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.

`(##ARH_31Y_NEET_BIO_C12_E01_038_S01.png"

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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