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PRINCIPLEOFINHERITANCEANDVARIATION

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Q-1-35214208

A person with 47 chromosomes due to an additional Y-chromosome

suffers from a condition called

(A)Down'ssyndrome

(B)Superfemale

(C)tuner'ssyndrome

(D)klinefelter'ssyndrome

CORRECTANSWER:D

SOLUTION:

HFKlinefelterfirstdescribedthisconditionin1942.The

chromosomenumberis2n=47withtheformula44A+

Phenotypicallytheseindividualsaremales,buttheycan

showsomefemalesecondarysexualcharacteristicsand

areusuallysterile.

WatchVideoSolutionOnDoubtnutApp

Q-2-30701408

Chromosomes found in the salivvaary glands of Drosophila are

(A)Lampbrush

(B)Polytene

(C)Supernumerary

(D)B-chromosomes.

CORRECTANSWER:B

Q-3-35214028

Among the following characters, which one was not considered by

Mendel in his experiments on pea?

(A)Stem-TallorDwarf

(B)Trichomes-GlandularorNon-glandular

(C)Seed-GreenorYellow

(D)Pod-inflatedorConstricted

CORRECTANSWER:B

SOLUTION:

Trichomesaretheepidermaltissuesstructure.When

epidermalcellsbecomeglandularhair,itiscalled

trichome.Thischaracterwasnotamongsttheseven

charactersofpea,whichmendelselectedforhis

hybridisationexperiments.

Q-4-30701434

Complete linkage is found in

(A)Birds

(B)Snakes

(C)FemaleDrosophila

(D)MaleDrosphila

CORRECTANSWER:D

Q-5-35214050

The term ''linkage'' was coined by

(A)THMorgan

(B)TBoveri

(C)GMendel

(D)WSutton

CORRECTANSWER:A

SOLUTION:

ThetermlinkagewascoinedbyTHMorgan.Hecarried

outseveraldihybridcrossesinDrosophilatostudy

genesthatweresex-linked.Hedescribedthephysical

associationofgenesonachromosome.

Q-6-35214033

Which of the following most appropriately describes haemophilia?

(A)X-linkedrecessivegenedisorder

(B)Chromosomaldisorder

(C)Dominantgenedisorder

(D)Recessivegenedisorder

CORRECTANSWER:A

SOLUTION:

HaemophiliaisX-linkedrecessivegenedisorder.Itisa

bloodclottingdisorderandshowscriss-cross

inheritance.Inthis,charactersfromfatherare

transmittedtodaughterandfrommothertoson.

Q-7-30701414

A chromosome with sub terminal centromere is

(A)Acentric

(B)Acrocentric

(C)Metacentric

(D)Telocentric

CORRECTANSWER:B

Q-8-35214046

A true breeding plant is

(A)onethatisabletobreedonitsown

(B)producedduetocross-pollinationamongunrelated

plants

(C)nearhomozygousandproducesoffspringofitsown

(D)alwayshomozygousrecessiveinitsgenetic

constitution

CORRECTANSWER:C

SOLUTION:

Atruebreedingplant(pureline)hashomozygousgenes

foracharacter(e.g.TTfortallorttfordwarf).Italways

producesoffspringswhicharetrue(pure)forits

characters.

Q-9-30701403

Term chromosome was coined by

(A)Hofmeister

(B)Sutton

(C)Boveri

(D)Waldeyer

CORRECTANSWER:D

Q-10-35214272

Two linked genes a nad b show 20% recombination the indivsuls of

a hybrid cross between ++/++ X ab/ab shaoll show gemetes:

CORRECTANSWER:C

SOLUTION:

+ + 80: ab : 20

+ + 50: ab : 50

+ + 40:ab40 : + a10 :+ b : 10

+ + 30:ab30 : + a20 :+ b : 20

Thegametesofadihybridcrossbetween

willbe++40:ab40:+a10:+

Q-11-35214084

Which one of the following cannot be explained on the basis of

Mendel's Law of Dominance?

(A)Thediscreteunitcontrollingaparticularcharacteris

calledafactor

(B)Outofonepairoffactorsoneisdominant,andthe

otherrecessive

(C)Allelesdonotshowanyblendingandboththe

charactersrecoverassuchin -generation

(D)Factorsoccurinpairs

+ + / + + × ab/ab

CORRECTANSWER:C

SOLUTION:

Outofthefollowingstatement(c)isincorrectbecause

thelawofdominancedoesnotoccuruniversally.After

Mendelseveralcaseswererecordedbyscientists,

whereacleardeviationfromlawofdominancewas

Where, hybridsexhibitedamixtureorblendingof

characteroftwoparents,thecaseisconsideredasthat

ofincompletedominanceorblendinginheritance.It

simplymeansthattwogenesofallelomorphicpairare

notrelatedasdominantorrecessive,butarenotrelated

asdominantorallelomorphicpairarenotrelatedas

dominantorrecessive,buteachofthemexpressesitself

partially.Inthecaseof4O'clockplant,whenplantswith

redflowersarecrossedwithplantshavingwhiteflower,

the hybridsbearpinkflower.Whenthesepinkflowers

areselfpollinated,theydevelopred,pinkandwhite

flowersintheratioof1:2:1respectively.

Q-12-30701443

Crossing over occurs at

(A)Singlestrandsatgeofchroomosmesduringpropase

(B)Twostrandstageduringzygotene

(C)MetaphaseIIofmeiosis

CORRECTANSWER:C

Q-13-18704887

Howmany types of gemete will be produced by an individual

having genotype AaBbcc:

(A)Four

(B)Three

(C)Two

(D)One

CORRECTANSWER:A

SOLUTION:

Q-14-35214077

Select the correct statement from the ones given below with respect

to dihybrid cross.

(A)Tightlylinkedgenesonthesamechromosomeshow

higherrecombinations

(B)Genesfarapartonthesamechromosomeshowvery

fewrecombinations

(C)Geneslooselylinkedonthesamechromosome

showsimilarrecombinationsasthetightlylinkedones

(D)Tightlylinkedgenesonthesamechromosomeshow

veryfewrecombinations

CORRECTANSWER:D

SOLUTION:

Morganandhisgroupfoundthatwhengeneswere

groupedonthesamechromosome,somegeneswere

verytightlylinked(showedverylowrecombination),

whileotherswerelosselylinked(showedhigher

recombination).Recombinationisaprocessof

rearrangementofgenesduringmeiosissothatagamete

containsahaploidgenotypewithanewgene

combination.

