450 ex2 key - Multi fléfl le-Choice 3 oints each 60 oints total For each of the following questions encircle the letter corresponding to the

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Unformatted text preview: Multi fléfl le-Choice 3 oints each 60 oints total For each of the following questions, encircle the letter corresponding to the BEST response. 1. 2.' 3. 4. Which of the following is NOT an assumption made in the derivation of the ichaselis-Menten equation? W C. D. E. The reaction proceeds with a large, negative change in free energy. The rate of formation of BS is balanced by the rate of its destruction, either to E + S or to P + E. The k.2 step can be ignored. Only one substrate is considered. (All of the above are assumptions usually made). _ Which of the following correctly defines KM? A (15> 3." Ct E. It is equal to the quantity kl/(lq + k2) It is the dissociation constant for the enzyme-substrate complex. _ It is equal to Vmax/Z. It is the substrate concentration giving half-maximal velocity. It is equal to the quantity k-1/(k1 + k2) Iodoacetate inactivates glyceraldehydes 3-phosphate dehydriogenase. Which of C. D. E. . the following best explains its mechanism of action? It combines with the -—SH group of cysteine. It forms a covalent bond with the —OH group of Ser. It competes with glyceraldehyde 3—phosphate for the substrate binding site. It binds to the Asp residue in the catalytictriad. It interferes with proton exchange by the sidechain of Lys. Which statement about a hemoglobin molecule is INCORRECT? A B. C. E. There are four polypeptide chains non—covalently associated. Each polypeptide chain is associated with one porphyrin ring. There is a total of four F e2+ atoms in oxyhemoglobin. One BPG can bind to each OLB dimer. HbAz contains at and 6 chains. Which of the following INCORRECT? A. There are eight regions of 0c helix. B. The regions between the helices frequ C. There is one porphyrin ring per molec B. One molec Hydrophili statements about the X ule of oxygen can be bound to the F e2+ c amino acid residues are buried in t -ray structure of myoglobin is ently contain Pro or B turns. ule. of the porphyrin ring. he interior. 6. Which of the following is an INCORRECT statement about NAD+ and FAD? A. NAD+ transfers one hydrogen as a hydride ion and the other as a proton, whereas FAD accepts two hydrogens as free radicals. B. They are both derived from water-soluble vitamins. . FAD is generally a stronger oxidant than is NAD+ ' NAD+ contains the isoalloxazine ring system whereas FAD does not. . Reoxidation of the reduced form of NAD+ yields more ATP than reoxidation of the reduced form of FAD. 7. Which of the following is an allosteric enzyme of glycolysis? A. triose phosphate isomerase B. enolase C. aldolase hexokinase glyceraldehyde 3-phosphate idehydro gen fructose 2-6 bisphOsphate, the rate of the fructose 1,6- bisphosphate phosphatase r 8. cw: On A. greater than B. equal, or approximately equal to, (963(5 C. less than ase eaction would be expected to be the rate at lower concentrations of fructose 2-6 bisphosphate. A lipoprotein with a hi density a; C. gher ratio of protein to lipi greater than equal, or approximately equal to, less than - a lipoprotein with a lower ratio of protein toilipid. (1 would be expected to have a 10. Which of the following IN CORRECTLY pairs a coenzyme with its function in t e pyruvate dehydrogenase reaction? a TPP : formation of thioesters :. Lipoic acid : acyl transfer C. Lipoic acid : oxidation D. NAD+ : oxidation E. FAD : oxidation 11. A derivative of which water-soluble vitamin is NOT required for the conversion of a-ketoglutarate to succinyl CoA in the TCA cycle? A. thiamin B. riboflavin .fl niacin pyridoxine E. pantothem'c acid 12. Per turn of the tricarboxylic acid cycle, how many NADH + H4r are produced? A. 0 B. C. 1 2 3 . 4 13. Per turn of the tricarboxylic acid cycle, how many FAD are produced? C. D. E JRUJNHO 14. How many protons are transported out of the mitochondrion when an electron pair passes from an FAD—linked substrate to oxygen? A. 2 B. 4 Q? 6 . 8' E. . 10 15. The following reactions are involved in the catabolism of galactose in the liver: galactose + ATP = galactose l-phosphate + ADP galactose l-phosphate + UDP-glucose = UDP-galactose + glucose l-phosphate UDP—galactose = UDP-glucose glucose 1-phosphate = glucose 6-phosphate When galactose is combusted to carbon dioxide and water in a typical liver cell, what is the NET yield of ATP? Assume the glycerophosphate shuttle is operating. A. 24 B. 26' C. 28 33 16. When glyceraldehyde is combusted to carbon dioxide and water in a typical cell, what is the NET yield of ATP? Assume the glycerol phosphate shuttle is operating. A. 12 B. 14 c? 15 . 