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NEETREVISIONSERIES
CELLCYCLE&CELLDIVISION
ReviseMostImportantQuestionstoCrackNEET2020
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Q-1-23761001
Who found that new cells develop from preexisting cells ?
(A)Remak
(B)Virchow
(C)PrevostandDumas
(D)Strasburger
CORRECTANSWER:A
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Q-2-10761358
Cells in G0 phase :
(A)terminatethecellcycle
(B)exitthecellcycle
(C)enterthecellcycle
(D)suspendthecellcycle
CORRECTANSWER:B
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Q-3-10761378
The shorter and longer arms of a submetacentric chromosome are
referred to as :
(A)m-armandn-armrespectively
(B)s-armandl-armrespectively
(C)p-armandq-armrespectively
(D)q-armandp-armrespectively
CORRECTANSWER:C
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Q-4-34342486
Anaphase promoting complex (APC) is a protein degradation
machinery necessary for proper mitosis of animal cells. If APC is
defective in a human cell, which of the following is expected to
occur
(A)Chromosomeswillnotcondense
(B)Chromosomeswillbefragmented
(C)Chromosomeswillnotsegregate
(D)Recombinationofchromosomearmswilloccur
CORRECTANSWER:C
SOLUTION:
Ifanaphasepromotingcomplexisdefectiveinahuman
cell,thechromosomeswillnotsegregateduring
anaphaseofmitosis.APCtriggersthetransitionform
metaphasetoanaphasebytaggingspecificproteinsfor
degradation.
ConceptEnhancerAnaphasestageofmitosisis
characterisedbytwoevents
(a)Splittingofcentromeresandsegregationof
chromosomes.
(b)Movementofchromatidstowardstheoppositepoles.
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Q-5-23761008
Colchicine is
(A)Mitoticpoison
(B)Prophasepoison
(C)Cytokinesispoison
(D)Noneoftheabove
CORRECTANSWER:A
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Q-6-34342491
Which of the following is not a characteristic feature during mitosis
in somatic cells ?
(A)Disapearanceofnucleolus
(B)Chromosomemovement
(C)Synapsis
(D)Spindlefibres
CORRECTANSWER:C
SOLUTION:
Synapsisispairingofhomologouschromosomes.It
occurduringzygotenestageofmeiosis.The
homologouschromosomescomecloserleadingtocross
overinthenextstagecalledpachytene.Thesearenot
observedduringmitosis.
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Q-7-34342495
Mathc the stages of meisos in Column I to their characteristic
features in Column II and select the correct option using the codes
given below
(A)
(B)
(C)
(D)
CORRECTANSWER:A
SOLUTION:
Variousphaseofmeiosisandtheircharacteristic
featuresare
Pachytene-Crossing-overtakesplace
Mataphase-I-Chromosomesalignatequatorialplate
Column-I Column-IIPachytene (i)Pairingofhomologouschromosomes
MetaphaseI (ii)Terminalizationofchiasmata
Diakinesis (iii)Crossing-overtakesplace
Zygotene (iv)Chromosomesalignataquatorialplate
A B C D
3 4 2 1
A B C D
1 4 2 3
A B C D
2 4 3 1
A B C D
4 3 2 1
Diakinesis-Terminalisationofchiasmata
Zygotene-Pairingofhomologouschromosomes
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Q-8-34342502
The enzyme recombinase is required in which stage of meiosis ?
(A)Pachytene
(B)Zygotene
(C)Diplotene
(D)Diakinesis
CORRECTANSWER:A
SOLUTION:
Crossingoverisanenzymaticprocessoccuringduring
thepachytenestageofprophase-I.Theenzyme
involvedinthisprocessiscalledrecombinasewhichaids
intherecombinationofgenesbetweenhomologous
chromosomes.
Duringzygotenestage,homologouschromosomespair
upbyaprocesscalledsynapsisandformacomplex
bivalentstructure.Diploteneismarkedbythedissolution
ofsynaptonemalcomplexandchaismaformation.While
diakinesisismarkedbyterminalisationofchiasmata(i.e.
chiasmatashiftstowardsperipheryofchromosome).
