Midterm2KEYSpring09

Midterm2KEYSpring09 - 818103-001 MIDTERM 2 Spring 09 K E a...

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Unformatted text preview: 818103-001 MIDTERM 2 Spring 09 K E a Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly Check all the a . ro riate box or boxes below that a uply to you: Comletin_ Incomlete — Senior Graduatin_ S rin_ O9 _ — A_ _ie Fan Note: There are 6 questions and a total of 14 numbered pages. Partial credit will be given. WRITE YOUR NAME ON THE TOP OF EACH PAGE, last name first. A blank sheet will be provided as scratch paper and to cover your exam. T= 298° K R: 8.314 J x mol-l x K-1 Faraday's constant (F) is 96.5kJ x volt-1 x mol -1 AGO' for the reaction ADP + Pi —> ATP + H20 = +305 k] x mole '1 0 AG” = - n F AEO' AG = AGO' + RT ln [products/reactants] AEO' = E0' (3) — E0' ((1) for on + 1 e-—> Ared E = BC" + RI ln A__0)g nF Ared I, , authorize the University to distribute publicly this graded exam (e.g., handed out in class, or left in a bin for me to pick up). Signature Date Honor Code: My signature below affirms that I wrote this exam in the spirit of the honor system of UCD. I neither received nor furnished any help during the exam. Signature BIS 103-001 MIDTERM 2 Spring 09 E 4 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly 1. (12 pts). 2,4-Dinitrophenol (2,4-DNP) has a profound effect on oxidative phosphorylation and electron transport. 2, 4- DNP is soluble in membranes and in water and can easily move across membranes. It also 15 a weak acid that picks up and releases protons (H+) easily. It 15 these two properties that are thought to lead to its effect on oxidative phosphorylation and electron transport. Please explain the following phenomena on the basis of our current understanding of energy generation in mitochondria. Assume all compounds can enter the mitochondrial matrix. (a). (4 pts). To a test tube of isolated human mitochondria suspended in a buffer and osmoticum, NADH, 2, 4- DNP, ADP, Pi and oxygen are added. Oxygen is consumed, but ATP is not synthesized. Briefly explain why. 2 ’4 DNP as an uncoupler, Ndncwflfiv HTOAVAJMT This MAMMflL H 951/1911an 15 msMflue/n‘l' +1) 619an ATD, Haw-em) “W‘W pwm 1314mm, all/m5 dad-m. Mow- W NAN-4 +0 01‘ ”4110ij DL'4-D HLD' (b). (4 pts). To a test tube of isolated human mitochondria suspended in a buffer and osmoticum, NADH, Pi and oxygen are added, but not ADP. There is no oxygen consumption until 2,4-DNP is added. Briefly explain why. The HTQMJMM «MC/((13 MCOWS +34% \ml’twut Sow; md'xam‘aw +0 Molaa if, wmmr AbP HWHAMJr (Mm+ 11¢ “Mud. Tm 030101an 15 1-19 Mayo +1: 411w club» Ftwflzwmes MMgomc) 9% DNP 1111!! Mama, H+05fl41m+ Mic/11x6 a lu+1m {wa- 0101307114, BISlO3-001 MIDTERM 2 Spring 09 K EY 5 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly (c). (4 pts). Accidental consumption of 2,4-DNP by humans leads to an increase in body temperature and profuse sweating. Based on your knowledge of 2,4—DNP explain the basis for this effect. 2,4 Du? will allow Maps/ruled Lumvmd’. inwaswL MDH a FADHL malm‘nm cam, W mmf ATP mum. rm b01143 will Cdt‘l war/W M SMal' +0 wt), Bree/r back down, 2. (22 pts). (a). 6 pts. Some bacterial species accumulate beta-hydroxybutryic acid as a form of stored energy. How many ATPs are produced when one mole of this molecule is completely oxidized to CO2 + H20 via beta oxidation and the TCA cycle and the reduced electron carriers are oxidized in the electron transport chain? For complete credit, show calculations and sources of ATP. Write your final answer on the line provided. a ~Z ATP far ACTIM‘I-m» H H . 0 A I H2 ' H Hac—clz—c -COOH H3 (1 -—’C ~ CHle “Say A OH OH ‘5 a T I 6 096 alrta afi ' 2. , fibula? A»): P ’* Q) ‘ NADDH -——-5 3 ATP H5C—E-CHt—“C'6w1i 0 , MA TCAIE‘erLH— ZAGJZ’Z 60A —" 5 244,113 NetATPyield 941%“ l 7 Q53“? BISlOS-OOI MIDTERM 2 Spring 09 K E if 6 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME . Please print clearly (b). (12 pts). Starting with citrate, what additional compounds are required for the synthesis of beta- hydroxybutryic acid in bacteria? In the table below, name them and indicate how many are required per mole of beta-hydroxybutryic acid synthesized. Indicate at what steps each required compound is needed. You don’t have to use all the rows in the table. Name of compound Moles required/mole beta- Step(s) that require(s) compound. h drox but ic acid To went ALif‘JL. all , ~ ,, \ 3 (b). (4 pts). The term “metabolic water” refers to water synthesized as a result of metabolic pathways. This metabolic water is critical for birds migrating great distances. Name two enzymes responsible for the synthesis of