BCH exam 2 Questions And Answers

BCH exam 2 Questions And Answers
-rCORRECTrrANSWER-HYDROLYSISrOFrNUCLEICrACIDS
Modificationrofrnucleicracidsrrequiresrtherabilityrtorhydrolyzertherphosphodiesterrbondsrthatr
holdrthemrtogether

2rMethods:
1.rAcid/BaserHydrolysis
2.rEnzymaticrHydrolysis
-rCarriedroutrbyr2rgeneralrtypesrofrnucleases
1-rExonucleases
2-rEndonucleases

2rSub-rTypes:
TyperA
Cleaver3'rend
*r(closerrtorbAserofrsugar)
TyperB
Clever5"rend
*aBoversugarr(andraboverhasr5rletters)

Cephalinr-rCORRECTrrANSWER-
Arglycerophospholipidrinrwhichrtheraminoralcoholrisrethanolaminerorrserine

LikerLecithin,ritrconsistsrofrarcombinationrofrglycerolresterifiedrwithrtworfattyracidsrandrphosp
horicracid.rWhereasrtherphosphatergrouprisrcombinedrwithrcholinerinrLecithin,ritrisrcombined
rwithrtherethanolaminerinrCephalin.




Coconutroilrisrparticularlyrhighrinr___________r__________r(bothrsaturated)randrcontainsrli
ttlerunsaturatedrfattyracidr-rCORRECTrrANSWER-lauricrandrmyristicracids

ComparerandrcontrastrCa+rATPaserandrH+,rK+rATPaser-rCORRECTrrANSWER-
Ca+rATPase:
Ca2+ractsrasrcellularrsignal
Musclercontraction:rnerverimpulser→rSRr→rreleaserofrstoresrCa2+r→r[rCa2+r]rincreases
Musclerrelaxation:rCa2+rhasrtorberpumpedrbackrintorSRrvesicles,rthisrisrdonerbyrCa2+rATP
ase
pumpsr2rCa2+rionsrINTOrSRrforreachrATPrhydrolyzes

GastricrH+/K+rATPase
couplesrATPrhydrolysisrtortherpumpingrofrH+rpitrofrthercelrandrK+rintorthercell

,electricallyrneutralrbecauserchargerisr+1rinrbothrdirections
therK+rionrisrpumpedroutralongrwithrarCl-
rionrinranotherrelectricallyrneutralrprocessrusingrassociatedrmembranertransportrsystem

netrresultrisrmaintenancerofrhighrHClr[r]rinrstomach
bcrpHrofrstomachrisr0.8rtor1randrcellsrthatrformrtherliningrhaverarpreferencerofr7.4rsorthererisra
rconcentrationrgradientracrossrthermucosalrcells

thisrconcentrationrdifferencerisressential,rBUTrbecauserofrpassiverforces,rthergradientrwontr
bermaintained

structurallyrveryrsimilarrtorNa+/K+rATPase

Definerarglycoproteinr-rCORRECTrrANSWER-
proteinsrthatrcontainroligosacchariderchainsr(glycans)rcovalentlyrattachedrtortheirrpolypepti
derbackbone.

-rcanrberanyrformr(mono,rdi,rpoly)rorrtheirrderivatives

DefinertherDr&rLrstereochemistryrofrcarbohydratesr&rhowritrisrdeterminedr-
rCORRECTrrANSWER-basedroffrglyceraldehyde,rCH2OHrdownrinrfisherrprojectionr

-rlookratrsiderofr-OHrgroupr

-OHronrright:rD-rconfigurationr
-OHronrleftrL-rconfigurationr

***rOHrofrhighestrnumberrCarbon

DemonstratertherdifferencesrbetweenrRNArandrDNA.
WhatrarerthermajorrdifferencesrbetweenrRNArandrDNA?rWhatrrestrictionsdoesrRNArpresen
t?r-rCORRECTrrANSWER-
RNArhasrOHrgroupratr2'rposition,rwhereas,rDNArhasronlyrarhydrogen
DoublerstrandedrRNAr→rcellrdealth
Restriction:rcanreasilyrberdestroyedrbyralkalinesrbecauserofrtherOHrgrouprpresent
Doesrnotrfollowrchargaff'srrule

DNArcontainsrThymine,rRNArhasrUracilrinstead
SinglerstrandedrDNAr→rcellrdealth

Describeractivertransportr-rCORRECTrrANSWER-
movementrofrparticlesracrossrplasmarmembranerAGAINSTr[r=rgradient
energyrcanrberprovidedrviarATP,rlightrenergy,rorrEnergyrstoresrinrionrgradient
UserofrLightrenergy:rusedrbyrcertainrproteinsrsuchrasrHalorhodopsinrorrBacteriorhodopsinrt
ordrivercellularrprocesses
lightrErsetsruprarprotonrgradientracrossrtherproteinrthatrdrivesrconformationalrchangesrinrpro
teinsrthatrfacilitaterprotonrexportrfromrcell
requiresrspecificrcarrierrproteins
ex:rabsorptionrofrglucoserandraminoracidsrbyrcellsrinrthersmallrintestine

,Allractivertransportrreactionsrarer_PROCESSESrOFrCOUPLED_rreactions.