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Q-9-34342510
Select the correct option with respect to mitosis
(A)Chromatidsstartmovingtowardsoppositepolesin
telophase
(B)Golgicomplexandendoplasmicreticulumarestill
visibleattheendofprophase
(C)Chromosomesmovetothespindleequatorandget
alignedalongequatorialplateinmetaphase
(D)Chromatidsseparatebutremainsinthecentreofthe
cellinanaphase
CORRECTANSWER:C
SOLUTION:
Inmetaphaseofmitosis,spindlefibresattachto
kinetochoreofchromosomes.Chromosomesaremoved
tospindleequatorandgetalignedalongmetaphasic
platethroughspindlefibrestobothpole.
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Q-10-34342520
In which stage of the cell cycle are histone proteins synthesised in a
eukaryotic cells ?
(A)During -stageofprophase
(B)DuringS-phase
(C)Duringentireprophase
G2
(D)Duringtelophase
CORRECTANSWER:B
SOLUTION:
DuringS-phaseofcellcyclesynthesisofhistone
proteinstakesplacebecauseatthisstagetheamountof
DNApercellgetdoubletothatofsomaticnumber.
Histoneproteinsarebasic(absentinprokaryotes)DNA.
DNAandhistonestogethercomprisechromatin,forming
bulkoftheeukaryoticchromosomes.Histonesareoffive
majorkindsH1,H2A,H2BandH4.H1histoneslink
neighbouringnucleosomes.
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Q-11-34342530
Which of the following occurs more than one and less than five in a
chromosome?
(A)Chromatid
(B)Chromosome
(C)Centromere
(D)Telomere
CORRECTANSWER:D
SOLUTION:
Achromosomeshasonecentromere,mayhavemany
chromomeres,twochromatids,butfourtelomers(two
eachattheoppositeendsofeachchromatid).
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Q-12-34342537
A bacterium divides every minutes. If a culture containing
cells/ml is grown for minutes. What will be the cell
concentration / ml after minutes
(A) cells
(B) cells
(C) cells
(D) cells
CORRECTANSWER:C
SOLUTION:
35 105
175
175
5 × 105
35 × 105
32 × 105
175 × 105
1 × 10535min−−−→ 2 × 105
70min−−−→ 4 × 105
105min−−−−→ 8 × 105
140min−−−−→ 16
× 105
175min
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Q-13-34342554
In salivary gland chromosomes/polytene chromosomes, pairing is
(A)absent
(B)occasional
(C)formedbetweennon-homologouschromosomes
(D)formedbetweenhomologouschromosomes
CORRECTANSWER:D
SOLUTION:
Polytenechromosomes/salivaryglandchromosomes
wasreportedbyBalbiani(1881)fromcellsofsalivary
glandsofChironomuslarva(insectofDipteradroup).
175min−−−−→ 32 × 105
Thepolytenechromosomesbecomegiantduetothe
endoduplication,i.e.,repeatedreplicationofchromatids
withouttheirseparationandcytokinesis.Infact,each
polytenechromosomeisformedbypairingoftwo
somatichomologouschromosomeswhichundergo
repeatedendomitosistoformnumerousstrands
attachedtoacommonlargechromocentre.
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Q-14-34342564
Meiosis-I is reductional division. Meiosis-II is equational division
due to
(A)pairingofhomologouschromosomes
(B)crossingover
(C)separationofchromatids
(D)disjunctionofhomologouschromosomes
CORRECTANSWER:C
SOLUTION:
Meiosis-Iiscalledheterotypicdivisionasthetwo
chromatidsofachromosomebecomegenetically
differentduetothecrossingover.Numberof
chromosomesisreducedtohalf,hence,calledreduction
division.Meiosis-IIisjustlikemitosisbutoccoursin
haploidnuclei,itiscalledhomotypicorequational
divisionasthechromosomesaredistributedequallyinto
daughtercellsandchromosomenumberremainsthe
sameindaughtercells.
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Q-15-36806002
The stage during which separation of the paired homologous
chromosomes begin is
(A)diakinesis
(B)diplotene
(C)pachytene
(D)zygotene
SOLUTION:
Theseparationofthepairedhomologouschromosomes
beginsindiplotenestage.Inthisphase,thedissolution
ofsynaptonemalcomplexbegins.Therecombined
homologouschromosomesofthebivalentsseparate
fromeachotherexceptatthesitesofcrossovers.
