生物化学与分子生物学（22级补学）学习通超星期末考试答案章节答案2024年

生物化学与分子生物学（22级补学）学习通超星期末考试章节答案2024年Hormonesaretypicallysynthesizedinonetypeoftissue,ofteninresponsetothereleaseofastimulatoryhormone.Whichoneofthefollowingcorrectlymatchesahormonewithitsstimulatoryhormoneanditssiteofsynthesis?

答案:Cortisol,ACTH,adrenalcortexAconsequenceofabetalipoproteinemiaisafattyliver(hepaticsteatosis).Thisoccursbecauseofwhichoneofthefollowing?

答案:InabilitytoproduceVLDLPatientswithelevatedserumLDLlevels(>120mg/dL)arefirstencouragedtoreducetheselevelsthroughacombinationofdietandexercise.Ifthisfails,theyareoftenprescribedstatins.Thekeyforstatintreatmentreducingcirculatingcholesterollevelsiswhichoneofthefollowing?

答案:UpregulationofLDLreceptors

Whichoneofthefollowingwouldyouexpecttoobserveinapatientlackingmicrosomaltriglyceridetransferprotein(MTP)aftereatinganormaldiet,inwhicheachmealconsistedof30%fat?

答案:SteatorrheaWhichoneofthefollowingsequencesplacesthelipoproteinsintheorderofmostdensetoleastdense?

答案:

HDL/LDL/VLDL/chylomicrons

WhichoneofthefollowingapolipoproteinsactsasacofactoractivatoroftheenzymeLPL?

答案:

ApoCIICholesterol,anditsprecursorsandproducts,haveavarietyoffunctionswithincells.Whichonestatementcorrectlydescribesafunctionofacholesterolprecursor,cholesterolitself,oraproductderivedfromcholesterol?

答案:PrecursorsofcholesterolcanbeconvertedtovitaminD.

Thestatinsarethemajorclassofmedicationsusedtolowerelevatedserumcholesterolbyinitiallyinhibitingthemajorrate-limitingstepofcholesterolsynthesis.WhichmetaboliteofthepathwaywouldaccumulateunderCconditionsoftakingastatin?

答案:

HMG-CoALow-doseaspirinisusedasapreventionofplateletaggregationandheartattacks,whereashigh-doseaspirinisusedasanantiinflammatorydrug.Low-doseaspirinisusedtoblocktheformationofwhicheicosanoid?

答案:Thromboxanes

Dietaryfattyacidsareprecursorsforsphingolipids.Ofthefollowing,whichoneisformedfromsphingolipids?

答案:Myelinsheath

Whichoneofthefollowingdrugsleadstothecovalentmodification,andinactivation,ofboththeCOX-1andCOX-2enzymes?

答案:AspirinIndividualswithadefectinglucose6-phosphatedehydrogenaseproduceNADPHforthesynthesisoffattyacidsowingtothepresenceofwhichoneofthefollowingenzymes?

答案:

Malicenzyme

Inhumans,prostaglandinsarederivedprimarilyfromwhichoneofthefollowing?

答案:

Arachidonicacid

Patientswithmedium-chainacyl-CoAdehydrogenase(MCAD)deficiencyexhibitfastinghypoglycemiaforseveralreasons.Insuchpatients,underfastingconditions,whichoneofthefollowingenzymesmaynotbefullyactivated,thusleadingtoaninabilitytocarryoutgluconeogenesis?

答案:Pyruvatecarboxylase

Apatientwithhyperlipoproteinemiawouldbemostlikelytobenefitfromalow-carbohydratedietifthelipoproteinsthatareelevatedinbloodarewhichofthefollowing?

答案:VLDL

Amoleculeofpalmiticacid,attachedtocarbon1oftheglycerolmoietyofatriacylglycerol,isingestedanddigested.Thefattyacidisstoredinafatcelland,ultimately,isoxidizedtocarbondioxideandwaterinamusclecell.Choosethemolecularcomplexinwhichthepalmitateresidueiscarriedfromthelumenoftheguttothesurfaceofthegutepithelialcell.

