1.WhichofthefollowingarePyrimidinebases?
a)AdenineandGuanine
b)GuanineandCytosine
c)CytosineandAdenine
d)ThymineandCytosine
CorrectAnswer-D
Ans:(D)CytosineandAdenine
InDNAandRNA,Pyrimidinebasesformhydrogenbondswiththeir
complementarypurines.
withthepyrimidinesthymine(T)andcytosine(C),respectively.
InRNA,thecomplementofadenine(A)isuracil(U)insteadof
thymine(T),sothepairsthatformareadenine:uraciland
guanine:cytosine.
pyrimidines.
1. Purines:TwomajorpurinebasesfoundbothinDNAsaswellas
RNAsare(i)adenine(A)and(ii)guanine(G).
2. Pyrimidines:Threemajorpyrimidinebasesare(i)cytosine(C),(ii)
RNAsandcytosineandthyminearefoundinDNAs.Uracilisnot
foundinDNAsQandthymineisnotfoundinRNAs.
Ref:RodwellV.W.(2011).Chapter32.Nucleotides.InD.A.Bender,
K.M.Botham,P.A.Weil,P.J.Kennelly,R.K.Murray,V.W.Rodwell
2.Majorcontributiontowards
gluconeogenesisisby?
a)Lactate
b)Glyerol
d)Alanine
e)None
CorrectAnswer-D
Di.e.Alanine
3.Whichofthefollowingisnotapyrimidine
base?
a)Cytosine
b)Uracil
c)Guanine
e)Adenine
CorrectAnswer-C
Ans.is'c'i.e.,Guanine
PurinesPyrimidines
GuanineUraciI
Thymine
Bothpurines(adenineandguanine)arefoundbothinDNA&RNA.
Amongpyrimidines-
RNA).
CytosineandthyminearefoundinDNA(uracilisnotfoundinDNA).
InDNA,adenineisalwayspairedwiththyminebytwohydrogen
bonds;andguaninealwayspairedwithcytosinebythreehydrogen
4.Glycogenstoragedisorderis-
a)Niemann?Pickdisease
b)Gaucherdisease
c)Tay-Sacksdisease
e)McArdlesdisease
CorrectAnswer-D
GlycogenstoragediseasetypeII,alsocalledPompedisease,is
anautosomalrecessivemetabolicdisorder[1]whichdamages
accumulationofglycogeninthelysosomeduetodeficiencyofthe
lysosomalacidalpha-glucosidaseenzyme.Itistheonlyglycogen
storagediseasewithadefectinlysosomalmetabolism,andthefirst
glycogenstoragediseasetobeidentified,
glucosidase:alsoknownasacidmaltase)onlongarm
ofchromosome17.
Mostcasesappeartobeduetothreemutations.Atransversion(T
G)mutationisthemostcommonamongadultswiththisdisorder.
Thegeneencodesaprotein--acidalpha-glucosidase(EC3.2.1.20)
--whichisalysosomalhydrolase.Theproteinisanenzymethat
normallydegradesthealpha-1,4andalpha-1,6linkages
inglycogen,maltoseandisomaltoseandisrequiredforthe
enzymeresultsintheaccumulationofstructurallynormalglycogen
inlysosomesandcytoplasminaffectedindividuals.
clinicalfeatures:
Accumulationofglycogeninlysosomes:Juvenileonsetvariant,
variant,muscledystrophy
5.Whichofthefollowingwillbemore
towardsthenegativepoleingel
electrophoresis?
b)50kbp
c)150bp
d)550bp
e)50000bp
Ans.is'b'i.e.,50kbp&'e'i.e.50000bp[RefVariousinternet
sites]
Ingelelectrophoresis,DNAmoleculesmovetowardspositiveendas
theyarenegativelychargedthemselves.
molecules.So,largerthemolecule,itismoretowardsthenegative
endandviseverse.
Polyacrylamidegelsareusuallyusedforproteins,andhavevery
highresolvingpowerforsmallfragmentsofDNA(5-500bp).
DNAbuthavegreaterrangeofseparation,andarethereforeused
forDNAfragmentsofusually50-20,000bpinsize,butresolutionof
over6Mbispossiblewithpulsedfieldgelelectrophoresis(PFGE)"-
wikipedia
6.Betagalactosidasedeficiencycauses?
a)Goucherdisease
b)Krabbe'sdisease
c)Fabry'sdisease
d)NeimannPickdisease
CorrectAnswer-B
Ans.is'b'i.e.,Krabbe'sdisease[RefHarper30th/ep.251&
29thiep.235]
Krabbedisease,alsoknownasgloboidcellleukodystrophyor
sphingolipidosiscausedbydeficientactivityofthelysosomal
hydrolasegalactosylceramidebeta-galactosidase(GALC).
GALCdegradesgalactosylceramide,amajorcomponentofmyelin,
andotherterminalbeta-galactose-containingsphingolipids,including
Beta-galactosidaseisalysosomalenzymeresponsibleforcatalyzing
thehydrolysisofgangliosides.Thedeficiencyofthisenzymecan
leadto1ofthefollowingconditions:GM1gangliosidosis,Morquio
syndromeB,andgalactosialidosis.
7.Trueregardingphenylketoneureais?
a)Mustyorderisduetophenylalanineinsweat
b)Deficientenzymeisphenylalaninehydroxylase
c)Autosomaldominant
d)Maybeassociatedwithimpairedmentaldevelopment
CorrectAnswer-B:D:E
Ans.is'b'i.e.,Deficientenzymeisphenylalanine
hydroxylase,'d'i.e.Maybeassociatedwithimpairedmental
development&'e'i.e.Infantsarenormalatbirth
InPhenylketonuriathereisinabilityofoxidationofphenylalanineinto
tyrosine.Thereisdefectivefunctionofphenylalaninehydroxylase.
Toxiclevelsofphenylalanine(andinsufficientlevelsoftyrosine)can
interferewithinfantdevelopmentinwayswhichhavepermanent
Thediseasemaypresentclinicallywithseizures,hypopigmentation
anda"mustyodor"tothebaby'ssweatandurine(dueto
phenylacetate,acarboxylicacidproducedbytheoxidationof
phenylketone).
progressiveimpairmentofcerebralfunctionwhichcanleadto
intellectualdisability,behavioralproblems,andmentaldisorders.
8.Methodsthatcanbeusedtoseeprotein-
proteininteractioninclude?
b)Fluorescenceresonanceenergytransfer
c)Fluorescencepolarization
d)Fluorescencecomplementation
e)Alloftheabove
Ans.is'e'i.e.,Alloftheabove[Refwiki]
Biochemicalmethods
1. Co-immunoprecipitation
2. Bimolecularfluorescencecomplementation(BiFC)
1. Bio-layerinterferometry
2. Dualpolarisationinterferometry(DPI)
3. Fluorescencepolarization/anisotropy
4. Fluorescenceresonanceenergytransfer(FRET)
9.Uncouplersofoxidativephosphorelation
include?
a)2,4-DNP
b)H2S
d)Thermogenin
e)Carboxin
CorrectAnswer-A:D
Ans.is'a'i.e.,2,4-DNP&'d'i.e.,Thermogenin[RefHarper
ChatterjeaShinde7th/ep.132;LippincottOlep.79]
Uncouplersblockthecouplingofoxidationwithphosphorylation.
Thesecompoundsallowthetransferofreducingequivalentsin
respiratorychainbutpreventthephosphorylationofADPtoATPby
Uncouplersmaybe:?
1. Natural:-Thermogenin,thyroxine,longchainFAs
2. Synthetic:-2,4-dinitrophenol(2,4-DNP),2,4-dinitrocresol(2,4-
DNC),andCCCP.
brownadiposetissue(brownfat).
Ituncouplesoxidationandphosphorylationbyactingasachannel
forH+ionssothathydrogeniongradientcannotbuildup
10.Pyridoxineisrequiredfor?
b)Carboxylation
c)Transamination
d)Transsulfuration
e)Oxidativedeamination
Ans.is'a'i.e.,Decarboxylation,'c'i.e.Transamination&'d'i.e.
Transsulfuration[RefHarper's30m/ep.557&29th/ep.536,
537]
1. Transamination:PLPactsascoenzymefortransaminases.
requirePLP.ThusPLPisinvolvedingenerationofimportant
biogenicamines:GABA,Serotonin,Melatonin,Histamineand
catecholamines(epinephrine,norepinephrine).
Inpyridoxindeficiency,3-hydroxykinurenineaccumulatesandis
Thus,xanthurenicacid(xanthurenate)excretioninurineisincreased
inpyridoxinedeficiency.Thuspyridoxinmaybeusedinxanturenic
aciduria.
11.Aminoacidsderivedfromtissuesare
a)Ammoniaformation
b)Ammoniumsalts
c)Ureacycle
d)Ureaformation
CorrectAnswer-E
Ans.is'e'i.e.,Aminoacidpoolofcells[Ref:Harper30"/ep.
298;NutritionbyPaulInsel,DonRoss,KimberleyMc?Mahon
4th/ep.242]
circulation.Theseavailableaminoacids,foundthroughoutthebody
tissuesandfluids,arecollectivelyreferredtoasaminoacidpool.
Theavailableaminoacidswillbeutilizedforproteinsynthesis.
Othersmayhavetheiraminogroupremovedandbeusedto
12.Co-factorsrequiredforfattyacid
synthesisinhumanare?
a)ATP
b)NADPH
d)Pyridoxine
e)Pentothenicacid
CorrectAnswer-A:B:C
Ans.is'a'i.e.,ATP,'b'i.e.NADPH&'c'i.e.,Biotin[RefHarper
pyridoxalphosphateisneededforelongationofalreadysynthesized
fattyacids,notforsynthesisitself.
Extramitochondrial(cytoplasmic)Systemisconcernedwithdenovo
synthesisoffattyacidfromacetylCoA,andispresentincytosaol.
CofactorrequirementsforfattyacidsynthesisareNADPH,ATP,
Mn+2,biotinandHCO3-(asasourceofCO2).
Themajorproductoffattyacidssynthesisispalmitate.Longerfatty
acidsareformedbyelongationreactionseitherinmicrosomes
13.AllareTruestatementsregardingOkazaki
fragmentEXCEPT?
a)RequiresDNApolymerase
b)Formsonleadingstrand
d)Requireshelicaseforopening
e)RequiresRNAprimer
CorrectAnswer-B
Ans.is'b'i.e.,Formsonleadingstrand[RefLippincott's5thiep.
DNApolymerasesresponsibleforcopyingtheDNAtemplatesare
onlyableto"read"theparentalnucleotidesequencein3'-5'
direction,andtheysynthesizethenewDNAstrandsonlyin5'-3'
direction.Therefore,2newlysynthesizedchainsmustgrowin
TheDNAchainwhichrunsinthe3'to5'directiontowardsreplication
forkascontinuedstrandiscalledleadingstrand.Thisrequiresonly
oneRNAprimer
TheDNAchainwhichrunsinthe5'to3'directionawayfromthe
discontinuouslyandrequiresnumerousRNAprimers.
Asthereplicationforkmoves,RNAprimersaresynthesizedat
specificintervals.TheseRNAprimersareextendedbyDNA
polymeraseIIIintoshortpiecesofDNAcalledOkazaki
14.AllaretrueregardingsatelliteDNA
EXCEPT?
a)RepeatedDNAsequencesintandem
b)Clusteredaroundcentromere
d)Transcriptionallyactive
e)Noneoftheabove
CorrectAnswer-D
Ans.is'd'i.e.,Transcriptionallyactive[RefHarper's30"'/ep.
RepetitivesequencesinDNAisalsocalled(satelliteDNA)
Theseconsistof5-500basepairlengthsrepeatedmanytimes.
Theseareoftenclusteredincentromeres(centralproteinof
chromosomeswheresisterchromatidsjoineachother)and
Themajorityofthesesequencesaretranscriptionally
inactiveandplayastructuralrole
microsatellitesequencesmostcommonlyarefoundasdinucleotide
repeatsofACononestrandandTGontheoppositestrand.
times.TheACrepeatsequencesoccurat50000-100000locationsin
humangenome.
15.Truestatementregardingt-RNAis?
a)Containscodon
c)Containsbluntends
d)Actsasaacceptorforaminoacidsinproteinsynthesis
e)Getsattachedtoribosomes
CorrectAnswer-B:D:E
foraminoacidsinproteinsynthesis&'e'i.e.Getsattachedto
ribosomes
[RepLippincoteselep.418;Harper's30'Vep.394]
tRNAistheSmallestofthethreemajorRNAShaving73to93
Acceptorarmconsistsofabasepairedstemthatterminatesin
thesequenceCCAatthe3'end.Thisistheattachmentsitefor
aminoacids.CCAtailisaddedduringpost-transcriptional
modification.
mRNA.Anticodonhasnucleotidesequencecomplementarytothe
codonofmRNAandisresponsibleforthespecificityofthetRNA.
ThroughTCarmtRNAgetsattachedtoribosome.
