Exam (elaborations)
BIO-251 FINAL EXAM QUIZ QUESTIONS WITH COMPLETE SOLUTIONS
- Course
- Institution
BIO-251 FINAL EXAM QUIZ QUESTIONS WITH COMPLETE SOLUTIONS
[Show more]
Content preview
BIO-251 FINAL EXAM QUIZ QUESTIONSWITH COMPLETE SOLUTIONS
1)aActinaisaoneaofatheamostaevolutionarilyaconservedaproteins.aWhatadoesathisatellayouaabou
tatheastructureaandafunctionaofathisaproteinainaeukaryoticacells?a-
acorrectaanswera✔✔Evolutionarilyaconserved-
hasn'taundergoneamuchachangeasinceaexistenceaofaeukaryotes.
Tellsausathatathisaproteinaisavitalaforacellularafunction.aTellsausaitacanadoaaavarietyaofafunctions
ainacells.
Itsasoaconservedabecauseaitaisaveryaimportantaforacells.aMultifunctionalamakesaitamoreawell-
conservedabecauseamonomersathatamakeait.aUpaareaveryasimple,aandaareaableatoacombinea
in.aaacomplexawayatoaperformaitsamanyafunctions.aItahasatoabeasomethingatoadoawithatheafacta
thatasoamanyaotheraproteinsacanabindatoait.aG-
actinahasalotsaofaaaasideachainsathatastickaout.aSequenceaofaaaasideachainsamakeaitamultifun
ctional.aEveryadifferentaproteinathatabindsatoaactinahasatoabindatoaaaspecificaplaceaonaactin.a
Mutationainaaaasideachainsacouldanegativelyaimpactatheabinding.
1)aIamentionedaphalloidinaisaaatoxicaproducedabyatheadeathcapamushroom.aItaisatoxicabecau
seaitabindsaacrossatwoaactinamonomersaandaholdsathematogether.aInacontrast,alatrunculin,aa
notheratoxina-athisaoneaisamadeainaspongesa-atightlyabindsatoaG-
actinamonomers.aDescribeatheaeffectaeachadrugawouldahaveaonaactinatreadmilling.a-
acorrectaanswera✔✔Phalloidin-
filamentsawillacontinueatoaelongate,aunableatoatakeafilamentsaoffaofachain.aPreventsadepoly
merization.aPolymerizationawouldastopaforathisawhenatheacellareachesabelowasomeathreshol
daofafreeaG-actin.
Latrunculin-awouldabind.aTo.aG-
actin,apreventapolymerization,astopaforceaagainstaPM,alengthaof.aF-
actinawouldagetashorterabecauseathereawouldabeadepolymerizationabutanotapolymerization.a
Levelaofamonomersainacellamayamakeadepolymerizationaslowadown
1)aLet'sathinkaaboutatheastagesaofadeath.aIfayouawereaaacrimeasceneainvestigatoraandayouaw
ereaexaminingaaabodyaataambientatemperature,ayou'daprobablyaknowatheafollowing:
Ifatheabodyafeelsawarmaandanoarigoraisapresent,adeathaoccurredaundera3ahoursabefore.
Ifatheabodyafeelsawarmaandastiff,adeathaoccurreda3-8ahoursaearlier.
Ifatheabodyafeelsacoldaandastiff,adeathaoccurreda8-36ahoursaearlier.
Ifatheabodyaisacoldaandanotastiff,adeathaoccurredamoreathana36ahoursaearlier.
Rigorarefersatoarigoramortis,awhichaisatheastiffeningaofaaabodyaafteraitadies.aKnowingawhatayo
uaknowaaboutacellulararespirationaandamyosin'saATPaseacycleaandamuscleafunction,aplease
aansweratheafollowingaquestions:aWhataisatheabasisaofarigoramortis?aWhyaisaitareferredatoaasa
stiffeningaandanotacontracting?aWhyadoesaitatakea3ahoursaforastiffeningatoaoccur?aWhyadoes
,athearigoraretreat?a-acorrectaanswera✔✔Basisaofarigoramortis-
aafteraATPahydrolyzed,aandaafteraeverythingaelseatakesaplace,aATPastops.aInadeath,aATParu
nsaout,acausesamusclesatoabeastiffabecauseanoaATPatoareleaseamyosinaheadafromaactin.
