2022-Final

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Queens University *

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310

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Chemistry

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Feb 20, 2024

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STUDENT NUMBER: ___________________________ page 1 of 15 COURSE NUMBER (310 or 316): _____________________________ QUEEN'S UNIVERSITY FINAL EXAMINATION – APRIL 23 2022 BCHM 310/316* FACULTY OF ARTS AND SCIENCE DEPARTMENT OF BIOMEDICAL & MOLECULAR SCIENCES Course Coordinator: Dr. G. Jones DEPARTMENT USE ONLY 1 2 3 4 5 6 7 8 SAQ MCQ Total TIME ALLOWED : 3 HOURS SECTIONS A & B CONSIST OF 48 MULTIPLE-CHOICE ANSWER QUESTIONS worth 1.25 marks each. Make sure to put your STUDENT IDENTIFICATION NUMBER on the multiple choice answer sheet. ANSWER ALL OF THE QUESTIONS . There is no penalty for an incorrect answer. For each multiple- choice question indicate the BEST or most appropriate answer by blackening, in pencil, the appropriate vertically-dotted area on the ANSWER SHEET . Incorrect answers may be erased. SECTION C CONSISTS OF 8 Essay ANSWER QUESTIONS worth 5 marks each. ANSWER ALL OF THEM in the space provided. Write your STUDENT IDENTIFICATION NUMBER and COURSE NUMBER (310 or 316) at the top of this page and on the multiple choice answer sheet. Finally, hand in BOTH the QUESTION SHEET and the ANSWER SHEET. Please note: “Proctors are unable to respond to queries about the interpretation of exam questions. Do your best to answer the exam questions as written.” "This material is copyrighted and is for the sole use of students registered in BCHM 310/316 and writing this exam. This material shall not be distributed or disseminated. Failure to abide by these conditions is a breach of copyright and may also constitute a breach of academic integrity under the University Senate's Academic Integrity Policy Statement."

SECTION A Page 2 of 15 For each question in this section blacken the area which corresponds to the BEST answer. A single answer is required for each question. 1. Which of the following enzymes/pathways is INCORRECTLY listed with its subcellular location : a. glucose-6-phosphatase- lumen of endoplasmic reticulum b. pyruvate dehydrogenase - mitochondrion c. malate dehydrogenase- mitochondrion d. active hexokinase IV (glucokinase)- nucleus e. phospholipid biosynthesis- endoplasmic reticulum 2. Identify the following steroidal molecule: a. testosterone b. estradiol c. 25-hydroxyvitamin D 3 d. cortisol e. progesterone 3. The CORRECT sequence of intermediates (not all shown in each answer) in the Citric Acid Cycle is: a. malate, fumarate, isocitrate, citrate, a -ketoglutarate b. citrate, isocitrate, a -ketoglutarate, succinyl CoA, succinate c. oxaloacetate, malate, isocitrate, a -ketoglutarate, fumarate d. citrate, succinyl CoA, a -ketoglutarate, malate, oxaloacetate e. malate, isocitrate, citrate, succinate, succinyl CoA 4. Which of the following amino acids is BOTH glucogenic and ketogenic ? a. alanine b. tyrosine c. aspartate d. glutamate e. serine 5. Which of the following statements about ω-oxidation of fatty acids is CORRECT: a. it involves a cytochrome P450, molecular oxygen & NADPH to oxidize the ω-carbon b. it involves sequentially acid, aldehyde and alcohol intermediates c. it uses catalase to regenerate FAD d. it shortens the fatty acid by cleaving off a C-2 unit e. it prepares the very long-chain chain fatty acid for mitochondrial β-oxidation

