Exam 2 Trial - . University of Houston BCHS 3304 Exam H...

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Unformatted text preview: . University of Houston BCHS 3304 Exam H Instructor Dr. Briggs Oct. 12, 2004 Printed Name: :Arl‘L Vii-“K”? Student lD#: ' § .3 --- l ' ‘ Multiple choice, 2 pts each (100 pts) ~ Circle letter (ie. a, b., 0., d., or e.) of the most correct answer, then mark it on the Scantron sheet with a #2 pencil. Mark BOTH the exam AND the Scant on sheet. A Rainachandran plot can be found at the end of the exam. '. S .v 1). Binding ofoxygen to the heme in either myoglobin or vhemoglgbingrequires: “ / a). A heme—heme dimer complex. ~ ' ,b)’. A iron liganded to a tyrosine. 0). His E‘V’linked to the iron The iron in the +3 oxidation sate @ His F8 linked to the iron \y A‘ 2). Which statement best describes a stagdgg‘d «()7 The amino acid side chains point to the inside of the helix. b). It always aligns parallel to a B—sheet. i. it is a 3.613 helix. ). It is stabilized by extensive ionic bonding. e). None of the above. 4 3). Changes in the concentration of wmmle does not affect the 02 binding to Hb? I I a). 02 I W W . 2o nth—€92 4). Hemoglobin releases 0; when: a). Too much oxygen is in the blood. Jr)? The pH is basic. 6)) The concentration of 2,3—bisphosphoglycerate is increased. d). The concentration of C02 decreases. e). The myoglobin concentrations are low. 5).. The slope of the Hill plot for oxygen binding to hemoglobin changes and becomes greater than 1 as . compared to the slope of the Hill plot for oxygen binding to myoglobin which is always 1: i a). Indicates that myoglobin can release more 02 than hemoglobin. b). Lndicates that the pH will not affect C02 binding. c . Indicates the mother’s hemoglobin will bind 02 tighter than fetal hemoglobin. h f t . . . . . . ., >,, a... . Indicates the binding of one molecule of 0-2 to hemoglobin enhances the binding of another. waver at“ “W I“ " ‘ S e). Indicates that carbon monoxide irreversibly binds to both proteins. ‘ a 4i ‘ I T .L l 10‘ \ "v \K ‘L l i ‘1 ‘3“! . .. +0 ' - 6). What is the ionic strength, I, of a 30 mM solution of K3P04? a . 1.80M . 180 mM c). 30 mM a). 900 mM e). 45 mM' 7). Why is the Eis—peptide bonddisfavored? \ H 1) 3T 7 1 Z a). Steric interactions between the Con atoms. f Ll a >< l J i— < §O<'73> m.b')‘."’Low rotational barrier of the peptide bond. Steric repulsion of side chains. ,3)? Large dipole moment of cis—isomer. vej’.” Low solubility of the cis—isomer. . L 0. 8). The d) dihedral angle of a peptide bond is described by rotation about the bond 3.). that is between the N and C atoms. b). that is between the Ca and CB atoms. [\lr C4 (653mm is between the COL and N atoms. v-..’ d). that is between the COL and C atoms. e). none of the above. 9). The W dihedral angle of a peptide bond is described by rotation about the bond 21). that is between the N and C atoms. b). that is between the COL and CB atoms. a w c). that is between the COL and N atoms. @ that is between the COL and C atorns. e). none of the above, 10). What is the most important interaction that holds an oohelix together? (31’ Electrostatic interactions. in}; Solvation .* Hydrophobic interactions. {)DHydrogen—bonding. ye): Protein folding. N» v“ R m Afrrgilyfletaékeratins consist of (3)! hair with high sulfur content. fir—beta—carotenes. c). alpha—amyloids. d . macrofibrils. e beta-pleated sheets. 12). The function of BPG is to ,3)? refine petroleum products. la .4 increase hernoglobin’s oxygen affinity. ‘ c decrease hemoglobin’s oxygen affinity. day. help myoglobin compete for oxygen with hemoglobin. X‘Aej)‘1'”helps keep hemoglobin in the R—state. The Bohr effect is related to the ArBPG ionization at 30 torr (the p02 in veins). ,bfi.’ ability of hemoglobin to bind oxygen in the presence of BPG. M ability of myoglobin to expel protons when binding oxygen. ability of hemoglobin to release protons when binding oxygen. e). ability of hemoglobin to “take up” protons when binding oxygen. . 4). What is the oxidized form of nicotinarnide adenine dinucleotide? “LA 3). NADH ( 7w NAD+ H Ar D x W W; e):-‘PIL’P‘ 15). A protein purification technique whose primary advantage in separation is based on digierenvces in size among proteins is affinity chromatography. gel filtration chromatography. 