BMB 514 Exam II - October 9, 2006, Exams of Biochemistry

Download BMB 514 Exam II - October 9, 2006 and more Exams Biochemistry in PDF only on Docsity! BMB 514 --- Exam II --- October 9, 2006 1A Name: __________________________________________ College: CHM COM (please print) (please circle) Please complete the following information on your Answer Sheet: (a) your name and signature (b) your student number (PID) (c) your college (in the area under SECTION): mark 001 for CHM student mark 002 for COM student (d) your version of the exam is 1A --- mark this in the area under FORM • There are 32 questions on this exam. For each question, mark the letter corresponding to what you consider is the BEST answer on the Answer Sheet provided. • When you leave the exam room, please turn in your Answer Sheet AND your exam to the proctors standing by the doors INSIDE the auditorium. Once you exit the auditorium, please leave the building. Hallway conversations disturb those still taking the exam. • There will be answer keys to this exam posted on the course website after the exam is completed. You may wish to copy your responses from your Answer Sheet onto the answer grid on the LAST page of this exam so that you can check your results. You can tear off the last page and take it with you. • You have 60 minutes to complete this exam. We will close the exam promptly at 8:30 a.m. Once we withdraw the boxes for the Answer Sheets from the doors, no additional Answer Sheets will be accepted. • Do well and good luck. 1. A person has consumed a large bag of candy corn and his blood glucose is very high (two times normal). Which of the following best describes the activity of hexokinase and glucokinase in the liver under these conditions? Hexokinase Glucokinase A) At Vmax At Vmax B) Below Vmax Below Vmax C) At Vmax Below Vmax D) Below Vmax At Vmax 2. A cell within your body requires high levels of NADPH and energy. Which of the following pentose phosphate pathway enzymes are necessary to produce these two things in the cell? A) glucose 6-phosphate dehydrogenase B) transketolase C) transaldolase D) All of the above E) B and C only 3. The conversion of mitochondrial oxaloacetate to cytosolic phosphoenolpyruvate involves all of the following EXCEPT: A) Malate transporter B) Malate dehydrogenase C) GTP D) Fumarase E) Phosphoenolpyruvate carboxykinase 4. Which of the following is FALSE with regard to carbohydrate digestion and absorption? A) The digestive process begins in the mouth by salivary amylases B) Stomach amylases convert dextrins to disaccharides C) Disaccharide hydrolysis occurs at the surface of mucosal cells D) Absorption of fructose occurs because of a concentration gradient E) The absorption of glucose requires a Na+/K+ ATPase 5. The reciprocal regulation between glycogen synthase and glycogen phosphorylase directly involves all of the following EXCEPT? A) Biological amplification B) cAMP C) Protein phosphorylation D) Adenylate cyclase E) Glucose 6-phosphate 14. Which of the following correctly describes the electron transport chain? A) Coenzyme Q accepts electrons from Complex III. B) Cytochrome C is a water soluble protein that donates electrons to Complex IV. C) NADH donates electron directly to complex II. D) Protons are pumped by Complexes I, II, III and IV. E) Cytochromes are carriers of electrons and protons. 15. A patient is brought into the hospital with symptoms of fatigue, loss of muscle control and other neurological abnormalities. Having taken biochemistry 514 you quickly hypothesize that the patient has the early signs on Wernicke-Korsakoff syndrome and lab tests verify a genetic defect in the patient’s transketolase gene. Which of the following vitamins would you prescribe to the patient to help alleviate the symptoms caused by this defect? A) Ascorbate B) Niacin C) Cobalamin D) Pyridoxal E) Thiamine 16. A patient is brought into the office suffering from complications in Cori’s disease (Type III, glycogen storage disease, amylo-1,6-glucosidase (debranching) deficiency). Which of the following