Stiffeningainsteadaofacontracting-
myosinaisanotamovingaactinafilamentsaalong,amyosinais.aBoundatoaactinaandaisaimmovable.a
Noacycleaofacontraction,asoawillaonlyabeastiff
Whya3ahours-thereawillastillabeasomeaATPaleftaoverawhichawillabeausedaupauntilaitaisagone.
Whyadoesarigorafinallyagoaaway?-
atheabodyabeginsatoadecayasoatheaproteinsawillabeadegraded,areleasingatheamyosinafromathea
actin.aactinafibersafallaapart,amyosinaheadsadegrade,abecomesapliableaagain
1)aYouaknowathatacanceracellamigrationaisaaakeyapartaofametastasis,awhichaisatheadeadliestaa
spectaofacancer.aSo,ayouawantatoadevelopaaadrugathatacanainhibitacanceracellamigration.aYou
aknowathatamyosin-2-
basedacontractionaisarequiredaforacellamigrationaandasoayouaspecificallyawantatoadevelopaaad
rugatoainhibitait,amyosin-2.a(Note:atheamyosin-
2athatapromotesamigrationaisaveryasimilaratoabutaultimatelyaaadifferentaisoformafromamusclea
myosin-2.aTheanon-muscleamyosin-
2aformsasmallerafilamentsathataareamoreadynamic,awhereasatheamyosin-
2athickafilamentsainamusclesaareaveryastableaandalargerastructures.)
a)aWhataaspectaofamigrationaisamyosin-
2ainvolvedain.aThinkaaboutatheastepsaofamigrationadiscussedainalecturea(andaseeafigurea17-
33ainayouratext).aWhereaisatheaforceabeingaproducedathatainvolvesamyosin-2?a-
acorrectaanswera✔✔Myosin-
2aisainvolvedainaretractiona(backaendaofacell).aForceabeingaproducedaisawhereaactinabringsau
paendaofacellabackaintoamiddle
a)aYouadevelopaaadrugathataseemsatoainhibitamyosin-
2,abutayouaareaunsureaofaitsamechanismaofaaction.aInageneral,ahowamightayouaknowawhethe
ratheadrugablocksaATPafromabindingatoamyosinaversusaallowingaATPatoabindabutablockingahy
drolysis?aCanayouathinkaofaaawayatoatestathisainaaabiochemicalaassayawithapurifiedaactinaanda
myosin-2?a-
acorrectaanswera✔✔YouacouldatrackatheaamountaofafreeaATP,aifathereawasaaacomparativelyal
owaamtaitawouldabeabindingaandaifathereawasaaahighaamount,aitawouldn'tabe.aIfaATPacannotabi
nd,ayoudahaveatheasameaamountaofaATPainayourasolutionaasayouastartedawith.aControl-
withoutadrug
Youracontrol,atheaATPawouldadecreaseaafteragoingathroughatheacycle
Experimental-ATPalevelsawouldastayahigheraifaATPabindingawasapreventedabyatheadrug.
Ifayouacarriedaoutatheasameaexperiment,acouldayouatellawhetheraitawasaableatoabindabutanotaa
bleatoahydrolyze?aNo-
aATPalevelsawouldastayatheasameaasacomparedatoawhenayouafirstaputaitain.adependsaonaratioa
concentrationaofaATPatoaactinaandamyosin.
