生物化學與分子生物學（22級補學）學習通超星期末考試答案章節(jié)答案2024年

生物化學與分子生物學（22級補學）學習通超星期末考試章節(jié)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血紅蛋白的結(jié)構(gòu)特點是

答案:具有兩個α亞基和兩個β亞基;每個亞基具有獨立的三級結(jié)構(gòu);亞基間靠次級鍵連接;整個分子呈球形有關(guān)mRNA的敘述正確的是：

答案:主要分布在胞液中;分子內(nèi)不含脫氧胸苷酸下列關(guān)于β-折疊結(jié)構(gòu)的論述哪些是正確的？

答案:是一種伸展的肽鏈結(jié)構(gòu);肽鍵平面折疊成鋸齒狀;兩條以上的多肽鏈可順向或反向平行;R基團交替分布在片層的上下方關(guān)于肽鍵的下列描述，正確的是：

答案:具有部分雙鍵性質(zhì);可為蛋白酶分解;是蛋白質(zhì)分子中的主要共價鍵;是一種比較穩(wěn)定的酰胺鍵;鍵長介于單、雙鍵之間蛋白質(zhì)分子中能吸收紫外光的氨基酸有：

答案:苯丙氨酸;色氨酸;酪氨酸下列關(guān)于蛋白質(zhì)結(jié)構(gòu)的敘述，哪些是正確的：

答案:二硫鍵對穩(wěn)定蛋白質(zhì)的構(gòu)象起重要作用;蛋白質(zhì)溶于水時，帶電荷的側(cè)鏈基團趨向于分布在分子表面;蛋白質(zhì)的一級結(jié)構(gòu)決定其高級結(jié)構(gòu)下列有關(guān)DNATm值的敘述哪些是正確的？

答案:與DNA鏈的長度有關(guān);與G—C對的含量成正比;(G＋C)／(A＋T)的比值越大，Tm值越高有關(guān)蛋白質(zhì)四級結(jié)構(gòu)的下列描述哪些是正確的：

答案:由兩個或兩個以上的亞基聚合而成;解聚后單獨的亞基喪失生物學功能;亞基間以次級鍵締合存在于DNA分子中的脫氧核糖核苷酸是：

答案:dAMP;dGMP;dCMP;dTMP下列哪些是酸性氨基酸：

答案:天冬氨酸;谷氨酸下列哪些是堿性氨基酸：

答案:精氨酸;組氨酸;賴氨酸組成蛋白質(zhì)的單位是：

答案:L-α-氨基酸胰島素分子A鏈與B鏈的交聯(lián)是靠：

答案:二硫鍵對α-螺旋的下列描述哪一項是錯誤的：

答案:通過疏水鍵維持穩(wěn)定不參與DNA組成的是：

答案:dUMP關(guān)于肽鍵的特點哪項敘述是不正確的？

答案:肽鍵的C—N鍵可以自由旋轉(zhuǎn)下列哪種核酸的二級結(jié)構(gòu)具有“三葉草”型？

答案:tRNA對α-螺旋的下列描述哪一項是錯誤的()

答案:通過疏水鍵維持穩(wěn)定關(guān)于蛋白質(zhì)結(jié)構(gòu)的論述哪項是正確的？

答案:一級結(jié)構(gòu)決定二，三級結(jié)構(gòu)氨基酸的等電點是：

答案:氨基酸凈電荷等于零時的溶液pH值下列含有兩個羧基的氨基酸是：

答案:谷氨酸蛋白質(zhì)的最大吸收峰波長是：

答案:280nm下列關(guān)于二硫鍵的敘述哪一項是錯誤的？

答案:二硫鍵是非共價鍵在下列哪種情況下，蛋白質(zhì)膠體顆粒不穩(wěn)定？

答案:溶液pH=pI關(guān)于核酸分子雜交的錯誤敘述是：

答案:RNA可與其編碼的多肽鏈結(jié)合為雜交分子維持蛋白質(zhì)一級結(jié)構(gòu)的化學鍵主要是：

答案:肽鍵下列哪一種氨基酸不含極性側(cè)鏈：

答案:亮氨酸核酸對紫外光的吸收是由以下哪種結(jié)構(gòu)產(chǎn)生的：

答案:嘌呤、嘧啶環(huán)上的共軛雙鍵下列哪種