would you expect to find in terms of amount and structure of the patient’s glycogen stores? Amount Structure A) Increased normal structure B) Increased short outer branching C) Normal minimal outer branching D) Normal very long branching E) Increased very long branching 17. The patient with Von Gierke’s disease (Type I glycogen storage disease, glucose 6- phosphatase deficiency) would have a build up of glucose 6-phosphate (G 6-P) inside his/her cells. Which of the following enzymes will most likely be DIRECTLY influenced by this increased G 6-P concentration? A) citrate synthase and phosphoglucose isomerase B) glucose 6-phosphate dehydrogenase and phosphoglucose isomerase C) glucose 6-phosphate dehydrogenase and phosphoglycerate kinase D) phosphoglucomutase and phosphoglycerate kinase E) citrate synthase and phosphoglucomutase 18. Following the complete depletion of your glycogen stores, all of the following are necessary to replenish your glycogen EXCEPT? A) glycogenin B) uridine tri-phosphate (UTP) C) α 1,6-glucosidase D) Branching enzyme E) Glycogen synthase 19. The transketolase and transaldolase reactions of the pentose phosphate pathway are all that is necessary to convert xylulose 5-phosphate and ribose 5-phosphate to which of the following? A) glyceraldehyde 3-phosphate and fructose 6-phosphate B) glucose 1-phosphate and glyceraldehyde 3-phosphate C) glucose 1-phosphate and fructose 6-phosphate D) erythrose 4-phosphate and dihydroxyacetone phosphate E) dihydroxyacetone phosphate and fructose 6-phosphate 20. Given the following reactions and hypothetical standard oxidation/reduction potentials: ½O2 + 2H+ + 2 e- H2O ΔE’o = 1.25 NAD+ + 2H+ + 2e- NADH + H+ ΔE’o = -0.25 What would the Standard State Free energy be of the following reaction? NADH + ½O2 + H+ NAD+ + H2O (Given: ΔGo’ = -nF ΔE’o and F = 23 kcal/volt mole e-) A) +69 kcal/mole B) -46 kcal/mole C) +46 kcal/mol D) -34.5 kcal/mole E) -69 kcal/mol 21. You are performing some experiments on mitochondrial poisons in the lab and have accidentally washed off the labels of two of your test samples. Given your extensive knowledge from BMB 514 you decide to go ahead with the experiment. You place your purified mitochondria, succinate and ADP into a test tube and you observe the expected decrease in oxygen within the tube (see figure below). Upon addition of poison X you see the oxygen consumption stops and further analysis of the sample shows a lack of ATP production in the presence of sample X. Upon the addition of sample Y (you now have X and Y in the tube) the oxygen consumption begins, however, you still have no ATP production. What is the most likely identity of poison X and Y? TIME [ O XY G EN ] Liver Mitochondria Succinate ADP O2= 0 [ O XY G EN ] X Y [ O XY G EN ] [ O XY G EN ] X Y A) 2,4 dinitrophenol oligomycin B) oligomycin 2,4-dinitrophenol C) antimycin 2,4-dinitrophenol D) rotenone oligomycin E) oligomycin rotenone 22. Isocitrate dehydrogenase carries out the conversion of isocitrate to α-ketoglutarate. Which of the following CORRECTLY describes this reaction? A) ATP is a positive regulator. B) The reactant, isocitrate can be directly converted to various amino acids. C) Produces the first mole of NADH in the tricarboxylic acid (TCA) cycle. D) It is one of the fastest reaction in the TCA cycle. E) It performs the committed step of the TCA cycle. 23. What is the correct sequence of enzyme types for the four repeated steps of beta-oxidation of fatty acids? A) condensing enzyme, reductase, dehydratase, reductase B) reductase, hydratase, reductase, beta-ketothiolase C) dehydrogenase, dehydratase, dehydrogenase, beta-ketothiolase D) dehydrogenase, hydratase, dehydrogenase, beta-ketothiolase E) condensing enzyme, dehydrogenase, hydratase, dehydrogenase 24. What are the products of beta-oxidation of a C18 fatty acid? A) 1 propionyl CoA, 8 acetyl CoA, 8 FADH2, and 8 (NADH + H+) B) 9 acetyl CoA, 8 FADH2, 8 (NADH + H+) C) 8 acetyl CoA, 8 FADH2, 8 (NADH + H+) D) 8 acetyl CoA, 7 FADH2, 7 (NADH + H+) E) 9 acetyl CoA, 9 FADH2, 9 (NADH + H+)