, Anotheraexperiment-agenerateamichaelisamentenacurve-
keepamyosinalevelsatheasame,achangealevelsaofaATP,aseeaifadrugacompetitivelyainhibitsait.aK
davalueawouldaincreaseaifaitaaffectedaATPabinding.aButacannotaanalyzeawhetheraatpawasabo
undaoranotatoamyosin
a)aAfterathinkingamoreaaboutathis,ayouadecideathatagivingaaapersonaaapillathatainhibitsamyosin
-
2amightanotabeaaagoodaidea,aevenaifaitadoesastopatumoracellametastasisareallyawell.aWhyaisath
at?a-
acorrectaanswera✔✔Notaaagoodaideaabecauseaitawouldaaffectahealthyacellsaasawellaasacance
racells.aWouldacauseaaalotaofaissuesaforatheaperson,aincludingamuscleacontractionaandacella
motility;adrugasoundsalikeatheadeathacapamushroomatoxins.
1)aMicrotubulesacanabeaformedainavitroafromatubulinathataisaboundatoaGTPaanaloguesathata(u
nlikeaGTP)acannotabeahydrolyzed.aWhatapropertiesawouldayouaexpectatheseamicrotubulesat
oapossess?aCouldasuchamicrotubulesastillashowadynamicainstability?a-
acorrectaanswera✔✔TheseaMTsawouldapolymerizeabutanotadepolymerize,asoathereawouldab
eanoneaoralessadynamicainstability.aGTPacapastabilizesatheaendsaofathe.aMTSaandahydrolyze
saafteraaalittleawhile.aTheseaMTsawouldanotashowadynamicainstabilityabecauseatheyawouldn't
abeadepolymerizing,aonlyapolymerizing—exceptionallyastable
1)aIfaanaindividualakinesinamoleculeacanamoveaataaarateaofa800anm/secainaanainavitroamotilitya
assay,awhataisatheamaximalaturnoveraratea(ATPamoleculesahydrolyzedaperasecond)abyaonea
ofatheamolecule'samotoradomains.aWhatainformationadoayouaneedatoaanswerathis?aThinkaab
outahowatheakinesinsawalk.aNoteathataa-aandab-tubulinaareaeachaabouta4anmainalength.a-
acorrectaanswera✔✔8nm/step.a100asteps/sec.aATPmolecaperasecondawouldabea100/secafor
atwoadomains,asoa50/secaforaONEadomain.
1)aBecauseacytoplasmicavesiclesaareaseenatoamoveainabothadirectionsawithinatheaaxonaofaaa
neuron,acanayouaconcludeathatasomeamicrotubulesaareaorientedawithatheiraplusaendafacingat
heaaxonaterminusaandaothersaorientedawithatheaoppositeapolarity?aWhyaorawhyanot?a-
acorrectaanswera✔✔WeacannotaconcludeathisabecauseaMTsaonlyagrowaoutaofaoneaspotainath
eacell,aplusasideagrowsaoutwardabutavesiclesaareaallowedatoamoveabackaandaforthabecauseat
heyaareakinesinsaandadyneins
1)aHowadoesasignalingabyahydrophobicamoleculesalikeatheasteroidahormonesadifferafromasig
nalingabyahydrophilicamoleculesalikeapeptideahormones?a-
acorrectaanswera✔✔Hydrophobicamoleculesalikeasteroidahormonesahaveaintracellularasigna
lingareceptors-
hydrophobicaallowsaitatoadiffuseathroughamembrane.aAdditionally,asignalingapathwayaisadiff
erent.aPeptideasignalingapathwayatransducedabyabindingatoasomeacellamembraneareceptora
whicharequiresamoreaofaaasignalacascadeathanasteroidasignalingapathway.aSteroidahormone
sagoarightatoanucleusawhereareceptorais,aallowsasteroidatoagoaintoanucleus—
shorterapathway.aSpeedaofaresponseainacellasignalingacanatellausaaalot-
twoawaysaweathinkaofathis:abindingaofamolecatoareceptor-
cascadearesultsainaactivationaoradeactivationaofaproteinsaalreadyathere-
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller AGRADEPROMASTER. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
79271 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now