16.Examplesofchaperonincludeallexcept?
b)Calnexin
c)Calbindin
d)BiP
e)Ubiquitin
Ans.is'c'i.e.,Calbindin&`e'i.e.Ubiquitin[RefHarper's30th/e
p.609;Vasudevan5thlep.17]
Chaperonesarepresentinawiderangeofspeciesfrombacteriato
humans.Manysocalled'Heatshockproteins'(HSP)are
SomeChaperonesandEnzymesInvolvedinFoldingthatare
LocatedintheRoughEndoplasmicReticulumareBiP
(immunoglobulinheavychainbindingprotein),GRP94(glucose-
regulatedprotein),GRP-170,GRP-78,Calnexin,CalreticulinPDI
isomerase),HSP47,ERp29
17.VitaminEdeficiencyinadultcauses?
a)Hemolysis
b)PosteriorcolumnInvolvement
d)Hairloss
e)Impairedimmunity
CorrectAnswer-A:B:C:D:E
Ans.is'All'i.e.,a,b,c,d&e[Ref:Harper's30th/ep.553&29th/e
vitaminEdeficiencyarecharacterizedbyaxonaldegenerationinthe
posteriorcolumnsandaselectivelossoflargecalibremyelinated
sensoryaxonsinthespinalcordandperipheralnerves.
Subacutecombineddegenerationofspinalcord,alsoknownas
lateralcolumnsofthespinalcordasaresultofvitaminB12
deficiency(mostcommon),vitaminEdeficiency,andcopper
deficiency.
VitaminEactiviyispresentinseveraltocopherols,themost
abundantandistakenasthestandard.
SeleniumandvitaminEsupplementeachotherbytheiranti-oxidant
property.
Hemolyticanemia-duetooxidativedamagetoredblood
Malabsorptionleadingtoliverandpancreaticproblems,Dryskin
andhairloss
18.VitaminCdeficiencyisassociatedwith?
a)Decreasedimmunity
c)Epistaxis
d)Seizures
e)Anemia
CorrectAnswer-A:B:C:E
healing,'c'i.e.,Epistaxis&`e'i.e.,Anemia[RefHarper's30thle
p.561-65;Internet]
GeneralsymptomsincludeLowgradefever,irritability,tachypnea,
digestivedisturbances,lossofappetite,weakness,weightloss,
AnemiaDuetodefectinutilizationofiron&folicacid.
Dermatological:-Dryskin,Follicularhyperkeratosis,coiledhair,
splittingofhair,Poorwoundhealing
Impairedimmunityleadingrecurrentinfections,Irritabilityandother
19.Trueabouttelomeraseis?
a)DNAdependentRNApolymerase
b)RNAdependentDNApolymerase
c)Reversetranscriptaseenzyme
e)Telomeraseincreasesthelongevityofcells
CorrectAnswer-B:C:E
Ans.is'b'i.e.,RNAdependentDNApolymerase,'c'i.e.Reverse
transcriptaseenzyme&`e'i.e.Telomeraseincreasesthe
Robbin's8th/ep.40,296]
Telomeraseisareversetranscriptase(RNAdependentDNA
polymerase)andisresponsiblefortelomeresynthesisand
maintainingthelengthoftelomers(replicationofendof
containthisenzyme.
Telomeraseisabsentfrommostofthesomaticcellsandhencethey
sufferprogressivelossoftelomeresandtheyexitthecellcycle.
Senscentcellslacktelomerasesotheirtelomeresgetshortenedby
20.Whichis/arenottransportprotein?
a)Transferrin
b)Collagen
c)Ceruloplasmin
e)Albumin
CorrectAnswer-B
Ans.is'b'i.e.,Collagen[Ref
http://www.gastrohep.com/ebooks/rodes/Rodes_2_4_1.pdf]
Albuminhascirculatingtransportproteinssuchassteroids,
thyroxine,triiodothyronine,fatsolublehormones,fattyacidstoliver,
unconjugatedbilirubin,manydrugs,Calcium,magnesium,cations&
anions.
HemoglobinOxygenfromlungtotisuues
Transferrinironionsintheferricform(Fe3+).
21.FullformofLCATis?
a)Lecithincholesterolacyltransferase
c)Lecithincholineacetyltransferase
d)Lecithincholinealcoholtransferase
e)LecithincoAtransferase
CorrectAnswer-A
Harper's30`Vep.272;Lippincott6thlep.234]
Lecithin-cholesterolacyltransferase(LCAT)ispresentinHDLand
esterifiesthecholesterolinHDL.MajoractivatorofLCATisApo-Al.
Apo-C1canalsoactivateLCAT.
coronaryarterydisease(inverserelationship)thananyotherknown
riskfactor.ThatmeanslowHDLisamuchstrongerpredictorof
coronaryarterydiseasethanincreasedLDLcholesterolorincreased
totalcholesterol
CoAcholesterolacyltransferase(ACAT).Thisenzymecatalyzes
transferofanacylgroupfromafattyacidderivativetocholesterol,
resultingintheformationofesterifiedcholeserol,andthischolesterol
esterisstoredforsubsequentuse.
22.Whichorgancannotuseketonebodies?
a)Brain
b)RBC
c)Muscle
d)Heart
CorrectAnswer-B:E
Ans.is'b'i.e.,RBC&`e'i.e.,Liver[RefHarper's30th/ep.227;
Vasudevanelep.145]
LiveritselfcannotutilizeketonebodiesasitlackstheenzymeCoA-
Besideliver,RBCsalsodonotutilizeketonebodies(onlyglucoseis
thesolefuelforRBCs).
Acetoacetateandp-hydroxybutyrateareusedinpreferenceto
glucoseasenergysourcebycertaintissues,e.g.heart,muscle,
predominantlyacetoacetateinstarvation.
Inextrahepatictissues,acetoacetateisactivatedtoacetoacetylCoA
bysuccinyl-CoA-acetoacetateCoAtransferase(thiophorase).
23.HGPRTareinvolve,andgoutcanbea
a)HGPRTdeficiency
b)HGPRToveractivity
c)PRPPsynthetasedeficiency
d)Glucose6-phosphatasedeficiency
CorrectAnswer-A:D
Answer.(a)HGPRTdeficiency,(d)Glucose6-phosphatase
deficiency
[Ref:Harper30th/354-56;Satyanarayan4th/269-70,394-951
HyperuricemiaoccursduetoGlucose6-phosphataseenzyme
defect.
HGPRTdeficiency(asseeninLesch-Nyhansyndrome):Increased
productionofpurines
Goutisusuallyprecededandaccompaniedbyhyperurlcemta
(plasmauricacidlevel>0.4Immol/L).
Hlperuricemiaiscausedbydacreasedrenalextretlon,lncreased
productlon"orincreasedintakeoturlcacid
24.Hyperphenylalaninemiaoccursdueto:
a)Phenylalaninehydroxylasedeficiency
b)Phenylalaninehydroxylaseoveractivity
c)Dihydrobiopterinreductasedeficiency
d)Tyrosinehydroxylasedeficiency
CorrectAnswer-A:C:E
Answer:(a)Phenylalaninehydroxylase...,(c)Dihydrobiopterin
reductase...,(e)Defectindihydrobiopterinbiosynthesis
Hyperphenylalaninemiasarisefromdefectsinphenylalanine
dihydrobiopterinreductase(typesIIandIII),orindihydrobiopterin
biosynthesis(typesIVandV).Alternativecatabolitesareexcreted.
PKUiscausedbyadcficiencyotphenylalaninehydroxyl.ase,isthe
mostcommonclinicallvencounteredinbornerrorofamino
Hyperphenylalaninemiamayalsobecausedbydeficienciesinany
oftheseveralenzymesrequiredtosynthesizeBH4,or
indihydropteridinereductase,whichregeneratesBH4fromBH2.
BH4isalsorequiredfortyrosinehydroxylaseandtryptophan
neurotransmitters,suchasserotoninandreversethecentral
nervoussystem(CNS)effectsduetodeficienciesin
neurotransmitters.
25.DuringDNAreplicationwhichbond
a)Phosphodiesterbonds
b)Phosphatebond
c)Hydrogenbond
d)Glycosidicbonds
CorrectAnswer-C
Answer:c.Hydrogenbond[Ref:Lippincott6th/397-400;Harper
30th/381-86;Satyanarayana4th/524-29]
WhenDNAreplicates,ahelicaseenzyme"unzips"thedoublehelix,
Thetwostrandsofthedoublehelixseparatewhenhydrogenbonds
betweenthepairedbasesaredisrupted.Disruptioncanoccurinthe
laboratoryifthepHoftheDNAsolutionisalteredsothatthe
nucleotidebasesionize,orifthesolutionisheated.
26.Oxidativephoephoryletlonnotinhiblted
by:
a)Fluoride
b)2,4-dinitrophenol(DNP)
c)Oligomycin
e)Ouabin
CorrectAnswer-A:D:E
Answer:(a)Fluoride,(d)Carboxin,(e)Ouabin(Ref:Harper
30th/132-33;Lippincott6th/79;Satyanarayan4th/233-34;
TherearethreesitesinrespiratorychainwhereATPisformedby
oxidativephosphorylation.Threesitesare-Sitel(Complex-I),Site
Il(ComplexIII)andSiteIll(ComplexIV).Complexll(Succinate
dehyfuogenaseFAD)isnotinvolvedinoxidativephosphorylation.
phenylhydrazone,Pentachlorophenol
Aspirin(inhighdose),Highconcentrationofthermogenin,thyroxine
andlongchainfreefattyacids,Antibiotics-valinomycin,gramicidinA
andnigercinareinhibitoresofoxidativephosphorylation
phosphorylation(sonotincludedinanswer)"?Chatterjea7h/134
"OuabainisacardiacglycosidethatactsbyinhibitingtheNW/IC-
ATPasesodium-potassiumionpump"-Harper30th/491
Fluoride:Itinhibitstheactivitiesofcertainenzymes.Sodium
aconitase(ofcitricacidcycle)"-Satyanarayan4th/420.
27.TrueaboutApolipoproteii.
a)Constituteperipheralregionofplasmalipoproteins
b)DividedintoA,B,Conly
lipoprotein(HDL)
d)ApoA,BandCarefurtherdivided
e)Roleinenzymeactivation
CorrectAnswer-A:C:D:E
majorprotein...,(d)ApoA,BandCare...,(e)Roleinenzyme...
[Ref:Harper30th/254-55;Satyanarayan4th/318;
http://noprniscairres.in/bitstream;onlinelibrary.wiley.com]
Apolipoproteins(apo)playveryimportantrolesinthesynthesisand
activatorsofcertainenzymesassociatedwithlipidandlipoprotein
metabolism
Apolipoproteinsaretheproteincomponentofplasma
lipoproteinswhichconsistofacoreoftriglyceridesandcholesterol
protein.
ApoA-Iisthemajorproteincomponentofhighdensity
lipoprotein(HDL)andaminorcomponentofchylomicronsandvery
lowdensitylipoprotein(VLDL).
majorclasses,AthroughE,withmostclasseshaving
subclasses,forexample,apolipoprotein(orapo)A-IandapoC-
II.
28.whichnNAcontalneabnormalpurineand
a)tRNA
b)23SrRNA
c)16SrRNA
d)5SrRNA
CorrectAnswer-A
Answer:a.tRNA
tRNAmoleculecontainahighpercentageofunusalbases,for
example,dihydrouracilandhaveextensiveintra-chainbasepairing
Lippincott6th/418.
ThetRNAmoleculescontainahighpercentageofunusualbases
(forexample,dihydrouracil)andhaveextensiveintrachainbase-
pairingthatleadstocharacteristicsecondaryandtertiarystructure.
"unusual"bases.Anunusualbaseisanypurineorpyrimidinering
excepttheusualA,G,C,andUfromwhichallRNAsare
29.Aminoacidscontaininghydroxylgroup:
a)Threonine
c)Serine
d)Tryptophan
e)Valine
CorrectAnswer-A:B:C
Serine,threonine,andtyrosineeachcontainapolarhydroxyl
groupthatcanparticipateinhydrogenbondformation.
Thesidechainsofasparagineandglutamineeachcontainacarbon
ylgroupandanamidegroup,bothofwhichcanalsoparticipatein
30.CytochromeP45Ois/areinvolvedln:
a)Hydroxylationofxenobiotics
b)Methylationofxenobiotics
c)Deaminationreaction
e)Druginteraction
CorrectAnswer-A:C:D:E
Ans.(a)Hydroxylationofxenobiotics,(c)Deaminationreaction,
(d)Involvedinhydroxylationofsteroids,(e)Druginteraction
Satyanarayan4th/639-40]
CytochromeP450sareinvolvedinphaseI(hydroxulation)ofthe
metabolismofxenobiotics,notinphaseII.Methylationof
xenobioticsoccurinphaseIIbymethyltransferase
31.Componentof50Sribosomalzubunit:
a)16SRNA
b)18SRNA
c)5.8RNA
d)5SRNA
CorrectAnswer-D:E
Answerd.5SRNA,(e)23SRNA(Lippincott6th/436):
The50Ssubunitisprimarilycomposedofproteinsbutalsocontains
single-strandedRNAknownasribosomalRNA(rRNA).rRNAforms
outthecatalyticfunctionsoftheribosome.
Itincludesthe5SribosomalRNAand23SribosomalRNA.
50Sincludestheactivitythatcatalyzespeptidebondformation
(peptidyltransferreaction),preventsprematurepolypeptide
initiation,elongation,andtermination),andhelpsproteinfoldingafter
synthesis.