metabolic water and write the reaction that each catalyzes. OTHflQ R x~.s Enzyme 1: ATP S‘fl’VTHAé E AM“. Reactionl: DP “' fl, % ATP +H 0 Enzymezzmb Reaction2: 9C T 3' :10 +QH+ fl...) QC TC 1' 2H 0 BIS 103-001 MIDTERM 2 Spring 09 7 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly 3. (14 pts). Concepts of Enzyme Regulation. Hypothetical biochemical pathways are shown below that give rise to compounds H and L, defense compounds that are secreted from the pancreas and circulate in the blood. The capital letters indicate metabolic intermediates (metabolites) whose inter-conversions are catalyzed by enzymes (NZ). The names of the enzymes are written above, below, or to the right of the reaction arrows (for example, NZ#2 catalyzes the inter-conversion of compounds B and C). H++ NADH NAD+ ATP ADP + Pi NZ#1 NZ#2 NZ#3 NZ#4 . < ? < Z NZ#8 NZ#5 NZ#6 NZ#7 ATP NZ#11 l ADP + Pi Question 3, Parts (a) and (b) on the next page refer to this diagram. BIS 103-001 MIDTERM 2 Spring 09 8 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly (a). (8 pts). Name two enzymes of the pathways above that are most likely to be key regulatory enzymes and for each one, briefly explain why you chose it. (There may be more than 2 possible, but just name two). 0 v‘ Enzyme # 4 % Why? PI’AxflSIDLbeLAQL‘d Irmmsllau) of £3ch pt. Enzyme# I Why? PH‘OéIOLprCALLj M Wtélw) £198!!!wa (ll) pal/AMA? (b.) (6 pts). The compounds listed below are allosteric regulators of th n me converti to L shown on the previous page For each, predict whether they would act as activators or inhibitors. ACT IVATOR ? ACT IVATOR ? Circle either activator or inhibitor. Is ATP an INHIBITOR or Is acetyl CoA an INHIBITOR or Is ADP an NHIBITOR or ACTIVATOR ? Is NAD+ an INHIBITOR or ACT IVATOR? .1: 5. K “ L \ Metabolite is a feed-back inhibitor of the step D to I. (in the blank space write name of one metabolite from pathway on previous page) of Metabolite ] l is a feed-forward activator of the step D to I. (in the blank space write name of metabolite from pathway on previous page) BIS 103-001 MIDTERM 2 Spring 09 . 9 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly 4. (18 pts). Electron transfer reactions. A recently discovered bacterial species carries out ATP synthesis coupled to the flow of electrons through a chain of carriers to some final electron acceptor. Some of the electron carriers are different than the ones found in other bacteria or in eukaryotic mitochondria, some are identical to those discussed in class. The carriers are listed below with their standard reduction potentials. Electron carriers in the newly discovered bacterium: Name of Carrier Ox1dized form of carrier Reduced Form of carrier NADH 2 C tochrome _ee (red) C tochrome _ee (ox) 1 1 _ _ Non-heme iron protein X Non-heme iron protein X _- (Fe 3+) form (Fe 2+) form Y FAD-protein Y FAD—protein Y —_ (mm) mm.) Z Non—heme iron protein Z Non-heme iron protein Z - (Fe 3+ form) (Fe 2+ form) (a). (5 pts). Using the information provided in the table, place the NAME of the electron carriers in the order in which they will support spontaneous electron flow. Order of spontaneous electron flow from left to right under standard conditions: Electrons E’° transferred l‘ _. NAB —>C¢;1TCree _. .2 —> X (first e- carrier) (2“d e- carrier) (3rd e- carrier) (4th e— carrier) (5th e- carrier) (b). (3 pts). Is it likely that oxygen could be the final electron acceptor in this organism? Circle YES 09 Why or why not? (DZ/H 0 half Ce,“ 2,01 MM is +0.3!(FKDM 11455.) L 1+ i9 ShafiflrMM )(‘5 $0,. Uha‘w s‘fandqyl COMd4 W5, +141 Wsk‘gf‘) Q,‘ firm X 4 01 maul—A YLo‘t hL MMS‘D’mc W jig Dz. XOWJ, )6," L‘ EA" E0: AQ’ (A20 '19 “2%, “9“??3), 3' 01+1H*+2e‘ ——5 142/0 ‘5" '(M 3 '0" f. A60 ['5 + “iMRXNo 14 C71 (Ma-NW.) MT SODNTAN£0M$ I BISlO3-001 MIDTERM 2 Spring 09 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly (c). (10 pts). What IS the maximum number of ATP molecules that could theoretically be synthesized, under standard conditions, per pair of electrons transferred through the carriers written above? For full credit, you must show your work and write your answer on the space provided. 