SECTION A Page 3 of 15 For each question in this section blacken the area which corresponds to the BEST answer. A single answer is required for each question. 6. The following coenzyme is involved in: a. methylation b. transamination c. single carbon transfer d. carboxylation e. hydroxylation 7. The lipid structure below is best classified as: a. 1-stearoyl, 2-linolenoyl phosphatidyl ethanolamine b. 1-palmitoyl, 2-linoleoyl phosphatidyl choline c. 1-palmitoyl, 2-linoleoyl phosphatidyl ethanolamine d. 1-palmitoyl, 2-linolenoyl phosphatidyl serine e. 1-stearoyl, 2-linolenoyl phosphatidyl choline 8. Which of the following statements about isoprenoid biosynthesis is INCORRECT: a. the rate limiting step of isoprenoid biosynthesis is HMG-CoA synthase b. isoprene units are branched 5-carbon modules made by decarboxylation of mevalonate c. isoprenoid synthesis involves the endoplasmic reticulum enzyme HMG-CoA reductase d. intermediates in the pathway such as C 5 , C 10 & C 15 are made as pyrophosphate derivatives e. squalene, a C 30 linear isoprenoid, is cyclized into a C30 steroidal structure, lanosterol 9. Which of the following statements about the regulation of Acetyl CoA carboxylase is CORRECT : a. It is inactivated by insulin b. it is dephosphorylated by a phosphatase stimulated by glucagon c. it is phosphorylated by a kinase stimulated by leptin and adiponectin d. it is partially activated by malonate e. it is allosterically inhibited by citrate 14

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SECTION A Page 4 of 15 For each question in this section blacken the area which corresponds to the BEST answer. A single answer is required for each question. 10. Tay-Sachs disease is a type of gangliosidosis caused by defective: a. sphingomyelinase b. b -galactosidase c. phosphorylase A d. hexosaminidase A e. phospholipase D 11. Identify the following isoprenoid: Is it: a. mevalonate b. acetoacetate c. ubiquinol d. malonate e. squalene 12. Which enzyme is unique to the glyoxylate cycle : a. citrate synthase b. aconitase c. isocitrate lyase d. isocitrate dehydrogenase e. malate dehydrogenase 13. Which is the principal anapleurotic pathway to maintain the citric acid cycle in muscle : a. pyruvate carboxylase b. malic enzyme c. pyruvate dehydrogenase d. PEP carboxylase e. PEP carboxykinase 14. Erythrocytes possess which one of the following enzymes: a. glyceraldehyde 3-phosphate dehydrogenase b. pyruvate dehydrogenase c. isocitrate dehydrogenase d. b -hydroxybutyrate dehydrogenase e. malate dehydrogenase

SECTION A Page 5 of 15 For each question in this section blacken the area which corresponds to the BEST answer. A single answer is required for each question. 15. Which of the following statements regarding important metabolic pathways is INCORRECT: a. pyruvate kinase is inactive in the fasting liver b. pyruvate carboxylase and PEP carboxykinase are absent from adipocytes c. glucose-6-phosphatase is absent from muscle d. glycerol kinase is absent from adipocytes e. 3 b -ketoacyl-CoA-transferase is absent from the liver 16. When ATP, ADP & Pi concentrations are at normal cellular concentrations, the pH is 7.0, the temperature is 25°C and the pressure is 101.3 kPa, the actual free energy of hydrolysis of ATP, ΔGp, in erythrocytes is: a. -30.5 kJ/mol b. -43 kJ/mol c. -52 kJ/mol d. -63 kJ/mol e. -75 kJ/mol 17. Which of the following statements about the citric acid cycle is INCORRECT : a. it involves succinyl CoA synthetase which can use GDP or ADP b. it directly generates the reducing equivalents 3 NADH and 1 FADH 2 per cycle c. it generates a -ketoglutarate which can be syphoned off to make heme d. it involves the consumption of two molecules of H 2 O per cycle e. it involves oxidative decarboxylation steps using thiamine pyrophosphate as a coenzyme 18. Which of the following would be INCORRECT for the composition of Very Low Density Lipoprotein ( VLDL) a. apolipoprotein CII b. 50% triglyceride c. 7% cholesterol d. 18% phospholipid e. 25% cholesteryl ester 19. Muscle contains which of the following combinations of transporters, enzymes and receptors: a. GLUT2, hexokinase I and ONLY the glucagon receptor b. GLUT4, hexokinase IV and BOTH glucagon and epinephrine receptors c. GLUT2, hexokinase IV and ONLY the glucagon receptor d. GLUT4, hexokinase I and ONLY the epinephrine receptor e. GLUT2, hexokinase IV, and BOTH glucagon and epinephrine receptors