32.Trueaboutroleofphospholipids:
a)Celltocellrecognition
c)PrecursorofSecondMessengers
d)Mediatorsofinflammation
e)Regulatemembranepermeability
CorrectAnswer-B:C:D:E
Messengers,(d)Mediatorsofinflammation,(e)Regulate
membranepermeability
(Ref:Harper30th/212,216,253-54;Robbins9th/83-84;
Satyanarayan4th/36-37)
recognitionandadhesion.
Theinositolispresentinphosphatidylinositolasthestereoisomer,
myoinositol.Phosphorylated
phosphatidylinositols(phosphoinositides)areminorcomponentsof
membranetrafficking.
Sphingomyelinsarealsofoundinlargequantitiesinthemyelin
sheaththatsurroundsnervefibers.Theyarebelievedtoplaya
roleincellsignalingandinapoptosis.
inositoltriphosphateanddiacylglyceol,thatareinvovedthe
actionofsomehoromones.
33.Correctstatementaboutmembrane:
a)Phospholipidsundergorapidlateraldiffusion
thanprotein
c)Hydrophobiccoreofthephospholipidbilayerremainsconstantly
inmotionbecauseofrotationsaroundthebondsoflipidtails
d)Phospholipdsthathaveonefattyacylgroup,cannotformthe
e)Phospholipidsspanwholebilayer
CorrectAnswer-A:C:D
Ans.a)Phospholipidsundergo...,(c)Hydrophobiccoreofthe
phospholipid...,(d)Phospholipdsthathaveonefattyacyl...
en.wikibooks.org]
Membranesaremainlymadeupoflipids,proteinsandsmallamount
ofcarbohydrate.Phospholipidsarethemostcommonlipidspresent
andtheyareamphipathicinnature.
motionbecauseofrotationsaroundthebondsoflipidtails.
Hydrophobictailsofabilayerbendandlocktogether.However,
becauseofhydrogenbondingwithwater,thehydrophilichead
groupsexhibitlessmovementastheirrotationandmobilityare
closertothehydrophilicheads.
Thelysophosphollpi.dshaveonlyonefattyacylgroup,itcannotform
thebilayerasthepolarheadsaretoolarge,similarlycholesterolalso
cannotformbilayersastherigidfitsedringsystenxsandadditional
nonpolartailsaretoolarge".
34.TrueaboutChromatin,remodeling:
a)EnergyisrequiredtodisplacethehistoneoctamersfromDNA
ortranslocatethemontoneighboringDNAsegments
b)Histonemodificationsbyspecificenzyme
d)Aberrationsinchromatinremodelingproteinsmaybe
associatedwithcancer
e)None
CorrectAnswer-A:B:D
Histonemodificationsby...,(d)Aberrationsinchromatin...
[Ref:Harper30th/735,438-39;Lippincott6th/422,460;Harrison
19th/102e-7]
Chromatinremodelingisthedynamicmodificationof
DNAtotheregulatorytranscriptionmachineryproteins,and
therebycontrolgeneexpression.
chromatinremodelingcomplexesdisplacethehistone
octamersfromDNAortranslocatethemontoneighboringDNA
sequencespecificregulatoryfactors.
histoneacetylaseandotherenzymaticactivitiesareassociated
withthecoregulatorsinvolvedinregulationofgene
transcription.
associatedwithhumandiseases,includingcancer.
35.Bestassessmentofproteinbinding
regionsonaDNAmoleculecanbedone
by:
b)RTPCR
c)Microarray
d)Westernblotting
e)Northernblotting
Answer-(a)DNAfootprinting[Ref:www.biotecharticles.com;
www.biologyexams4u.comLippincott6th/473]
DNAfootprinting-Anin-vitrotechniquetofindoutprotein
bindingregionsonaDNAmolecule.Thetechniqueisalso
(enzymes)areinteractingwithDNAinthenucleusfor
regulatingactivitieslikereplication,transcription,translation
etc.
DNAFootprintingisamoleculartechniqueusedtoidentifythe
Thistechniquemainlyusedtoidentifythetranscriptionfactors
whichbindtopromoter,enhancerorsilencerregionofgeneto
regulateitsexpression.Thereforetheregulationoftranscript
ionofagenecanbestudiedusingthismethod.
36.Nucleosomecontains:
a)DNA
b)RNA
c)Chromatin
d)Histone
CorrectAnswer-A:D
Ans:a.DNAd.Histone[RefHarper30th/371-72;Lippincott6th/
409]
Histonesarehighlyalkalineproteinsfoundineukaryoticcellnuclei
nucleosomes.
Theyarethechiefproteincomponentsofchromatin,actingas
spoolsaroundwhichDNAwinds,andplayingaroleingene
regulation.
appropriateionicconditions,thesamex-raydiffractionpatternis
formedasthatobservedinfreshlyisolatedchromatin.Biochemical
andelectronmicroscopicstudiesconfirmtheexistenceof
reconstitutednucleosomes.
overthesurfaceofthedisk-shapedhistoneoctamer
37.EnzymeusedinDNArepairis/are:
a)DNAgyrase
b)DNApolymerase
d)DNAligase
e)None
CorrectAnswer-B:D
Ans:b.DNApoly...,d.DNA(RefHarper30th/382,389-92;
Whenthestrandcontainingthemismatchisidentified,an
endonucleasenicksthestrandandthemismatchednucleotide(s)
is/areremovedbyanexonuclease.
Additionalnucleotidesatthe5'-and3'-endsofthemismatchare
usingthesisterstrandasatemplate,byaDNApolymerase.
The3'-hydroxylofthenewlysynthesizedDNAisjoinedtothe5'-
phosphateoftheremainingstretchoftheoriginalDNAstrandby
DNAligase
38.AllareUreacycleenzymesexcept:
a)Ornithinetranscarbamylase
b)Carbamoyl-phosphatesynthetaseI
c)Argininosuccinase
e)Argininosuccinicacidsynthetase
CorrectAnswer-D
Answer:(D)Citrullinesynthase[RefHarper30th/290-96,
29th/274-88;Lippincott
39.PhospholipaseA2acton:
a)Phosphoglycericacid
b)Phosphate
c)Ca+
d)Phosphatidyl-inositol
CorrectAnswer-D
Ans:d.Phosphatidyl-inositol
Phospholipaseshydrolyzethephosphodiesterbondsof
phosphoglycerides,witheachenzymecleavingthephospholipidata
Phospholipasesreleasemoleculesthatcanserveasmessengers
(forexample,DAGandIP3),orthatarethesubstratesforsynthesis
ofmessengers(forexample,arachidonicacid.
Phospholipasesareresponsiblenotonlyfordegrading
phospholipasesAlandA2removespecificfattyacidsfrom
membrane-boundphospholipids;thesecanbereplacedwith
alternativefattyacidsusingfattyacylCoAtransferase.
40.Non-polaraminoacidsare:
b)Lysine
c)Isoleucine
d)Arginine
e)Asparginine
Ans:a.Prolinec.Isoleucine[RefHarper30th/16-22;Lippincott
6th/1-9;Satyanarayan4th/48]
AcidicandPolarsidechainsAsparticAcidGlutamicAcid
BasicandPolarsidechainsArginine,Lysine,Histidine
Threonine,Tyrosine
NonPolarAminoAcidswithNonPolarsidechainsGlycine,
Alanine,Valine,Leucine,Isoleucine,Proline.
41.Trueaboutsqualene:
b)Itisoneofthemajorcarbohydratesofbody
c)Itinvolvesinthesynthesisofcholesterol
d)Itinvolvesinthesynthesisofsteroids
e)None
Ans:(C)Itinvolvesinsynthesisofcholesterol,(D)Itinvolvesin
synthesisofsteroids
Squaleneisahydrocarbonandatriterpene,andisanaturaland
vitalpartofthesynthesisofallplantandanimalsterols,including
Squaleneisusedincosmetics,andmorerecentlyasan
immunologicadjuvantinvaccines.
Itisanatural30-carbonorganiccompoundoriginallyobtainedfor
commercialpurposesprimarilyfromsharkliveroil(henceitsname),
well,includingamaranthseed,ricebran,wheatgerm,andolives.
Squaleneandomega2fattyacidhasunlikeomega3fishoilsmore
completeandeffectivechemicalgroups.
42.Molecularweightofproteincanbe
a)SDS-PAGE
b)Gelfiltrationchromatography
c)Agarosegelelectrophoresis
d)Ultracentrifugation
CorrectAnswer-A:B:D
Ans:(A)SDS-PAGE(B)Gelfiltrationchromatography(D)
Ultracentrifugation[RefHarper30th/28;Shinde7th/772-74;
Satyanarayan4th/725,60;Vasudevan5th/482-851
ofproteins"(Vasudevan5th/482)
"SDS-PAGEisapopulartechniquefordeterminationofmolecular
weightofproteins"(Satyanarayan4th/725)
"Sodiumdodecylsulfate-polyacrylamidegelelectrophoresis(SDS-
weight(MW)ofanunknownprotein".
"Thegelfiltrationchromatographytechniqueisusedfor"Separation
ofproteinmolecules,purificationofproteins&molecularweight
determinations"Ultracentrifugationisanindispensabletoolforthe
addition,thistechniqueisalsoemployedindeterminationof
molecularweightofmacromolecules\
43.GelusedinRNAelectrophoresis:
a)Agarosegel
c)PolyacrylamideSDS(Sodiumdodecylsulphate)impregnated
Polyacrylamidegel
d)A&C
e)None
Ans:a.Agarosegel
SeparationofRNAinagarosegelsisusedforanumberofdifferent
purposes,includingNorthernblotstomonitorRNAexpression
levels,checkingRNAintegrityandsizeselectionofRNAforcloning
SeparationofRNAbasedonfragmentlengthrequiresconditions
thataredifferentfromDNAanalysis.
ThemostfrequentlyuseddenaturantsforRNAagarosegel
electrophoresisareformaldehyde,formaldehyde/formamide,and
ThemostefficientRNAdenaturantismethylmercuryhydroxide.
Becauseofthehazardsassociatedwiththisdenaturant,itisthe
leastusedsystemforRNA
44.Whichoffollowingreleases/provide
a)ConversionofADPtoATP
b)Breakingofhighenergybondtolowenergybond
c)Conversionofpyruvatetolactate
d)Electricalgradientacrossinner&outersideofmitochondria]
e)Passageofe-throughFADinelectrontransportchain
CorrectAnswer-B:D:E
Ans:(B)Breakingofhigh...(D)Electricalgradientacross...(E)
Passageofe-throughFAD....
producingATP).Inanaerobicglycolysis,pyruvateactsasa
temporaryH-store.
Itdehydrogenation(oxidizes),thereducedNADH+H+backto
oxidizedNAD+,sothatglycolysiscancontinueevenintheabsence
again.
ElectrontransportiscoupledtothephosphorylationofADPbythe
transport("pumping")ofprotons(H+)acrosstheinnermitochondrial
membranefromthematrixtotheintermembranespaceat
Thisprocesscreatesanelectricalgradient(withmorepositive
chargesontheoutsideofthemembranethanontheinside)anda
pHgradient(theoutsideofthemembraneisatalowerpHthanthe
inside).
Theenergygeneratedbythisprotongradientissufficienttodrive
ATPsynthesis.Thus,theprotongradientservesasthecommon
intermediatethatcouplesoxidationtophosphorylation.
45.Restrictionendonucleasecleaves:
a)dsDNA
c)Histone
d)Protein
e)ssDNA
CorrectAnswer-A
Restrictionendonucleases(restrictionenzymes),which
cleavedouble-stranded(ds)DNAintosmaller,moremanageable
fragments,hasopenedthewayforDNAanalysis"
Restrictionenzyme(REorRestrictionEndonuclease)isanenzyme
knownasrestrictionsitesQ
ThecutDNAfragmentsbyREmayhavestickyends(cohesive
ends)?orbluntsends?dependingonthemechanismusedby
enzyme
recombinantDNAexperiments(hybridorchimericDNAmolecules)
Restrictionenzymeisnamedaccordingtotheorganismfromwhich
itwasisolated
46.Trueaboutgeneticcode:
b)Itistotalnumberofchromosomeinthebody
c)Itisnucleotidesequencewhichcodesforaminoacids
d)ItcodesforDNA
e)None
Ans:c.Itisnucleotidesequencewhichcodesforaminoacids
MendelianGeneticsiswidelyregardedasthecornerstoneof
classicalgenetics.Itisasetofprimarybeliefsrelatingtothe
transmissionofhereditarycharacteristicsfromparentorganismsto
Thegeneticcodeisadictionarythatidentifiesthecorrespondence
betweenasequenceofnucleotidebasesandasequenceofamino
acids.
TheNucleotideSequenceofanmRNAMoleculeConsistsofa
EncodedProtein
47.Whichofthefollowingisfeature(s)of
diabeticketoacidosis:
a)Decreasedtriglyceridelevel
c)TLipoprotein
d)Decreasedketonebodies
e)HighAniongapacidosis
CorrectAnswer-B:C:E
Aniongapacidosis[RefHarper30th/231;Lippincott6th/339,
345;Satyanarayan4th/481,682;Harrison19th/2417-18]
DKAischaracterizedbyhyperglycemia,ketosis,andmetabolic
acidosis(increasedaniongap)alongwithanumberofsecondary
hyperlipoproteinemiaarecommonlyfoundaswell
Increasedlacticacidproductionalsocontributestotheacidosis.The
increasedfreefattyacidsincreasetriglycerideandVLDLproduction.