Q-15-35214205

HJ Muller was awarded Noble Prize for his

(A)discoverythatchemicalscaninducegenemutations

(B)discoverythationizingradiationscaninducegene

mutations

(C)workongenemappinginDrosophila

(D)effortstopreventstheuseofnuclearweapons

CORRECTANSWER:A

SOLUTION:

HJMullerwasawardedNobelPrizefordiscoveringthat

ionizingradiationscaninducegenemutations.

Q-16-18704910

In a population of 1000 individuals 360 belong to genototype AA

,480 to Aa and the remaining 160 to aa Based on this data ,the

frequency of allele A in the population is

(A)0.6

(B)0.7

(C)0.4

(D)0.5

CORRECTANSWER:A

SOLUTION:

(a)AccordingtoHardyWeinbergprinciple

+2pq+q^(2)=1,(p+q)^(2)=1 P^(2)=360

P^(2)=36 q^(2)=160 q^(2)=16

q=sqrt(.16)=.4.As""p+q=1`

so,pis0.6.

Q-17-35214907

[" 8.A man,after a tour,finds that he had spent "],[" every day as

many rupees as the number of "],[" days he had been on tour.How

long did his "],[" tour last,if he had spent in all "21,296" ? "]

P 2 ( ∀ )outof1000 ∈÷ idual or

outof100 outof1000 or

outof100so,

Q-18-35214076

Which one of the following conditions correctly describes the

manner of determining the sex in the given example?

(A)XOtypeofsexchromosomesdeterminemalesexin

grasshopper

(B)XOconditioninhumansasfoundinTurner

syndrome,determinesfemalesex

(C)Homozygoussexchromosomes(XX)producemale

inDrosophila

(D)Homozygoussexchromosomes(ZZ)determine

femalesexinbirds.

CORRECTANSWER:A

SOLUTION:

GrasshopperisanexampleofXOtypeofsex

determinationinwhichthemaleshaveonlyoneX-

chromosomebesidestheautosomes,whereasfemales

haveapairofX-chromosomes.

Q-19-18705022

Lathyrus odoratus is an example of which of the following genes

(A)Supplementrygenes

(B)Complementrygenes

(C)Lethelgenes

(D)Condominantgenes

CORRECTANSWER:B

SOLUTION:

Incomplementarygeneaction,9:7ratioisobtainedin

inwhichtwodominantgenesareresponsibleforred

flowercolour.

Q-20-35214214

The polytene chromosomes were discovered for the first time in

(A)Drosophila

(B)Chironomus

(C)Muscanebulo

(D)Muscadomestica

CORRECTANSWER:B

CCppWhite

ccPPWhite

SOLUTION:

Polytenechromosomeswerefirsttimediscoveredbythe

ItaliancytologistEGBalbiani(1881)inthesalivarygland

cellsofChironomuslarva.

Q-21-30701441

Greater is the distance between the two genes on a chromosome

(A)Greateristelinkagestrength

(B)Lesseristhelinkagestreangth

(C)Linikagestrengthremainsunchangeed

(D)Thereisnorelationshipbetweenthetwo

CORRECTANSWER:B

Q-22-35214035

A cell at telophase stage is observed by a student in a plant brought

from the field. He tells his teacher that this cell is not like other cells

at telophase stage. There is no formation of cell plate and thus the

cell is containing more number of chromosomes as compared to

other dividing cells. This would result in

(A)polyploidy

(B)somaclonalvariation

(C)polyteny

(D)aneuploidy

CORRECTANSWER:A

SOLUTION:

Polyploidcellshaveachromosomenumberthatismore

thandoublethehaploidnumber,e.g.Triticumaestivum

(wheat)isahexaploid(6n).

Q-23-30701453

The blue green algae and bacteria contain

(A)Onelinkagegroup

(B)Twolinkagegroups

(C)Threeelinkagegroups

(D)Noneoftheabove

CORRECTANSWER:A

Q-24-35214199

The hereditary material (DNA) present in the bacterium E.coli is

(A)singlestrandedRNA

(B)doublestrandedRNA

(C)singlestrandedDNA

(D)doublestrandedDNA

CORRECTANSWER:D

SOLUTION:

Bacterialchromosomeissingle,circulardoublestranded

DNAmolecule.

Q-25-30701409

A giant chormosome with a number of chromonemata is

(A)Lampbrushchromosome

(B)Heterochromosome

(C)supernumerarychromosome

(D)`Polytenechromosome

CORRECTANSWER:D

Q-26-35214045

If a colourblind man marries a woman who is homozygous for

normal colour vision, the probability of their son being colourblind

(B)0.5

(C)0.75

CORRECTANSWER:A

SOLUTION:

Ifacolourblindmanmarriesawomanwhois

homozygousfornormalcolourvision,theprobailityof

theirsonbeingcolourblindiszero.Colourblindnessisa

recessivesex-linkedtraitinwhichtheeyefailsto

distinguishbetweenappearsonlywhenbothsex

chromosomescarryrecessivegene .However,

inhumanmales,thedefectappearsduetosingle

recessivegene becauseYchromosomedoes

notcarrygeneforcolourvision.Thisdiseaseshows

criss-crossinheritance.

(X cX c)

(X cY )

Thus,thereiszeroprobabilityofsonbeingcolourblind.

Hence,option(a)iscorrect.

Q-27-18705039

Incomplete dominance is found in

(A)Pisumsativum

(B)Antirrhinummajus

(C)Both(a)and(b)

(D)Noneofthese

CORRECTANSWER:B

SOLUTION:

(b)IncompletedominanceisfoundinAntirrhinummajus

(snapdragon)andMirabillisjalapa(4O'clockplant).

Q-28-35214203

Different mutations referrable to the same locus of chromosome

give rise to

(A)pseudoalleles

(B)polygenes

(C)oncogenes

(D)multiplealleles

CORRECTANSWER:D

SOLUTION:

Thephenomenonofmultipleallelismisthesimultaneous

occurrenceofmorethantwoalleles(multiplealleles)at

agivengenelocus.Anymutationoccurringwithina

gene(atthesamelocus)willgiverisetoanewformor

newalleleofthatgene.