Describerandrexplainrther""mosaic":rpartrofrtherfluidrmosaicrmodelr-rCORRECTrrANSWER-
Amphipathicrmoleculesrconstituterliquidrcrystallineraggregatesrinrwhichrtherpolarrgroupsrar
erdirectedrtowardsrtherouterrphaserandrthernon-polarrgroupsrarersituatedrinsidertherbilayer
Transmembranerproteinsrwhichrpassrthroughrtherlipidrbilayerrpossessrtheirractiversidertowa
rdsrouterrphaserandrhydrophobicrpartrtowardsrinteriorrandrarerofrapprotientersidertorfitrinrtherl
ipidrbilayer
Therdistributionrofrphospholipidsrinrtherouterrandrinnerrsurfacerisrhighlyrasymmetrical
Therouterrlayerrconsistsrmainlyrofrlecithinrandrsphingomyelinrwhilertherinnerrlayerrisrcompos
edrmainlyrofrphosphatidylethanolaminerandrphosphatidylserine
Glycolipidsrarermainlyrpresentrinrouterrhalfrofrtherbilayer
Thermainrcomponentrofrtherplasmarmembranerisrtherphospholipidrbilayerrwithrhydrophilicrp
olarrheadsrofrtherlipidsrorientedroutwardsrandrhydrophobicrtailsrtowardsrinsiderformingrtherc
orerofrplasmarmembrane

Describerandrexplainrther"fluid"rpartrofrtherfluidrmosaicrmodelr-rCORRECTrrANSWER-
Fluidity:
Fluidr2Drmodel
Thermainrcomponentrofrtherplasmarmembranerisrtherphospholipidrbilayerrwithrhydrophilicrp
olarrheadsrofrtherlipidsrorientedroutwardsrandrhydrophobicrtailsrtowardsrinsiderformingrtherc
orerofrplasmarmembrane
phospholipidsrarerfreertormoversideways
membranerproteinsrmayrberfluidrorranchored
anchoredrstrengthenrmembrane
proteinsrandrlipidsrarerfreertormoverlaterally,rbutrNOTrfacertorface
membranesrarerinrmotionrwithrfastrdriftingrlipidsrandrslowerrdriftingrproteins

describerbulkrflowr&ritsrsubtypesr-rCORRECTrrANSWER-
ulkrFlow:rVesiclesrarerusedrtortransportrlargerparticlesracrossrplasmarmembrane
requiresrenergy

2rTypes:
Exocytosis
cytoplasmicrvesiclesrmergerwithrplasmarmembranerandrreleaseritsrcontents
ex:rgolgirbodyrvesiclesrmergerwithrplasmarmembranerandrreleasertheirrcontents
ex:rnervercellsrreleaserNT

Endocytosis
PMrsinksrinward.rpinchesroffr&rformsrarvesicle
vesicleroftenrmergesrwithrgolgirforrprocessingr&rsortingrofritsrcontents

-->r3rKinds:
Phagocytosis
"cellreating"
membranersinksrinrandrcapturesrsolidrparticlesrforrtransportrintorcell

, ex:rbacteria,rcellrdebris,rfod

Pinocytosis
cellr"drinking"
cellrbringsrinrliquid

ReceptorrMediated
membranersinksrinrandrformsrarCOATEDrPIT
therpitrpinchesrclosedrtorformrarvesicleraroundrtherbondrsubstance
cytoskeletonraidsrinrpullingrinrthermembranerandrvesiclerformation
ReceptorrproteinsrinrPMrbindrspecificrsubstances
e.g.rvitamins,rhormones

Describerchannelrproteinsr-rCORRECTrrANSWER-ChannelrProteins:
facilitatesractiverORrpassivertransport
providesrcorridorsrthatrallowrspecificrmoleculesrorrionsrtorcrossrthermembrane

uniport,rsymport,rorrantiport

Describerdifferentrfunctionsrperformedrbyrtherplasmarmembrane.r-rCORRECTrrANSWER-
Thermainrfunctionrofrplasmarmembranerisrtorseparaterthercytoplasmrinrthercellrfromrtheroutsi
de

Otherrfunctionsrcanrber
Exclusionrorrremovalrofrtoxicrmoleculesrandrions
Importrofrcellrnutrients
Energyrtransductionr(fromrsurroundingrsystems)r
Cellrlocomotionr
Reproductionr
Signalrtransductionr
Cell-cellrcommunication

Describerfacilitatedrdiffusionr-rCORRECTrrANSWER-
small,rpolarrmoleculesrandrionsrdiffuserthroughrpassivertransportrproteins
withrconcentrationrgradient

DescriberhowrtheroligosacchariderchainrofrglycoproteinsrfunctionsrinrSelectinsr&rMucinsr-
rCORRECTrrANSWER-

Mucinrisrfoundrinrsecretionrofrgastrointestinal,rrespiratory,randrreproductivertractsrandrmem
branesr
-rlubricantr&rimmunologicrfunctionsr
-rexhibitsrhighrcontentrofro-glycanrchainsr
-rrepeatingrAArsequencerSet,rThr,r&rPro
-rprotectiverbarrier,rcell-cellrinteractions,rmayrcontain/maskrsurfacerantigensr