203f07_e2_key

203f07_e2_key - Chemistry 203 Lg(Fall ‘07 Exam#2 Last...

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Unformatted text preview: Chemistry 203 Lg (Fall ‘07) Exam #2 Last Name: October 23, 2007; 11200-1 1 :50 am. First Name: Prof. Richard Brutchey USC ID: Prof. Charles E. McKenna T.A: INITIAL OF LAST NAME Please do not open this exam until you are told to do so. Write legibly to avoid confiJsion. GOOD LUCK ! ! . Maximum Questlon # , Score Grader Pomts 1 - 7 28 __l 8 - 13 24 ~—l——————l____—+ 14 - 19 24 20 - 25 24 Bonus 4 '——_———.————_T——_—‘_‘__—‘ TOTAL 104 I will observe the rules of Academic integrity while taking this exam. Student Signature Circle the most nearly correct answer. (4 points each) (1) Which among the following does N_Ol have a polar covalent bond: a) H—OH @) Hi-CHs)‘ c) H-OCH3 d) F-CH3 (2) Reason(s) for synthesizing a new drug analog: a) Increase potency b) Decrease side effect c) Increase oral bioavailability ) All of the above (3) Which of the following statements are true for the methane (CH4) molecule: i) The molecule has a tetrahedral geometry ii) The H—C-H bond angles are 120° iii) The carbon is sp3 hybridized iv) The 0 bonds result from sp-l-sp3 overlap between the carbon and hydrogen atoms a) i, ii, and iii b) i, iii and iv (c) i and iii ) d) iii and iv (4) The Michaelis-Menten equation is: V = Vmax - [S] / (Km + [8]), where Vmax = k2 ' [E0] ([E0] = initial enzyme concentration, Vmax = maximum reaction rate) Which statement is not true: a)'The reaction rate is de endent on substrate concentration (b) Adding more enzyme has no effect on the maximum reaction rate ) c) Given a series of substrate concentrations and their corresponding reaction rates, along with the initial enzyme concentration, you can determine k2 d) As more substrate is added, the rate ultimately reaches Vmax (5) The compound below contains: HSCO‘Q—CHQCHQN H2 WWW—m. a) Both an amine and an ether group?) b) Both an amine and an ester group c) Both an amide and an acid group d) Both a ketone and an aldehyde group (6) Name the missing elements, in order from 1 through 5: a) C, 0, Ne, Ca, S b) C, O, Xe, Ca, Se c) O, C, Ne, K, Se (d) C, 0, Ne, M2? } (7) For Michaelis-Menten kinetics, V = Vmax' [S]/(Km + [8]). Which statements are true: i) A small value of Km means the substrate has a high affinity for the active site ii) A small value of Km means the substrate has a low aflinity for the active site iii) When [S] >> Km, then V = Vmax iv) When [S] >> Km, then V = 1/2 Vmax la) i and iii b) i and iv c) ii and iii d) ii and iv KEY (8) The following Lineweaver-Burk relationships were plotted for a substrate with and without the presence of an inhibitor. 1N + inhibitor I no inhibitor 1/S Which of the following statements are true? i) The Michaelis-Menten constants for the two enzymatic reactions with and without inhibitor are the same ii) The maximum reaction rates for the two reactions with and without the inhibitor are the same iii) The inhibitor is competitive iv) The inhibitor is non-competitive a) i and iii c) ii and iii d) ii and iv (9) According to the induced fit theo ' i a) An enzyme active site adjusts itself to enhanced binding to a substrate b) A substrate fits into a rigid enzyme active site like a lock into a key -..,’ c) Only one substrate can bind to a particular active site in an enzyme (1) None of the above is true (10) In water at neutral pH, the predominant structure of an amino acid would be: a) NHz-CHR-COzI—I b) -CHR—C02+ (c) *NH3—CHR-C02‘z d) None of the above (l 1) In amino acids NHzCHRCOzH, the R group could be: a) Ionic b) Polar c) Non-polar (1) Any of the above (12) Which on of the ' g