BIO-251 FINAL EXAM QUIZ QUESTIONS WITH CORRECT ANSWERS RATED A+

BIO-251 FINAL EXAM QUIZ
QUESTIONS WITH CORRECT
ANSWERS RATED A+
1)QActinQisQoneQofQtheQmostQevolutionarilyQconservedQproteins.QWhatQdoesQthisQtellQyouQaboutQth
eQstructureQandQfunctionQofQthisQproteinQinQeukaryoticQcells?Q-QCORRECTQANSWERS-
EvolutionarilyQconserved-hasn'tQundergoneQmuchQchangeQsinceQexistenceQofQeukaryotes.

TellsQusQthatQthisQproteinQisQvitalQforQcellularQfunction.QTellsQusQitQcanQdoQaQvarietyQofQfunctionsQinQ
cells.

ItsQsoQconservedQbecauseQitQisQveryQimportantQforQcells.QMultifunctionalQmakesQitQmoreQwell-
conservedQbecauseQmonomersQthatQmakeQit.QUpQareQveryQsimple,QandQareQableQtoQcombineQin.QaQ
complexQwayQtoQperformQitsQmanyQfunctions.QItQhasQtoQbeQsomethingQtoQdoQwithQtheQfactQthatQso
QmanyQotherQproteinsQcanQbindQtoQit.QG-


actinQhasQlotsQofQaaQsideQchainsQthatQstickQout.QSequenceQofQaaQsideQchainsQmakeQitQmultifunction
al.QEveryQdifferentQproteinQthatQbindsQtoQactinQhasQtoQbindQtoQaQspecificQplaceQonQactin.QMutation
QinQaaQsideQchainsQcouldQnegativelyQimpactQtheQbinding.




1)QIQmentionedQphalloidinQisQaQtoxicQproducedQbyQtheQdeathcapQmushroom.QItQisQtoxicQbecauseQit
QbindsQacrossQtwoQactinQmonomersQandQholdsQthemQtogether.QInQcontrast,Qlatrunculin,QanotherQt


oxinQ-QthisQoneQisQmadeQinQspongesQ-QtightlyQbindsQtoQG-
actinQmonomers.QDescribeQtheQeffectQeachQdrugQwouldQhaveQonQactinQtreadmilling.Q-
QCORRECTQANSWERS-Phalloidin-


filamentsQwillQcontinueQtoQelongate,QunableQtoQtakeQfilamentsQoffQofQchain.QPreventsQdepolymeri
zation.QPolymerizationQwouldQstopQforQthisQwhenQtheQcellQreachesQbelowQsomeQthresholdQofQfree
QG-actin.



Latrunculin-QwouldQbind.QTo.QG-
actin,QpreventQpolymerization,QstopQforceQagainstQPM,QlengthQof.QF-
actinQwouldQgetQshorterQbecauseQthereQwouldQbeQdepolymerizationQbutQnotQpolymerization.QLev
elQofQmonomersQinQcellQmayQmakeQdepolymerizationQslowQdown



1)QLet'sQthinkQaboutQtheQstagesQofQdeath.QIfQyouQwereQaQcrimeQsceneQinvestigatorQandQyouQwereQe
xaminingQaQbodyQatQambientQtemperature,Qyou'dQprobablyQknowQtheQfollowing:

IfQtheQbodyQfeelsQwarmQandQnoQrigorQisQpresent,QdeathQoccurredQunderQ3QhoursQbefore.

,IfQtheQbodyQfeelsQwarmQandQstiff,QdeathQoccurredQ3-8QhoursQearlier.

IfQtheQbodyQfeelsQcoldQandQstiff,QdeathQoccurredQ8-36QhoursQearlier.

IfQtheQbodyQisQcoldQandQnotQstiff,QdeathQoccurredQmoreQthanQ36QhoursQearlier.

RigorQrefersQtoQrigorQmortis,QwhichQisQtheQstiffeningQofQaQbodyQafterQitQdies.QKnowingQwhatQyouQk
nowQaboutQcellularQrespirationQandQmyosin'sQATPaseQcycleQandQmuscleQfunction,QpleaseQanswerQt
heQfollowingQquestions:QWhatQisQtheQbasisQofQrigorQmortis?QWhyQisQitQreferredQtoQasQstiffeningQan
dQnotQcontracting?QWhyQdoesQitQtakeQ3QhoursQforQstiffeningQtoQoccur?QWhyQdoesQtheQrigorQretreat
?Q-QCORRECTQANSWERS-BasisQofQrigorQmortis-
QafterQATPQhydrolyzed,QandQafterQeverythingQelseQtakesQplace,QATPQstops.QInQdeath,QATPQrunsQout,Q


causesQmusclesQtoQbeQstiffQbecauseQnoQATPQtoQreleaseQmyosinQheadQfromQactin.

StiffeningQinsteadQofQcontracting-
myosinQisQnotQmovingQactinQfilamentsQalong,QmyosinQis.QBoundQtoQactinQandQisQimmovable.QNoQcy
cleQofQcontraction,QsoQwillQonlyQbeQstiff

WhyQ3Qhours-thereQwillQstillQbeQsomeQATPQleftQoverQwhichQwillQbeQusedQupQuntilQitQisQgone.