ZygoteneisthesecondstateofprophaseIofmeiosis.It
isassociatedwiththeformationofsynapsis.Nextstage
ispachyteneduringwhichcrossingoveroccursbetween
non-sisterchromatidsofthehomologouschromosomes.
Diakinesisisthefinalstageofmeioticprophase-I.Thisis
markedbyterminalisationofchiasmata.
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Q-16-26856394
Of the total duration of cell cycle, the interphase lasts more than
(A)
(B)
(C)
(D)
CORRECTANSWER:A
SOLUTION:
95 %
5 %
90 %
92 %
Ofthetotaldurationofcellcycle,theinterphaselasts
morethan95%.
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Q-17-34342517
Synapsis occurs between
(A)amaleandafemalegamete
(B)mRNAandribosomes
(C)spindlefibresandcentromere
(D)twohomologouschromosomes
CORRECTANSWER:D
SOLUTION:
Inzygoteneofprophase-Ihomologouschromosomes
pairup.Thisprocessiscalledsynapsis.One
chromosomeofthepairisfromthemaleparentandone
fromthefemaleparent.
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Q-18-34342547
Lampbrush chromosomes are visible
(A)prophaseofmitosis
(B)diploteneofmeiosis
(C)metaphaseofmeiosis
(D)interphase
CORRECTANSWER:B
SOLUTION:
LampbrushchromosomeswerereportedbyW
Flemming(1882)anddescribedbyRuckert(1892)from
nucleiofyolkrichprimaryoocytesofnewtsandfrog
(amphibians).Thesearealsofoundinspermatocytesof
manyanimals.Thesearefoundinspermatocytesof
manyanimals.Thesearefoundinpermanentdiplotene
stageofmeiosisanddonotundergocellcycle.
Eachsuchchromosomehasadoublemainaxismade
upofDNAandhistones.Thechromosomesarecoiled
andheldatmanyplacesformingcrosslikestructure
calledchiasmata.Loopsarisinglaterallyhasuncoiled
DNAwhichhelpsinrapidtranscriptionandyolk
synthesis.
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Q-19-34342560
In meiosis, the daughter cells differ from parent cell as well as
amongst themselves due to
(A)segregation,independentassortmentandcrossing
over
(B)segregationandcrossingover
(C)independentassortmentandcrossingover
(D)segregationandindependendassortment
CORRECTANSWER:B
SOLUTION:
Thedaughtercellsdifferfromparentcellaswellas
amongstthemselvesduetothesegregationand
crossingovertakingplaceinthem.Meiosis-Ibringsgene
recombinationsandhaploidyofnumberof
chromosomes.Crossingoverduringpachytene
producesnewcombinatonofgenesandisthemajor
sourceofnewgeneticvariationsinthesexually
reproducingorganisms.
Anaphase-IresultsinsegregationofMendelianfactors,
essentialforsexualreproduction,italsointroduces
geneticvariability.
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Q-20-34342539
How many mitotic divisions are needed for a single cell to make
128cells
(A)7
(B)14
(C)28
(D)64
CORRECTANSWER:A
SOLUTION:
Asinglemitoticdivisionresultsintheproductionoftwo
cellsfromsinglecell.
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width="80%">
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Q-21-26856401
If a cell possesses twice as much DNA as in the functional cell, the
cell
(A)ispreparingtodivide
(B)hascompleteddivision
(C)hasceasedtofunction
(D)hasreducedendofitslifespan
CORRECTANSWER:A
SOLUTION:
IfacellpossessestwiceasmuchDNAasinthe
functionalcell,thecellispreparingtodivide.
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Q-22-26856425
Multinucleated condition arises due to karyokinesis is not followed
by cytokinesis , is called
(A)Syncytium
(B)Coenocytic
(C)Synkaryon
(D)Coenozoic
CORRECTANSWER:A
SOLUTION:
Multinucleatedconditionarisesduetokaryokinesisisnot
followedbycytokinesisiscalledsyncytium.
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Q-23-26856437
Which of the phase is the longest?
(A)Prophase
(B)Metaphase
(C)Anaphase
(D)Telophase
CORRECTANSWER:A
SOLUTION:
Prophaseofmitosisisthelongestphase.
