ex_02_sp05_key - 74%st Kgg True-False 2 points each Decide...

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Unformatted text preview: 74%st Kgg True-False 2 points each Decide Whether each of the following statements is true or false. If it is true, mark “T” in the blank following the item. If it is false, correct the statement in a relevant way so that it becomes true. I . U] 10. agfflWfidm-afL Enzymes decrease the free energy of reactions they catalyze. A — u--""' An uncompetitive inhibitor combines with ES but not with E. I 7, Allosteric enzymes typically have quaternary structure. Diisopmpylfluorophosphate inactivates trypsin, chyrnotrypsin, and 5‘6 n VIE, acetylcholinesterase by reacting with threoni-rre' residues at the active site. I0 :0 at” HDL has ahighcfpercentage of lipid (on a dry weight basis) than LDL. Hemoglobin has four polypeptide chains, four heme groups, four iron atoms, run- but binds only one BPG. } Oxygen can only bind reversibly to hemoglobin and rnyoglobin if iron is in the f...-‘ F e2+ state. i Vincristine and vinblastine (anti-tumor agents) bind to tubulin and inhibit ——0 microtubule polymerization. I When muscle contracts, the distance between the Z lines of a sarcomere mag/5r The nicotinamide ring of NAUr can donatc‘a hydride ion. _____. decreases. / 11. 12. 13. 14. 15. 16. 17. 18. 19. 20 v._—-I- The isoalloxazine ring of FAD can accept two hydrogen free radicals. 1 Conversion of glucose and fructose to lactate generates the same number of _,..——-" ATP’s. Z . AMP and fructose 2,6 bi spho sphate are potent allosteric of phosphofructokinase- 1 (PFK- l ). 9K Thiamine pyrophosphate (TPP) is a co-factor involved in the decarboxylation of}! ketoacids. In each turn of the citric acid cycle, two carbon atoms enter, and two exit as C02. '7" #fl‘. Biotin is a cofactor involved in carboxylation reactions. _._—-——" Cyanide and carbon monoxide are inhibitors of electron transport. As a pair of electrons passes from NADH + H+ to oxygen, 10 protons are a-I-'-‘-'- extruded from the inner mitochondrial compartment. / Re-entry of four protons into the inner mitochondial compartment is required '7" for the synthesis and export of one ATP. Complete combustion of glucose to carbon dioxide and water in a typical animal 3 50 cell yields filiTP if the malate-aspartate shuttle is used and )1 if the glycerol- phosphate shuttle is used. [\J Point values for the following items are given in parentheses next to the item number. 21. (5) Suppose an organism were found which could carry out anaerobic glycolysis with the conversion of pyruvate to compound X, a compound other than lactate or ethanol. What conditions must be fulfilled by the reaction(s) leading from yruv'a-te to X? Mal/9+ MHZ be reef/nerd, 22. (15) Below are shown two oxygen-dissociations of hemoglobin. Decide which curve is appropriate for each of the following descriptors. % Sat P02 a) the curve at the higher concentration of BPG ’2 b) the curve at the higher pH c) the curve at the higher pC02 Z d) Assuming one curve is the curve for the lungs and the other for the tissues, which corresponds to the tissues? 2’ e) Assuming one curve corresponds to HbA and the other to HbF, which is the one for HbF? { —3 23. (10) In each part of this question an allosteric enzyme is listed together with some possible allosteric effectors. You are to decide whether the effector is an allosteric activator (mark +) or an allosteric inhibitor (mark -). a) b) d) hexokinase ,_—-- glucose 6-phosphate pyruvate kinase ._—— ATP pyruvatc dehydrogenase .——.. ATP # acetyl CoA ._—-—- NADH citrate Synthase dru-I‘ ATP isocitrate dehydrogenase fl ATP 'l" ADP isocitrate dehydrogenase _--- succinyl CoA NADH 24. (12) The effects of a linear inhibitor are depicted on the plot below UVi MS] a) Classify the inhibition according to type. awn PERI—(7L) Vé b) Provide a polsqsipl baesysiforthe )9 /€§ IT” 1 f K ' F“ J’ 5.: 2794,7— wflflmbmfis “NHL ‘5 a? u 6 brnfllfij ‘5“! 0) Give a kinetic mechanism for this typfinc inhibition Ev-S % 53—3? *5? +— f VJT‘ £7 ~ F—u d) Canthe inhibition betovercome‘? If so,how? I; / D ‘ 935/ by Mei/V?wa 25. (5) Suppose glucose labeled with 14C in position 2 were added to a glycolytic preparation. Draw the structure of pyruvate and indicate which carbon atom would be labeled. Ca0* 3:0 (has 26. (5) On the plot below, Show the values for Vmax and KM Km [3] 26. (8) In a hypothetical energy-producing metabolic pathway, A is converted to P in a series of steps, with the net production of 4 ATP, 4 NADH + H+, and 2 FADHz. 3) Calculate the total ATP yield as A is converted to P. Show your work. New 44:2, 5:70 ,_ u 5 i'lq'iDHZ 2 7“! ' 5 4 b) What important assumption have on made in answering pgyt (a)? all a We Tedd, in 734,143 midwa- amémm, ddaaf‘ 0) ATP is an allosterie effector of one of the regulatory steps in the pathway. What would you want that effect to be? Explain briefly. de he? rs «Qt/1104" "‘ f . 77“? Pang/wag “QT-ya 7Z5) 214;); I74? 65, we wan/d7 W455 d) What important thermodynamic characteristic should that regulated step (above) have? Explain briefly.Z b e I‘ Frey/"Q )n‘s') ,6 ' fl.” {4 if Maw / 7; Maw/Ia, WW3? Fa “Fa/He‘sfies. Fay/1006” 5 “jg [WWI/J P TheEnd ...
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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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ex_02_sp05_key - 74%st Kgg True-False 2 points each Decide...

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