VLDLclearanceisalsoreducedbecausetheactivityofinsulin-
Hypertriglyceridemiamaybesevereenoughtocausepancreatitis.
Reducedinsulinlevels,incombinationwithelevationsin
catecholaminesandgrowthhormone,increaselipolysisandthe
releaseoffreefattyacids.Normally,thesefreefattyacidsare
theliver.
48.Secondmessengeris/are:
a)Ca2+
b)DNA
d)cDNA
e)None
CorrectAnswer-A
Ans:a.Ca2+[RefHarper30th/501,91-92,179,343;Lippincott
Nucleotides,suchascyclicadenosinemono-phosphate(cAMP)and
cyclicguanosinemonophosphate(cGMP),serveassecond
messengersinsignaltransductionpathways.
Twoofthemostwidelyrecognizedsecondmessengersystemsare
system,whichisparticularlyimportantinregulatingthepathwaysof
intermediarymetabolism.
49.Nucleicacidamplificationtechniquesare:
a)PCR
c)DNACloning
d)NextgenerationDNAsequencing
e)None
CorrectAnswer-A:B
9th/180;Lippincott6th/479;Harrison19th/150e-7;http://link.
springer.corn]
Real-timePCRautomatesthelaboriousprocessofamplificationby
quantitatingreactionproductsforeachsampleinevery
Thereareseveralmethodsforamplification(copying)ofsmall
numbersofmoleculesofnucleicacidtoreadilydetectablelevels.
TheseNAATsincludePCR,LCR,stranddisplacementamplification,
andself-sustainingsequencereplication.
completeor(inreal-timedetection)asamplificationproceeds.The
sensitivityofNAATsisfargreaterthanthatoftraditionalassay
methodssuchasculture.
50.Whichofthefollowingis/aretrueabout
a)Absoluteconcentrationofacid&salt
b)Relativeconcentrationofacid&saltinsolution
c)IncreaseoftemperatureincreasespH
d)AriseinH+concentrationdecreasespH
CorrectAnswer-B:D
Ans:(B)Relativeconcentration...,(D)AriseinH*concentra
tion....
"WhenpHmeasuredatroomtemperaturethereisnodirect
AriseinH+concentrationdecreasespHwhileafallinH+
concentrationincreasespH.ThereverseistrueforOH-
concentration
Theratioofsalttoacidconcentration-Actualconcentrationsofsalta
pH,solongastheratiooftheconcentrationsremainsthesame
51.Truestatement(s)aboutMagnetic-
activatedcellsorting:
a)Itisamethodtoseparatespecificcellfromcomplexmixture
c)Antibody-coatedmagneticnanoparticlesareused
d)Antibodiesusedarespecificforcertaincellsurfacemarkers
e)Magneticfieldisapplied
CorrectAnswer-A:C:D:E
Antibodiesusedare...,(E)Magneticfieldisappli...
MACS,isaproceduredevelopedbyMiltenyiBiotectoseparatecells
fromcomplexmixturesusingantibody-coatedmagneticnano
particles.
expressedonyourpopulationofinterest(positiveselection),or
expressedonundesiredcelltypes(negativeselection).
Afteraddingtheantibody-coatedbeadstothecellmixtureand
incubating,thesuspensionisaddedtoaspecialsingle-use
whileunlabeledcellsflowthrough.
52.Whichofthefollowingis/aretrueabout
Translation:
a)N-formylmethionineisfirstaminoacidinprokaryotes
c)ElongationfactorEF-1&EF-2usedinprokaryotes
d)ElongationfactorPisusedineukaryoticorganism
e)Threeinitiationfactorsarerequiredinprokaryotes
CorrectAnswer-A:E
30th/419-23;Lippincott6th/438-42;Satyanarayan4th/554-60]
Ineukaryotes,thefirstaminoacidincorporatedismethionine(AUG
codon).Butinprokaryotes,thesamecodonattractsN-formyl
methionine,whichisthefirstaminoacid"(Vasudevan5th/432)
factorrequiredforefficientpeptidebondsynthesison70S
ribosomesfromfMet-tRNAfMet.Itprobablyfunctionsindirectlyby
alteringtheaffinityoftheribosomeforaminoacyl-tRNA,thus
increasingtheirreactivityasacceptorsforpeptidylStepsinProtein
Inprokaryotes,threeinitiationfactorsareknown(IF-1,IF-2,andIF-
3),whereasineukaryotes,thereareoverten(designatedeIFto
indicateeukaryoticorigin).EukaryotesalsorequireATPforinitiation.
53.TwostrandsofDNAis/areheldby:
b)Hydrogenbond
c)Covalentbond
d)Ionicbond
e)Vanderwaalforce
Answer(b)hydrogenbond[RefHarper30th/359;Lippincott
6th/396-97;Satyanarayan4th/75]
Thetwostrandsareheldtogetherbyhydrogenbondformed
bycomplementarybasepairs"(Satyanarayan4th/75)
AandTandthreebetweenGandC.Thesehydrogenbonds,plus
thehydrophobicinteractionsbetweenthestackedbases,stabilize
thestructureofthedoublehelix.
54.Silverstainingisdonefor:
b)RNA
c)Karyotypinganalysis
d)Protein
e)Collagen
Answer-(A)DNA(B)RNA(C)Karyotypinganalysis(D)Protein
(E)Collagen
Silverstainingisahighlysensitivemethodfordetectingproteinsand
nucleicacids(dsDNA&RNA)inpolyacrylamideslabgels.
ofatargetinmicroscopyofhistologicalsections;intemperature
gradientgelelectrophoresis;andinpolyacrylamidegels.
Silverstainingisthemostsensitivemethodforpermanentstaining
ofproteinsornucleicacidsinpolyacrylamidegels.
targetsofinterest,namelyintracellularandextracellularcellular
componentssuchasDNAandproteins,suchastypeIIIcollagen
andreticulinfibresbythedepositionofmetallicsilverparticlesonthe
targetsofinterest.
55.PolymeraseIIIsynthesizes:
a)Fragment28SofrRNA
b)Fragment23SofrRNA
c)Fragment5SofrRNA
d)tRNA
CorrectAnswer-C:D
Ans:c.andd[RefHarper30th/395-98;Lippincott428]
"RNApolymeraseIIIsynthesizestRNA,5SrRNA,andsomesnRNA
andsnoRNA"(Lippincott428)
56.Non-codingRNAis/are:
a)miRNA
b)SiRNA
c)tRNA
d)mRNA
CorrectAnswer-A:B:C:E
Ans:a.miRN...,b.SiRNA...,c.tRNA...,e.rRNA...,[RefHarper
30th/394-95,368;en.wikipedia.org;Lippincott6th/417]
AlleukaryoticcellshavetwomajorclassesofRNA,theprotein
abundantnon-proteincodingRNAsdelineatedonthebasisofsize:
thelargeribosomalRNAs(rRNA)andlongnoncodingRNAs
(lncRNAs)andsmallnoncodingRNAstransferRNAs(tRNA),the
smallnuclearRNAs(snRNAs)andthemicroandsilencingRNAs
ThemRNAs,rRNAsandtRNAsaredirectlyinvolvedinprotein
synthesiswhiletheotherRNAsareparticipateineithermRNA
splicing(SnRNAs)ormodulationofgeneexpressionbyaltering
mRNAfunction(mi/SiRNAs)and/orexpression(lncRNAs).These
57.Trueaboutsuccinatedehydrogenase
defect-
a)DeficiencyofcomplexII
b)Tumorigenesis
d)DefectinETC
e)Mitochondrialencephalopathy
CorrectAnswer-A:B:C:D:E
ANSWER-(A)DeficiencyofcomplexII(B)Tumorigenesis
encephalopathy
Mitochondrialsuccinatedehydrogenase(SDH)catalysesthe
oxidationofsuccinatetofumarateintheKrebscycle(citricacid
cycle).
SDH-A;(ii)SDH-B;(iii)SDH-C;and(iv)SDH-D.
Functionsofsuccinatedehydrogenaseare:?
1. CatalysesoxidationofsuccinateorfumarateinTCAcycle/citric
acidcycle.
II)SuccinatedehydrogenaseactsascomplexIIinETC.
DefectinSDHcausesdefectinmitochondrialETC.Whichleadsto
mitochondria!encephalopathyandmyopathy
(encephalomyopathy)ThisisduetomutationinSDHAsubunit
MutationinSDH-B,-Cand-Dsubunitscausestumorformation,
especiallyparaganglioma/pheochromocytoma/carotidbodytumor
Thus,thesesubunitsareregardedasatumorsuppressorgene.
58.Allaretrueaboutglycosaminoglycans
a)Proteinassociatedwithglycosaminoglycansiscalledcore
proteins
b)Maybeassociatedwithconnectivetissues
c)Highlypositivelycharged
e)ComponentofECM
CorrectAnswer-C
Ans.is'c'i.e.,Highlypositivelycharged[RefHarper30"/ep.
786]
attached.Proteoglycansconsistsof95%ofcarbohydratesand5%
ofprotein.Toknowthestructureofproteoglycans,oneshouldknow
thestructureofglycosaminoglycans.
Glycosaminoglycansareheteropolysaccharide
moredifferentmonosaccharideunitortheirderivatives).
Glycosaminoglycansarelinear(unbranched)polysaccharides,with
repeatingdiasaccharideunits.Eachdisaccharideunitconsistsofan
aminosugarandanacidsugar(sugaracid).
arealsocalledmucopolysaccharides.
Theyarenegativelycharged.
59.Mechanismsforregulatingenzyme
activityareALLEXCEPT
b)Allostericactivation
c)Competitiveinhibition
d)Inductionofgenesforenzymesynthesis
e)Repressionofgeneforinhibitionofenzymesynthesis
Ans.is(c)Competitiveinhibition[Ref:Harper319`Vep.89-
94;Lippincott6"/ep.62-64;Vasudevan5thiep.42-50;Shinde
Asthenamesuggests,thereiscompetitionbetweeninhibitorand
normalsubstrateforthecatalyticbindingsiteoftheenzyme.Thisis
structuralconfiguration.Therefore,enzymecannotdifferentiate
thesetwoandbothcanbindtotheenzyme.BothESandEI
complexesareformed.ButonlyEScanformproduct.
60.Truestatementare-
b)Linoleicacidisessentialfattyacid
c)Hydrogenationconvertsunsaturatedfattyacidtosaturated
fattyacid
d)Rancidityoffoodisduetolipidperoxidation
CorrectAnswer-B:C:D
Ans.is"B"i.e.,Linoleicacidisessentialfattyacid;"C"
Hydrogenationconvertsunsaturatedfattyacidtosaturated
fattyacid;'d'i.e.,Rancidityoffoodisduetolipid
Thethreepolyunsaturatedfattyacids(PUFAs),namely,linoleicacid
linolenicacidandarachidonicacidarecalledessentialfattyacids.
theyarecalledessentialfattyacidsbecausehumanbeingsrequire
thesefattyacidsbutcannotsynthesizethem.
hydrogenation.Itreducesthenumberofdoublebondsin
unsaturatedfats,Ashydrogenationreducesnumberofdouble
bonds,unsaturatedfattyacidsmaygetconvertedtosaturatedfatty
acid,ifalldoublebondsarereduced.
aging,isreferredtoas"rancidity".Ranciditymaybedueto
hydrolysis(bylipase)oroxidationoffat.
61.Truestatement(s)aboutlipiddigestion
andabsorption-
b)Absorptionoflong-chainfattyacidsisgreatestintheupper
partsofthesmallintestine
c)Bileacidhasnoroleinfatabsorption
d)Fattyacidsafterabsorptionarereesterifiedtotriglycerides
e)Gastriclipaseisthemajorenzyme
CorrectAnswer-A:B:D
Ans.is'a'i.e.,Micellesplayanimportantroleinlipids
absorption;'b'i.e.,Absorptionoflong-chainfattyacidsis
acidsafterabsorptionarereesterifiedtotriglyceridesinthe
enterocytes[RefGanong251h/ep.481-83;Harper..30thlep.
253-54;Guyton12thIep.421-23;Lippincott6th/ep.1761.
Micellesformationistheprocessinwhichdigestedfats(FFAsand
(micelles)sothattheycanbeabsorbedmoreefficiently.Thus,
micellesformationhelpsinabsorptionofdigestedfats.
Fatdigestionessentiallybeginsintheduodenumwithentryof
pancreaticandbiliarysecretions.Pancreaticjuicecontainslipase
pancreaticlipasedigeststriglycerides(triacylglycerols)intofreefatty
acidsand2-monoglycerides(2-monoacylglycerols).
Afterfatdigestion,fattyacidsandmonoglyceridesareabsorbedin
thesmallintestine,especiallyinthejejunumandsomeamountalso
againformtriglycerides.
62.Gluconeogenesisisfavouredinfasting
stateby-
a)ActivationofpyruvatecarboxylasebyacetylCoA
byactivationofpyruvatekinase
c)Increasedfattyacidoxidationinliver
d)Hydrolysisoffructosel,6-bisphosphatebyfructosel,6-
bisphosphatase
CorrectAnswer-A:C:D
Ans.is'a'i.e.,Activationofpyruvatecarboxylasebyacetyl
CoA;'c'i.e.,Increasedfattyacidoxidationinliver;'d'i.e.,
Hydrolysisoffructose1,6-bisphosphatebyfructose1,6-
[Ref:Satyanarayan4thiep.258-63;Harper30thiep.188;
Lippincott6fVep.117-123;Shinde7m/ep.347]
Theactivationofpyruvatecarboxylaseandreciprocalinhibitionof
PDHcomplexbyacetyl-CoAderivedfromtheoxidationoffattyacids
pyruvateandinstimulatinggluconeogenesis.