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Q-24-26856454
Which of the following is unique to mitosis and not a part of
meiosis
(A)Homologouschromosomescrossover
(B)Homologouschromosomespairandformbivalent
(C)Homologouschromosomesbehaveindependentely
(D)Chromatidsareseperatedduringanaphase
CORRECTANSWER:C
SOLUTION:
Homologouschromosomesbehaveindependentlyinto
completedbytheendofpachytene.
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Q-25-34342499
During which phase(s) of cell cycle amount of DNA in a cell
remains at 4C level if the initial amount is denoted an 2C
(A)
(B)
(C)Only
(D)
CORRECTANSWER:D
G0 and G1
G1 and S
G2
G2 and M
SOLUTION:
DuringtheSorsyntheticphase,theDNAcontent
doubles,i.e.,from2Cto4Cforalldiploidcells.The
phasefollowstheS-phaseandiscalledsecondgrowth
phaseorpremitoticgapphase.InG_(2)`phasethe
synthesisofDNAstopstherefore,theDNAlevelremains
4Cifinitialwas2C.
However,theformationofRNAandproteincontinueas
theyarerequiredforthemultiplicationofcellorganelles,
spindleformationandcellgrowth.Thisamountbecomes
half(i.e.)2Conlyduringanaphase(inmitosis)when
chromosomesseparate.
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Q-26-34342563
G2
A bivalent of meiosis i consists of
(A)twochromatidsandonecentromere
(B)twochromatidsandtwocentromeres
(C)fourchromatidsandtwocentromeres
(D)fourchromatidsandfourcentromeres
CORRECTANSWER:C
SOLUTION:
Eachpairofhomologouschromosomecarryingone
maternalandonepaternalchromosomeofsimilartypeis
calledbivalent.Eachchromosomehastwosister
chromatidsandacentromere.Thus,bivalents
possessesfourchromatids,twocentromeres.This
bivalentwithfourchromatidsiscalledpachytenetetrad
(quadrivalent).
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Q-27-26856404
Which of the following cells in an adult animal do not appear to
exhibit division
(A)Bonemarrowcells
(B)Upperlayerofepiderms
(C)Heartcells
(D)Alloftheabove
CORRECTANSWER:C
SOLUTION:
Heartcellsinanadultanimaldonotappeartoexibit
division.
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Q-28-26856436
Centromere is rquired for
(A)Crossingover
(B)Transcription
(C)Cytoplasmiccleavage
(D)Movementofchromosomestowardspoles
CORRECTANSWER:D
SOLUTION:
Centromereisrequiredformovementofchromsomes
towardspoles.
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Q-29-26856444
Prophase -I is subdivided into five phases based on
(A)chromosomalmovement
(B)chromosomalalignment
(C)chromosomalbehaviour
(D)chromosomalstructure
CORRECTANSWER:C
SOLUTION:
Prophase-Iissubdividedintofivephasesbasedon
chromosomalbehaviour.
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Q-30-13842225
Human cells in culture show a cell cycle to be completed in
approximately.
(A)42hours
(B)24hours
(C)24minutes
(D)24seconds.
CORRECTANSWER:B
SOLUTION:
Atypicalhumancelldividesonceinapproximatelyevery
24hours.
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Q-31-13842265
Select the correct mathc
(A)Quiescentphase- phase
(B)Synthesisphase- phase
(C)Centromeresplittting-Anaphase
(D)Chromosomalcondensation-Telophase
CORRECTANSWER:C
SOLUTION:
phaseisknownasquiescentphaseSphaseis
knownassynthesisphase.Chromosomalcondensation
occursinmetaphase.
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Q-32-13842268
G2
G1
G0
Match column I with column II and select the correct option from
the given codes.
(A)iv,ii,i,iii
(B)ii,iv,i,iii
(C)ii,iv,iiii,i
(D)iv,iii,ii,i
CORRECTANSWER:B
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Q-33-34342538
ColumnI ColumnIIV-shapedatanaphase (ii)Acrocentricchromosome
L-shapedatanaphase (ii)Metacentricchromosome
J-shapedatanaphase (iii)Telocentricchromosome
I-shapedatanaphase (iv)Sub-metacentricchromosome
During cell division in apical meristem nuclear membrane reappears
in
(A)metaphase
(B)anaphase
(C)telophase
(D)cytokinesis
CORRECTANSWER:C
SOLUTION:
Duringtelophase,nuclearenvelopeinitiallyreforms
aroundeachchromosomeindividuallywhichlateron
fusetoformcompletenuclearenvelope.