SECTION A Page 6 of 15 For each question in this section blacken the area which corresponds to the BEST answer. A single answer is required for each question. 20. Which of the following statements regarding bioenergetics & the electron transport chain is CORRECT: a. the standard reduction potential, E° ¢ of any half-reaction with 1M oxidised and reduced species in the test cell at pH 7.0, measured using a hydrogen electrode in which H 2 gas at 101.3 kPa is in contact with 1 M H + , at pH = 0, and arbitrarily assigned an emf value of 0.00 volts b. by convention, the standard reduction potential, E° ¢ of any half reaction is depicted with the electron donor on the left and the electron acceptor on the right c. E° ¢ for half reaction involving O 2 + 2H + + 2 electrons à H 2 O has a strongly negative value. d. for the electron transport chain to work properly electron donors must pass on electrons to acceptors with half reactions with a more negative E° ¢ e. when two half reactions are combined, then by convention: ΔE° ¢ = E° ¢ of the electron donor minus E° ¢ of the electron acceptor 21. When phospholipase A 2 metabolizes phosphatidyl inositol (PIP 2 ) it can generate: a. phosphatidyl inositol trisphosphate (PIP 3 ) b. diacylglycerol (DAG) c. prostaglandin PGH 2 d. phosphatidic acid e. inositol 22. Which of the following statements about carbohydrate biochemistry is INCORRECT : a. galactose is an epimer of glucose differing in stereochemistry ONLY at C-2 b. in determination of D- & L-configuration, the reference carbon for glucose is C-5 c. the anomeric carbon of glucose is C-1 d. fructose is a 6-carbon ketose e. glucose exists in solution as two 6-membered ring structures a - and b -glucopyranose 23. Platelet derived growth factor (PDGF) regulates growth of target cells by a mechanism involving: a. adenylate cyclase b. PI-3 kinase c. PI-specific phospholipase C d. Adenylate cyclase and PI-specific phospholipase C e. PI-3-kinase and PI-specific phospholipase C 24. Caffeine blocks which of the following enzymes: a. 5-lipoxygenase (5-LO) b. phospholipase A 2 c. cyclo-oxygenase-2 (COX-2) d. HMG-CoA reductase e. cyclic nucleotide phosphodiesterase -END OF SECTION A-

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SECTION B Page 7 of 15 For the following questions, ONE or MORE of the statements (1-4) are correct. Indicate on your answer sheet which letter A through E is the correct answer (A) if only 1, 2 and 3 are correct (B) if only 1 and 3 are correct (C) if only 2 and 4 are correct (D) if only 4 is correct (E) if ALL are correct 25. Glycolysis: 1. forms NADH during anaerobic periods which can be recycled to NAD via lactate dehydrogenase 2. consumes 2 ATPs during the initial preparatory phase 3. involves a NET production of 5-7 ATPs/glucose molecule en route to pyruvate 4. will use other sugars besides glucose including mannose, galactose and fructose 26. Thiamine pyrophosphate is a coenzyme for one or more steps within which of the following pathways: 1. pentose phosphate pathway 2. ketogenesis 3. pyruvate dehydrogenase 4. glycolysis 27. Activation and action of Adipocyte Lipases involves: 1. phosphorylation of the lipid droplet protein, perilipin by protein kinase A 2. dissociation of the CGI-58 protein which activates adipose triglyceride lipase (ATGL) 3. phosphorylation of hormone sensitive lipase (HSL) which converts DAG->MAG 4. release of glycerol and free fatty acids, both to be recycled by the adipocyte 28. NADPH is generated by which of the following enzymes : metabolic steps : 1. isocitrate dehydrogenase: α-ketoglutarate -> succinyl CoA 2. glucose-6-phosphate dehydrogenase : glucose 6-phosphate -> 6-phosphoglucono-lactone 3. malic enzyme : malate -> oxaloacetate 4. 6-phosphogluconate dehydrogenase : 6-phosphogluconate -> ribulose 5-phosphate 29. Lipoprotein particle structure involves: 1. a shell comprising a phospholipid bilayer 2. an interior containing triglyceride and cholesteryl esters 3. free cholesterol distributed throughout the particle 4. apolipoprotein C-II which activates lipoprotein lipase 30. Which of the following molecules is paired CORRECTLY with its direct precursor from the citric acid cycle or glycolysis: 1. glutamate ; ∝ -ketoglutarate 2. alanine; pyruvate 3. aspartate ; oxaloacetate 4. heme; succinyl CoA

