Page 1 EXAM3Fall2009ReviewExamBCHS3304,SECTION#21734,GENERALBIOCHEMISTRYI©2009Dr.GlenBLeggePage 2 • I. (2 points each) True (A) or False (B)? Bubble in the circle marked “A” if the following statement is True or bubble in the circle marked “B” if the following statement is False. T F 1. Formation of glycosidic bonds results in the elimination of a water molecule. T F 2. Cyclization of D-fructose to form a hemiketal results in the elimination of a water molecule. T F 3. An allosteric effect occurs when the binding of one ligand or substrate influences the binding of a second or additional ligand or substrate. T F 4. D-glucose and D-mannose are epimers. T F 5. An enzyme of gluconeogenesis which yields ATP is phosphofructokinase. T F 6. NADH is a high energy compound produced by the Pentose Phosphate Pathway. T F 7. Phosphorylationalwaysdown‐regulates(inactivates)enzymes.T F 8. Glucose-6-phosphate can be used to synthesize ATP through substrate-level phosphorylation. T F 9. Under aerobic conditions in muscle NADH reduces pyruvate to lactate. T F 10. Hydrolysis of ATP to ADP and Pi is an exergonic process T F 11. Glycolysis occurs in the cytosol. T F 12. Sucrose is a disaccharide formed from an (α1,2β) glycosidic linkage between D-glucose and D-fructose. T F 13. In metabolism the three main pathways for energy production are gluconeogenesis, Citric Acid Cycle, and oxidative phosphorylation. T F 14. Peptidoglycans are an essential component of bacterial cell walls T F 15. Oxidation describes the loss of electrons from an atom, compound or molecule.Page 3 II. Matching The enzymatic mechanism of aldolase is shown below. For questions 16-24, match the correct substrate/product/ intermediate/group or point along the enzyme-catalyzed reaction pathway by selecting “A-J”. Note: “A-J” may be used more than once. A. water B. FBP C. Free Enzyme D. DHAP E. protonated Schiff base F. conjugate base G. Lys H. GAP I. Enediolate J. EnaminePage 4 II. Matching: (continued) Glycolysis converts glucose ultimately to pyruvate via a series of enzymes. For questions 25-33, match the correct chemical structure with the appropriate step that is produced or consumed in the glycolysis pathway indicated by selecting “A-J”. Note: “A-J” may be used more than once.Page 5 II. Matching (continued) For questions 34-37, match the correct co-factor with its appropriate figure by selecting “A-H” on your scantron sheet. Note: “A-H” may be used more than once. 34. ADP 35. CoASH 36. NAD+ 37. TPPPage 6 II. Matching (continued) For questions 38-40: If glucose is isotopically labeled with [14C] on a single carbon atom as indicated below (*) and metabolized in the glycolysis pathway, which product in the glycolysis pathway would contain the label? Note: “A-F” may be used more than once.Page 7 41. AcetylCoA:A. isahighenergycompound.B. isacarrierofacetyloracylgroups.C. canbeusedtodriveendergonicprocesses.D. isbothA.andB.E. isA.B.andC. 42. GlycosidicbondsbetweentwosugarsA. canformonlythrougha1‐2linkage.B. canformonlythrougha1‐4linkage.C. canformonlythrougha1‐6linkage.D. canformthrougha1‐2,1‐4or1‐6linkage.E. canformonlythroughapeptidebond. 43. Whatis/arepossiblemetabolicfatesofpyruvateinhumans?A. Conversion to lactate under aerobic conditions B. Conversion to lactate under anaerobic conditions C. Conversion to acetyl CoA under anaerobic conditions D. Conversion to ethanol under anaerobic conditions E. All of the abovePage 8 44. SugarmoleculescanbedrawnbyeitherusingtheFischerprojection(linearform)ortheHaworthprojection(cyclicform)toillustratetheorientationofthehydroxylgroups.BelowtotheleftisshowntheFischerprojectionforD‐glucose.WhichoftheHaworthprojectionstotherightrepresentsα‐D‐glucopyranose?HHHOHHOHCH2OHHCH OOHHHHOOHHOHHCH2OHHOHHOHHOHCH2OHHHHHOHHOHCH2OHHHHHOHOHHCH2OHHOHHHOHHOHCH2OHHOOHOHOHOHOOHOHOOHOHOHOHA.B.C.D.E.D-glucose 45. WhichoftheenzymesofGlycolysisareirreversible,andwhichofthoseenzymesservesastheprimaryfluxcontrolstep?A. Hexokinase,GAPDehydrogenase,andPyruvateKinase;withGAPDehydrogenaseasthefluxcontrolstep.B. Hexokinase,Phosphofructokinase,andPyruvateKinase;withPyruvateKinaseasthefluxcontrolstep.C. Hexokinase,Phosphofructokinase,andAldolase;withHexokinaseastheprimaryfluxcontrolstep.D. PhosphoglucoseIsomerase,TriosePhosphateIsomerase,andPhosphoglycerateKinase;withTriosePhosphateIsomeraseasthefluxcontrolstep.E. Hexokinase,Phosphofructokinase,andPyruvateKinase;withPhosphofructokinaseasthefluxcontrolstep.Page 9 46. Phosphofructokinase‐1:A. isinhibitedbyATP.B. hasahigheraffinityforfructose‐6PinthepresenceofAMP.C. isphosphorylatedinresponsetohormones.D. isthemostimportantcontrolpointinglycolysis.E. isalloftheabove. 47. Whichofthefollowingstatementsaboutglycogensynthesisorbreakdowniscorrect?A. Glycogensynthaseextends1‐6linkagesthroughanoxoniumionintermediate.B. Thereisonlyonenon‐reducingendofaglycogenpolysaccharide.C. Glycogensynthaseextends1‐4linkagesthroughanoxoniumionintermediate.D. Monosaccaridesderivedfromglycogenproduces2ATPmoleculesfromglycolysis.E.