MetaphaseChromosomesarearrangedequatorialplate.
AnaphaseChromosomessplitlongitudinally.Chromatids
migratetowardsoppositepoles.
CytokinesisDivisionofcytoplasm.
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Q-34-34342562
Mitotic anaphase differs from metaphase in possessing
(A)samenumberofchromosomesandsamenumberof
chromatids
(B)halfnumberofchromosomesandhalfnumberof
chromatids
(C)halfnumberofchromosomesandsamenumberof
chromatids
(D)samenumberofchromosomesandhalfnumberof
chromatids
CORRECTANSWER:D
SOLUTION:
Mitoticmetaphaseisthebeststagetoobservethe
structure,sizeandnumberofchromosomesinacell.
Centromeresofallchromosomesliecloselyatequator
andtheirarmsindefferentdirectionstowardspoles.
Chromosomesareshortestinmetaphasebutthickestin
anaphase.
Inanaphase,centromereofeachchromosomedivides
sothateachsistershromatidnowhasitsown
centromere.Thus,mitoticanaphaseinpossessingsame
numberofchromosomesandhalfnumberofchromatids.
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Q-35-13842233
Synthesis of histone proteins occurs in
(A) phase
(B)interphase
(C)anaphase
(D) phase.
CORRECTANSWER:B
SOLUTION:
ReplicationofDNAalongwiththesynthesisofnuclear
proteinssuchasthehistonesoccurduring5phaseof
interphase.
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Q-36-13842243
Mitotic spindle is mainly composed of __ proteins.
G1
G0
(A)tublin
(B)myosin
(C)actin
(D)actomyosin
CORRECTANSWER:A
SOLUTION:
Spindlefibresarestructuresformedfrommictrobubules
inthecytoplasmduringcelldivision.Microtubulesare
madeupoftubulinprotein.Spindlefiberesmove
chromatidsorchromosomesdiametricallyapartand
gatherthemintwod=clustersatoppositeends(poles)of
thecell.
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Q-37-34342514
Given below is schematic break-up of phases of cell cycle. Which
one is correct matching ?
(A)B-metaphase
(B)C-karyokinesis
(C)D-syntheticphase
(D)A-cytokinesis
CORRECTANSWER:C
SOLUTION:
Cellcyclecompletesintwosteps,i.e.interphaseandM-
phase.Interphaseiscompletedinthreesuccessive
stages -phase(postmitoticphase),S-phase
(syntheticphase)and -phase(premitoticorpost
syntheticphase).Inthegivenfigure.Disrepresenting
theS-phase(syntheticphase)ofcellcycle.
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Q-38-26856446
The beginning of diplotene is recognised by the
G1
G2
(A)Dissolutionofthesynaptonemalcomplex
(B)Tendencyoftherecombinedhomologous
chromosomesofthebivalentstoseparatefromeach
other
(C)Meioticspindleisassembled
(D)BothAandB
CORRECTANSWER:D
SOLUTION:
Thebeginningofdiploteneisrecognisedbythe
dissolutionofthesynaptonemalcomplexandtendency
oftherecombinedhomologouschromosomesofthe
bivalentstoseparatefromeachother.
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Q-39-13842240
In which of the following stages, a choromosome is minimum
coiled?
(A)interphase
(B)Metaphase
(C)Prophase
(D)anaphase.
CORRECTANSWER:A
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Q-40-13842267
The separation of two chromatids of each chromosome at early
anaphase is initiated by
(A)theinteractionofcentromerewiththechromosomal
fibres
(B)theelongationofmetaphasicspindle
(C)theforceofrepulsionbetweenthedivided
kinetochores
(D)allofthese
CORRECTANSWER:C
SOLUTION:
Kinetochoreisaplate-likestructurebywhich
microtubulesofthespindleattachtothecentromereofa
chromosomeduringnucleardivision.Thecentromereof
eachchromosomedividesintotwo,sothateach
chormatiedcomestohaveitsowncentromere.Thetwo
chromatidsnowstartrepellingeachotherandseparate
completelytobecomedaughterchromosmes.the
daughterornewchromosmes.Thedaughterornew
chromosomesmovetowardsthepolesofspindlealong
thepathoftheirchromosomefibres.
