中山大学生命科学学院试卷生物化学I标准答案（2005年秋季学期,A卷）B)TwointernalaminoacidsofthetetrapeptidecannothaveionizableRgroups.专业(班级)：姓名：学号：C)Thetotalnetchargeiszero.D)Onlytheaminoandcarboxylterminicontributecharge.阅卷教师：4.Whichwouldelutefirstfromagel-exclusionchromatographiccolumn?A)anegativelychargedproteinofMW=40,000题号一二三四五合计B)apositivelychargedproteinofMW=40,000分数C)aproteinatitsisoelectricpointofMW=30,000D)apolysaccharideofMW=100,000警示《中山大学授予学士学位工作细则》第六条：“考试作弊不授予学士学5.Inanaqueoussolution,proteinconformationisdeterminedbytwomajor位”。factors.Oneistheformationofthemaximumnumberofhydrogenbonds.Theotheristhe:A)formationofthemaximumnumberofhydrophilicinteractions.一、选择唯一正确答案（每小题1.5分，共15分）B)maximizationofionicinteractions.1.Withregardtoaminoacids,whichstatementisfalse?C)minimizationofentropybyformingawatersolventshellaroundtheA)Aminoacidscanactasprotondonorsandacceptors.protein.B)AllaminoacidsdiscoveredinorganismareLenantiomers.D)placementofallhydrophobicaminoacidresidueswithintheinteriorofC)AnLaminoacidcanbeDextrorotary.theprotein.D)Non-standardaminoacidscanbefoundinthehydrolysisproductofa6.YoucandestabilizeaduplexDNAmoleculeinanaqueoussolutionbyprotein.A)Decreasingtheconcentrationofsalt.2.Inahighlyacidicsolution,pH=1.3,thedominantformofglycineis:B)Decreasingtheconcentrationoforganicsolvents.A)NH-CH-COOH；B)NH+-CH-COOH；C)NH-CH-CO–；D)NH+-CH-COO–.22322232C)AdjustingthepHtoavaluenear7.3.Intheisoelectricformofatetrapeptide:D)Addingadetergent.A)Theaminoandcarboxylterminiarenotcharged.1中山大学生命科学学院试卷7.WithregardtoDNA,whichstatementisfalse?二、看图填空（每小题5分，共25分）A)Triplehelixandtetraplextendtoappearatsiteswherereplication,1.Considerthisfigurewhichshowsoxygenbindingtorecombinationortranscriptionisinitiatedorregulated.myoglobinorhemoglobin.For(1-7)indicatewhichB)HydrogenbondsaretheonlyforcetostabilizeDNAstructure.(oneormore)curve(s)fitthedescription(5points).C)TheabsorbanceofDNAat260nmwillrisewhenitisdenatured.D)Z-DNAtractsmayplayanroleintheregulationoftheexpre