Q-29-35214066

If both parents are carriers for thalassaemia, which is an autosomal

recessive disorder, what are the chances of pregnancy resulting in

an affected child?

(A)Nochance

(B)0.5

(C)0.25

CORRECTANSWER:C

SOLUTION:

Inthegivenquestionsincebothparentscarrya

haemoglobinopathytraitofthalassemiatheriskis25%

foreachpregnancyforanaffectedchild.

RR-Unaffected(25%)

Rr-Carrier(50%)

rr-Affected(25%)

So,thechancesofpregnancyresultinginanaffected

childis25%.

Q-30-30701415

A chromosome with centromere near the middle is called

(A)Metacentric

(B)Submetacentric

(C)Acrocentric

(D)Telocentric

CORRECTANSWER:B

Q-31-35214252

One gene pair hides the effect of another. The pheomenon is:

(A)epistasis

(B)dominance

(C)mutation

(D)Noneofthese

CORRECTANSWER:A

SOLUTION:

Epistasisisthephenomenonbywhichagene

suppressesthephenotypicexpressionofanon-allelic

Q-32-18705056

Coupling and repulsion are the two faces of

(A)Crossingover

(B)Linkage

(C)Chiasmata

(D)Mutation

CORRECTANSWER:B

SOLUTION:

(b)Thetendencyofparentalcombinationstoremain

together,whichisexpressedintermsoflowfrequencyof

recombinationsiscalledlinkage.

Q-33-35214032

A disease caused by an autosomal primary non-disjunction is

(A)down'ssyndrome

(B)klinefelter'ssyndrome

(C)tuner'ssyndrome

(D)sickle-cellanaemia

CORRECTANSWER:A

SOLUTION:

Non-disjunctionisthefailureofchromosomestodisjoin

orseparateandmoveawaytooppositepoles.Non-

disjunctionof21stchromosomeduringoogenesisisthe

causeofdown'ssyndrome.Itoccursduetothe

presenceofanadditionalcopyofchromosomeno.21

(trisomyof21stchromosome)ishumans.

Q-34-30701457

Maize has 10 pairs of chromosomes.How many linkage groups does

it have ?

CORRECTANSWER:B

Q-35-18704882

Mendal was te native of

(A)France

(B)Sweden

(C)India

(D)Austria

CORRECTANSWER:D

SOLUTION:

(d)Hewasansabbort(heat)ofAugustionmonasteryof

St.Thomasatbrun,AugustionmonasteryofSt.thomsat

brunn,Austriain1847

Q-36-35214063

Which of the following statements is not true of two genes that

show 50% recombination frequency?

(A)Thegenesmaybeondifferentchromosomes

(B)Thegenesaretightlylinked

(C)Thegenesshowindependentassortment

(D)Ifthegenesarepresentonthesamechromosome,

theyundergomorethanonecrossoversineverymeiosis

CORRECTANSWER:B

SOLUTION:

Outofthegivenstatements(b)isincorrectbecausethe

tightlylinkedgenesonchromosomesshow100%

parentaltypesand0%recombinants.Twogenesthat

undergoindependentassortmentindicatedbya

recombinantfrequencyof50%areeitheronnon-

homologouschromosomesorlocatedfarapartina

singlechromosome.

Asthedistancebetweentwogenesincreases,crossover

frequencyincreases.Morerecombinantgametes,fewer

parentialgametes.

Q-37-35214061

A human female with Turner's syndrome

(A)has45chromosomeswithXO

(B)hasoneadditionalX-chromosome

(C)exhibitsmalecharacters

(D)isabletoproducechildrenwithnormalhusband

CORRECTANSWER:A

SOLUTION:

AhumanfemalewithTurnersyndromehastheabsence

ofoneoftheX-chromosome,i.e.45withXO(or44+

XO).Turnersyndromeisachromosomalconditionthat

affectsthedevelopmentinfemales.Themostcommon

featureofTurnersyndromeisshortstature,which

becomeevidentbytheageof5.Aneasilylossof

ovarianfunctionisalsoverycommon.

Theovariesdevelopenormallyatfirst,buteggcells

usuallydieprematurelyandmostoveriantissue

degeneratesbeforebirth.

Q-38-18705088

When synapsis is complete all along the chromosomes, the cell is

said to have entered a stage called

(A)Zygotene

(B)Pachytene

(C)Diplotene

(D)Diakinesis

CORRECTANSWER:B

SOLUTION:

(b)Thesynapsis,pairingofhomologouschromosomes

takesplaceduringzygotene.Synapsisresultsinthe

formationofbivalentsduringzygotene.Theformationof

specialproteionaceousstructurecalledsynaptonemal

complexoccur.Afterzygotenestagecellentersin

pachytenestageinwhichthebivalentsbecome

spiralled,shortenedandthickened.

Q-39-35214247

Out of 8 ascospores formed in Neutrospora the arrangement is 2a :

4a : 2a showing

(A)nocrossingover

(B)somemeiosis

(C)secondgenerationdivision

(D)firstgenerationdivision

CORRECTANSWER:C

SOLUTION:

InNeurosporaaftercrossingoverbetweenthegeneand

centromere,thepairedarrangementofascosporesisAA

aaaaAAor2a:4a:2a.Thisisknownassecond

divisionsegregation.

Q-40-18705108

the long and short arms of chromosome are designated respectively

(A)pandqarms

(B)qandparms

(C)mandparms

(D)landsarms

CORRECTANSWER:B

Q-41-35214093

Point mutation involves

(A)insertion

(B)changeinsinglebasepair

(C)duplication

(D)deletion

CORRECTANSWER:B

SOLUTION:

Thepointmutationsinvolvealterationsinthestructureof

genebyalteringthestructureofDNA,i.e.changein

singlebasepair.Pointmutationsareoftwotypes,i.e.

basepairsubstitutionandframeshiftsubstitution.

Insertionistheadditionofoneormorenitrogenous

basestoanucleotidechain.

Duplicationisthepresenceofoneblockofgenesmore

thanonceinahaploidcomponent.

Deletionistheremovalofoneormorenitrogenous

basesfromanucleotidechain.

