? A) ADP B) pyridoxal phosphate C) NADT D) oxaloacetate E) (none of the above) 28. As discussed in class, aspartate is synthesized in organisms from : A) a~keto glutarate B) glutamine C) pyruvate D) oxaloacetate E) glutamate l—semialdehyde 29. Which of the following is required in the conversion of phenylalanine to tyrosine? A) tetrahydro folate B) carnitine C) tetrahydrobiopterin D) tetrahydrogentisate E) phenylpyruvate 30. The NEAREST precursor in the biosynthesis of serine is: A) pyruvate B) threonine C) 3—phosphoglycerate D) oxaloacetate E) none of the above 31. Sulfur can be resalvaged by the regeneration of methionine via the of A) nucleophilic addition, H28. B) methylation, homocysteine C) transport, S-adenosyl methionine D) hydrolytic cleavage, S-adenosyl methionine E) (none of the above) 32. Asparagine is synthesized in one enzyme-catalyzed reaction in which is one of the substrates. A) ot-ketoglutarate B) oxaloacetate C) NADPH D) glutamine E) pyruvate 33. Which of the following is FALSE concerning the first enzyme in the pathway that produces urea? [Note: You should answer "E" if A, B, C, and D, are all true] A) The enzyme is located inside the mitochondria. B) The enzyme produces AMP as one of its products. C) The enzyme utilizes ammonia as a substrate D) The enzyme is activated by N-acetylglutarnate. B) All of the above are true. 34. Defects or deficiencies of one or more enzymes of the urea cycle are detrimental to an ‘ organism primarily to the build—up of: A) aspartate. B) AIVLP. C) urea. D) ammonia. E) citrulline. 35. The step of the urea cycle that directly produces phOSphate in a single enzyme-catalyzed reaction also produces: A) citrulline B) argininosuccinate C) ornithine D) fumarate E) none of the above 36. Ifammonia is labelled with 15N, where will that label appear in argininosuccinate? (D @ @fij/Hg’ J} J "ooc~ CHZ—CH “NH — C —— Axe—(CH2); —CH I H I COO, NH COO— A)l 4‘ B)2 @ (2)3 D) 4 E) two ofthe above (1 through 4) 37. Three enzymes are utilized to convert fumarate to aspartate as a supplement to the urea cycle. Those enzymes are fumarase. malate dehydrogenase, and : A) citrate synthase. B) oxaloacetate decarboxylase. C) aspartate aminotransferase. D) malic enzymes E) asparaginase. 38. Which of the following amino acids is solely ketogenic? A) tryptophan B) tyrosine C) glutamine D) lysine E) serine 39. Which of the following amino acids will produce oxaloacetate in the degradation pathway discussed in class and in your textbook? A) glutamate B) tyrosine C) serine D) asparagine E) leucine 40. Alcaptonuria is a metabolic disorder in which homo gentisic acid levels are elevated in the degradation of: A) tryptophan B) tyrosine C) threonine D) homocysteine E) valine 41. If you ingest radioactive [HQ-phenylalanine, many metabolites in your cells will ultimately become radioactive. The earliest of these metabolites will be: A) B-hydroxybutyrate B) oxaloacetate C) fumarate D) 3—pho sphoglycerate E) a—ketoglutarate 42. Sweaty-feet syndrome is a severe metabolic disorder caused by a deficiency of an enzyme used in the degradation of : A) valine B) leucine C) tryptophan D) tyrosine E) two of the above 43. Which of the following agents are synthesized by specific cells, can be stored, and elicit a biological response on cells other than those in the immediate neighborhood? A) prostaglandins B) hormones C) neurotransmitters D) pheromones E) two of the above 44. Which of the following transports vasopressin to target cells? A) LDL B) blood albumin C) neurophysin D) hormone binding complex B) none of the above 45. Elevated production of will result in the generation of T3 and T4. A) thyrotropin releasing factor B) phenylalanine C) prostaglandin A2 D) indomethacin E) catalase ' 46. The rate—determining step in leukotriene formation is: A) the reaction of glutathione. B) the release of arachidonate from membranes. C) the formation of leukotriene A4. D) inhibited by aspirin. E) the production of prostaglandin H2. 47. The step in eicosanoid metabolism inhibited by aspirin is: A) the generation of arachidonate. B) the formation of the cyclopentane ring. C) the production of thromboxane. D) the production of prostacyclin. E) (none of the above) 48. The degradation of prostaglandins involves : A) nitric oxide B) m-oxidation (omega—oxidation) C) interaction of leukotrienes with prostaglandins D) reaction with glutathione E) opening of the cyclopentane ring 49. Glutathione plays several roles in most living organisms. These include: A) oxidation/reduction reactions B) detoxification pathways C) prostaglandin production D) reaction with free radicals B) All of the above are true. 50. Leukotrienes: A) are potent muscle-contractants. B) are generated from prostaglandin H; C) activate cholesterol biosynthesis. D) regulate body temperature. E) do none of the above. =end: ...
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Old_Exam_3__2007 Fall_ - BCH 4024 INTRODUCTION TO...

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