Bio Exam 2- RNAi Questions and Answers Updated 2026

Bio Exam 2- RNAi Questions and
Answers Updated 2026
RNABcanBfoldBintoBanB

__________:BDoubleBhelicalBRNABwithBWatson-CrickBbase-
pairingBandBGUBwobbleB(weak)Bpairs

__________:BObservedBforBalternatingBrCrGBsequencesBunderBextremeBsaltBconcentrationsB(lik
eB6MBNaClO4)

TheB__________B(typicalBDNABform)BhasBneverBbeenBobservedBinBRNAB-BAnswerA-form,BZ-
form,BB-form



DNABisBmostlyBfoundBinBhelicalBforms.BInBgeneral,BRNAsB(likeBproteins)BadoptBmoreBdiverseB
andBcomplexB____________________.BThisBstructuralBdiversityBcorrelatesBwithBtheBwideBvariet
yBofBRNAB__________.B-BAnswerthree-dimensionalBstructure,Bfunctions



TheBprimaryBstructureBofBRNABisBitsB__________________.BIt'sBsecondaryBstructureBconsistsB
ofB_____________,B_____________,BandBisB____________________BItsBtertiaryBstructureBisBit
sB__________________B-
BAnswernucleotideBsequence,Bloops,Bhelices,BsingleBandBdoubleBstranded,B3-DBfolding



ABcell'sBnoncodingBRNAsBconsistBofB(besidesBsiRNABandBmiRNA):B-
BAnswerrRNAs,BtRNAs,BsnRNAsB(smallBnuclearBRNAs,BfunctionBinBnuclearBprocessesBlikeBsplici
ngBpre-mRNA),BsnoRNAsB(smallBnucleolarBRNAs,BchemicallyBmodifyBrRNA),BpiRNAsB(piwi-
interactingBRNAs,BbindBtoBpiwiBproteinsBandBprotectBgermlineBcellsBfromBtransposableBeleme
nts),BandBlncRNAsB(longBnoncodingBRNAs,BserveBasBscaffoldsBandBregulateBcellBprocessesBsuc
hBasBX-chromosomeBinactivation)



siRNAsB(noncodingBRNA)B-
BAnswersmallBinterferingBRNAs,BturnBoffBgeneBexpressionBbyBdirectingBtheBdegradationBofBsel
ectiveBmRNAsBandBtheBestablishmentBofBcompactBchromatinBstructures



miRNAsB-
BAnswermicroRNAs,BregulateBgeneBexpressionBbyBblockingBtranslationBofBspecificBmRNAsBandB
causingBtheirBdegradation



EarlyBhypothesisBforBhowBanti-senseBRNABinterferesBwithBgeneBexpressiomB-
BAnswerTheBsenseBstrandBisBtheBstrandBofBDNABorBRNABthatBhasBtheBsameBsequenceBasBth
eBmRNA.BTheBanti-

, senseBstrandBisBthatBDNABorBRNABstrand'sBcomplementaryBpair,BwhichBisBusedBasBaBtemplat
eBforBmRNABsynthesisB(henceBwhyBmRNABhasBsameBsequenceBasBsenseBstrand).B



ItBhasBhypothesizedBthatBanti-
senseBRNAB(RNABformedBwithBtheBsenseBstrandBasBaBtemplate)BwouldBbaseBpairBwithBmRNA
BandBblockBtheBribosomesBfromBaccessingBit,BthusBdisruptingBtranslation.BThisBinterferenceBsh
ouldBbeBSTRANDBSPECIFICB(onlyBantisenseBRNABshouldBbeBableBtoBdisruptBsenseBmRNABtrans
lationBifBinjectedBintoBaBcell),BandBinterferenceBshouldBbeBDOSAGEBDEPENDENTB(theBmoreBa
ntisenseRNABinjected,BtheBmoreBmRNABinterference)



Surprisingly,BinBaBstudyBthatBusedBanti-senseBRNABtoBstudyBtheBfunctioningBofBtheBpar-
1BgeneBinBC.Belegans,BitBwasBfoundBthatBin-
vitroBsynthesizedB__________BworkedBequallyBasBwellBasBanti-
senseBRNABinBinterferingBwithBpar-
1BfunctionBandBinducedBtheB________________BofBembryonicBlethality-Bwtf??B-
BAnswerSenseBRNA,BsameBpercent



AnotherBsurprise:BpotentBandBspecificBgeneticBinterferenceBbyBdouble-
strandedBRNABinBC.BelegansB-
BAnswerWhy:BRNABinterferenceBwasBproposedBtoBresultBfromBanBantisenseBmechanismBthatB
dependsBonBhybridizationBbetweenBinterferingBRNABandBendogenousBmRNA.BTheBstudyBwante
dBtoBexamineBwhatBformBofBRNABwasBrequiredBforBRNABinterferenceB



How:BscientistsBinjectedBdifferentBformsBofBRNAB(sense,Bantisense,BandBdsRNA)BintoBC.Belega
nsBandBobservedBtheirBeffectsBonBgeneBexpression



What:B1)BdsRNABwasBsubstantiallyBmoreBeffectiveBatBproducingBinterferenceBthanBeitherBstran
dBwasBindividually.B2)BonlyBaBfewBmoleculesBofBdsRNABwereBrequiredBperBaffectedBcell.B3)BT
heBinterferenceBwasBevidentBinBbothBtheBaffectedBanimalsBandBtheirBprogeny



SoBwhat:BABsimpleBantisenseBmechanismBisBnotBlikely,BthereBcouldBbeBaBcatalyticBorBamplific
ationBcomponentBinBtheBRNAiBprocess,BandBRNABinterferenceBisBinheritable



TheBpuzzle:BwormBstudyB#2BfoundBthatBdsRNABisB_______________________BthanBanti-
senseBRNABinBinterferingBwithBmRNA!BEmbryosBfromBparentBinjectedBwithBanti-
senseBRNABofBmex-3BgeneBshowedBreducedBlevelsBofBmex-
3BmRNA,BwhichBindicatedB________________.BEmbryosBinjectedBwithBdsRNABofBmex-
3BshowedBnoBmex-3BmRNA,BwhichBindicatedB________________________.B-
BAnswerMoreBpotent,BsomeBinterference,BstrongBinterference