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Q-41-13842281
Which phase of mitosis is essentially the reverse of prophase in
terms of nuclear changes?
(A)S-phase
(B)Anaphase
(C)Telophase
(D)Interphase
CORRECTANSWER:C
SOLUTION:
Duringtelophaseofmitosisviscosityofcytoplasm
decreases.Anewnuclearmembraneisformed(either
fromoldernuclearenvelopeorER)aroundeachsetof
chromosomes.Chromosomesoverlapforming
chromatin.TheNucleolarorganiserregionofsatelite
chromosomesproducenucleolusforeachdaughter
nucleus.Nucleoplasmsurroundsintheareaof
chromatin.Thegelstateofspindleisconvertedintosol
stateanddisappears.Inthiswaytwodaughternuclei
areformedatthepolesofspindle.Hence,thisphaseis
justreverseofprophase.
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Q-42-34342558
Balbiani rings (puffs ) are sites of
(A)DNAreplication
(B)RNAandproteinsynthesis
(C)synthesisofpolysaccharides
(D)synthesisoflipids
CORRECTANSWER:B
SOLUTION:
Inpolytenechromosomes(salivarygland
chromosomes).Largeswellingsarecalledpuffsor
Balbianirings,namedaftertheirdiscoverer.Insuch
rings.DNAisactive,uncoiledforrapidtranscriptionof
RNAorproteinsynthesis.
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Q-43-23761005
A mitogen of plant origin is
(A)Colchicine
(B)Epidermalgrowthfactor
(C)Cytokinin
(D)Lymphokine.
CORRECTANSWER:C
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Q-44-10761388
The correct sequence of phases of cell cycle is :
(A)
(B)
(C)
G1 → S → G2 → M
M → G1 → G2 → S
G1 → G2 → S → M
(D)
CORRECTANSWER:A
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Q-45-34342488
Which of the following option gives the correct sequence of events
during mitosis
(A)Condensation nuclearmembranedisassembly
crossingover segregation telophase
(B)Condensation nuclearmembranedisassembly
arrangementatequator centromeredivision
segregation telophase
(C)Condensation crossingover nuclear
membranedisassembly segregation telophase
S → G1 → G2 → M
→
→ → →
→
→ →
→ →
→ →
→ →
(D)Condensation arrangementatequator
centromeredivision segregation telophase
CORRECTANSWER:B
SOLUTION:
Duringmitosisfollowingeventsoccursasfollows
Condensationofchromosomalmaterial,whichtakes
placeatearlyprophasestage.Duringlateprophase
nuclearmembranedisintegrates.
Thenchromosomesgetarrangedateequatorinthe
metaphasestage.Afterthatsplittingofcentromereand
segregationofchromosomesoccurintheanaphase
stage.Intelophasestage.chromosomesmoveto
oppositepolesofthecell.Itislaststageofmitosis.
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→ →
→ →
Q-46-34342493
When cell has stalled DNA replication fork , which checkpoint
should be predominantly activated
(A)
(B)
(C)M
(D)Both
CORRECTANSWER:A
SOLUTION:
Stalledforksactivatecheckpointsignalingandpause
replication.Since, /ScheckpointchecksDNA
damage,cellssizepriortoS-phase(i.e.DNAreplication
phase),thischeckpointwouldbeactivatedbystalled
G1 /S
G2 /M
G2 /M and M
G1
DNAreplicationfork.
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Q-47-34342498
Arrange the following events of meiosis in correct sequence
(a) Crossing over
(b) Synapsis
Terminalisation of chiasmata
(d) Disappearance of nucleolus.
(A)II,I,IV,III
(B)II,I,III,IV
(C)I,II,III,IV
(D)II,III,IV,I
CORRECTANSWER:B
(c)
SOLUTION:
Thecorrectsequenceofeventsofmeiosisare
Synapsisinzygotene Crossingoverin
pachytene Terminalisationofchaismatain
diplotene Disapperanceofnucleolusindiakinesis.
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Q-48-34342509
Given below is the representation of a certain event at a particular
stage of a type of cell division. Which is this stage
→
→
→
(A)Prophase-Iduringmeiosis
(B)Prophase-IIduringmeiosis
(C)Prophaseofmitosis
(D)Bothprophaseandmetaphaseofmitosis
CORRECTANSWER:A
SOLUTION:
Duringzygotenestageofprophase-Iofmeiosis-I,
bivalentchromosomesclearlyappearastetrads.