Thereciprocalrelationshipbetweenthesetwoenzymesaltersthe
metabolicfateofpyruvateasthetissuechangesfromcarbohydrate
oxidation(glycolysis)togluconeogenesisduringthetransitionfrom
Fructose-2-6-bisphosphateisformedbyphosphorylationoffructose-
6-phosphatebyphosphofructokinase-2.Thisenzymeisa
bifunctionalenzymethatalsohasfructose-2,6-bisphosphatase
activitywhichisresponsibleforbreakdownoffructose-2,6-
Thisbifunctionalenzymeisunderallostericcontroloffructose-6
phosphatewhichstimulatesphosphofructokinase-2activityand
inhibitsfructose-2,6-bisphosphataseactivity.
63.AIIaretrueaboutHexose
a)ProduceNADPHinoxidativephaseofpathway
b)DoesnotproduceATP
c)Occursintestes,ovaries,placentaandadrenalcortex
d)Producesribose5-phosphateinoxidativephaseofpathway
CorrectAnswer-D
Ansis.'d'i.e.,Producesribose5-phosphateinoxidativephase
ofpathway[RefHarper30thiep.196-200;Lippincottelep.145;
Satyanarayan4thIep.270-71]
6-phosphategiveriseto3moleculesofCO,and3moleculesof5-
carbonsugars(ribulose-5-phosphate).
Thelatterarerearrangedtogenerate2moleculesofglucose-6-
phosphate(throughfructose-6-phosphate)and1molecule
HMPshuntoccursinthecytosol.Itishighlyactiveinliver,adipose
tissue,adrenalcortex,lens,cornea,lactating(butnotthe
nonlactating)mammarygland,Gonads(testis,ovary)and
erythrocytes.Activityofthispathwayisminimalinmuscleandbrain,
64.Post-translationmodificationofprotein
includesallexcept:
a)Removalofpeptide
b)5'capping
d)Proteinfolding
e)Covalentmodification
CorrectAnswer-B:C
Ans.isB.,5'capping&`ci.e.,intronsplicing[Ref;
4p.443-441
5'cappingandintronsplicingarepost-transcriptionalmodification
(notpost-translationalmodification.
Thisisthefirstprocessingreaction.5'-endofmRNAiscappedwith
Thiscaphelpsininitiationoftranslation(proteinsynthesis)and
stabilizesthestructureofmRNAbyprotectingfrom5'-exonuclease
Removalofintrons(splicing):?Eukaryoticgenescontainsome
codingsequenceswhichcodeforproteinandsomeinterveningnon-
65.Whichofthefollowingisnottrueabout
transcription
a)SynthesisofprecursorsforthelargeandsmallribosomalRNAs
b)FormationoftRNAtranscript
precursorsforthelargeribosomalRNAs
d)RNApolymeraseIisresponsibleforthesynthesissmall
ribosomalRNAs
e)BindingofRNApolymeraseonDNA
Ans.is'c'i.e.,RNApolymeraseIIisresponsibleforthe
synthesisofprecursorsforthelargeribosomalRNAs;&'d'i.e.,
RNApolymeraseIisresponsibleforthesynthesissmall
ribosomalRNAs.
RNA,eukaryoteshavethreedifferentRNApolymerases:I,II,II
RNApolymeraseI:Itcatalyzesthesynthesisoflargeribosomal
RNA(rRNA),i.e.28SrRNA,18SrRNAand5.8SrRNA.
TheserRNAsarecodedonclass-Igene,i.e.classIgeneis
RNApolymeraseII:?ItcatalyzesthesynthesisofmRNA,small
nuclearRNA(sn-RNA)andmiRNA.Theseproductsarecodedby
classIIgene,i.e.classIIgeneistranscribedbymRNA.ClassII
genedifferfromclassIandIIIinthatoneofitstranscribedproducts
RNApolymeraseIII:?ItcatalyzesthesynthesisoftRNAand5S
rRNA.TheseproductsarecodedbyclassIIIgene.
BesidesthesethreenuclearRNApolymerases,inaeukaryoticcell,
afourthtypeofRNApolymeraseisfoundinmitochondrialmatrix
prokaryoticRNApolymerase,mtRNAPcatalyzesthesynthesisofall
thethreetypesofRNA,i.e.mRNA,tRNAandrRNA
66.Ultravioletradiationexposurecancauses
DNAdamageby-
b)DNAbreakage
c)Thyminedimerformation
d)AcetylationofDNA
e)MethylationofDNA
Ans.is'a'Pyrimidinedimersformation;&'c'i.e.,Thyminedimer
formation[RefHarper30/ep.761;Lippincott0/ep.412]
UVraysexposureresultsincovalentjoiningoftwoadjacent
pyrimidines(usuallythymine)toformpyrimidinedimers(thymine-
thymineandcytosine-cytosinedimersarealsoformedbutatslower
rates.
Ultravialet(UV)radiations:-Inducedimerizationofadjacent
pyrimidinestoproducepyrimidinedimers.
67.TrueaboutDNAphotolyase-
a)RepairdamagecausedbyUVlight
b)Foundonlyinhuman
c)Usevisiblelight
d)Breakspyrimidinedimers
CorrectAnswer-A:C:D
Ans.is'a'i.e.,RepairdamagecausedbyUVlight;'c'i.e.,Use
visiblelight;&'d'Breakspyrimidinedimer[Ref:PankajNaikp.
496]
photolyase.ItisaDNArepairenzymewhichbindtothedamaged
regionofDNAandgetexcitedbylightenergyabsorbedbyN5,N'?-
methenyltetrahydrofolate,whichisboundtothephotolyase.The
processiscalledphotoreactivation.
endofthespectrum.
Theexcitedphotolyasethencleavesthedimerintooriginalbases.
Theseenzymesoccurinalmostalllivingorganismsexposedto
sunlight,theonlyexceptionbeingplacentalmammalslikehumans
injectionofanelectronintotheDNAlesiontotriggerthecleavageof
cyclobutane-pyrimidinedimers.
PhotolyaseisparticularlyimportantinrepairingUVinduceddamage
inplants.Thephotolyasemechanismisnolongerworkingin
efficientnucleotideexcisionrepairmechanism.
68.TrueaboutDNAGyrase-
a)AtypeoftopoisomeraseI
b)AtypeoftopoisomeraseII
d)Overcometheproblemofsupercoils
e)None
CorrectAnswer-B:C:D
Ans.is'b'i.e.,AtypeoftopoisomeraseIL;"c'i.e.,Acton
[RefLippincottetc401;StayanarayanxlaVep.528J
TopoisomeraseI4Removesnegativesupercoiling.
TopoisomeraseIIRelaxespositivesupercoilsandformsnegative
supercoilingbycondensation.ofchromosome.
recombinationthatarerequiredforDNAtobeexchanged.
69.Whichofthefollowingenzymesofurea
cycleis/arenotpresentinmitochondria?
a)Carbamoylphosphatesynthetase-1[CPS-1]
c)Arginosuccinase
d)Arginosuccinatesynthase
e)Ornithinetranscarbamylase
CorrectAnswer-B:C:D
Arginosuccinatesynthase[RefHarper's30th/ep.291]
Ammoniaisultimatelydisposedofbyformationofureaby"Kreb's
Henseleitureacycle"intheliver.
Ureacycletakesplacebothinmitochondriaandcytosol.
remainingreactionsoccursincytosol
Argininosuccinatesynthasecatalyzestheformationof
argininosuccinatefromcitrullineandaspartate.Thisreaction
requiresIATP,but2highenergyphosphatebondsareconsumedas
providesoneofthetwonitrogenatomsthatappearinurea(The
otheroneisprovidedbyammoniaNH4).
Argininosuccinatelyase(argininosuccinase)catalysesthecleavage
ofargininosuccinateintoarginineandfumarate.Fumarateentersin
Arginasecatalysestheformationofureafromargininebyhydrolytic
cleavageofargininetoyieldureaandornithine.Ornithineisthus
regeneratedandcanentermitochondriatoinitiateanotherroundof
theureacycle.
70.Regulatoryenzymesofglycolysisare-
a)Phosphofructokinase
b)Pyruvatekinase
c)BPGkinase
d)Hexokinase
CorrectAnswer-A:B:D
Ans.'a'i.e.,Phosphofructokinase,'b'i.e.,Pyruvatekinase&'d'
i.e.,Hexokinase[RefHarper's30thlep.170-177]
Glycolysisisregulatedat3stepswhichareirreversible.These
andglucokinase,(2)PhosphofructokinaseI,and(3)Pyruvate
kinase.
Hexokinaseisfoundinmostofthetissueexceptliverandcomes
intoplaywhenbloodglucoseislow.Itisnotaffectedbyfeedingor
metabolism,itisalsoinvolvedinmetabolismoffructoseand
galactose.
PhosphofructokinaseIisthemajorregulatoryenzymeofglycolysis.
Itcatalyzesthe3rdreactionofglycolysis,i.e.,fructose-6-P-a
limitingstep"forglycolysis.
Itisallostericallyactivatedby:Fructose-6-phosphate,fructose2,6-
bisphophate,AMP,ADP,K.andphosphate.Itisallosterically
inhibitedby:ATP,citrate,Ca+2,Mg+2,andlowpH.
synthesisinresponsetoinsulinanddecreasesinresponseto
glucagon.
PyruvatekinaseisenzymethatcatalyzesconversionofPEPto
pyruvate.Pyruvatekinaseisaninducibleenzymethatincreasesin
isactivatedbyfructose-1,6bisphosphateandinactivatedbyATP
andalanine.
71.Whichofthefollowingis/areto-6fatty
acid(s)
b)Arachidinicacid
c)Gammalinolenicacid
d)Alphalinolenicacid
e)Oleicacid
Ans.is'a'i.e.,Linoleicacid,'b'i.e.,Arachidinicacid&'c'i.e.,
Gammalinolenicacid[Ref:Harper's30thlep.2141
Linoleicacid(18carbon:Chemicalformula'aCH,-(CH,),-CH=CH
-CH2-CH=CH-(CH2)7-COOH
2doublebondsat915(betweenC-9andC-10)and12'(betweenC-
12andC-13)positionswhennumberingisstartedfromcarboxyl
carbon.
co-systemC:18:2:w-6,9,i.e.18carbonfattyacidwith2double
positionswhennumberingisstartedfromterminalmethylcarbon.So
linoleicacidisco-6fattyacid,asthefirstdoublebondisat6th
positioninco-systemclassification.
Arachidonicacid(20carbon)ChemicalformulaC20H32O2
72.Nonreducingsugarsareallexcept-
a)Glucose
b)Maltose
c)Sucrose
d)Fructose
CorrectAnswer-A:B:D:E
Ans.is'a'i.e.,Glucose;b'i.e.,Maltose;'d'i.e.,Fructose&`e'
i.e.,Galactose[RepDineshPuri3"'/elep.24]
Reducingsugarsaresugarswhichhavefreealdehydeorketone
aldehydeorketonegroup,theycanreducecertainheavymetallic
cationsinanalkalimediumandintheprocesstheythemselvesget
oxidizedtoamixtureofsugaracids.
Glucoseandgalactosehavefreealdehydegroupatcarbon-1,and
glucoseandgalactoseiscarbon-1andoffructoseiscarbon-2.
Sucrose(disaccharideofglucoseandfructose)isformeddueto
formationofa-glycosidicbondbetweencarbon-1ofglucoseand
carbon-2offructose(Glucose-al2-Fructose).Thus,reducing
inglycosidicbondformationandthereforelosttheirreducing
property.Hence,sucroseisanon-reducingdisaccharide.
73.ApointegratedinHDLis-
a)ApoAl
c)ApoD
d)ApoB48
e)ApoB100
CorrectAnswer-A:B:C
Harper's30th/ep.257,255;Chatterjee6th/ep.382]
Apo-A1isfoundinHDL,Chylomicrons,siteofsynthesiisLiver,
intestine,andfunctioninMajorstructuralproteinofHDL,major
activatorofLCAT.
synthesis-liver,functionasMediatesuptakeofchylomicron
remnantsandIDLbyLDLreceptorsinliver.
Apo-D--foundinHDL-Spleen,brain,testes,adrenal
74.Poorwoundhealinginvitamin'C'
a)Inhibitionofcollagensynthesis
b)Defectivecollagensynthesis
c)Defectivepost-translationalmodificationofcollagen
d)Defectivehydroxylation
CorrectAnswer-A
Ans.is"a"Inhibitionofcollagensynthesis
Ascorbicacid(VitaminC)isalsocalledantiscorbuticfactor.Itisvery
heatlabile,especiallyinbasicmedium.Ascorbicaciditselfisan
cortex.
Ascorbicacidfunctionsasareducingagentandscavangeroffree
radicals(antioxidant).Itsmajorfunctionsare
1. vitaminCisessentialfortheconversionofprocollagentocollagen,
synthesis,itplaysaroleintheformationofmatrixofbone,cartilage,
dentineandconnectivetissue.
