UW Madison Bio 101 Exam 3 Questions and Answers 2025 Latest Update

UW Madison Bio 101 Exam 3 Questions
and Answers 2025 Latest Update
DefineAneuroscience,AnervousAsystems,AandAneurons.A-ACORRECTAANSWERSA-
Neuroscience:AanyAscienceAthatAdealsAwithAtheAstructureAorAfunctionAofAtheAnervousA
systemAorAtheAbrain
Neurons:AcellsAthatAsendAandAreceiveAelectricalAorAchemicalAsignalsA(nerveAcells)
NervousAsystems:AcircuitsAofAneuronsAthatAintegrateAinternalAandAexternalAinformation
HowAdoAneuronsAandAnervousAsystemsAdifferAinAassociationAwithAspeciesAcomplexity?A-
ACORRECTAANSWERSA-

MoreAcomplexAorganismsAhaveAmoreAcomplexAnervousAsystemsAandAmoreAneuronsA
(hydra-->cephalization-->bilateralAsymmetry)
WhatAisAtheACNS?A-ACORRECTAANSWERSA-
TheACentralANervousASystem:AbrainAandAspinalAcord
WhatAisAtheAPNS?A-ACORRECTAANSWERSA-
TheAPeripheralANervousASystem:AnerveAcellsAoutsideAtheACNS
DescribeAtheA3AtypesAofAneuronsAfoundAinAtheACNSAandAPNSAandAhowAtheyAcanAworkAtog
etherAtoAregulateAbehavior.A-ACORRECTAANSWERSA-SensoryAneurons:APNS-->CNS
Interneurons:A"talk"AtoAotherAneurons
MotorAneurons:ACNS-->PNS
(sensoryAinput-->integration-->motorAoutput)
WhichAtypeAofAneuronAisAaffectedAbyALouAGehrig'sAdiseaseA(ALS)?A-
ACORRECTAANSWERSA-

MotorAneuronsA(loseAtheAabilityAofAtheAbrainAtoAinitiateAandAcontrolAmuscleAmovement)
WhatAareAtheApartsAofAaAneuron?AWhatAdoAtheyAdo?A
ListAtheApartsAofAaAneuronAinAorderAofAtheAdirectionAinAwhichAanAelectricalAsignalAwouldAtypi
callyAtravelAdownAaAneuron.A-ACORRECTAANSWERSA-Dendrites:AreceiveAsignals
CellAbody:AcontainsAcellAmachineryA
AxonAhillock:AintegratesAsignalAdeciderA
Axon:AsendsAsignalsAtoAsynapticAterminalsA
SynapticAterminals:AsendsAsignalsAtoAotherAcellsA(neurons,Amuscles,Aglands,Aetc.)
WhatAareAglialAcells?ANameA3AandAdescribeAwhatAtheyAdo.A-ACORRECTAANSWERSA-
WrapsAitselfAaroundAanAaxonAtoAformAaAsegmentAofAtheAmyelinAsheath,AmostAabundantAcell
sAinAtheAbrain,Anourish/supportAneurons,AhelpAwithAmentalAdisorders
OligodendrocytesA(CNS)--increaseAsignalingAspeed
SchwannAcellsA(PNS)--increaseAsignalingAspeed
--AstrocytesAandAmicroglia
WhatAdiseaseAisAassociatedAwithAmyelinAdegeneration?A-ACORRECTAANSWERSA-
MultipleAsclerosis
WhatAtypeAofAsignalsAtravelAdownAneurons?A-ACORRECTAANSWERSA-ElectricalAsignals
WhatAtypeAofAsignalsAtypicallyAtravelAbetweenAneurons?A-ACORRECTAANSWERSA-
ChemicalAsignals