Q-42-18705105

The distance between the genes a,b,c and d in mapping units are a-

d=3,5, b-c=1,a-b=6,c-d=1.5, a-c=5. Find out the sequence of

arrangeent of these genes

(A)acdb

(B)abcd

(C)acbd

(D)adcb

CORRECTANSWER:D

Q-43-35214197

A mutation at one base of the first codon of a gene produces a non-

functional protein. Such a mutation is referred as

(A)frameshiftmutation

(B)mis-sensemutation

(C)non-sensemutation

(D)reversemutation

CORRECTANSWER:B

SOLUTION:

Ifmutationatonebaseofthefirstcodonofagenetakes

placethenallthesubsequentcodonswillbeoutof

register(geneticcode).Thisresultsintotheformationof

mis-senseproteinwhichisformedduetothemutationin

thefirstbaseoffirstcodonandthuscalledmissense

mutation.

Q-44-18705123

Heterochromatin remains condensed in which part of chromosome

(A)secondaryconstrictions-I

(B)secondaryconstrictions-II

(C)Telomeres

(D)Bothaandb

CORRECTANSWER:A

SOLUTION:

(a)Eachchrosomehasacentromere(primary

construction)butinsomecasessecondaryconstruction

isalsopresent,morespecificallycalledas'secondary

construction-II'.Itspositionisconstantforparticular

chromosomeheterochrmatiniscondensedinthisregion

.Inman'secondaryconstruction-II'ispresentin

chrosomenumber andY.Nuclear

organizeriscalled'secondaryconstruction-I'.

1, 10, 13, 16

Q-45-35214089

Select the incorrect statement from the following

(A)linkageisanexceptiontotheprincipleof

independentassortmentinheredity

(B)galactosemiaisaninbornerrorofmetabolisms

(C)smallpopulationsizeresultsinrandomgeneticdrift

inapopulation

(D)baldnessisasexlimitedtrait

CORRECTANSWER:D

SOLUTION:

Outofthegivenstatements(d)isincorrectbecause

baldnessisnotasex-limitedtrait.

Q-46-18705091

Chiasma shows the sites of

(A)Spindleformation

(B)Synapsis

(C)Crossingover

(D)Noneofthese

CORRECTANSWER:C

SOLUTION:

(c)Morganproposedthatchaismataleadtocrossing

overbybreakageandreunionofhomologous

chromosomes.

Q-47-30701416

Puffs or balbiani rings in salivary gland chromsosomes are sites of

(A)DNAreplication

(B)DNAduplication

(C)RNAsynthesis

(D)Proteinsynthesis

CORRECTANSWER:C

Q-48-18705079

What is the unit of crossing over

(A)Cistron

(B)Muton

(C)Recon

(D)Noneoftheabove

CORRECTANSWER:C

SOLUTION:

(c)Recon-Unitofrecombination

Muton-Unitofmutation

Cistron-Unitoffunction

Q-49-35214038

Match the terms in column I with their description in column II and

choose the correct option.

CORRECTANSWER:A

SOLUTION:

Dominance-Expressionofonlyonealleleina

heterozygousorganism.

Codominance-Sidebysidefullexpressionofboth

alleles. resemblesbothparents.

ColumnI ColumnIIA. Dominance 1. ManygenesgovernasinglecharacterB. Codominance 2. InaheterozygousorganismonlyonealleleexpressesitselfC. Pleiotropy 3. InaheterozygousorganismbothallelesexpressthemselvesfullyD. Polygenicinheritance 4. Asinglegeneinfluencesmanycharacters

A B C D2 3 4 1

A B C D4 1 2 3

A B C D4 3 1 2

A B C D2 1 4 3

Pleiotropy-Singlegenecanexhibitmultiplephenotypic

expression,e.g.,Phenylketonuria.

Polygenicinheritance-Manygenesgovernasingle

character,e.g.Humanskincolour.

Q-50-35214041

Pick out the correct statements.

I. Haemophilia is a sex-linked recessive disease.

II.Down's syndrome is due to aneuploidy.

III. Phenylketonuria is an autosomal recessive gene disorder.

IV. Sickle-cell anaemia is an X - linked recessive gene disorder.

(A)IIandIVarecorrect

(B)I,IIIandIVarecorrect

(C)I,IIandIIIarecorrect

(D)IandIVarecorrect

CORRECTANSWER:C

SOLUTION:

Sickle-cellanaemiaisanautosomalrecessivegene

disorderinwhichsickle-celledRBCsareformedinstead

ofnormalones.Theycarryverylesscontentof as

theirhaemoglobinismalformed.Thepersonsuffering

fromthisdiseaseshowsymptomsofanaemia.

Q-51-30701410

Lampbrush chormosome occur in

(A)Salivaryglands

(B)Lymphglands

(C)Cancercells

(D)Oocytes

CORRECTANSWER:D

Q-52-35214048

The mechanism that causes a gene to move from one linkage group

to another is called

(A)inversion

(B)duplication

(C)translocation

(D)crossingover

CORRECTANSWER:C

SOLUTION:

Translocationistheprocesscausingagenetomove

fromonelinkagegrouptoanother.Itistheseparationof

achromosomesegmentanditsuniontoanon-

homologouschromosome.Itisoftwotypes-simpleand

reciprocalInsimpletranslocationonechromosome

showsdeletionordeficiencywhileanonhomologous

chromosomecomestohaveanadditionalsegment.In

reciprocaltranslocationtwonon-homologous

chromosomesexchangesegmentsbetweenthemselves

tocreatenewlinkagegroupsinboththechromosomes

Hence,option(c)iscorrect.

Q-53-30701417

Chromosome theory of inheritane was proposed by

(A)Sutton(1902)

(B)`Boveri(1902)

(C)BothSutton(1902)andBoveri(1902)

(D)Correns(1909)

CORRECTANSWER:C

Q-54-30701462

Alkaptonurics excreate excess of

(A)Urine

(B)Albumen

(C)Malonycaeticacid

(D)Homogentisicacid

CORRECTANSWER:D

Q-55-35214098

Two genes R and Y are located very close on the chromosomal

linkage map of maize plant. When RRYY and rryy genotypes are

hybridised, then segregation will show

(A)highernumberoftherecombinanttypes

(B)segregationintheexpected9:3:3:1ratio

(C)segregationin3:1ratio

(D)highernumberoftheparentaltypes

CORRECTANSWER:D

SOLUTION:

HighernumberoftheparentaltypesformedwhenRRYY

andrryygenotypesarehybridisedgivingthecondition

thatRandYgenesarecloselylinked.Lawof

independentassortmentdoesnotapplicablewhenthe

geneofdifferentcharacteroccupythesame

homologouschromosomei.e.arelinkedgene.