2. VitaminCisrequiredforpost-translationalmodificationby
hydroxylationofprolineandlysineresiduesconvertingtheminto
75.MicroSatelliteinstabilityisseenin?
a)Huntington'sdisease
b)Lynchsyndrome
c)Spinocerebellarataxia
e)Colorectalcancer
CorrectAnswer-A:B:C:D:E
Ans.is'a'i.e.,Huntington'sdisease;'b'i.e.,Lynchsyndrome;
'c'i.e.,Spinocerebellarataxia;'d'i.e.,HNPCC;&'e'i.e.,
Microsatelliteinstabilityisgeneticinstabilityinshortnucleotide
repeats(microsatellites)duetohighmutationrateasaresultof
defectsinmismatchrepairofDNA.
Sometimesreplicationerrorsescapetheproofreadingfunction
Theseerrorsarerepairedlater.
Animportantpointisthattherepairsystemmustbeableto
discriminatebetweentheparent(template)strandandthenew
daughterstrandbecauseitisthebaseonthedaughterstrandparent
Methylgrouponparentstrandattachedtoadenine(methylated
adenine)nearthemismatchservesasatagbywhichtherepair
systemidentifies.
SeveralNeurologicaldiseasearecharacterizedbymicrosatellite
dystrophy,Fragile-Xsyndrome,Friedreich'sataxiaand
spinocerebellarataxia.
76.UDP-glucoseisusedfor-
a)Glycogensynthesis
c)Bilirubinmetabolism
d)Gangliosidesynthesis
e)Heparinsynthesis
CorrectAnswer-A:B:C:E
metabolism;'c'i.e.,Bilirubinmetabolism;&`e'i.e.,Heparin
synthesis[RefBasicmedicalbiochemistryp.475]
UDP-glucoseisderivedfromglucose-6-phosphateviaglucose-l-
phosphate.
OtherusesofUDP-glucoseare-
1. Inuronicacid(glucoronicacid)cycletogenerateUDPglucuronate.
2. Galactosemetabolism
Glycosylationofproteins,lipidsandproteoglycans.
1. Conjugationofbilirubin,benzoicacid,sterols,estrogenanddrugs.
2. Biosynthesis
77.ComplementaryDNAdiffersfromgenomic
DNAin-
b)Hasintrons
c)Hasonlyexons
d)Usesreversetranscriptase
e)Larger
Ans.is'a'i.e.,Hascodedsegments;'c'i.e.,Hasonlyexons;&
'd'i.e.,Usesreversetranscriptase.[Ref:Lehninger5"Yep.940-
9601
Collectionofcloned(recombinant)DNAfragmentsiscalledDNA
1)Genomiclibrary:-
TheentiregenomicDNA(bothexonsandintrons)ofanorganismis
cutintosmallpiecesbyrestrictionendonucleases.
Eachandeveryfragmentisthenclonedwithsuitablevector.These
2)ComplementaryDNA(cDNA)library:-
IncDNAlibraryonlyexonsarerepresented.Itisconstructedsoas
toincludeonlythosegenesthatareexpressed.
cDNAlibraryismorespecializedandexclusiveDNAlibrary.
doublestrandedDNAs(cDNAs)areproducedfromthesemRNAsby
reversetranscriptase.TheresultingDNAfragmentsarethen
insertedintoasuitablevectorandcloned
78.Whichofthefollowingenzymeshave
[PolymeraseChainReaction]
a)Taqpolymerase
b)PFUPolymerase
c)Thermosthermophilus
e)T-7polymerase
CorrectAnswer-B:E
Ans.is'b'i.e.,PFUPolymerase;&'e'i.e.,T-7polymerase[Ref
TextbookofPCRbyMikeMcPherson]
reducingtheintroductionofamplificationerrorsinPCRproducts.
SeveralthermostableDNApolymeraseswith3'5'exonuclease-
dependentproofreadingactivityhavebeenintroducedforhigh.
PfuDNApolymeraseDerivedfromPyrococcusfusarious.
KODHiFiDNApolymeraseIsolatedfromThermococcus
Kodakaraensis.
T7DNApolymerase.
79.EnzymesrequiredformRNAsynthesis
a)RNApolymeraseI
b)RNApolymeraseII
c)Primase
d)Topoisomerase
CorrectAnswer-B
Ans.is'b'i.e.,RNApolymeraseII[RefHerper's30"'/ep.390-
400]
ItcatalyzesthesynthesisofmRNA,smallnuclearRNA(sn-RNA)
TheseproductsarecodedbyclassIIgene,i.e.classIIgeneis
transcribedbymRNA.
ClassIIgenedifferfromclassIandIIIinthatoneofitstranscribed
products(mRNA)istranslatedintoprotein.
80.WhichDNApolymerasehas/have
proofreadingactivity-
a)DNApolymeraseI
b)DNApolymeraseII
c)DNApolymerasea
e)DNApolymerasey
CorrectAnswer-A:B:D
Ans.is'a'i.e.,DNApolymeraseI;'b'i.e.,DNApolymeraseII;&
'd'i.e.,DNApolymerase
activities:?
1. 5'3'exonucleaseactivity,Polymeraseactivity(5'3'
polymeraseactivity),3'5'exonucleaseactivity,
2. DNApolymeraseI:-Helpsingapfillingandsynthesisbetween
RNAprimerbydeoxyribonucleotides.Ithas(i)3'5'exonuclease
activity,(ii)5'3'exonucleaseactivityand(iii)polymerase(5'3'
polymerase)activity.
3. DNApolymeraseI:-Helpsingapfillingandsynthesisbetween
RNAprimerbydeoxyribonucleotides.Ithas(i)3'5'exonuclease
activity,(ii)5'3'exonucleaseactivityand(iii)polymerase(5'
3'polymerase)activity.
4. DNApolymeraseII:-Helpsin(i)proofreading(3'?5'exonuclease
5. DNApolymeraseIII:-Itisthemainenzymethatsynthesizes
prokaryoteDNA,i.e.,synthesisofleadingandlaggingstrand.Ithas
(i)513'polymerase(orsimplypolymerase)activityforDNA
synthesis,and(ii)3'-->51exonucleaseactivityforproofreading.
81.30SribosomeINTERACTSwithall
except?
a)mRNA
b)ATP
c)GTP
e)Elongatingfactor
CorrectAnswer-B:E
ANS-'b'i.e.,ATP;&'e'i.e.,Elongatingfactor[RefDineshPurl
Yalep.482,483]
between30Sribosomalsubunit,mRNAandformylmettRNA.GTP
servesassourceofenergy.Threeinitiationfactors(IF1,IF2,IF3)
arealsorequiredforformationofthiscomplex.
Thenthereisformationof70Sinitiationcomplexbyjoiningof50S
theribosome.`A'-siteisstillempty.
Elongationfactors:EF-Tu,EF-Ts,EF-G.
82.Components/genesinvolvedinRISC
complex-
b)MiRNA
c)rRNA
d)Drosha
e)Dicernuclease
Ans.is'a'i.e.,Pasha;'b'i.e.,MiRNA;'d'i.e.,Drosha;&'e'i.e.,
Dicernuclease[RefTextbookofmolecularbiologyp.7121]
RNA-inducedsilencingcomplex(RISC)isamultiproteincomplex
thatincorporatesonestrandofadoublestrandedsmallinterfering
RISCusesthesiRNAormiRNAasatemplateforrecognizing
complementarymRNA.
OnceRISCfindscomplementarystrandofmRNA(withhelpof
miRNAorsiRNA),itactivatesRNAasetocleave(degrade)mRNA.
toloaddsRNAfragmentsintoRISCinordertotargetmRNA.The
RLCconsistsofdicer,thehumanimmunodeficiencyvirus
transactivatingresponseRNA-bindingprotein(TRBP)and
Argonuate2.
nucleards-RNAbindingprotiencalledDGCRinhuman(Pashain
Dorsophila)andcleavesthehairpinregionoutoflongprecursor
RNAgeneratingapre-miRNA.
83.30SribosomeCONSISTofallexcept-
b)ATP
c)GTP
d)InitiatingfactorandElongatingfactor
e)None
Ans.isNone[RefLippincates5th/ep.436]
Ribosomesarelargecomplexesofr-RNAandproteinswithone
largeandonesmallsubunits.
Thesmallsubunitbindsm-RNA,thusguidinginteractionbetween
informationwithexiquisitefidelity.Hencesmallsubunitis
responsibleforaccuracy,whereasthelargesubunitcatalyzes
theformationofpeptidebond.
Ribosomesarecomposedoftwounequalsubunits.
Prokaryotic(70S)ribosomeismadeof50Sand30Ssubunits.
60Ssubunitofeukaryotescontains5SrRNA,5.8SrRNA,28S
rRNAandmorethan50polypeptides.40Ssubunitcontains18S
rRNAandabout30polypeptidechains.
84.Whichofthefollowingisrequiredfor
unwindingofDNA-
a)Helicase
b)Primase
c)SSBP
e)Topoisomerase
CorrectAnswer-A
Ans.is'a'i.e.,Helicase[Ref:Harper's30thlep.383&29thp.367]
protein
DNApolymerases Deoxynucleotidepolymerization
Helicases
ProcessiveunwindingofDNA
Relievetorsionalstrainthatresults
fromhelicaseinducedunwinding
DNAprimase
InitiatessynthesisofRNAprimers
Single-strand
bindingproteins
dsDNA
Sealsthesinglestrandnick
betweenthenascentchainand
Okazakifragmentsonlagging
strand
85.Trueaboutcollagen:
a)Doublehelixstructure
c)Triplehelixstructure
d)-pleatedstructure
e)Componentofconnectivetissueofbody
CorrectAnswer-C:E
47,627-32;Lippincott6th/43-48;Vasudevan5th/254-55]
Incollagen,thecollagenhelix,ortype-2helix,isamajorshapein
secondarystructure
Allcollagenhaveatriplehelicalstructure.
ateverythirdpositionoftriplehelicalportionofachain.
Thisrepeatingstructure,representedas(Gly-x-y)n,isanabsolute
requirementfortheformationofthetriplehelix.
300nmlongand1.5nmindiameter,itismadeupofthree
conformationofaleft-handedhelix(itsnameisnottobeconfused
withthecommonlyoccurringalphahelix,aright-handedstructure).
Thesethreeleft-handedhelicesaretwistedtogetherintoaright-
handedcoiledcoil,atriplehelixor"superhelix"
constitutesapproximately25%oftheproteinofmammals.
Itprovidesanextracellularframeworkforallmetazoananimalsand
existsinvirtuallyeveryanimaltissue.Atleast28distincttypesof
collagenmadeupofover30distinctpolypeptidechains(each
86.Atisoelectricpoint(p1)netchargeof
aminoacisis:
a)-1
b)+1
d)+1
e)0
CorrectAnswer-E
Ans:e.0...[RefHarper30th/201]
zero"(Harper30th/20)
"Isoelectricpoint(pI)isapHinwhichnetchargeofaminoacidis
zero.Incaseofproteinsisoelectricpointmostlydependsonseven
chargedaminoacids:glutamate(6-carboxylgroup),aspartate(13-
histidine(imidazolesidechains),lysine(c-ammoniumgroup)and
arginine(guanidiniumgroup).
87.HexosaminidaseAdeficiencycauses:
a)Niemann-pick
c)Hurlersyndrome
d)Gaucher'sdisease
e)Krabbe'sdisease
CorrectAnswer-B
6th/212;Harrison19th/432e,433e
HexosaminidaseAdeficiencyisanenzymedeficiencythatcauses
brainandothernervecellstodie,whichcanleadtosevere
neurologicalandmentalproblems.
anenzymecalledbeta-hexosaminidaseA.Thisenzymehelpsbreak
downaparticularfattyacidcalledGM2ganglioside.
Withoutadequateamountsoffunctionalenzymes,GM2ganglioside
willbuildupinnervecellsandcausethemtodie.
infantile(Tay-Sachsdisease),juvenile,chronic,oradult-onsetforms.
88.Mitchondrialmatrixcontainsenzymesof:
a)Pyruvatedehydrogenase
b)TCAcycleenzyme
d)ATPsynthase
e)-oxidationenzymes
CorrectAnswer-A:B:D
Ans:a.Pyruvatedehydrogenase,b.TCAcycleenzyme,d.ATP
MatrixoftheMitochondrionisgel-likesolutionintheinteriorof
mitochondriais50%protein.Thesemoleculesincludetheenzymes
responsiblefortheoxidationofpyruvate,aminoacids,fattyacids(by
n-oxidation),andthoseofthetricarboxylicacid(TCA)cycle.
matrixofmitochondria.Inaddition,thematrixcontainsNAD+and
FAD(theoxidizedformsofthetwocoenzymesthatarerequiredas
hydrogenacceptors)andADPandPi,whichareusedtoproduce
ATP.
89.Whichofthefollowinggroup(s)are
presentinnaturalaminoacids:
a)Imidazolegroup
b)Tetrapyrrolegroup
c)Indolegroup
e)Ketogroup
CorrectAnswer-A:B:C:D
Ans:a.Imidazole...,b.Tetrapyrrole...,c.Indole...,d.