0). SDS'PAGE chromatography. d). ion exchange chromatography. e). hydrophobic interaction chromatography. v.4 - mommy-g» .«v 16). SDS—PAGE is a). a dehydrating gel technique. b . an anaerobic gel technique. 7c . a denaturing gel technique. Vd). a hydrophilic gel technique. e). none of the above. 17). Define the term “apoenzyme”. F“ a . An enzyme with all required cofactors An enzyme missing one or more cofactors c). A denatured enzyme d). A prosthetic group " 1e). An enzyme with no bound substrate K18) How many heads does a myosinmolecule have? a). Fifty Two Thousands d). Several hundred e). None 19). What is the W that provides the energy for the movement of myosin heads in striated muscle cells? a ADP . ATP 0). Sugar d). Water e). Light 20). What is the approximate spacing between pleats in a beta pleated sheet? /' a). 13 atoms / b . two turns 7.0 A d). 3.6 A e). 0.5 light years 21). Which of the following amino acids is MOST LIKELY to be found on the‘surface of the protein at pHZQZ3 3% I WWW.-. .. . . . _ bpqayf C M510: 45" Svfsé’zc Q Glu Airbed e)”.er 22). How many protons are released on the binding of a single oxygen molecule to hemoglobin? 1‘ t). 4.0 / b). 3.6 c). 2.6 d . 1.6 23). Enzymes increase the rates of chemical reactions by , ‘V' a ( a . lowering the pH required for the reaction. ' é. reducing the gap between reactants and the transition state. c). making them diffusion limited. d). sequestering the catalytic residues from protons. e). reducing the gap between the reactants and products. 24). On binding of an oxygen molecule, hemoglobin goes from the ' a). R state to the S state. b). S state to the R state. c . R state to the T state. I . T state to the R state. 9 e). D state to the L state. 25). If the Hill coefficient for a protein that binds more than one copy of a ligand is 1.5, the protein exhibits a . negative cooperativity. é positive cooperativity. c). non—cooperativity. @ d). neutrality. e). electrostatic steering. {@The P50 of hemoglobin is 26 torr. What is the fiactional saturation of hemoglobin (YOZ) at 60 torr? Assume at n=3 for this calculation. b). 0.50 ML 7 y (1:... JV: W“’" . \ \‘q w~ ‘m\/ S\ .———-"~ .- (x t/ P. L EN LRSYDPKFQ 359,. it kt...) , Agifp W) ’9 a). 1 (“skis \ (4!; i 27% How many Wed residues are there between these two aligned protein sequences? 28).. How far above the porphyrin ring system in the heme group is the Fez+ ion in the deoxy state of hemoglobin? a). 0.0 A b). 0.2 A 9 3i $125: E). 0.8 A ’4) 29). What is the actual (NOT computed) Yoz of hemoglobin at a partial oxygen pressure of 100 ton? a). 0.55 fifl " 7 7 b). 0.91 C 0.95 .qu 0.97 . e). 1.00 m 5 "‘7 30). SDS~PAGE separates proteins by a. Size . - ~- a", . mass ' ' f' i; 0. charge »/ ll‘i‘o (are ’1 @75hape We v MC» «M f e). affinity “MR”... ........r..m—.......m-~wWW «MP—.wWVF . ,. ....._..._..____ .._‘m_:‘.,,__. _..._... .. W’ 31).;AififinLty chromatography is used to separate proteins by a). size b . mass ligand binding (:1 . salting out e). salting in 32). Which residues in the seven—residue repeat (abcdefg) of oc—keratin provide a mechanism by which o-keratin polymers associate to form a coiled coil? 1 ( a). a, b b). a, c at: a) at. o E ~ F‘s e).c,f . J 33). An enzyme with its cofactors is called a . lonely. 6! a holoenzyrne. c). a denatured enzyme. d). a prosthetic group. e). an apoenzyme. 34). List the l ‘ngalor molecular components of the Lthinwfiiarils, in muscle tissue? '8')? Coiled—coil, myosin head, myosin tail by Hemoglobin, myoglobin, heme c). Acne, tropomiosin, tropunen d . ATP, calcium, acetylcholine Actin, tropomyosin, troponin 35). What function(s) does the formation of carbamates serve in hemoglobin? Transport C02 b . Degrade C02 c . They facilitate the binding of oxygen. . They facilitate release of oxygen. @ aandd 36). Describe “salting out”. a). Precipitation of salt in high salt concentration solutions. b). Proteins are more soluble at low salt concentrations. _ c). Precipitation of proteins in low salt concentration solutions—“WHN 3 @. Precipitation of proteins in high salt concentration solutions. \ .- , v . , . _ C) a t e). Hypertensron resulting from high salt intake. 