WhyQdoesQrigorQfinallyQgoQaway?-
QtheQbodyQbeginsQtoQdecayQsoQtheQproteinsQwillQbeQdegraded,QreleasingQtheQmyosinQfromQtheQacti


n.QactinQfibersQfallQapart,QmyosinQheadsQdegrade,QbecomesQpliableQagain



1)QYouQknowQthatQcancerQcellQmigrationQisQaQkeyQpartQofQmetastasis,QwhichQisQtheQdeadliestQaspec
tQofQcancer.QSo,QyouQwantQtoQdevelopQaQdrugQthatQcanQinhibitQcancerQcellQmigration.QYouQknowQth
atQmyosin-2-
basedQcontractionQisQrequiredQforQcellQmigrationQandQsoQyouQspecificallyQwantQtoQdevelopQaQdrugQ
toQinhibitQit,Qmyosin-2.Q(Note:QtheQmyosin-
2QthatQpromotesQmigrationQisQveryQsimilarQtoQbutQultimatelyQaQdifferentQisoformQfromQmuscleQmy
osin-2.QTheQnon-muscleQmyosin-
2QformsQsmallerQfilamentsQthatQareQmoreQdynamic,QwhereasQtheQmyosin-
2QthickQfilamentsQinQmusclesQareQveryQstableQandQlargerQstructures.)

a)QWhatQaspectQofQmigrationQisQmyosin-
2QinvolvedQin.QThinkQaboutQtheQstepsQofQmigrationQdiscussedQinQlectureQ(andQseeQfigureQ17-
33QinQyourQtext).QWhereQisQtheQforceQbeingQproducedQthatQinvolvesQmyosin-2?Q-
QCORRECTQANSWERS-Myosin-


2QisQinvolvedQinQretractionQ(backQendQofQcell).QForceQbeingQproducedQisQwhereQactinQbringsQupQen
dQofQcellQbackQintoQmiddle

, a)QYouQdevelopQaQdrugQthatQseemsQtoQinhibitQmyosin-
2,QbutQyouQareQunsureQofQitsQmechanismQofQaction.QInQgeneral,QhowQmightQyouQknowQwhetherQth
eQdrugQblocksQATPQfromQbindingQtoQmyosinQversusQallowingQATPQtoQbindQbutQblockingQhydrolysis?
QCanQyouQthinkQofQaQwayQtoQtestQthisQinQaQbiochemicalQassayQwithQpurifiedQactinQandQmyosin-2?Q-


QCORRECTQANSWERS-


YouQcouldQtrackQtheQamountQofQfreeQATP,QifQthereQwasQaQcomparativelyQlowQamtQitQwouldQbeQbind
ingQandQifQthereQwasQaQhighQamount,QitQwouldn'tQbe.QIfQATPQcannotQbind,QyoudQhaveQtheQsameQa
mountQofQATPQinQyourQsolutionQasQyouQstartedQwith.QControl-withoutQdrug



YourQcontrol,QtheQATPQwouldQdecreaseQafterQgoingQthroughQtheQcycle

Experimental-ATPQlevelsQwouldQstayQhigherQifQATPQbindingQwasQpreventedQbyQtheQdrug.



IfQyouQcarriedQoutQtheQsameQexperiment,QcouldQyouQtellQwhetherQitQwasQableQtoQbindQbutQnotQabl
eQtoQhydrolyze?QNo-
QATPQlevelsQwouldQstayQtheQsameQasQcomparedQtoQwhenQyouQfirstQputQitQin.QdependsQonQratioQcon


centrationQofQATPQtoQactinQandQmyosin.



AnotherQexperiment-QgenerateQmichaelisQmentenQcurve-
keepQmyosinQlevelsQtheQsame,QchangeQlevelsQofQATP,QseeQifQdrugQcompetitivelyQinhibitsQit.QKdQvalu
eQwouldQincreaseQifQitQaffectedQATPQbinding.QButQcannotQanalyzeQwhetherQatpQwasQboundQorQnotQ
toQmyosin



a)QAfterQthinkingQmoreQaboutQthis,QyouQdecideQthatQgivingQaQpersonQaQpillQthatQinhibitsQmyosin-
2QmightQnotQbeQaQgoodQidea,QevenQifQitQdoesQstopQtumorQcellQmetastasisQreallyQwell.QWhyQisQthat?
Q-QCORRECTQANSWERS-


NotQaQgoodQideaQbecauseQitQwouldQaffectQhealthyQcellsQasQwellQasQcancerQcells.QWouldQcauseQaQlot
QofQissuesQforQtheQperson,QincludingQmuscleQcontractionQandQcellQmotility;QdrugQsoundsQlikeQtheQd


eathQcapQmushroomQtoxins.



1)QMicrotubulesQcanQbeQformedQinQvitroQfromQtubulinQthatQisQboundQtoQGTPQanaloguesQthatQ(unli
keQGTP)QcannotQbeQhydrolyzed.QWhatQpropertiesQwouldQyouQexpectQtheseQmicrotubulesQtoQposse