Q-56-18705213

"Nu body" was shown by

(A)Darlington

(B)Johanssen

(C)Woodcock

(D)TeminandBaltimore

CORRECTANSWER:C

SOLUTION:

(c)Woodcock(1973)observedthestructureof

chromatinunderelectronmicroscope.Hetermedeach

beadedstructureonchromosomeasnucleosome.

Q-57-35214102

Test cross involves

(A)crossingbetweentwogenotypeswithrecessivetrait

(B)crossingbetweentwo hybrids

(C)crossingthe hybridwithadoublerecessive

genotype

(D)crossingbetweentwogenotypeswithdominanttrait

CORRECTANSWER:C

SOLUTION:

Thetestcrossinvolvesthecrossingof hybridwitha

doublerecessivegenotypicparent.Bytestcross,the

heterozygosityandhomozygosityoftheorganismcan

betested.

Thus,theoffspringwillbe100%dominant,ifthe

individualwhichcrossedwithrecessiveparent,i.e.(tt)

washomozygousdominantandratiowillbe50%

dominantand50%recessiveiftheindividualwas

heterozygousdominant.Indihybridtestcross,ratiowill

be1:1:1:1.

Q-58-18705270

Human blood groups are example of a

(A)Gradulism

(B)Cline

(C)Gradientofdiplodiy

(D)Polymorphism

CORRECTANSWER:D

Q-59-18705212

The peroson who discovered 'Y' Chromosomes was

(A)McCarthy

(B)McClung

(C)GregorMendel

(D)NettiStevens

CORRECTANSWER:D

Q-60-35214104

In which mode of inheritance do you expect more maternal

influence among the offspring?

(A)Autosomial

(B)Cytoplasmic

(C)Y-linked

(D)X-linked

CORRECTANSWER:B

SOLUTION:

Themorematernalinfluencecanbeexpectedinthe

cytoplasmicinheritance,i.e.theinheritanceofgenes

containedinthecytoplasmofacell,ratherthanthe

nucleus.

Thereasonisthatthefemalereproductivecellorthe

egghasalargeamountofcytoplasmcontainingmany

suchorganelleswhichcontaintheirowngenesandcan

reproduceindependently,e.g.mitochondriaand

chloroplastandwhichareconsequentlyincorporated

intothecytoplasmofallthecellsoftheembryo.

Themalereproductivecells(spermorpollen)consist

almostsolelyofanucleus.Cytoplasmicorganellesare

thus,notinheritedfromthemaleparent.

Thisiswhy,thecytoplasmicinheritanceisalsocalled

maternalinheritance.

AgenelocatedintheX-chromosomeissaidtobeX-

linkedanditsinheritanceiscalledX-linkedinheritance.

Inthis,amaletransmitshisX-chromosomeonlytohis

daughterswhileafemaletransmitsoneofherX-

chromosomestotheoffspringofbothsexes.

Q-61-30701526

Theroy of heterogamesiss for sex determination was proposed by

(A)Morgan

(B)Darwin

(C)Correns

(D)Bridges

CORRECTANSWER:C

Q-62-35214107

Phenotype of an organism is the result of

(A)mutationsandlinkages

(B)cytoplasmiceffectsandnutrition

(C)environmentalchangesandsexualdimorphism

(D)genotypeandenvironmentalinteractions

CORRECTANSWER:D

SOLUTION:

Phenotypeistheobservablecharacteristicsorthetotal

appearanceofanorganism.Itisdeterminedbyits

genes,therelationshipsbetweentheallelesandbythe

interactionduringdevelopmentbetweenitsgenetic

constitution(genotype)andtheenvironment.

Q-63-30701497

The frequency of mutation in a species can be increased by the use

(A)X-rays

(B)UV-rays

(C)Nitrousacid

(D)Alltheabove

CORRECTANSWER:D

Q-64-35214190

Loss of an X-chromosome in a particular cell, during its

development, results into

(A)diploidindividual

(B)triploidindividual

(C)gynandromorphs

(D)Both(a)and(b)

CORRECTANSWER:C

SOLUTION:

Gynandromorphsarethoseindividualsinwhichonepart

ofthebodyisfemalewhileanotherpartismale.It

occursduetotheirregularityinmitosisatthefirst

cleavageofthezygote.OneoftheX-chromosomesof

anXX(female)zygotelagsinthespindle,onedaughter

nucleusreceivesonlyoneX-chromosomes.whilethe

otherreceivestwoX-chromosomes.Amosaicbody

patternisthusestablishedwhichisknownas

gynandromorph.

Q-65-35214113

A man and a woman, who do not show any apparent signs of a

certain inherited disease, have seven children (2 daughters and 5

sons). Three of the sons suffer from the given disease but none of

the daughters are affected. Which of the following mode of

inheritance do you suggest for this disease ?

(A)Autosomaldominant

(B)Sex-linkeddominant

(C)Sex-limitedrecessive

(D)Sex-linkedrecessive

CORRECTANSWER:D

SOLUTION:

Ingivenproblem,diseaseistheresultofsex-linked

recessivegenes.Asneithermannorwomanshows

signsofdiseaseitmeanswomanwouldbecarrierfor

disease.Intheirchildrennonofthedaughterssuffer

fromdisease,whilethesonsweresuffered,itmeans

daughtersarealsocarrier(i.e.X-linkedrecessive).

Suppose,genotypeofman=XY

Genotypeofwoman=

(d-diseasecausinggene)

Foreachdeliverytheprobabilityforeachcombinationis

25%.So,amongsevenchildren2normaldaughter,3

diseasedsonsand2normalsonsarepossible.

