Legge Practice Exam BCHS 3304 Fall 2005Note: This homework will not be collected. However, quizzes and exams will assume that you have completed and understand the homework assignment and could answer related questions. Inthis homework you are also given a practice exam II, which you may use as a study tool.1). An enzyme catalyzes a reaction without itself being __________ in the process. It does this by __________ of the reaction. Enzymes preferentially bind the ____________ in an ideal situation. The extent to which an enzyme will catalyze a reaction is ultimately dictated by the ___________ for the reaction.: An enzyme catalyzes a reaction without itself being consumed/altered in the process. It does this by lowering the activation energy of the reaction. Enzymes preferentially bind thetransition state in an ideal situation. The extent to which an enzyme will catalyze a reactionis ultimately dictated by the equilibrium constant for the reaction.2). What happens if you add more enzyme to an enzyme-catalyzed reaction already operating at Vmax?a). KM will decrease.b). No change.c). Observed rate will be faster.d). kcat will increase.e). Observed rate will be slower.: (c), the observed rate of reaction will be faster.3). The basis for enzyme-substrate specificity is:a). shape/geometry.b). Keq.c). stereospecificity.d). electronic complementarity.e). none of the above.f). a, d, and c.g). all of the above.: (f), Shape/geometry, electronic complementarity, and stereospecificity are the basis for enzyme-substrate specificity.4). Given the following equation:E + S  ES  E + Pk1 = the rate of formation of the Michaelis Complex.k-1 = the rate at which the Michaelis Complex falls apart to E + S.k2 = the rate at which the Michaelis Complex forms E + P.When [ET] = [ES], which of the following expressions defines the Vmax?a). Vmax = __k-1 + k2__ k1b). Vmax = k1[S]c). Vmax = k2[ES]d). Vmax = k-1[ES]e). Vmax = __[E] [S]__ [ES]: (c), when [ET] = [ES], then Vmax = k2[ES].5). Some enzymes require a necessary metal ion cofactor for catalysis. Which of the following isnot a potential property that a metal ion may impart to an enzymatically catalyzed reaction?a). May act as a super acid. b). May shield and stabilize charges.c). May facilitate redox reactions. d). May bind and orient substrates.e). May exclude inhibitors from the active site.: (e), metal ions do not exclude inhibitors from the active site.6). Two different enzymes have the same value for Vmax but very different KM values. Which of the following is true?a). The enzyme with the lower KM will approach Vmax at lower [S].b). The enzyme with the higher KM will approach Vmax at lower [S].c). The Vmax values cannot be the same if the enzymes have different KM values.d). The Vmax and KM values for each enzyme will increase when more enzyme is added to their respective reactions.e). The steady-state [ES] is the same for each enzyme at all [S].: (a), the enzyme with the lower KM will approach Vmax at lower [S].7-8). Write the Michaelis-Menton equation of enzyme kinetics and list and describe the two assumptions that are required for this equation to apply.a) Assumption of equilibrium k-1 >> k2 b) assumption of steady state ([S] >> [E])9). Discuss the importance of Vitamin C in the creation and stabilization of Collagen Quaternary Structure.Required for the formation of hydroxyproline, which can form stabilizing intra-strand hydrogen bonds between collagen fibers.10). Which of the following accurately describes the catalytic strategy and intermediate employed by the RNase A reaction mechanism?a). Acid-Base Catalysis with a 2, -3’ cyclic intermediate.b). Acid-Base Catalysis with a tetrahedral intermediate.c). Covalent Catalysis with a tetrahedral intermediate.d). Covalent Catalysis with a Schiff Base intermediate.e). Electrostatic Catalysis with an oxonium intermediate.: (a), RNase A utilizes acid-base catalysis to form a 2, -3’ cyclic intermediate.11). Match the appropriate type of inhibition with the resulting effect on kinetic parameters.a). Competitive inhibition I). Decreases Vmaxb). Non-competitive inhibition II). Decreases KM and Vmaxc). Uncompetitive inhibition III). Increases KMd). Mixed inhibition IV). Decreases Vmax + increases KM: Competitive inhibition (a) increases KM (III). Non-competitive inhibition (b) decreases Vmax (I). Uncompetitive inhibition (c) decreases both KM and Vmax (II). Mixed inhibition (d)decreases Vmax and increases KM (IV).  SKSVmaxMov12). Which of the following describes the cleavage pattern of the (NAG-NAM)3 hexamer in the presence of water with a heavy oxygen isotope?a). Cleavage between the D and E sugars with the 18O occupying the C-1 position of the D-sugar.b). Cleavage between the D and E sugars with the 18O occupying the C-4 position of the E-sugar.c). Cleavage between the D and E sugars with the 18O occupying the C-1 position of the E-sugar.d). Cleavage between the D and E sugars with the 18O occupying the C-4 position of the D-sugar.e). Cleavage between the D and E sugars with the 18O occupying the C-1 position of the D- and E-sugar.: (a), cleavage between the D and E sugars with the 18O occupying the C-1 position of the D-sugar.13). An enzyme is said to be “perfect” when it operates at a diffusion-controlled limit. What does this imply about the values of Vmax and KM for a “perfect” enzyme?a). The values of both Vmax and KM are very high.b). The values of both Vmax and KM are very low.c). The value of Vmax is very high and the value of KM is very low.d). The value of Vmax is very low and the value of KM is very high.e). Nothing is implies by this statement.: (c), the value of Vmax is very high and the value of KM is very low.14). What will happen to the value of an enzyme’s kcat (turnover #) if more of the enzyme is added to the enzymatically catalyzed reaction already operating at Vmax?a). kcat will increase. b). kcat will decrease.c). No change. d). Enzyme efficiency will increase.e). Enzyme efficiency will decrease.: (c), no change.15). In the Chymotrypsin reaction mechanism, which amino acid residue serves as a potent nucleophile during the formation of the tetrahedral intermediate (covalent catalytic step)?a). His 57 b). His 119c). Asp 102 d). Asp 52e). Ser 195: (e), Ser 195.16). Write the net reaction (all reactants and products) that is catalyzed by the enzyme Aspartate Transcarbamoylase and