,WhatAdoesAtheAsquidAhaveAtoAdoAwithAneuroscience?AAreAneuronsAsimilarAinAsquidAandAot
herAanimals?A-ACORRECTAANSWERSA-
SquidsAhaveAnervesAwithAgiantAaxons.AElectricalApropertiesAofAneuronsAareAsimilarAacrossA
species
DefineAmembraneApotential.A-ACORRECTAANSWERSA-
AAvoltageAthatAeveryAcellAhasAacrossAitsAplasmaAmembraneA(i.e.,AanAelectricalAchargeAdiffe
rence)--theAinsideAofAtheAcellAisAnegativeArelativeAtoAtheAoutside
DefineArestingApotential.A-ACORRECTAANSWERSA-
TheAmembraneApotentialAofAaAneuronAthatAisAnotAtransmittingAsignalsA(usuallyAaroundA-
70mV)--dependsAonAtheAionicAgradientsAthatAexistAacrossAtheAplasmaAmembrane
HowAareAK+AandANa+AionsAdistributedAwithinAandAoutsideAaAneuronAthatAisAatAitsArestingAm
embraneApotential?A-ACORRECTAANSWERSA-
RestingApotential:AthereAareAdifferencesAinAionsAacrossAtheAplasmaAmembrane
K+=insideAandANa+=outside
ChannelsAareAselectivelyApermeableAtoAK+AorANa+A(ionAchannelsAareAclosedAinAaAneuronA
atArest
MoreApositiveAoutsideAandAmoreAnegativeAinside
WhatAisAmeantAbyAselectiveApermeability?A-ACORRECTAANSWERSA-
AAmembraneAallowsAcertainAmoleculesAorAionsAtoApassAthroughAitAbyAmeansAofAactiveAorAp
assiveAtransport
DefineAtheArestingAmembraneApotentialAinAtermsAofAmillivoltsA(mV),AK+,ANa+,AtheAionicAgra
dientAandAtheAsodium-potassiumApump.A-ACORRECTAANSWERSA-
RestingAmembraneApotentialAisAusuallyAaroundA-
70mV,AhaveAK+AonAtheAinsideAofAtheAcell,AhaveANa+AonAtheAoutsideAofAtheAcell,AionAchanne
lsAareAclosed,AandAtheAsodium-
potassiumApumpA(helpsAmaintainArestingApotential)AisAaAformAofAactiveAtransportAthatAmov
eAK+AintoAtheAcellAandANa+AoutAofAtheAcellA(2:3Aratio)
UnderAwhatAcircumstancesAareAionsAactivelyAtransportedAacrossAtheAmembrane?AUnderA
whatAconditionsAareAtheyApassivelyAtransported?A-ACORRECTAANSWERSA-
ActiveAtransportAofAionsAhelpsAmaintainArestingApotential--
sodiumApotassiumApumpA(K+AionsAareAleakyAsoAadditionalAK+AleavesAtheAneuron)--
ionsAinAaAneuronAatArestAareAunderApressure
PassiveAtransportA(notAatArestingApotential)AoccursAacrossAconcentrationAgradientsAfromAhi
ghAtoAlowAconcentrationAandAacrossAelectricalAgradientsAbecauseAionsAareAattractedAtoAop
positeAcharges
ExplainAtheAconcentrationAandAelectricalAgradientsAandAtheApressureAtheyAplaceAonAK+Aan
dANa+Aions.AWhichApressureAisAmoreApowerfulAforAK+AinAaAneuronAatArest?A-
ACORRECTAANSWERSA-

ConcentrationAgradient:ANa+AcomesAinAandAK+AgoesAoutAElectricalAgradient:AbothANa+Aan
dAK+AcomeAinABUTAIfAaAK+AchannelAopensAtheAK+AimmediatelyAexitsAbecauseAtheAconcent
rationAgradientAisAstrongerAthanAtheAelectricalAgradient
WhatAisAaAvoltage-gatedAchannel?A-ACORRECTAANSWERSA-
TransmembraneAproteinsAthatAformAionAchannelsAthatAareAactivatedAbyAelectricalAsignalsAf
romAotherAneuronsAthatAcauseAionAchannelsAtoAopen
ExplainAhyperpolarizationAandAdepolarizationAinAtermsAofAtheAmembraneApotentialAandAion
AchannelsAinvolved.ABeAableAtoArepresentAthemAinAaAfigureA(asAonAtheAlectureAslides).A-