答案:Bilesaltmicelle

Whichoneofthefollowingisinvolvedinthesynthesisoftriacylglycerolsinadiposetissue?

答案:FattyacidsobtainedfromchylomicronsandVLDL

Anewbornchildhasbeendeterminedtobeunabletooxidizephytanicacidandisplacedonadietcontainingverylowlevelsofthisunusualfattyacid.Theorganellemostlikelytocontainthedefectiveenzyme,orbealteredinthisdisorder,iswhichoneofthefollowing?

答案:PeroxisomeApatientwithdiabetesinketoacidosishasaspecificodortothebreath.Whichoneofthefollowingcompoundsisresponsibleforthisodor?

答案:AcetoneVitaminB12isarequirementinthecompleteoxidationofwhichofonethefollowingfattyacids?

答案:Odd-chain-length

A6-month-oldinfantisbroughttoyourofficebecauseoffrequentcryingepisodes,lethargy,andpooreating.Thesesymptomswereespeciallynoticeableafterthechildhadhadanearinfection,atwhichtimehedidnoteatwell.Theparentsstatedthatthissituationhashappenedbefore,buttheyfoundiftheyfedthechildfrequently,thelethargicepisodescouldbereducedinnumber.Theresultsofbloodworkindicatedthatthechildwashypoglycemicandhypoketotic.Sixtoeightcarbon-chaindicarboxylicacidsandacylcarnitinederivativeswerefoundintheurineofthechildaswell.Basedonyourunderstandingoffattyacidmetabolism,whichenzymewouldyouexpecttobedefectiveinthischild?

答案:MCAD

IfyourpatienthasclassiccarnitinepalmitoyltransferaseIIdeficiency,whichoneofthefollowinglaboratorytestresultswouldyouexpecttoobserve?

答案:

ElevatedbloodacylcarnitinelevelsInwhichoneofthefollowingtimespanswillfattyacidsbethemajorsourceoffuelforthetissuesofthebody?

答案:Whilerunningthelastmileofamarathon

Elevatedlevelsofketonebodiescanbefoundinthebloodofpeoplewithuntreatedtype1diabetesandindividualsonseverediets.Amajordifferenceinthelaboratoryfindingsofmetabolitesinthebloodofeachtypeofindividual(type1diabetesvs.thediet)wouldbewhichofthefollowing?

答案:Glucoselevels

TheATPyieldfromthecompleteoxidationof1molofaC18:0fattyacidtocarbondioxideandwaterwouldbeclosesttowhichoneofthefollowing?

答案:120AlackoftheenzymeETF:QOmayleadtodeathbecauseofwhichoneofthefollowingreasons?

答案:TheenergyyieldfromfattyaciduseisdramaticallyreducedTheabsenceofwhichhormonelistedwouldresultinaninabilitytoraisethepHofthepartiallydigestedfoodleavingthestomach,leadingtoaninabilitytodigestlipidsintheintestine?

答案:IntestinalsecretinApatienttryingtoloseweightistakinganover-the-counter“fatblocker”thatsupposedlyblocksfatabsorptionfromthegastrointestinaltract.Ifthissupplementtrulyblockedfatabsorption,forwhichvitaminbelowcouldthepatientpotentiallydevelopadeficiency?

答案:

KApatienthasbeentakinganexperimentaldrugtoreduceweight.Thedrugleadstosignificantsteatorrheaandsomenight-blindness.Apotentialtargetofthisdrugiswhichoneofthefollowing?

答案:Cholecystokininrelease

Pancreatitiscanleadtoablockageofthepancreaticductthat,inturn,leadstosteatorrhea.Thesteatorrheaismostlikelycausedbytheabsenceofwhichoneofthefollowing?