37). Explain why individuals with severe cyanide or carbon monoxide poisoning are often given blood transfusions instead of oxygen—rich gas? ' a), Because oxygen has a higher binding affinity to heme than cyanide and carbon monoxide. CE)? Because cyanide and carbon monoxide have a higher affinity; for heme than oxygen. c). Because air primarily contains nitrogen. d). Because heme is oxidized to the 111' state. e). Because heme is reduced to the 11 state. Given the following (1) and w angles, what is the secondary structure of this residue? Phi(¢>, deg) Psi(\u, deg) —72 -48 (a). Alpha helix (right handed) . Parallel beta strands . Alpha helix (left handed) d). Anti—parallel beta strands e). Collagen coil x) :thwmé 39). Name the type of secondary structure exhibited by the pair of beta—strands in the figure below. aye-trailer beta strands \ H Bag) \pi g0» M Q s: c w Anti-parallel «strands\ \ . \ _,c)a-A-1¥>ha strands ' 1‘) ‘7 m) “A b l7 96 giving CL \ I Q‘e‘wv é)e-Pi'strands ). L fth d d l h tr d e, e ane apasans H 6ND) my, 5/” IMTLén‘j {Aet’n ml?” 40). Given the following (3) and w angles, what is the secondary structure of this test e. hid), deg) Psiw, deg) 120 105 a . Alpha helix (right handed) Parallel beta strands (left handed) a? Anti—parallel beta strands e)r‘(;ollagencoil ‘ 41). What statement about silk fibroin is most true? a . It is primarily made up of alpha helices. . It is made up primarily of beta sheets. Q) M ‘ V I” “Cf—ms made up of alpha-beta barrels. W “m ‘90?“ W d). It is made up of beta barrels. veH is made up of alpha barrels. : 0 Mg 42Wmhggcrder would you expect the amino acids Glu, Lys, and Val to be eluted from a diethylaminoethyl amo exchange) column? é a) Lys, Val, Glu - , , ys c). Val,Lys, Glu W175 e). Glu, Lys, Val J (v _ , dm‘é/r/‘Vl/OJNWI.’ “'43). In the contraction cycle ofmyosin molecules as they walk along thin filaments in striated muscle cells, Pi is ’ released causing V- ‘x a). a power stroke. b . cocking of the myosin head. a weak binding of the myosin head the actin on the thin filament. PL 6/ stlgng binding of the myosin head the actin on the thirlfilament. e). opening of the binding site in the myosin head. 44). What part of the IgG antibody is responsible for binding_directly with antigens? W a). Constant region. fig/'0“ a!» \. 9V . . Variable regionfi/7@_ C % Hypervariable loops « d). Light chain. if] e). Heavy chain. ‘ ‘r .r w tat glean 45). What is the specific amino acid mutation that occurs in the Sickle form of hemoglobin? a) Glu6Val \-.t\\ ' ‘ Val6Glu I 2 ‘- c). Asp6Val Gt, l/(k l A d). Val6Asp e). lle6Val 46). Fully describe the subunit composition of a protein from the following information. Molecular mass by gel filtration: kD\’ L J u " ‘ ” Molecular mass by SDS-PAGE: 130 kD and .79 id)“ / ‘ ' Molecular mass by SDS-PAGE with 2-mercapt0ethanol: 60 kD and 70 kD v a). One 130 kD polypeptide and one 70 kD polypeptide. b). One 130 kD polypeptide and two 70 kD polypeptides. c . Two 60 kD polypeptides and one 70 kD polypeptide. ® One 60 kD polypeptides and two 70 kD polypeptides. e). Two 60 kD polypeptides and two 70 kD polypeptides. a», g in», 47). What is the subunit composition of a protein from the following information. Molecular mass by gel filtration: 200 kD Molecular mass by SDS—PAGE: 100 kl) Molecular mass by SDS-PAGE with 2-mercaptoethanol: 40 id) and 60 kD a). one 40 kD polypeptide and one 60 kD polypeptide. C b . two 40 kD polypeptides and one 60 kD polypeptide. two 40 kD polypeptides and two 60 kD polypeptide. d). three 40 kD polypeptides and two 60 kD polypeptide. .\ e). three 40 kD polypeptides and three 60 kD polypeptide. l + fie of ' 48)“. In what order will the amino acids andyeu be eluted from a carboxymethyl column (cation eXchange) at pH 6_ (1e. which will come’éff first, second, and third?)? HRS A . L H' érg - a v. ._ ~ \ v r % Leu i' Me (3 d . , , ‘ t e His, Leu, Arg 49). The 1352 ofmyoglobin QB torr. What is the fractional saturation of myoglobin (Y 02) at an oxygen partial pressure of 45 torr? p, ‘ “ K x a . y K “a 5 1 \§ $009.? / _— ~:_/5q 2 9 z); i t fl (5- 0797 Q tn 3% x (5.: at - at is» » 3" 50), How many Eesiduesa per turn do the coiled-coil helices of a—kerat'm contain? M54. )' 3 5 ‘ " C - ~ $‘3 \ .’ «kw J'vgr (e99 m n 3‘ (a dk'wfim W K “54,343,4‘3233614345331‘14321» Aziémaziiaui} O mm ,M m . 1W wmmmmwm W, MWW kg ...
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Exam 2 Trial - . University of Houston BCHS 3304 Exam H...

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