Q-66-30701484

A classical example off allopolyploid is

(A)Brassica

(B)raphnobrassica

(C)Raphanius

(D)Alltheabove

CORRECTANSWER:B

Q-67-35214138

When a cluster of genes shows linkage behaviour they

(A)donotshowindependentassortment

(B)inducecelldivision

(C)donotshowachromosomemap

(D)showrecombinationmeiosis

CORRECTANSWER:A

SOLUTION:

Linkedgenesdonotshowindependentassortment

becausetheyarelocatedonthesamechromosome.But

geneswhicharelocatedonthesamechromosomes

(calledlinkedgenes)donotassortindependently.Such

typeofgenesarecalledlinkedgenesandthis

phenomenoniscalledaslinkage.

Q-68-30701477

Aneuplody is the term applied for the

(A)Genemutation

(B)chromosomalmutation

(C)Crhromosomalmutationsinvolvingtheadditionor

lossofoneormorechromoso9mes

(D)Chromosomalmutationinvolvingtheadditionofone

ormorecompletesetofchromosomes

CORRECTANSWER:C

Q-69-35214116

A male human is heterozygous for autosomal genes A and B and is

also hemizygous for haemophilic gene h. What proportion of his

sperms will be abh?

CORRECTANSWER:A

SOLUTION:

1813211614

ThegenotypeofhumanmaleinquestionmustbeAaBb

Hence typesofgameteswouldbe

formed.AB ,ABY,aB

aBY,Ab ,AbY,ab ,abY.

Hence, proportionofhisspermswouldbeabh.

Q-70-30701645

One barr body is found in man of genotype

(B)XXXY

(C)XXY

2 × 2 × 2 = 8

CORRECTANSWER:C

Q-71-18705161

The point at which the polytene chromosomes appeart to be

attached togeher is known as

(A)Centriole

(B)Chromocentre

(C)Centromere

(D)Chromomere

CORRECTANSWER:B

Q-72-35214182

Mental retardation in man, associated with sex chromosomal

abnormality is usually due to

(A)reductioninX-complement

(B)increaseinX-complement

(C)moderateincreaseinY-complement

(D)largeincreaseinY-complement

CORRECTANSWER:B

SOLUTION:

Sterilemaleswithundevelopedtestes,mental

retardation,etc.areduetoincreaseintheirX-

complementwhichtakesplaceinadisordercalled

Klinefelter'ssyndrome.Theseareformedbyunionofan

XXeggandanormalYspermornormalXeggand

abnormalXYsperm.Theindividualthushas47

chromosomes(44+XXY)

Q-73-18705176

Balbiani rings are present in

(A)Polysomes

(B)Autosomes

(C)Polytenechromosomes

(D)Noneofthese

CORRECTANSWER:C

SOLUTION:

(c)PolytenechromosomeswasdescribedbyKollar

(1882)andfirstreportedbyBallbiani(1881).Theyare

foundinsalivaryglandsofinsects(Drosophila)and

calledassalivaryglandchromosomes.

Q-74-18705211

Some genes in bacteria and virus mau bcode for more than one

polypetide, they are called in

(A)Overlappinggenes

(B)Jumpinggene

(C)Splitgene

(D)Noneofthese

CORRECTANSWER:A

Q-75-35214132

Two crosses between the same pair of genotypes or phenotypes in

which the sources of the gametes are reversed in one cross, is

known as:

(A)dihybridcross

(B)reversecross

(C)testcross

(D)reciprocalcross

CORRECTANSWER:D

SOLUTION:

Sincegenotypes/phenotypesofbothparentsaresame-

onlysourcesofgametesarereversed,thesecrossesare

calledreciprocalcrosses.

Q-76-18705214

"Cytochimeras" means

(A)Cellhavinghalodpid

(B)Cellshavingtwonuclei

(C)Cellshavingdifferentchromosomesotherthan

vegetativecells

(D)Noneofthese

CORRECTANSWER:C

SOLUTION:

(c)Chimerasaretheindividualhavingthedifferent

genotypesinitsdifferentparts.

Q-77-35214162

Ratio of complementary genes is

CORRECTANSWER:D

SOLUTION:

Incaseofcomplementarygenes,theratioof9:7is

obtainedin -generation.Thiswasfirstdiscoveredby

BatesonandPunnett.

Complementarygenesarethosegeneswhichexpress

9 : 3 : 4

12 : 3: 1

9: 3: 3: 4

themselveswhenpresenttogether.Noneofexpress

themselveswhenpresenttogether.Noneofthesetwo

getexpressedyourselfwhenpresentalone.

Q-78-35214123

In a mutational event, when adenine is replaced by guanine, it is the

case of

(A)frameshiftmutation

(B)transcription

(C)transition

(D)transversion

CORRECTANSWER:C

SOLUTION:

Incaseoftransition,purinebaseisreplacedbyanother

purine(e.g. )andpyrimidineisreplacedby

anotherpyrimidine(e.g. )andviceversa.In

caseoftransversionpurineisreplacedbyapyrimidine

andviceversa.

Q-79-30701502

Cholchicine interferes in

(A)Spindleorganisation

(B)DNAreplication

(C)Chromosomecondensation

(D)Polyploidy

CORRECTANSWER:A

A ⇔ G

C ⇔ T

Q-80-35214137

Which of the following discoveries resulted in a Nobel Prize

(A)Recombinationoflinkedgenes

(B)Geneticengineering

(C)X-raysinducesex-linkedrecessivelethalmutations

(D)Cytoplasmicinheritance

CORRECTANSWER:C

SOLUTION:

HJMullerwasawardedNobelPrizein1946forhis

discoveryoftheproductionofmutationbyX-ray

radiation.

Q-81-30701546

Huntington 's chorea appears at the age of

(A)25-55years

(B)15-25years

(C)50-60years

(D)10-15years

CORRECTANSWER:A

Q-82-35214118

The recessive genes located on X-chromosome in humans are

always

(A)lethal

(B)sublethal

(C)expressedinmales

(D)expressedinfemales

CORRECTANSWER:C

SOLUTION:

TherecessivegeneslocatedonX-chromosomein

humansarealwaysexpressedinmalesbecausea

femalemaybehomozygousorheterozygouswhilemale

isalwayshemizygous(i.e.onlyalleleispresent).

Haemophilia,colourblindnessaresomehuman

diseaseswhicharefrequentlyfoundinmales.