答案:Colipase

TypeIIIhyperlipidemiacanbecausedbyadeficiencyofapoE.Analysisoftheserumofpatientswiththisdisorderwouldexhibitwhichoneofthefollowing?

答案:Elevatedtriglyceridelevels

Bilesaltsmustreachaparticularconcentrationwithintheintestinallumenbeforetheyareeffectiveagentsforlipiddigestion.Thisisbecauseofwhichoneofthefollowing?

答案:Thebilesaltsolubilityinthelumenisacriticalfactor.

Inorderforthelipidsinchylomicronstobeusedbythetissuesofthebody,thenascentchylomicronsneedtobeconvertedtomaturechylomicrons.Thisconversionrequireswhichoneofthefollowing?

答案:

HDL血红蛋白的结构特点是

答案:具有两个α亚基和两个β亚基;每个亚基具有独立的三级结构;亚基间靠次级键连接;整个分子呈球形有关mRNA的叙述正确的是：

答案:主要分布在胞液中;分子内不含脱氧胸苷酸下列关于β-折叠结构的论述哪些是正确的？

答案:是一种伸展的肽链结构;肽键平面折叠成锯齿状;两条以上的多肽链可顺向或反向平行;R基团交替分布在片层的上下方关于肽键的下列描述，正确的是：

答案:具有部分双键性质;可为蛋白酶分解;是蛋白质分子中的主要共价键;是一种比较稳定的酰胺键;键长介于单、双键之间蛋白质分子中能吸收紫外光的氨基酸有：

答案:苯丙氨酸;色氨酸;酪氨酸下列关于蛋白质结构的叙述，哪些是正确的：

答案:二硫键对稳定蛋白质的构象起重要作用;蛋白质溶于水时，带电荷的侧链基团趋向于分布在分子表面;蛋白质的一级结构决定其高级结构下列有关DNATm值的叙述哪些是正确的？

答案:与DNA链的长度有关;与G—C对的含量成正比;(G＋C)／(A＋T)的比值越大，Tm值越高有关蛋白质四级结构的下列描述哪些是正确的：

答案:由两个或两个以上的亚基聚合而成;解聚后单独的亚基丧失生物学功能;亚基间以次级键缔合存在于DNA分子中的脱氧核糖核苷酸是：

答案:dAMP;dGMP;dCMP;dTMP下列哪些是酸性氨基酸：

答案:天冬氨酸;谷氨酸下列哪些是碱性氨基酸：

答案:精氨酸;组氨酸;赖氨酸组成蛋白质的单位是：

答案:L-α-氨基酸胰岛素分子A链与B链的交联是靠：

答案:二硫键对α-螺旋的下列描述哪一项是错误的：

答案:通过疏水键维持稳定不参与DNA组成的是：

答案:dUMP关于肽键的特点哪项叙述是不正确的？

答案:肽键的C—N键可以自由旋转下列哪种核酸的二级结构具有“三叶草”型？

答案:tRNA对α-螺旋的下列描述哪一项是错误的()

答案:通过疏水键维持稳定关于蛋白质结构的论述哪项是正确的？

答案:一级结构决定二，三级结构氨基酸的等电点是：

答案:氨基酸净电荷等于零时的溶液pH值下列含有两个羧基的氨基酸是：

答案:谷氨酸蛋白质的最大吸收峰波长是：

答案:280nm下列关于二硫键的叙述哪一项是错误的？

答案:二硫键是非共价键在下列哪种情况下，蛋白质胶体颗粒不稳定？

答案:溶液pH=pI关于核酸分子杂交的错误叙述是：

答案:RNA可与其编码的多肽链结合为杂交分子维持蛋白质一级结构的化学键主要是：

答案:肽键下列哪一种氨基酸不含极性侧链：

答案:亮氨酸核酸对紫外光的吸收是由以下哪种结构产生的：

答案:嘌呤、嘧啶环上的共轭双键下列哪种