, ACORRECTAANSWERSA-
Hyperpolarization:AanAincreaseAinAtheAmagnitudeAofAtheAmembraneApotentialA(insideAisAmo
reAnegative)--K+AisAinsideA
Depolarization:AaAreductionAinAtheAmagnitudeAofAtheAmembraneApotentialA(insideAisAmoreA
positive)--Na+AisAoutside
WhatAisAmeantAbyAgradedApotentials?A-ACORRECTAANSWERSA-
HyperpolarizationAandAdepolarizationAareAbothAcalledAgradedApotentialsAbecauseAtheAmag
nitudeAofAtheAchangeAinAmembraneApotentialAvariesAwithAtheAstrengthAofAtheAstimulus
WhatAhappensAwhenAaAdepolarizationAcrossesAtheA"thresholdApotential"?A-
ACORRECTAANSWERSA-

AAstimulusAstrongAenoughAtoAproduceAaAdepolarizationAthatAreachesAthresholdAtriggersAaA
differentAtypeAofAresponseAcalledAanAactionApotentialAandAtheAneuronA"fires"
DefineAactionApotential.A-ACORRECTAANSWERSA-AAbriefAall-or-
noneAdepolarizationAofAaAneuron'sAplasmaAmembrane
IsAtheAtypeAofAsignalAthatAcarriesAinformationAalongAaxons
HowAareAactionApotentialsAdifferentAfromAgradedApotentials?A-ACORRECTAANSWERSA-
GradedApotentialsAcanAbeAdepolarizingAorAhyperpolarizing
ActionApotentialsAalwaysAleadAtoAdepolarizationAofAmembraneAandAreversalAofAtheAmembr
aneApotential
HowAdoAactionApotentialsAvaryAinAresponseAtoAweakAvsAstrongAstimuli?A-
ACORRECTAANSWERSA-WeakAstimuli:AlowAfrequencyAofAactionApotentials

StrongAstimuli:AhighAfrequencyAofAactionsApotentials
ExplainAeachAstepAofAtheAactionApotential.A-ACORRECTAANSWERSA-
1.ARestingAstage:AwhereANa+AandAK+AchannelsAareAclosed
2.ADepolarization:ANa+AchannelsAopenAandANa+AdiffusesAintoAtheAcellA
3.ARisingAphase:AmanyANa+AchannelsAopenAandAmanyANa+ArushesAintoAtheAcell--
AnAactionApotentialAisAtriggersAwhenAtheAthresholdApotentialAisAreached--
Na+AchannelsAopenAatA-
50mVAandANa+ArushesAintoAtheAcellAandAdepolarizesAtheAmembraneAPOSITIVEAFEEDBA
CK
4.AFallingAphase:AK+ArushesAoutAofAtheAcell--
Na+AchannelsAareAinactivatedAatA40mVAandAK+AchannelsAopenAatA40mV--
potassiumAionsAexitAtheAcellAandAhyperpolarizeAtheAmembraneAslightlyAbelowAtheArestingAp
otentialA
5.AUndershoot:AK+AslowlyAclosing,ANa+Ainactivated--
K+AchannelsAcloseAandANa+AchannelsAchangeAfromAinactivatedAtoAcloseAstateAandAtheAres
tingAmembraneApotentialAisAstoredA(duringAtheArefractoryAperiodANa+AchannelsAareAinactiv
ated)
HowAdoAdifferentAtoxinsAaffectAionAchannels?AHowAareAtheseAtoxinsAused?A-
ACORRECTAANSWERSA-ToxinsAthatAtargetAionAchannelsAhaveAevolvedAasAself-

defenseAorApreyAcapturingAmechanisms
Tetrodotoxin:AforAdefenseA
Aex.APufferAfish:ABlocksAK+Achannels

Alpha-AandAbeta-Atoxins:AtoAcaptureAprey
Aex.AScorpion:AShiftsAopeningAandAclosingAofANa+Achannels

Apamin:AforAdefense