Guanidinium(RefHarper30th/20-23;Lippincott6th/I-11;
Imidazolegroup:Histidine,Betacarboxylgroup:Asparticacid
(Vasudevan5th/19)Gammacarboxylgroup:Glutamicacid
(Vasudevan5th/19)?-aminogroup:Lysine(Vasudevan5th/19).
SpecialgroupsinAminoacidsVasudevan5th/17:Benzenegroup-
ProlineGuanidiniumgroup-ArgininePhenolgroup-Tyrosine
90.Whichofthefollowingvitamindeficiency
causetriadofmentalconfusion,
ophthalmoplegia&ataxia:
b)VitB1
c)VitB6
d)VitC
e)Vit.B12
Ans:b.VitBl[RefLippincott6th/378-79;Harrison19th/96e,
18th/594-96;Harper30th/555-56,28th/468]
Classically,Wernicke'sencephalopathyischaracterizedbythetriad
ofophthalmoplegia,ataxia,andmentalconfusion,butconfusion&a
by(Kaplan11th/796-799)
Thiaminedeficiencyinitsearlystageinducesanorexiaand
nonspecificsymptoms(e.g.,irritability,decreaseinshort-term
memory).
centralnervoussystem(CNS)manifestationsknownasWernicke's
encephalopathy,whichconsistsofhorizontalnystagmus,
ophthalmoplegia(duetoweaknessofoneormoreextraocular
muscles),cerebellarataxia,andmentalimpairment
91.Whichofthefollowingenzyme(s)is/are
involvedingluconeogenesis:
a)Pyruvatecarboxylase
b)Phosphoenolpyruvatecarboxykinase
c)Phosphofructokinase-1
e)Pyruvatedehydrogenase
CorrectAnswer-A:B:D
Ans:a.Pyruvatecarboxylase,b.Phosphoenolpyruvate
carboxykinase,d.Glucose6-phosphatase,[RefHarper
Lippincott4th/329J]
glucose-6-phosphatase,fructose-1,6-bisphosphatase,andPEP
carboxykinase/pyruvatecarboxylase.
92.Gelusedinelectrophoresisis/are:
b)Polyacrylamideplaingel
c)PolyacrylamideSDS(Sodiumdodecylsulphate)impregnated
Polyacrylamidegel
d)alloftheabove
CorrectAnswer-D
Ans.d-alloftheabove[www.lonza.com/go/literature/2043;
Shinde7th/7741]
SeparationofRNAinagarosegelsisusedforanumberofdifferent
levels,checkingRNAintegrityandsizeselectionofRNAforcloning
experiments.SeparationofRNAbasedonfragmentlengthrequires
conditionsthataredifferentfromDNAanalysis.
Theseincludesamplepreparation,theuseofsampleandgel
oftheexperimentandthesizeoftheRNAbeingseparatedarethe
primarydriversindeterminingwhichdenaturingsystemtouse.
ThemostfrequentlyuseddenaturantsforRNAagarosegel
electrophoresisareformaldehyde,formaldehyde/formamide,and
93.Whichofthefollowingmethod(s)is/are
usedfordetectionofnucleicacid:
a)Northernblotting
b)Southernblotting
d)Microarray
e)ELISA
CorrectAnswer-A:B:D
Ans:a.Northern...,b.Southern"',d'Microarray'
Technique
GelUsed Purpose
Analysed
Southern
Yes
DetectDNAchanges
blot
Northern
Yes
MeasuresmRNAamounts&size
blot
Western
Yes
Measuresproteinamount
blot
ASO
No
DetectsDNAmutations?
RNAor
MeasuresmanymRNAlevelsat
No
cDNA
onetime
Proteins?
ELISA
or
No
antibodies?
Measuresabundance,distribution,
posttranslai.iurimodifications,
Proteomics Proteins?
Yes
interactionsofcellularproteins
interactionsofcellularproteins
94.Mucopolysacchidosis,whichisa
lysosomalstoragedisease,occursdueto
a)Hydrolaseenzyme
b)Dehydorgenaseenzyme
c)Lipaseenzyme
d)Phosphatase
CorrectAnswer-A
Ans:a.Hydrolaseenzyme[RefHarper30th/638-39,29th/589,
599,600;Lippincott6th/163-64J
Themucopolysaccharidosesarehereditarydiseasescausedbya
inthedegradationofheparansulfateand/ordermatansulfate
Theyareprogressivedisorderscharacterizedbyaccumulationof
glycosaminoglycansinvarioustissues,causingarangeof
symptoms,suchasskeletalandextracellularmatrixdeformities,and
Childrenwhoarehomozygousforanyoneofthesediseasesare
apparentlynormalatbirth,thengraduallydeteriorate.Insevere
cases,deathoccursinchildhood.
Diagnosisisconfirmedbymeasuringthepatient'scellularlevelof
havebeenusedtotreatHurlerandHuntersyndrome
95.Sulphurofcysteinarenotused/utilizedin
bodyforthefollowingprocess/product:
a)Helpinconversionofcyanidetothiocyanate
c)Introductionofsulphuratominmethionine
d)Disulfidebondformationb/wtwoadjacentpeptide
e)None
CorrectAnswer-C
30th/301-02,313-14,29th/285-86;Lippincott6th/263-68;Shinde
7th/471-73,578;Vasudevan5th/191;Satyanarayan3rd/361]
TheH2Sderivedfromthecysteinemaybeoxidizedtosulfites&
thiosulfateserfurtheroxidizedtosulfate.
pyruvate.ThebetamercaptopyruvatecantransferStoCNtoform
thiocynate(SCN).
ThesulphurmayberemovedeitherasH2Sorelementalsulphuror
assulfite,Cysteineondecarboxylationgivesbetamercapto
Formationofcysteineisbyusingthecarbonskeletoncontributedby
serine&sulphuroriginatingfrommethionine.
96.Whichoneofthefollowingstatements
aboutproteinstructureiscorrect:
structure
b)Theformationofadisulfidebondinaproteinrequiresthatthe
twoparticipatingcysteineresiduesbeadjacenttoeachotherin
theprimarysequenceoftheprotein
ofcovalentbondsamongthesubunits
d)Thedenaturationofproteinsalwaysleadstoirreversiblelossof
secondaryandtertiarystructure
e)Theinformationrequiredforthecorrectfoldingofaproteinis
polypeptidechain
CorrectAnswer-E
Ans:e.Theinformationrequiredforthecorrect...[RefHarper
3001/36-41,29th/36-40;Lippincott6th/24,13-20]
betweenthesidechainsoftheaminoacidresiduesofthe
polypeptidechain
Thetwocysteineresiduesthatreacttoformthedisulfidebondmay
beagreatdistanceapartintheprimarystructure(oronseparate
dimensionalfoldingofthepolypeptidechain.Denaturationmay
eitherbereversibleorirreversible.
Quaternarystructurerequiresmorethanonepolypeptidechain.
Thesechainsassociatethroughnoncovalentinteractions"
ordersofstructurearestabilizedbyweakforces--multiplehydrogen
bonds,salt(electrostatic)bonds,andassociationofhydrophobicR
groups.
Proteindenaturationresultsintheunfoldinganddisorganizationof
peptidebonds.Denaturationmaybereversibleor,morecommonly,
irreversible.
97.Trueaboutretinol:
a)Formpartofrhodopsin
c)Activelytakepartinvisualcycle
d)Implicatedingrowth&differentiationoftissue
e)Notformedbyretinoicacid
CorrectAnswer-B:D:E
d.Implicatedingrowth&differentiationoftissue,&e.Not
formedbyretinoicacid,
[RefHarper30th/547-51,29th/526-28;Lippincott6th/381-83;
Shinde7th/152-56;Vasudevan5th/284-86]
acidcannotgiverisetotheformationofretinalorretinol"
Retinoicacidisimplicatedingrowth&differentiationoftissue,itis
necessaryforthereproductivesystem.Retinol
actslikeasteroidhormoneincontrollingtheexpressionofcertain
reproduction
Retinylesterspresentinthedietarehydrolyzedintheintestinal
mucosa,releasingretinolandfreefattyacids.Retinolderivedfrom
estersandfromthecleavageandreductionofcarotenesisre-
secretedasacomponentofchylomicronsintothelymphaticsystem.
Retinylesterscontainedinchylomicronremnantsaretakenupby,
andstoredin,theliver.
retinolisreleasedfromtheliverandtransportedtoextrahepatic
tissuesbytheplasmaretinolbindingprotein(RBP).
98.Inprolongfastingglycerolisformedfrom
triglyceride.Whichofthefollowing
statement(s)is/aretrueregarding
glycerol:
b)Itisdirectlyusedbytissuesforenergyneeds
c)Itisformedduetoincreasedactivityoflipoproteinlipase
d)Itisformedduetoincreasedactivityofhormonesensitive
lipase
CorrectAnswer-D:E
Ans:d.Itisformedduetoincreasedactivityofhormone
sensitivelipase,&e.Glycerolactsasasubstratefor
gluconeogenesisintheliver,[RefHarper30th/262,149,
Fasting:Inadiposetissuethedecreaseininsulinandincreasein
glucagonresultsininhibitionoflipogenesis,inactivationof
lipoproteinlipase,andactivationofintracellularhormone-sensitive
lipase.
glycerol(whichisasubstrateforgluconeogenesisintheliver)and
freefattyacids,whichareusedbyliver,heart,andskeletalmuscle
astheirpreferredmetabolicfuel,thereforesparingglucose.
TheglycerolproducedfromTAGdegradationisusedasa
LipolysisIsControlledbyHormone-SensitiveLipase,whichis
?activatedbyACTH,TSH,glucagon,epinephrine,norepinephrine,
andvasopressinandinhibitedbyinsulin,prostaglandinE1and
nicotinicacid
stressanddecreasedbyfeedingandinsulin.Conversely,feeding
increasesandfastingandstressdecreasetheactivityoflipoprotein
lipase
99.Pyruvatedehydrogenasecomplexuses
a)Biotin
b)Lipoicacid
c)NAD
d)FMN
CorrectAnswer-B:C:E
Ans:b.Lipotic.acid.,c.NAD&e.TPP(RefHarper30th/172-74,
29th/174-75;Lippincott6th/109-11;Satyanarayan3rd/253-54]
PyruvateDehydrogenaseComplex(PDH)Satyanarayan
Itisfoundonlyinmitochondria,HighactivityofPDHarefoundin
cardiacmuscle&kidney
TheenzymePDHrequiresfivecofactors(coenzymes)namely-TPP,
lipoamide(itcontainslipoicacidlinkedtoc-aminogroupoflysine),
Pyruvatedehydrogenaseirreversiblyconvertspyruvate,theend
productofglycolysis,intoacetylCoA,amajorfuelfortheTCAcycle
andthebuildingblockforfattyacidsynthesis.
ThePDHcomplexcontainsfivecoenzymesthatactascarriersor
pyrophosphate(TPP),E2requireslipoicacidandCoA,andE3
requiresFADandNAD+.
100.InconversionofpyruvatetoacetylCoA
&CO2,whichofthefollowingcoenzyme
a)Biotin
b)Lipoicacid
c)TPP
d)Pyridoxalphosphate
CorrectAnswer-B:C
Ans:b.Lip...&c.TPP[RefaboveQ;Harper30th/172-74,
29th/174-75;Lippincott6th/109-11;Satyanarayan3rd/253-54]
Pyruvatedehydrogenaseirreversiblyconvertspyruvate,theend
cycleandthebuildingblockforfattyacidsynthesis".(Lippincott
6th/109-10)
101.Trueaboutureacycle:
a)Nitrogenoftheureacomesfromalanine&ammonia
c)Onconsumptionofhighamountofprotein,excessofurea
formed
d)Occurmainlyincytoplasm
e)Synthesisofargininosuccinateconsumesenergy
Ans:c.Onconsumptionofhigh...,d.Occurmainlyin
cytoplasm&e.Synthesisofarginosuccinate....[RefHarper
30th/290-96,29th/274-88;Lippincott6th/253-55;Shinde7th/450-
51;Vasudevan5th/180-811]
mg/dl.Higherproteinintakemarginallyincreasesbloodurealevel.
CitrullinePlusaspartateformsargininosuccinate,catalysedby
enzymeArgininosuccinatesynthase.ThereactionrequiresATP.
Cleavageofargininosuccinate,catalyzedbyargininosuccinase,
aspartateskeletonasfumarate(requirenoATP)".
Ureahastwoaminogroups,onederivedfromammonia&other
fromaspartate.Carbonatomissuppliedfromcarbondioxide.
102.Gangliosidescontains:
b)Galactose
c)Sulphate
d)Serine
e)Sailicacid
Ans:b.Galactose&e.Sailicacid[RefHarper30th/218,250-51,
29th/146,136,234;Lippincott6th/209;Vasudevan5th/78;
ChatterjeaShinde7th/45,58-61].
Agangliosideisamoleculecomposedofaglycosphingolipidwith
NeuNAc,anacetylatedderivativeofthecarbohydratesialicacid,
makestheheadgroupsofgangliosidesanionicatpH7,which
distinguishesthemfromglobosides.