amino acids is NOT chiral: “ C—OH H3C‘\\\ b) H H2N fi H C ‘ C—OH 3 \HC‘\\\‘ I H 0) CH3 d) (13) When lithium metal is mixed with fluorine gas, the result is: a) Covalent (shared) bond, Li-F b) Ionic bond Li' F + (c) Ionic bond, L? F- d) Disulfide bond (14) Which among the following is the least polar molecule: a) CH3OH b) CH3-O-CH3 c) H20 d) (15) The bonding interactions that affect tertiary protein structure, from strongest to weakest, are: a) Ionic > disulfide > hydrogen bonding % van der Waals b) Disulfide > ionic z van der Waals > hydrogen bonding c) Van der Waals > ' ' z ' ' 1de ( d) Disulfide > ionic 3 hydrogen bonding > van der Waals (16) The picture below shows, within a protein: (a) Formation of a covalent disulfide bond i b) Formation of a peptide bond c) Formation of a van der Waals bond d) Formation of a hydrogen bond (17) HzN—C—CozH (18) (19) This reaction is best characterized as: F! R + HzN—C—COZH H H a) Oxidation reaction b) Reduction reaction c) Hydrolysis reaction d) Dehydration reaction Which of the following are secondary confirmations of proteins: i) Alpha helix ii) Beta sheet iii) Gamma twist iv) Random coil a) iand ii b) iand iv c) i, ii, and iii The figure below shows four hypothetical drug (2 types) receptor (2 types) interactions. Which interaction is predicted not to result in hydrogen bonding: (20) Which of the following statements regarding enzymes is true: a) An enzyme makes the reaction thermodynamically favorable b) An enzyme makes the reaction thermodynamically unfavorable c) An enzyme increases the activation energy of the reaction d) An enzyme lowers the activation energy of the reaction (21) The electrone ativi of atoms in the periodic table tends to: a) Increase from left to right b) Increase from right to left c) Increase from top to bottom d) Increase from top right to bottom left (22) How many valence electrons does carbon (C) have: a)2 c)6 d)8 (23) Lipitor, shown below, contains which of the following functional groups: Lipitor (atorvastatin) a) Amine, pyrrole, ester, alcohol, and carboxylic acid b) Amine, pyridine, aromatic hydrocarbon, thiol, and ester c) imidazole, aromatic h drocarbon alcohol, and carbox 'lic acid Amide, pyrrole, aromatic hydrocarbon, alcohol, and carboxylic acid KEY (24) Which of the following statements regarding a protein’s overall tertiary structure are true: i) The interior of the tertiary protein structure is comprised mainly of amino acids with hydrophilic side chains ii) The overall tertiary structure is a combination of the various secondary structures iii) The protein’s primary sequence has no influence of the final 3-D tertiary structure iv) Protein folding is afiected by covalent, ionic, van der Waals, and hydrogen-bonding interactions a) i, ii, iii, and iv b) 3, ii, and iv lc) ii and iv) d) iv only (25) Which of these amino acids have side chains that would interact with a second hydrophobic side chain via van der Waals interactions at pH = 7: O O O 0 II II II II H2N—CH—C—OH H2N—CH—C—OH H2N—CH_C—OH H2N_CH_C—OH CH—CH3 CH2 CH2 CH2 i, l, i=0 h (L, in in h Val Ser Asp Lys b) Val and Lys c) Ser, Asp, and Lys d) Val, Ser, Asp, and Lys BONUS (4 extra points) Which of the following statements are true for the ethyne (HCECH) molecule: i) The carbon atoms possess a trigonal planar geometry ii) The H-C-C bond angles are 180° iii) The carbon atoms are sp hybridized iv) The CEC bond is comprised of three 1: bonds a) i, ii, iii, and iv b) ii, iii, and iv 1c) ii and iii l d) ii and iv 10 ...
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203f07_e2_key - Chemistry 203 Lg(Fall ‘07 Exam#2 Last...

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