SECTION B Page 8 of 15 For the following questions, ONE or MORE of the statements (1-4) are correct. Indicate on your answer sheet which letter A through E is the correct answer (A) if only 1, 2 and 3 are correct (B) if only 1 and 3 are correct (C) if only 2 and 4 are correct (D) if only 4 is correct (E) if ALL are correct 31. Which of the following enzymes couples with inorganic pyrophosphatase to provide the energy released from inorganic pyrophosphate (iPP) to drive its/their respective reactions: 1. UDP-glucose pyrophosphorylase 2. fatty acyl CoA synthetase 3. methionine adenosyl transferase 4. glycogen phosphorylase 32. Which of the following statements about the biosynthesis of docosahexaenoic acid (DHA) from an essential fatty acid in mammals is (are) CORRECT: 1. the initial steps alternate between firstly a) elongation and then b) desaturation steps 2. desaturation steps involve sequentially: Δ 6 -desaturase, Δ 5 -desaturase & Δ 4 -desaturase 3. it starts with linoleate, 18:2Δ 9,12 and involves the intermediate 22:5Δ 6,9,12,15,18 4. the final step involves removal of a C-2 unit by β-oxidation in the peroxisomes 33. Which of the following enzymes is (are) involved in substrate-level phosphorylation ? 1. phosphoglycerate kinase 2. succinyl-CoA synthetase 3. pyruvate kinase 4. creatine kinase 34. Glycogen breakdown in muscle eventually results in increased glycolysis because: 1. muscle lacks glucose-6-phosphatase to create free glucose 2. glucose-6-phosphate will not cross the plasma membrane 3. muscle pyruvate kinase is not inhibited because muscle lacks glucagon receptors 4. epinephrine triggers the muscle phosphorylase to catalyze the release of glucose-6-phosphate 35. Which of the following statements about the Pentose Phosphate Pathway is (are) CORRECT 1. it generates ribose-5-phosphate used in the biosynthesis of RNA, DNA and coenzymes 2. it generates NADPH used in cholesterol and fatty acid biosynthesis 3. it maintains cellular levels of glutathione used in antioxidant defences 4. lack of sufficient PPP protects against the malarial parasite, Plasmodium falciparum

SECTION B Page 9 of 15 For the following questions, ONE or MORE of the statements (1-4) are correct. Indicate on your answer sheet which letter A through E is the correct answer (A) if only 1, 2 and 3 are correct (B) if only 1 and 3 are correct (C) if only 2 and 4 are correct (D) if only 4 is correct (E) if ALL are correct 36. Which of the following lipids contribute to the negative charge across the plasma membrane: 1. phosphatidyl choline 2. phosphatidyl serine 3. phosphatidyl ethanolamine 4. phosphatidyl inositol 37. PI-specific Phospholipase C- b subtypes possess which of the following regulatory domains: 1. pleckstrin homology domain (PH) 2. Src homology domain 2 (SH2) 3. G-protein binding domain (G) 4. Src homology domain 3 (SH3) 38. Which of the following inhibitors are correctly matched with their protein targets in the Electron Transport Chain or ATP-synthase 1. Amytal and Complex 1 of ETC 2. Antimycin A and Complex 3 of ETC 3. Cyanide and Complex 4 of ETC 4. Oligomycin and F1 of ATP synthase 39. Which of the following statements about the action of Steroid Hormone Receptors is (are) CORRECT 1. they all possess highly conserved DNA binding domains 2. they all bind to heat-shock proteins when they are not bound to their hormone 3. they have poorly conserved steroid hormone binding domains 4. they all trigger increased rates of translation not transcription of specific mRNAs 40. Coupling of the Electron Transport Chain and Oxidative Phosphorylation is only feasible because: 1. the inner mitochondrial membrane is impermeable to protons 2. proton transporters allow protons to pass down a concentration gradient into the intermembranal space 3. the outer mitochondrial membrane is permeable to organic acids but not protons 4. ATP synthase pumps protons back into the matrix up a concentration gradient 41. E coli grown at a range of temperatures decreasing from 40 ° C to 10 ° C the membrane fatty acid composition changes: 1. it will increase its content of palmitoleic acid (16:1) from 9% to 28% of total fatty acids 2. it will decrease its content of palmitic acid (16:0) from 48% to 18% of total fatty acids 3. it will increase its content of oleic acid (18:1) from 12% to 38% of total fatty acids 4. it will become richer in hydroxymyristic acid as compared to myristic acid (14:0)

