Ex_02_sp06_key - Multiple-Choice 3 points each 60 points total For each of the following questions encircle the letter corresponding to the BEST

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Multiple-Choice. 3 points each. 60 points total For each of the following questions, encircle the letter corresponding to the BEST response. 1. Which of the following is NOT an assumption made in the derivation of the Michaselis-Menten equation? A Bi 63 D. E. Only one substrate is considered. The rate of formation of BS is balanced by the rate of its destruction, either to E + S or to P + The reaction is at equilibrium. The k4 step can be ignored. (All of the above are assumptions usually n1 ade.). 2. Which of the following correctly defines KM? A. E: It is equal to the quantity kp’flcl + k2) It is the dissociation constant for the enzyme-substrate complex. It is equal to Vmaxfll. It is the substrate concentration giving half-maximal velocity. it is equal to the quantity k.fi(k1 + kg) 3. Serine residues occupy the active site of trypsin, chymotrypsin, acetylcholinesterase, and many other enzymes. What property of Ser is associated with its catalytic role in those enzymes? A. B. It has a sidcchain group capable of hydrogen bond formation. It readily forms amides. Its functional group may be acylated. It is found near the surface of these enzymes. it may form acid anhydrides. 4. Which statement about a hemoglobin molecule is INCORRECT? A. B. C. D. CPD There are four polypeptide chains non—covalently associated. Each polypeptide chain is associated with one porphyrin ring. There are a total of four F e2+ atoms in oxyhemoglobin. One BPG can bind in a central cavity. HbF centains or and B chains. Which of the following statements about the X-ray structure of myoglobin is INCORRECT? A There are eight regions of a helix. B The regions between the helices frequently contain Pro or B turns. There is one porphyrin ring per molecule. Q One molecule of oxygen can be bound to the Fe3+ of the porphyrin ring. E. Hydrophobic amino acid residues are buried in the interior. Which of the following is a correct statement about NAD" and FAD? A. FAD transfers one hydrogen as a hydride ion and the other as a proton, whereas NAD+ accepts two hydro gens as free radicals. They are both derived from water-soluble vitamins. NAD+ is generally a stronger oxidant than is FAD. D. NAD+ contains the isoalloxazine ring system whereas FAD does not. B. Reoxidation of the reduced form of FAD yields more ATP than reoxidation of the reduced form of NAD+. Which of the following is NOT an allosterie enzyme of glycolysis‘? A. hexokinase . phosphefructokinase-l (PFK-l) aldolase puruvate kinase At higher concentrations of 5‘-AMP, the rate of the phosphofructokinase-l reaction is ’0 greater than I. equal, or approximately equal to, C. less than the rate at lower concentrations of 5'-AMP. A lipoprotein with a higher ratio of protein to lipid would be expected to have a density greater than equal, or approximately equal to, C. less than a lipoprotein with a lower ratio of protein to lipid. 10. Which of the following TNCORRECTLY pairs at coenzyme with its function in the pyruvatc dchydrogenase reaction? A. TPP : decarboxylation B. Lipoic acid : acyl transfer C. Lipoic acid : oxidation . Coenzyme A : formation of thioesters FAD : reduction 1 l. A derivative of which water-soluble Vitamin is NOT required for the conversion of or-kctoglularatc to succinyl CoA in the TCA cycle? A. thiamin B. riboflavin C. niacin biotin ,. pantothenic acid 12. Per turn of the tricarboxylie acid cycle, how many C0; are produced? A. 0 B. I C? 2 . 3 E. 4 13. How many protons are transported out of the mitochondri on when an electron pair passes from an FAD-linked substrate to oxygen? A. 2 B. 4 Q? 6 . 8 E. 10 14. How many protons are transported out of the milOChODdI'iOIl when an electron pair passes from an NAB-linked substrate to oxygen? A. 2 B. 4 C. 6 . 8 IO 15. 16. 17. 18. The following reactions are involved in the catabolism of fructose in the liver: Fructose + ATP = Fructose l-phosphate + ADP Fructose 1-phosphate —— DHAP + glyccraldehyde Glyceraldchyde + ATP = glyceraldehyde 3-phosphate + ADP When fructose 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 so E. 32 When glyceraldeh yde is combusted to carbon dioxide and water in a typical liver cell, what is the NET yield of ATP? Assume the glycerophosphatc shuttle is operating. A. 12 B 14 <25» 15 . 