Pachytenestageischaracterisedbytheappearanceof
recombinationnodules,thesitesatwhichcrossingover
(exchangeofgeneticmaterial)occursbetweennon-
sisterchromatidsofthehomologouschromosomes.
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Q-49-34342512
Which stages of cell division do the following figures A and B
represent respectively
(A)Metaphase-Telophase
(B)Telophase-Metaphase
(C)Lateanaphase-Prophase
(D)Prophase-Anaphase
CORRECTANSWER:C
SOLUTION:
Inthegivenfigures
ALateanaphaseischaracterisedbyfollowingevents
(i)Centromeressplitandchromatidsseparate.
(ii)Chromatidsmovetooppositepoles.
B.Prophaseischaracterisedbycentrioleseparation.
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Q-50-34342523
Which one of the following precedes re-formation of the nuclear
envelope during M phase of the cell cycle.
(A)Decondensationfromchromosomesandreassembly
ofthenuclearlamina
(B)Transcriptionfromchromosomesandreassemblyof
thenuclearlamina
(C)Fromationofthecntractileringandformationofthe
phragmoplast
(D)Formationofthecontractileringandtranscription
formchromosomes
CORRECTANSWER:A
SOLUTION:
Attelophasestage,nuclearmembranevesicles
associatewiththesurfaceofindividualchromosomes
andfusetoreformthenuclearmembranes,which
partiallyencloseclustersofchromosomesbefore
coalescingtoreformthecompletenuclearenvelope.
Duringthisprocessthenuclearporesreassembleand
thedephosphorylatedreassociatetoformthenuclear
lamina.Oneofthelaminaproteins(lamina-B)remains
withthenuclearmembreanefragmentsthroughout
mitosisandmayhelpnuclearreassembly.Afterthe
nucleusreforms,thechromosomesdecondenseand
RNAsynthesisresumes,causingthenucleolusto
reappear.
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Q-51-34342535
Crossing over in diploid organism is responsible for
(A)dominanceofgenes
(B)linkagebetweengenes
(C)segregationofalleles
(D)recombinationoflinkedalleles
CORRECTANSWER:D
SOLUTION:
Thegenespresentonthesamechromosomedonot
alwaysremaintogether.Theseusuallygetseparated
andrecombinewithgenespresentonhomologous
chromosomestoformnewcombinations(recombinants).
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Q-52-34342541
Which of the folliwng structure will not be common to mitotic cell
of a higher plant
(A)Cellplate
(B)Centriole
(C)Centromere
(D)Spindlefibres
CORRECTANSWER:B
SOLUTION:
Centrosomeisfoundinanimals,Euglena,Nitella,some
fungiandmembersofdinoflagellate.Itisfoundnearthe
nucleus.
Centrioleisnotcommontomitoticcellofhigherplants.
Mainfunctionofcentrosomeisattimeofcelldivision
whenthetwocentriolesseparateandmoveontwo
poles.Asterandspindleareformedfromitwhichhelpin
themovementofchromatids.Theyformbasalbody,
cilia,flagella,etc.
CentrioleisrichintubulinandATPase.
Centriolesreplicatein -phaseofinterphaseofcell
cyclebutdonotinitiatecelldivision.
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Q-53-34342553
Best stage to observe shape, size and number of chromosome is
(A)interphase
(B)metaphase
(C)prophase
(D)telophase
CORRECTANSWER:B
G2
SOLUTION:
Metaphasecanbecharacterisedbythechromosomes
thatareleastcoiledwhichshowmaximumcondensation
andareshortestinlength.Itisthebeststatetostudythe
structure.Sizeandnumberofchromosomeisprepared
atmataphase.
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Q-54-34342518
The salivary gland Chromosomes in the dipteran larvae, are useful
in gene mappin because
(A)thesearemuchlongerinsize
(B)theseareeasytostain
(C)thesearefused
(D)theyhaveendoreduplicatedchromosomes
CORRECTANSWER:D
SOLUTION:
Balbiani(1881)wasthefirstpersonwhoobserved
salivaryglandchromosomesinthesalivaryglandsof
Chironomuslarvae.Thesechromosomesareveryuseful
ingenemappingbecausetheyhaveendoreduplicated
chromosomes.Thesechromosomesareformeddueto
theprocessofendoduplicationorendopolyploidyor
endomitosis.Inthisprocessthenuclearmembrenedoes
notrupturebutchromosomesbecomedoubleandthey
donotseparatefromeachother.
