ADVANCED BIOCHEM ACS EXAM QUESTIONS AND ANSWERS UPDATE RATED A+

ADVANCED BIOCHEM ACS EXAM QUESTIONS AND ANSWERS UPDATE RATED A+ Coenzymes required by the pyruvate dehydrogenase multienzyme complex are - Correct Answer - Thiamine pyrophosphate, lipoic acid, Fad, CoA, & NAD+ A kinase is an enzyme that... - Correct Answer - transfers a phosphoryl group from ATP Which of these contains a thioester bond: - Correct Answer - succinyl CoA In setting up an assay for measuring the total amount of an enzyme present in an unknown sample, the substrate concentration should preferably be: - Correct Answer - 10 fold higher than Km Dialysis would be most useful for the separation of: - Correct Answer - A ammonium sulfate from an enzyme An inhibitor that increases Km and does not alter the V max value is - Correct Answer - A competitive inhibitor Which amino acid side chain would not be expected would not be expected to participate in covalent enzyme catalysis - Correct Answer - Leu Which statement is correct concerning the T(deoxy) and R(oxy) states of tetrameric hemoglobin - Correct Answer - In the T to R transition, the central cavity of the tetramer decreases in size, preventing the binding of the allosteric modulator 2,3,- biophosphylglycerate When the energy needs of the cell are satisfied, acetyl-CoA accumulates and serves as a positive allosteric effector for - Correct Answer - pyruvate carboxylase To determine the Km value for an enzyme reaction, which parameter is normally varied, while keeping the others constant - Correct Answer - substrate concentration In a yeast cell growing aerobically on glucose, which would provide most of the energy for growth? - Correct Answer - glycolysis to TCA cycle and oxidative phosphorylation Cleavage of disulfide bonds in globular proteins may be brought about by - Correct Answer - Reaction with excess B-mercaptoethanol at pH 8 in 6 M urea The alpha helical secondary structure found in protein - Correct Answer - is disrupted by proline, amine H and carbonyl O What can you conclude about the thermodynamic spontaneity of a reaction that has a negative value for delta H and positive for delta S - Correct Answer - The reaction is spontaneous The kinetics of most enzymatic reactions can be described in terms of Km and Vmax. Which best describes Km? - Correct Answer - the substrate concentration required to give half maximal velocity Which compound would penetrate a neutral membrane most rapidly by free diffusion? - Correct Answer - ethanol The analysis of proteins by SDS-PAGE: - Correct Answer - yields the subunit molecular weights for an oligomeric protein Gel filtration chromatography separates on the basis of - Correct Answer - size and shape The conversion of a zymogen to an active proteolytic enzyme usually occurs as a result of - Correct Answer - Proteolytic cleavage of the zymogen The carnitine derivatives of long chain fatty acids are used - Correct Answer - To transport fatty acids across the mitochondrial membrane Which of these lipid classes contains glycosidic linkages - Correct Answer - ganglioside G-proteins become active when they bind - Correct Answer - GTP only Hydroxyproline is: - Correct Answer - a non-standard amino acid formed by the post translational modification of a protein A technique that is not widely used to amplify DNA sequences is: - Correct Answer - polymerase chain reaction If the carboxyl carbon of palmitic acid (16:0) is the number 1 carbon, which carbon of the original palmitate has been oxidized after the first cycle of Beta-oxidation - Correct Answer - C3 After the respiratory inhibitor cyanide is added to a suspension of actively respiring, tightly coupled mitochondria... - Correct Answer - The rate of oxygen consumption will decrease The products of the TCA cycle in higher organisms are - Correct Answer - NADH, CO2, GTP, FADH2 Which metabolic process requires a branching enzyme? - Correct Answer - Glycogen synthesis