18 E. 19 When glyceraldchydc is converted to pyruvate in glycolysis, how many NA D+ are converted to NADH + H“? A. 0 ‘ .. 2 T). 3 E. 4 Which of the following enzymes of the TCA cycle requires FAT) for activity? A. citrate synthase B. C. isocitrate dehydrogenase malatc dchydrogenase furnarase succinate dehydrogenase 19. Which of the following TNCORREC'I‘LY pairs a compound with its effects on electron transport and oxidative phosphorylation? A. Cyanide : Inhibitor of cyt c oxidase B. Carbon monoxide : : Inhibitor ol‘cyt c oxidase C. Oligornyein : inhibitor of ATP synthase D. 2,4 dinitrophenol : uncoupling agent CED Rotenone : allosteric activator of ATP synthase 20. Which of the following would be the expected result when oligomycin and dinitrophenol are added to isolated mitochondria? Electron transport would occur, but oxidative phosphorylation would not. a . Neither electron transport nor oxidative phosphorylation would occur. . Electron transport and oxidative phosphorylation would occur, but only from FAD—linked substrates. Electron transport and oxidative phosphorylation would occur, but only from NAB-linked substrates. E. Electron transport and oxidative phosphorylation would occur from both FADJinked and ND-linked substrates. C D Short Answer {Credit for each item is given in parentheses! 21. (6) Human red blood cells lack mitochondria and therefore must use an anaerobic means of energy production. The glycolytic pathway is the major energy source for human red blood cells with glucose serving as the substrate, and lactate being the product. (a) Why is lactate, rather than pymvate, the prod ct? D if n 71m 1" encmres 7th flj’l (4;) ,p ‘fiifl.’ chem/de 3"? dwflmj Maw. (13) A not of how many ATP is produced as glucose is converted to lactate? L2? *2” 22. (4) Chymotrypsin Can catalyze the following reaction: p—nitrophenyl acetate (PNPA) + H20 = p—nitrophenolate (PN?) + acetate (Ac) When transient phase (pie-steady stale) kinetics of the reaction are studied, the following kinetic profile is obtained. EHI'INGIV-IIHIII. mm “In I Human Fain PIBII'I II.“ Acetate or pNOf pllenr late release rm llll‘. IIIII Ilium I!“ cum um wnm In. Write a chemical equation for the appearance of p—nitrophcnolate. (You may use words or abbreviations.) 517.”st WNW —> fizw'm 7 1;- ?N P Write a chemical equation for the appearance of acetate...»- - flz~ Ser- Ac. +1425 '—'> 5/1259? 0 H , +7‘la. Label each of the above equations "fast" or "slow." 23. (10) Below are shown two oxygen-dissociations ol‘hemoglobin. Decide which curve is appropriate for each of the following descriptors. % Sat .002 a) the curve at the higher concentration of BPG Z b) the curve at the lower pH c) the curve at the higher p00: 2— (1) Assuming one curve is the curve for the lungs and the other for the tissues, 2. which corresponds to the tissues? e) Assuming one cuwe corresponds to HbA and the other to HbF, which is the one for HbA? 2" . 24. 25. (4) Explain, define, or characterize the following briefly. allosteric enzyme M/Ajld ma) (a) 9 mu! I ’4 - ~ 1 ed 4 . . lfs 5‘0:th dry—Ii/‘a’alas .. ’Jnhzéi‘fdlfl (f) uncoupling agent ,..——I 7L5 1" .5 112,3 It W Aime-Se *7“ WWBZWQ 37” fiatrxgllhz’: 40me “Hep M (6) When respiring mammalian cells are suddenly and neatly deprived of their oxygen, :1 further small quantity of carbon dioxide is produced. Why? What limits the magnitude 01‘ this effec ? ‘ ' I finite; )4? 77,: 7‘09 ojcle Mtg/Wig; 40mg 7"” a” recent. ma Mi?“ v FAD are P (10) The effects of a linear inhibitor at. two different concentrations are depicted on the plot below we] (a) Classify the inhibition according to type. (:10 mfg-fijfl (b) Providcapossible baiis forthe inhibit n \ ‘ 9% If) Jabsijni'E. an; m hiégqum fie) n 5’ i (0) Give a kinetic mechanism ‘11); this type of inhibition [5 n? =2- :3 H: 73%? E L- AL ((1) Can the inhibition he overpcomc‘? If so, how? r 5’ .-—- ‘ jES/ bj 1v”!an A— (6) Put a circie around "+1" for the line corresponding to the higher concentration of inhibitor. The End 9 ...
View Full Document

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.

Page1 / 9

Ex_02_sp06_key - Multiple-Choice 3 points each 60 points total For each of the following questions encircle the letter corresponding to the BEST

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online