2‘15 39M owmlaBLe {CI 330.5 KT/moefor l (on Low») Theoretical Maximum # of ATP q ATP 10 BIS 103-001 MIDTERM 2 Spring 09 1 1 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly 5. (20 pts). (a). (6 pts). Bacteria grown on acetate as the sole carbon source contain high levels of three enzymes that are not present when cells are grown on glucose as the sole carbon source. Name two enzymes found at high levels in acetate grown cells that are required for growth on acetate. Enzyme]: Isoahalz 536.5... Emmi; malab 956! my Extra credit (1 pt). What is the third activity is required so that acetate can be an energy source for bacteria? Name the type of activity or give a common name. Emmi; Amati: 00A (432% fig; wA #MfWSL (b). (7 pts). Malonyl CoA is one of the compounds that is essential for the synthesis of fatty acids. (5 pts). Write, using structures, the reaction that leads to the production of malonyl CoA. Include the names (no structures) of any required co—factors. Write a balanced reaction. Do not draw the structures of nucleotides. You may use Pi for inorganic phosphate. [9 o o CHQC’QIAA «t Mo; 49473 .___..._.., ‘9‘.— cuL~'c'.-§aoA 1 , ‘ 0 , banal. PL' 1 AM (2 pts). What is the name of the enzyme that catalyzes the above reaction? Enzymename Aug LJA (azhg&%(fi$( J BIS 103-001 MIDTERM 2 Spring 09 12 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly (c). (7 pts). The female mallard duck produces a 12-carbon 3-OH fatty acid pheromone hormone. Write the series of enzyme-catalyzed reactions by which the pheromone can be synthesized from its corresponding saturated fatty acyl-CoA ester. Draw structures of the starting material, all of the intermediates and the final product. Include the names of cofactors, if required for the reaction. 0°40 /\/\/\/\/\/h\3mA 3Zl FAD HDHL (.9 WSW“ o I“ BIS 103-001 MIDTERM 2 Spring 09 13 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly 6. (14 pts). Multiple choice (2 pts. each, really). Circle the best answer. There is only 1 correct answer per question. a). Both glucagon binding to its receptor at the plasma membrane of liver cells and epinephrine binding to its receptor at the plasma membrane of skeletal muscle cells cause: i. activation of glycogen phosphorylase and glycogen synthase. ii. a decrease in the intracellular levels of F2,6bisP. iii. an increase in GLC release into the blood. ® increased glycogen breakdown and slowed glycogen synthesis. v. increased glycogen synthesis and slowed glycogen breakdown. b). Which of the following statements is true abdut allostery? i. Allosteric effectors, when bound to enzymes, inhibit enzyme activity. ii. cAMP is an allosteric effector of phosphofi'uctokinase-l. iii. Allosteric effectors that indicate an energy rich cell are ATP, NAD+ and acetyl CoA. iv. Allosteric regulation requires enzymes to mediate its effects. @Allostery is a mechanism to change enzyme specific activity. 0). Which of the following net conversions take place in a metabolic situation that requires the synthesis of much more NADPH than ribose—S-P and ATP? The arrows represent one more enzymatic steps and indicate the direction of the carbon flow (not whether the flow is reversible or not, and the conversions are not balanced). ‘ i. G-3—P (glyceraldehyde-3-P) —> —> pyruvate Q GLC-6-P —* Fructose-6—P bo‘fl" . @ R1bose-5-P+ Xylulose-S—P —> —> Fructose-6—P + G-3-P (glyceraldehyde—3-P) W MU ‘ iv. Xylulose-S-P —> ribulose-S-P v. Fructose-6—P + G-3-P (glyceraldehyde-3-P) —-> —-> xylulose-S-P+ribose-5-P BIS103-001 MIDTERM 2 Spring 09 14 Instructor: Callis Name May 21, 2009 LAST NAME, FIRST NAME Please print clearly d). One or more Cellular need for NADPH is: Q fatty acid synthesis ii. glutathione oxidation iii. glyoxylate cycle iv. ketone body synthesis v. all of the above e). Which of the following statements are true about ketone bodies? i. Ketone body synthesis increases when NAD+ is limiting. The brain uses ketone bodies for energy when the carbohydrates are limited. iii. . Plants produce ketone bodies when converting fatty acids into carbohydrates. iv. The glyoxylate cycle catabolizes ketone bodies to carbohydrates. v. Ketone'bodies are catabolized by glycolysis and TCA cycle pathways in the brain. f. Which of the following statements about ATP synthase is true? i. The rate of NADH oxidation regulates the rate of ATP synthesis. ii. ATP synthase is a molecular motor regulated by a pH difference across a membrane. iii. ATP synthase undergoes conformational changes around the nucleotide binding sites. iv. None of the above statements are true. 6 All of the above statements are true. h. Which of the following statements about a proton motive force (PMF) is true? 0 The PMF is the driving force for oxidative phosphorylation. ii. The PMF results from a difference in the concentration of proteins across the inner mitochondrial membrane of eukaryotic organisms. iii. All other factors unchanged, the PMF decreases in magnitude as NADH oxidation increases. . iv. The PMF increases in magnitude as ATP synthesis increases. v. The PMF is the driving force for net NADH synthesis. ...
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