Updated 2026
DefineBRNAiB-
BAnswerThereBareBthreeBdifferentBtypesBofBsncRNAs,BwhichBareBclassifiedBaccordingBtoBtheirB
biogenesisBandBfunction.BOneBisBRNAiBwhichBisBaregulatoryBsystemBoccurringBwithinBeukaryoti
cBcellsB(cellsBwithBaBclearlyBdefinedBnucleus)BthatBcontrolsBtheBactivityBofBgenes.BRNAiBfuncti
onsBspecificallyBtoBsilence,BorBdeactivate,Bgenes.
InBorderBwords,BinhibitionBofBgeneBexpressionBinBwhichBaBproteinBcomplex,BcontainingBaBpar
tiallyBcompletedBRNABstrandBbindsBtoBanBmRNA,BleadingBtoBdegradationBorBreducedBtranslati
onBofBtheBmRNA
smallBnoncodingBRNAsB-BAnswerSmallBnon-
codingBRNAsB(sncRNAs)BareBhighlyBabundantBRNAs,BtypicallyB<100BnucleotidesBlong,BthatBact
BasBkeyBregulatorsBofBdiverseBcellularBprocesses.
retrovirusB-
BAnswerABretrovirusBisBaBtypeBofBRNABvirusBthatBinsertsBaBcopyBofBitsBgenomeBintoBtheBDN
ABofBaBhostBcellBthatBitBinvades,BthusBchangingBtheBgenomeBofBthatBcell.
WhatBwasBtheBsurprisingBresultBMelloBandBFireBgotBduringBtheirBstudiesBwithBC.Belegans?B-
BAnswerNobelBPrize-
winningBresearchBfromBAndrewBFireBandBCraigBMelloBinB1998BdemonstratedBthatBwhenBdoub
le-
strandedBRNAB(dsRNA)BisBintroducedBintoBtheBcellsBofBC.Belegans,BitBleadsBtoBaB"potentBand
Bspecific"BdegradationBofBcomplementaryBmRNAsBthroughBaBprocessBweBcallBRNABinterferenc
eB(RNAi).BTheBdiscoveryBofBRNAiBinB1998BledBtoBanBalmostBimmediateBrevolutionBinBtheBinv
estigationBofBgeneBfunction.BAsBlongBasBaBgene'sBsequenceBisBknown,BoneBcanBquicklyBsynth
esizeBdsRNABcorrespondingBtoBthatBsequenceBtoBinhibitBorB"knockBdown"BthatBgene'sBfunctio
n.
WhatBisBsimilarBbetweenBsiRNAsBandBmiRNAs?B-
BAnswerTheBprocessBofBRNABinterferenceB(RNAi)BcanBbeBmoderatedBbyBeitherBsiRNABorBmiR
NA,BbutBthereBareBsubtleBdifferencesBbetweenBtheBtwo.BBothBareBprocessedBinsideBtheBcellB
byBtheBenzymeBcalledBDicerBandBincorporatedBintoBaBcomplexBcalledBRISC.BsiRNA,Bhowever,Bi
sBconsideredBexogenousBdouble-
strandedBRNABthatBisBtakenBupBbyBcells,BorBentersBviaBvectorsBlikeBviruses,BwhileBmiRNABisB
singleBstrandedBandBcomesBfromBendogenousB(madeBinsideBtheBcell)Bnon-
codingBRNA,BfoundBwithinBtheBintronsBofBlargerBRNABmolecules.
, proteinBdroshaB-BAnswericroRNAB(miRNA)BgenesBareBtranscribedBasBprimary-miRNAsB(pri-
miRNAs),BwhichBareBtrimmedBatBtheB5′BandB3′BendsBbyBDroshaBtoBformBpre-miRNAs
happensBinBnucleus!
microRNAB(miRNA)BandBsmallBinterferingBRNAB(siRNA)BuseBaBsimilarBprocessBandBproteinsBto
BregulateBgeneBexpression.BWhichBofBtheBfollowingBisBmoreBcommonlyBassociatedBwithBtheB
miRNABpathway?B-
BAnswerTheBproteinBDroshaBisBfoundBinBtheBmiRNABpathwayBbutBnotBtheBsiRNABpathway.F
ABresearcherBisBstudyingBplantBdevelopment.BSheBisolatesBaBmutantBandBdiscoversBthatBtheB
pieceBofBDNABthatBisBmutatedBdoesBnotBcodeBforBaBprotein.BHowever,BthisBpieceBofBDNABis
BcomplimentaryBtoBaBgeneBknownBtoBfunctionBinBearlyBembryonicBplantBdevelopment.BTheB
mutantBsheBidentifiedBmostBlikelyBfunctionsBasBa(n)B________.B-BAnswermicroRNAB(miRNA)
UnlikeBsiRNAs,B____________BareBderivedBfromBtheBself-
complementaryBtranscriptsBofBmiRNABgenes.B-BAnswermiRNAs
WhatBisBtheBroleBofBDicerBinBRNA-inducedBgeneBsilencing?B-
BAnswerItBcleavesBlongerBRNAsBintoBshort,BregulatoryBRNABmolecules.
TheBregulatoryBsiRNAsBandBmiRNAsBareBinvolvedBinBsuppressionBofBgeneBexpression.
WhatBisBtheBsubstrateBofBtheBDicerBenzyme?B-BAnswerpre-mRNA
decirBenzymeB-
BAnswerDicer,BalsoBknownBasBendoribonuclease,BisBanBenzymeBthatBinBhumansBisBencodedBb
yBtheBDICER1Bgene.B...BDicerBfacilitatesBtheBactivationBofBtheBRNA-
inducedBsilencingBcomplexB(RISC),BwhichBisBessentialBforBRNABinterference.
DoByouBexpectBpri-miRNAsBhaveBanBORF?B-BAnswerNoBitBdoesBnotBcodeBforBproteins
DoBpri-miRNAsBundergoBprocessing?.B-
BAnswerYes.BTheseBinitialBareB"cappedBandBtailed,"BandBsomeBcontainBintronsBlikeBmessenger
BRNAs.