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Q-55-34342559
Number of chromatids per chromosome at metaphase is
(A)twoeachinmitosisandmeiosis
(B)twoinmitosisandoneinmeiosis
(C)twoinmitosisandfourmeiosis
(D)oneinmitosisandtwoinmeiosis
CORRECTANSWER:A
SOLUTION:
Inmetaphase,chromosomesarethick,shortestleast
coiledandminimuminsize.Eachchromosomehasits
bothchromatidsattachedatcentromere,orientedatthe
equatorofspindleapparatus.
Inmeioticmetaphase,each,chromosomewithtwo
chromatidsinabivalentisconnectedtothespindlepole
ofitssidebyakinetochoremicrotubuleinsteadoftwoas
inmetaphaseofmitosis.
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Q-56-26856403
Haploid complement of chromososme of an organism is
(A)Genotype
(B)Phenotype
(C)Genome
(D)Geneticsystem
CORRECTANSWER:C
SOLUTION:
Haploidcomplementofchromosomeofanorganismis
calledgenome.
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Q-57-26856424
Read the following statements and find out the incorrect statement.
(A)Inananimalcell,cytokinesisisachievedbythe
appearanceofafurrowintheplasmamembrane.
(B)Furrowformationstartsinthecentreofcelland
growsoutwardtomeettheexistinglateralwalls
(C)Cellplaterepresentsthemiddlelamellabetweenthe
wallsoftwoadjacentplantcell.
(D)Duringcytokinesis,organelleslikemitochondriaand
plastidsgetdistributedbetweenthetwodaughtercells.
CORRECTANSWER:B
SOLUTION:
Inananimalcell,cytokinesisisachievedbythe
appearanceofafurrowintheplasmamembrane.
Cellwallformationstartsinthecentreofcellandgrows
outwardtomeettheexistinglateralwalls.
Cellplaterepresentsthemiddlelamellabetweenthe
wallsoftwoadjacentplantcells.
Duringcytokinesis,organelleslikemitochondriaand
plastidsgetdistributedbetweenthetwodaughtercells.
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Q-58-13842239
Which of the following pstatements is correct ?
(A)Animalscansowmitoticdivisionsinbothhaploidand
diploidcells.
(B)AfterSphasethenumberofchromosomesbecomes
doublei.e.,2nto4n.
(C)Duringthe phase,proteinsaresynthesisedin
preparationformitosiswhilecellgrowthcontinues.
(D)Sorsynthesisphasemarkstheperiodduringwhich
RNAsynthesistakesplace.
CORRECTANSWER:C
SOLUTION:
Animalscanshowmitoticdivisionsonlyindiploidcells.
AfterSphasethenumberofchromosmesremainsthe
samei.e.,2nSorsynthesisphasemarkstheperiod
duringwhichDNAsysthesistakesplace.
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Q-59-13842264
G2
During anaphasic movements of chromosomes, ___ of each
chromosome is/are towards the pole and ___ of the chromosome
trail(s) behind.
(A)centromere,arms
(B)arms,centromere
(C)chromatids,centromere
(D)noneofthese
CORRECTANSWER:A
SOLUTION:
Inanaphasicmovementofchromosomes,the
centromeresleadthepathwhilethearmstrailbehind.
AsaresulttheanaphasicchromosomesappearV.,L,J-
andI-shaped.Theshapesareformedrespectivelyin
metacentric,submetacentric,acrocentricandtelocentric
chromosomes.
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Q-60-34342525
Crossing over that results in genetic recombination in higher
organisms occurs between
(A)sisterchromatidsofbivalent
(B)non-sisterchromatidsofabivalent
(C)twodaughternuclei
(D)twodifferentbivalents
CORRECTANSWER:B
SOLUTION:
Theprocessofcrossingovertakesplaceinpachytene
stageofprophase-Iofmeiosis-I.Inthisprocesssome
genesoftwonon-sisterchromatidsofabivalentare
exchanged.
Theprocessofcrossingoverisdepicted
Sisterchromatidsofone
duplicatechromosome
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