Q-83-30701627

An auxotroph is a (an):

(A)Plantcapableofsynthesisingowncrbohydrates

(B)Plantshowingquickbendingresponsetosunlight

(C)Amutatnhavinglosttheabilitytosynthesisieoneor

morenutrients

(D)Anorganismdependentonanotherfornutritional

requirements

CORRECTANSWER:C

Q-84-35214155

Inheritance would be extranuclear in case of

(A)KillerParamecium

(B)KillerAmoeba

(C)Euglena

(D)Hydra

CORRECTANSWER:A

SOLUTION:

Extranuclearinheritanceorcytoplasmicinheritanceis

theinheritanceofthecharactersofonlyoneparent

(generallythefemaleparent).E.g.somestrainsof

Parameciumcalledkillerstrain.

Q-85-35214121

Lack of independent assortment of two genes A and B in fruit fly

Drosophila is due to

(A)repulsion

(B)recombination

(C)linkage

(D)crossingover

CORRECTANSWER:C

SOLUTION:

THMorgan(1910)explainedthelackofindependent

assortmentinDrosophiliaduetothelinkage.When

genescloselypresentadhereorlinktogetherinagroup

andtransmittedasasingleunit,thephenomenonis

calledlinkage.Itstopstheprocessofindependent

assortment.Incompletelinkageisbrokendowndueto

thecrossingover.

Q-86-18705126

The largest gene in man is :

(A)Dystrophin

(B)Insulingene

(C)Betaglobingeneofhaemoglobin

(D)Tumorsuppressorgene

CORRECTANSWER:A

Q-87-30701472

If a part of chromosome gets separted and reattached in reverse

positoion to the same chromosome, the mutation is called

(A)Inversion

(B)Transverion

(C)Transloction

(D)Genemutation

CORRECTANSWER:A

Q-88-35214166

Mutation generally produces

(A)recessivegenes

(B)lethalgenes

(C)polygenes

(D)dominantgenes

CORRECTANSWER:A

SOLUTION:

Mutationsgenerallyproducerecessivegenes.Mutation

isasuddenheritablechangeinthecharacteristicsofan

organism.Theindividualwhichshowstheseheritable

changesisknownasmutant.

Q-89-30701479

What term is appied to the gene mutation wher a base is replaced by

another base?

(A)Duplication

(B)Aneuploidy

(C)Euploidy

(D)Substitution

CORRECTANSWER:D

Q-90-35214178

Albinism is known to be due to an autosomal recessive mutation.

The first child of a couple with normal skin pigmentation was an

albino. What is the probability that their second child will also be an

albino?

CORRECTANSWER:B

SOLUTION:

Since,albinismisarecessivecharacter,achildwillbe

albinoonlyifitishomozygousforalbinismgenes.Since,

parentshavenormalskin,itmeanstheyare

heterozygous.Asaresultofcrossbetweentwo

heterozygousparents25%ofthechildrenwillbe

homozygousrecessive.Thenatureofhtesecondchildis

notaffectedinanywaybythenatureofthefirstchild

becausebothareindependentevents.

Q-91-30701506

The scientist who first discorved cytoplasmic inheritance was

(A)Correns

(B)Rhoades

(C)Mendel

(D)Morgan

CORRECTANSWER:A

Q-92-18705142

Genes which are cofined to differential region of the Y-

chromosome only are called :

(A)Mutant

(B)Autosomal

(C)Holndric

(D)Completelysex-linked

CORRECTANSWER:C

SOLUTION:

(c)ThegenespresentonthedifferentialpartofY

chromosomearepasseddirectlyfromfathertosonand

arecalledasHolandricgenes.

Q-93-35214164

During organ differentiation in Drosophila, an organ is modified to

another organ (such as wings may be replaced by legs). Genes

responsible for such metamorphosis are called

(A)doubledominantgenes

(B)plastidgenes

(C)complementarygenes

(D)homeoticgenes

CORRECTANSWER:D

SOLUTION:

Homeoticgenesarecontrolgeneswhicheitherbe

gettingexpressedorbyremainingsilentduring

development,influencethedifferentiationoforgans.

Thesehavebeenfoundininsectsnonenematodeand

someplants.ADNAsequencecalledhomeobox,

presentinthesegenes,isinvolvedinspecificationof

organs.

Amutationthatcausesabodyparttodevelopin

appropriatepositioninanorganism,iscalledhomeotic

mutation,e.g.inDrosophila,suchmutationmaycause

legstodevelopontheheadinplaceofantennae.

Q-94-18705341

Mongoloid condition is releated to or In monglolism a patient

(A)Monosomy

(B)Trisomy

(C)Nullisomy

(D)Noneoftheabove

CORRECTANSWER:B

Q-95-35214158

Male XX and female XY sometime occur due to :

(A)deletion

(B)transferofsegmentsinXandY-chromosomes

(C)aneuploidy

(D)hormonalimbalance

CORRECTANSWER:D

SOLUTION:

Hormondalinbalancemayleadtodevelopmentofmale

charactersinfemaleorviceversa.Deletionisthe

removalofoneoffewnitrogenousbasesfroma

nucleotidechain.Aneuploidyisachromosomal

aberrationinwhichcertainchromosomesarepresentin

extracopiesorcertainaredeficientinnumber.

Q-96-18705219

Which of the following is incorrectly paired

(A)SrygeneXchromosome

(B)2n-2-nullisomic

(C)Nucleiodprokaryote

(D)Polytecnic

CORRECTANSWER:A

Q-97-18705300

Example of qualilative inheritance is

(A)Colourofskin

(B)Colourblindness

(C)Klinefelter'ssyndrome

(D)Alkaptonuria

CORRECTANSWER:A

Q-98-35214145

There are three genes a, b, c, percentage of crossing over between a

and b is 20%, b and c is 28% and a and c is 8%. What is the

sequence of genes on chromosome?

(A)b,a,c

(B)a,b,c

(C)a,c,b

(D)Noneofthese

CORRECTANSWER:A

SOLUTION:

Accordingtothegivenquestionthesequenceofgenes

sonchromosomeareb,a,c.

Q-99-18705245

In slpit genes, the coding sequences are called

(A)Cistrons0

(B)Operons

(C)Exons

(D)Introns

CORRECTANSWER:C

SOLUTION:

(c)Unwantedportion(introns)ofgenesissplicedoff

andremainingparti.e.,exonsgetjoinedbyligase.