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SECTION B Page 10 of 15 For the following questions, ONE or MORE of the statements (1-4) are correct. Indicate on your answer sheet which letter A through E is the correct answer (A) if only 1, 2 and 3 are correct (B) if only 1 and 3 are correct (C) if only 2 and 4 are correct (D) if only 4 is correct (E) if ALL are correct 42. Triglyceride biosynthesis: 1. involves only fatty acids and glycerol-3-P to provide the energy for biosynthesis 2. features specific acyl transferases which favour saturated fatty acids 3. involves a final step of adding a fatty acid to phosphatidic acid 4. in the liver starts with glycerol kinase 43. Which of the following coenzymes are required by the enzyme pyruvate dehydrogenase? 1. NADH 2. Lipoic acid 3. Thiamine pyrophosphate 4. Coenzyme A 44. Heme biosynthesis involves: 1. δ-levulinate as an initial intermediate 2. an amino acid precursor, glycine or glutamate 3. assembly of 4 porphyrin rings to form protoporphyrin 4. insertion of a metal ion, Fe 2+ by the enzyme ferrochelatase 45. The glycerol-3-phosphate shuttle or bypass: 1. transports FADH 2 instead of NADH across the IMM into the mitochondrial matrix 2. uses mitochondrial Complex 2 to feed electrons from FADH 2 to ubiquinone 3. it is more energy efficient than the alternative malate-aspartate shuttle 4. it is faster and therefore used by insect flight muscle 46. Thermogenin (UCP-1) is: 1. a 32kDa membrane proton channel found in brown, beige and white adipocytes 2. upregulated in adipocytes in response to norepinephrine released as a result of neuronal signals 3. opened by free fatty acids released by adipocyte lipases 4. involved in synthesis of ATP in tissues around the major organs of newborn babies 47. The coenzyme below is required with NADPH & molecular oxygen in the following enzymatic reactions: 1. phenylanlanine -> tyrosine (3-hydroxyphenylalanine 2. tyrosine -> L-DOPA (L-3,4-dihydroxyphenylalanine) 3. tryptophan -> 5-hydroxytryptophan 4. testosterone -> estrogen

SECTION B Page 11 of 15 For the following questions, ONE or MORE of the statements (1-4) are correct. Indicate on your answer sheet which letter A through E is the correct answer (A) if only 1, 2 and 3 are correct (B) if only 1 and 3 are correct (C) if only 2 and 4 are correct (D) if only 4 is correct (E) if ALL are correct 48. Biotin is a coenzyme for which of the following metabolic steps: 1. pyruvate -> oxaloacetate 2. pyruvate -> acetyl CoA 3. acetyl CoA -> malonyl CoA 4. oxaloacetate -> phosphoenolpyruvate (PEP) -END OF SECTION B-

SECTION C Short Answer Questions Page 12 of 15 49. Briefly outline the signal transduction steps & enzymatic events involved in insulin’s action on glycogen synthesis in the muscle. (5 marks). 50. How do cancer cells modify their metabolic pathways to achieve their overall goals ? Which pathways or steps are over-expressed and what is the metabolic consequence for normal cells & the organism? (5 marks).

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SECTION C Short Answer Questions Page 13 of 15 51. Starting with glycerol & free fatty acids , describe the biosynthesis of phosphatidyl choline in the liver. (5 marks). 52. Describe the metabolic activities of the liver 10 days into a fast/starvation period. What is the liver providing to the other tissues? (5 marks).

SECTION C Short Answer Questions Page 14 of 15 53. What is the role of Fructose-2,6-bisphosphate in glucose metabolism. What exactly does it do and how is its concentration regulated? (5 marks) 54. Outline the steps of the Urea Cycle and its connection to the Citric Acid Cycle . (5 Marks)

SECTION C Short Answer Questions Page 15 of 15 55. Compare and contrast the pathways of Fatty acid b -oxidation and Fatty acid Biosynthesis . (5 Marks). 56. How is the theory of the Boyer Binding Change Mechanism supported by the structural data acquired by study of the ATP-synthase ? Describe an experiment which shows movement of the enzyme. (5 marks). -END OF EXAM-

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