16 E. 18 17. When 14C02 is added to a suspension of Chlorella, the first stable labeled compound that can be isolated is A. ribulose 1,5 bisphosphate 5 s glyceraldehyde 3-phosphate a 3-phosphoglycerate . xylulose 5-phosphate E. ribose 5-phohphate 18. Which enzyme of the TCA cycle is membrane-associated? A. citrate synthase B. aconitase C. malate synthetase D. funarase QED succinate dehydrogenase 19. Which of the following CORRECTLY pairs a compound with its effects on electron transport and oxidative phosphorylation? ” Cyanide : Inhibitor of cyt c oxidase 3. Carbon monoxide : Inhibitor of succinate dehydrogenase C. Oligomycin : uncoupling agent . D. 2,4 dinitrophenol : inhibitor of ATP synthase 20. Which of the following would be the expected result when dinitrophenol is added - to isolated mitochondria? . Electron transport would occur, but oxidative phosphorylation would not. 3. Neither electron transport nor oxidative phosphorylation would occur. C. Electron transport and oxidative phosphorylation would occur, but only from FAD-linked substrates. D. Electron transport and oxidative phosphorylation would occur, but only from NAD-linked substrates. E. Electron transport and oxidative phosphorylation would occur from both FAD-linked and NAD-linked substrates. Short Answer Credit for each item is iven in arentheses. 21. (4) Red blood cells derive their energy by converting glucose to lactate. (a) Why is lactate, rather‘than pyruvate, the prodch WV A5 neij ' ' (b) A net of how many ATP is produced as glucose is converted to lactate? Z 22. 23. 24. (6) (0) (4) Give the function of each of the following in the light reactions of photosynthesis. (a) photosystem I _I_’ ,__.7 IV db '35 17‘ '7' 7+ (b) photosystem II (27% the electron transport chain joining the two photosystems ~7 297’? most rapidly labeled? Explain briefly. (4) suppress photorespiration? Explain briefly Vl WP. filly/Mg f5}? Carboy/we C4 M90 79mm“? w Min/K bdrflfflj Me m l M ' ' Car” _3 f) {6 F” ll.f Him/*1 a ( «Lg Amuq When glucose labeled with 14C in carbon atom 3 is added to a liver cells preparation, which carbon atom of pyruvate would be expected to become Briefly define photoreSpiration. What adaptation do C4 plants have to r) éflhSé; Z} , - 9/77 figf.axfhfiai, 25. (8) Below are shown two oxygen-dissociation curves for hemoglobin. Decide which curve is appropriate for each of the following descriptors. % Sat P02 a) the curve at the lower concentration of BPG I . b) the curve at the higher pH I c) the curve at the higher pCOz 2— d) Assuming One curve corresponds to HbA and the other to HbF, which is the one for HbA? 2' .____._._3 26. (14) Data on the effects of an enzyme inhibitor are given in the following table. Substrate V(mmol m[ min" ) Concentration ( (a) Graph the data using a double—reciprocal plot. Label the line for the inhibited case. (b) Classify the inhibition according to type. My}? P9798 (0) Provide a possible physical basis for the 'nhibitio 9 Z bin/é; M 6? ég/7Q/AWVL 7cm); .5 wig/2137 6‘2 fir (d) Give a kinetic mechanism for this type of inhibitionkd E y—S rs: 55 49 ? t Z": 3’: 1 \l W‘ 51’ «HS $ 5745 (6) Can the inhibition by increasing substrate concentration? Answer "yes" or I10. (i) Calculate values for KM and Vmax giving the appropriate units. Show your work. __ x in7l— :3 Hme : v/Zé‘ w§fizmM .\ me; «- gee graph NQQH’ (g) Calculate a value for the inhibitor constant, Ki , assuming the inhibitor was present at a final concentration of 1.0 mM in the reaction mixture. Show your work. Eben), Graph Mex-k Page V v 11:19? , a .13?" w .. 1:1“..w-¢;. .‘..-us11 u :1.sz if? xL.L.+...ML;+,+J;. : smnywyWI. ..sr(a1; r-1a. _ x-x,+-. x-w-.w,e, . , m {A $1,, ‘ lnyv.wl« Is 3H warn. ..H” 4" “avg.” u 4+ LI,¢2« h *1 . w V n . . ~ . . rv\:¢4x!rxi.; ; .3”. }~3,“ :kuunt+(¢rt w . . n a r- H , vxwyvr.&¢ykx1wl Mx‘_ . _ ‘ :1 73))». .tv. .vvyau,.-.w;,. .4. .1344 3,-.ffhiwi -4; .5w M m , »EW«}_ . . 7 4 v4.3. .ei~)x x5 ‘T .szilnr . xx: . <1v‘(|3r-L:;: m 13...? :r: .3; Ii}! \u _ ¢ . “ . u _ rvw;lxl :.¢:; _ _ . L2W#¥E f%i%. . . w _ . . + :Ttxzktxy x: {[5743 515”); . , :Hz+,.m,i_ “ w T . . H I . _. fl , .)let.+nxsl 1.“: ‘ xyxxxvt.‘ ,, , _ . , m ,, meiwA‘Ags ,.+x.:xx.;.. 71.“. . .T L.1T.. ,. s.vm_:.,$...- LET“. 1L7 V. ~ . _ w . m w H _ . H ‘ “taiir ’9‘:L|(r.(1, «I sic“ ...
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This note was uploaded on 09/14/2009 for the course MCB 450 taught by Professor Mintel during the Summer '07 term at University of Illinois at Urbana–Champaign.

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450 ex2 key - Multi fléfl le-Choice 3 oints each 60 oints total For each of the following questions encircle the letter corresponding to the

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