Q-100-18705256

Which of the following is genetically dominant in man

(A)Colourblindness

(B)Rhpositive

(C)Haemophilia

(D)Albinism

CORRECTANSWER:B

SOLUTION:

(b)ThedifferencebetweenRhpositiveandRhnegative

dependonasinglepairofgenes(rr)withthegene

responsiblefortheRhpositiveconditiondominant(RR,

Q-101-35214127

Pattern baldness, moustanches and beard in human males are

examples of :

(A)sexdifferentiatingtraits

(B)sexdeterminingtraits

(C)sexlinkedtraits

(D)sexlimitedtraits

CORRECTANSWER:D

SOLUTION:

Sexlimitedtraitsarethosewhicharelimitedtoonesex

only.Moustaches,beardarefoundinhumanmalesonly.

Itwassuggestedonthebasisofstatisticalanalysisthat

prematurebaldnessiscontrolledbyadominantgene,

whichexpressesonlyinthepresenceofacertainlevel

ofmalehormone(androgen).

Q-102-30701542

Phenylketonura is

(A)Sexlinkeddominanttrait

(B)Sexlinkedrecesivetrait

(C)Autosomaldominanttrait

(D)Autosomalrecessivetrait

CORRECTANSWER:D

Q-103-18705162

Balbiani discovered special type of chronomus larva which are

recognized by the presence of

(A)Bands

(B)Loosps

(C)Bothbandsandloops

(D)Alltheabove

CORRECTANSWER:C

Q-104-35214143

Genetic map is one that :

(A)showsthestagesduringthecelldivision

(B)showsthedistributionofvariousspeciesinaregion

(C)establishessitesofthegenesonachromosome

(D)establishesthevariousstagesingeneevolution

CORRECTANSWER:C

SOLUTION:

Geneticmapisadiagramwhichshowstherelative

positionofgenesonachromosome.Strutevantin1911

preparedthefirstgeneticmapoftwochromosomesof

fruitfly.

Q-105-18705284

Rh factor is named after

(A)Man

(B)Rat

(C)Monkey

(D)Chimpanzee

CORRECTANSWER:C

SOLUTION:

Rhesusmonkey(Macaarhesus).

Q-106-18705255

In human beings, the colour of skin is controlled by

(A)Multiplealleles

(B)Lethalgens

(C)Polytgeniceffect

(D)Noneofthese

CORRECTANSWER:A

SOLUTION:

(a)Theskincolourofapersonistheresultofan

interactionbetweentwopairsofgenes.

Q-107-18705166

Lampbrush chromosomes are visible

(A)Indiploteneofmeiosis

(B)Inprophaseofmeiosis

(C)Ininterphase

(D)Inmetaphaseofmeiosis

CORRECTANSWER:A

Q-108-35214139

In Drosophila, the sex is determined by

(A)theratioofpairsofX-chromosomestothepairsof

autosomes

(B)whethertheeggisfertilisedordevelops

parthenogenetically

(C)theratioofnumberofX-chromosomestothesetof

autosomes

(D)XandY-chromosomes

CORRECTANSWER:A

SOLUTION:

CalvinBridgesdemonstratedthatinDrosophilia,thesex

isdeteminedbyratioofthenumberofX-chromosomes

tothesetsofautosomes.Accordingtogenicbalances

theoryofsex-determination,Y-chromosomeof

Drosophiliadoesnotimportantforthedeterminationof

Q-109-30701564

Allsomees are the name of

(A)Sexchromosomes

(B)Swellingsonthechromosomes

(C)Chromosomesotherthantheoneswhichdetermine

(D)Nucleolusorganisingregionsofchromosomes

CORRECTANSWER:A

Q-110-35214156

Number of Barr bodies in XXXX female would be

CORRECTANSWER:C

SOLUTION:

ThenumberofBarrbodiesinXXXXfemaleare3.Barr

bodyisacondensedmassofchromatinfoundinthe

nucleiofplacentalmammalswhichcontainoneormore

X-chromosomes,sonamedafteritsdiscoversMurray

Barr.ThenumberofBarrbodiesisonelessthanthe

numberofX-chromosomespresent.

Q-111-30701489

When chromosome sets are present in multiple of 'n', the condition

is termed

(A)Diploidy

(B)Haploidy

(C)Euploidy

(D)Aneuploid

CORRECTANSWER:C

Q-112-35214140

Genes for cytoplasmic male sterility in plants are located in

(A)nucleargenome

(B)cytosol

(C)chloroplastgenome

(D)mitochondrialgenome

CORRECTANSWER:D

SOLUTION:

Mitochondriaareoriginatedfrompre-existing

mitochondri.Thesearesemi-autonomous,living

organellespresentinalleukaryoticcells.Thesecontain

DNA(mtDNA).Theavailableevidencesshowthatthe

geneslocatedinmtDNAcontrolthecytoplasmicmale

sterility.

Q-113-18705189

The linkage map of X-chromosome of fruit fly has 66 units with

yellow body gene Y at one end and bobbed hair B gene at he other

end. The recombination frequency between these two genes Y and

B should be

(B)0.66

(C)0.5

(D)0.055

CORRECTANSWER:B

SOLUTION:

(b)Theactualdistancebetweentwogenesissaidtobe

equivalenttothepercentageofcrossingoverbetween

thesegenesi.e .Crossingoverchancesbetween

yandbgenessuggestthatthesearetobeplacedon

thechromosomeatadistanceof66units.

Q-114-18705362

Edward's syndrome, Patau's syndrome and Down's syndrome are

due to

(A)Mutationduetomalnutrition

(B)Changeinsexchromosomes

(C)Changeinautosomes

(D)Changeinbothsexchromosomesandautosomes

CORRECTANSWER:C

SOLUTION:

Thereisalargescalepossibilityofautosomal

aneuploidyinhumanbeings.

Q-115-18705201

Polytene Chromosomes are formed by

(A)Endoreduplicationofchromosomes

(B)Somanticpairingofhomologolouschromosomes

(C)Somanticpairingofnon-homologouschromosomes

(D)Germinalpairingofnon-homologouschromosomes

CORRECTANSWER:A

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