Gangliosidesarepresentandconcentratedoncellsurfaces,withthe
plasmamembraneandtheoligosaccharideslocatedonthe
extracellularsurface,wheretheypresentpointsofrecognitionfor
extracellularmoleculesorsurfacesofneighboringcells.Theyare
foundpredominantlyinthenervoussystemwheretheyconstitute
103.WhichofthefollowingRNAcontains
unusalbases:
a)mRNA
b)rRNA
d)30SRNA
e)50sRNA
CorrectAnswer-B:C
Ans:c.tRNA[RefHarper30th/pg394.
example,dihydrouracilerhaveextensiveintra-chainbasepairing
thatleadstocharacteristicsecondary6.,tertiarystructure"-
Lippincott6th/418.
ThetRNAmoleculescontainahighpercentageofunusualbases
pairingthatleadstocharacteristicsecondaryandtertiarystructure.
EachtRNAservesasan"adaptor"moleculethatcarriesitsspecific
aminoacid--covalentlyattachedtoits3'-end--tothesiteofprotein
synthesis.Thereitrecognizesthegeneticcodesequenceonan
peptidechain
104.AllaretrueaboutstructureofDNA
except:
a)Right-handedhelix
c)Phosphateformbackbone
d)Deoxyriboseformsbackbone
e)Nitrogenbasesformbackbone
CorrectAnswer-E
Lippincott6th/395-400;Ananthanarayan9th/54)
Eachchainofdoublehelixhasabackboneofdeoxyribose&
phosphateresiduesarrangedalternately.Attachedtoeach
deoxyriboseisoneofthe4nitrogenousbases:A,G,CforT"
ThecommonformofDNAissaidtoberight-handed.Inthetest
tube,double-strandedDNAcanexistinatleastsixforms(A-E&Z)"
Withtheexceptionofafewvirusesthatcontainsingle-stranded(ss)
DNA,DNAexistsasadoublestranded(ds)molecule,inwhichthe
TheAformisproducedbymoderatelydehydratingtheBform.Itis
alsoaright-handedhelix,butthereare11basepairsperturn,
andtheplanesofthebasepairsaretilted20"
awayfromtheperpendiculartothehelicalaxis..Z-DNAisa
(Note:deoxyribose-phosphatebackbone"zigzags,"hence,the
name'S"-DNA)
105.Whichofthefollowingisfalse:
a)RatioofA:T&G:Cisapproximatelyequalto1:1
c)A+T=G+C
d)A+C=G+T
e)A+G=C+T
CorrectAnswer-B:C
Satyanarayan3rd/73;Lippincott4th/291;Ananthanarayan
9th/54-55]
ChargaffrulestatedthatinDNAmoleculestheconcentrationof
deoxyadenosine(A)nucleotidesequalsthatofthymidine(T)
nucleotidesequalsthatofdeoxycytidine(C)nucleotides(G=C)
Thetwostrandsofthisdouble-strandedhelixareheldbyboth,
hydrogenbondsbetweenthepurineandpyrimidinebasesofthe
respectivelinearmoleculesandbyvanderWaalsandhydrophobic
Thepairingsbetweenthepurineandpyrimidinenucleotidesonthe
oppositestrandsareveryspecificandaredependentupon
hydrogenbondingofAwithTandGwithC
"Theratioofeachpairofbases(A?T)/(G+C)thoughconstantfor
Ananthanarayan9th/54
106.Trueaboutrestrictionenzyme:
a)Alsok/arestrictionendonuclease
b)Producestickyends
d)Obtainedfromvirus
e)Breaksatsugar-phosphatebond
CorrectAnswer-A:B:E
Ans:a.Alsok/a.restriction...,b.Producestickyends&e.
28th/388-90;Lippincott4th/465-66;Satyanarayana3rd/580]
REcanspecificallyrecognizeDNAwithparticularsequenceof4-6
mucleotidesandcleave.Therecognitionsequencesare
palindromicQ(i.e.,twofoldrotationalsymmetry"(Lippincott4th/466)
recognitionnucleotideknownasrestrictionsitesQ.TocuttheDNA,
arestrictionenzymemakestwoincisions,onethrougheachsugar-
phosphatebackboneQ(i.e.eachstrand)oftheDNAdoublehelix.
Thisenzymecanrestrictviralreplicationsocalledrestriction
ThecutDNAfragmentsbyREmayhavestickyends(cohesive
ends)QorbluntsendsQdependingonthemechanismusedby
enzyme.DNAfragmentswithstickyendsareparticularlyusefulfor
recombinantDNAexperiments(hybridorchimericDNAmolecules).
througheachsugar-phosphatebackbone(i.e.eachstrand)ofthe
DNAdoublehelix.
107.GenesinCpPislandisinactivatedby:
a)Methylation
c)Ubiquitisation
d)Acetylation
e)None
CorrectAnswer-A
4,18th/668,679;Robbins9th/893;Satyanarayan3rd/359,572;
Lippincott4th/460-62;ChatterjeaShinde7th/346,426;en.
wikipedia.org/wiki/DNA_methylationj
CpGislands:Methylationofcytosinebyamethyltransferaseis
6th/709
CytosineinthesequenceCGofDNAgetsmethylatedtoform5'-
methylcytosine.AmajorportionofCG(about20%)inhumanDNA
existsinmethylatedform.Ingeneral,methylationleadstolossof
Theroleofepigeneticcontrolmechanismsinthedevelopmentof
humancancerisunclear.However,ageneraldecreaseinthelevel
ofDNAmethylationhasbeennotedasacommonchangeincancer.
Inaddition,numerousgenes,includingsometumor-suppressor
tumorigenesis.
108.Whichofthefollowingis/aretrueabout
PCRexcept:
a)UsesheatlabileDNApolymerase
c)IstechniqueforDNAamplification
d)UsedtoyieldmultiplecopiesofDNA
e)Reversetranscriptase-PCRisusedforquantificationofRNA
CorrectAnswer-A
59;Lippincott6th/479-83,5th/497-83;Chatterjeaer
Shinde7th/267-272]
SpecificityQisbasedontheuseoftwooligonucleotideprimersthat
hybridizetocomplementarysequenceonoppositestrandsofDNA&
heatorhighpH,givingrisetosinglestrandedDNA.Thesingle
strandedDNAservesasatemplateforsynthesisofa
complementarystrandbyreplicatingenzymes,DNApolymerase.
EarlyPCRreactionusedanE.coliDNApolymerasethatwas
stableDNApolymerase(TaqpolymeraseYfromThermusaquaticus,
obviatesthisproblem&hasmadepossibleautomationofthe
reaction,sincethepolymerasereactionscanberunat70?C
109.Whichofthefollowingtechniquesare
a)RT-PCR
b)Microarray
c)Allele-specificoligonucleotide(ASO)
d)Westrenblot
CorrectAnswer-A:B:C:E
Ans:a.RT-PCR,b.Microarray,c.Allele-specific
oligonucleotide(ASO)&e.DNAsequencing,
[RefLippincott6th/473;Harper30th/470,29th/483-85;Harrison
Mutationalanalysis:Morediscretesequencealterationsrelyheavily
ontheuseofPCR,whichallowsrapidgene
amplificationandanalysis.Moreover,PCRmakesitpossibleto
performgenetictestingandmutationalanalysiswithsmallamounts
cells,orhairroots.DNAsequencingcanbeperformeddirectlyon
PCRproductsoronfragmentsclonedintoplasmidvectorsamplified
inbacterialhostcells"(Harrison19th/444).
SouthernblottingcandetectDNAmutationssuchastheinsertionor
Itcanalsodetectpointmutationsthatcausethelossorgainof
restrictionenzymecleavagesites.Suchmutationscausethepattern
ofbandstodifferfromthoseseenwithanormalgene.
Acomprehensiveapproachtogenome-scalestudiesconsistsof
microarrays,orDNAchips.Usedtodeterminethegeneexpression
patternofthousandsofgenessimultaneously.Microarraysallowthe
detectionofvariationsinDNAsequenceandareusedformutational
analysisandgenotyping.
110.Whichofthefollowingtechniqueis/are
acid:
a)MALDI-TOFMS
b)Branched-chainDNA(bDNA)
c)PCR
e)Biochemicalphenotyping
CorrectAnswer-B:C
Ans:(B)Branched-chainDNA(bDNA)&(C)PCR[RefHarper
29th/26;Lippincott6th/482,485;Harrison19th/150e-3-6,183e-1,
publication/8597456_DNA_analysis_by_MALDI-TOP]
QuantitativeNAATsareavailableforHIV(PCR),cytomegalovirus
(PCR),hepatitisBvirus(PCR),andhepatitisCvirus(PCRand
TMA).
(Nucleicacidamplificationtechniques)forquantitativenucleicacid
testing.Insuchtesting,bDNAattachestoasitedifferentfromthe
target-bindingsequenceoftheoriginalprobe.
Chemiluminescence-labeledoligonucleotidescanthenbindto
signalisdetectedbychemiluminescence.bDNAassaysforviral
loadofHIV,hepatitisBvirus,andhepatitisCvirushavebeen
approvedbytheFDA.
TheadvantageofbDNA.assaysoverPCRisthatonlyasingle
heating/annealingstepisrequiredtohybridizethetarget-binding
probetothetargetsequenceforamplification.
111.Whichofthefollowingis/aremost
severe/dangerouschangeingene:
a)Deletion
c)Mutation
d)Translocation
e)Duplication
CorrectAnswer-A:B
30th/416-19;Lippincott6th/434;Harrison19th/432-34;Robbins
9th/160-61;Harshmohan7th/2551.
Deletion&Insertioncouldbepossibleanswer(Pleasegothrough
explanationgiven&otherreferencesfordecidingappropriate
FrameshiftMutationsResultfromDeletionorInsertionof
NucleotidesinDNAThatGeneratesAlteredmRNAs
Thedeletionofasinglenucleotidefromthecodingstrandofagene
resultsinanalteredreadingframeinthemRNA.
region,thecorrespondingmRNAwhentranslatedwillprovidea
proteinfromwhichismissingthecorrespondingnumberofamino
acids.Becausethereadingframeisatriplet,thereadingphasewill
notbedisturbedforthosecodonsdistaltothedeletion.
withinthenormalterminationcodon(nonsensecodon),thereading
ofthenormalterminationsignalisdisturbed.Suchadeletionmight
resultinreadingthroughaterminationsignaluntilanothernonsense
codonisencountered.
generesultinanmRNAinwhichthereadingframeisdistortedupon
translation,andthesameeffectsthatoccurwithdeletionsare
reflectedinthemRNAtranslation.Thismayresultingarbledamino
acidsequencesdistaltotheinsertionandthegenerationofa
throughthenormalterminationcodon
112.TruestatementregardingLactate
dehydrogenasedeficiency:
a)Fumaratelevelincreases
c)Musclecrampsmayoccur
d)Itoperatesinanaerobiccondition
e)ItisthekeyenzymeofKrebcycle
CorrectAnswer-B:C:D
30th/171,69,28th/149-151;Harrison19th/433e2;Lippincott
4th/103,111;Chatterjea&Shinde7th/313]1
FumarateisconvertedtomalatebyfumaraseenzymeinKrebcycle
(sofumaratelevelincreasesindefectiveenzymefunctioningin
dehydrogenasedeficiency,Lactatedehydrogenasecatalyse
conversionofpyruvicacidtolacticacid.
Lactatedehydrogenasedeficiencyisaconditionthataffectshowthe
bodybreaksdownsugartouseasenergyincells,primarilymuscle
Therearetwotypesofthiscondition:lactatedehydrogenase-A
deficiency(sometimescalledglycogenstoragediseaseXI)and
lactatedehydrogenase-Bdeficiency.
Peoplewithlactatedehydrogenase-Adeficiencyexperiencefatigue,
113.Hyaloronicacidiscomposedof:
a)N-acetylglucosamine
b)N-acetylgalactosamine
c)Glucuronicacid
e)Iduronicacid
CorrectAnswer-A:C
Ans:a.N-acetylandc.Glucuronic[RefHarper30th/156,159,
637,640,28th/119,534-39;Lippincott4th/159,163;Chatterjeaer
CompositionofHyaluronicAcid:Itiscomposedofrepeatingunitsof
N-acetylglucosamine&D-Glucuronicacid.Onhydrolysis,ityields
equimolecularquantitiesofD-Glucosamine,D-Glucuronicacid&
aceticacid.
amongvariousanimalsandtissues,includingsynovialfluid,the
vitreousbodyoftheeye,cartilage,andlooseconnectivetissues.
Hyaluronicacidisespeciallyhighinconcentrationinembryonic
tissuesandisthoughttoplayanimportantroleinpermittingcell
attractwaterintotheextracellularmatrixandthereby"loosenitup"
maybeimportantinthisregard.
114.ThesizeofMicrosatelliterepeat
sequenceis:
b)2-6bp
c)1-3kb
d)>3kb
e)5-20bp
Ans:b.2-6bp
sequencesof2-5bprepeatedupto50times.Mayoccurat50000-
100000locationsinthegenome"-Harper30th/377-78,28th/404
Short(2-6bp),inherited,tandemrepeatunitsofDNAoccurabout
Becausetheyoccurmorefrequently--andintheviewoftheroutine
applicationofsensitivePCRmethods--theyarereplacingRFLPsas
themarkerlociforvariousgenomesearches.
115.AllarefeatureofRefsumdiseaseexcept:
b)Defectinpoxidation
c)Accumulationofphytanicacid
d)Peripheralneuropathy
e)Treatedbyremovingphytanicacidprecursorsfromdiet
Ans:b.Defectinpoxidation[RefHarper30th/231,614,28th/I91,
493;Lippincott4th/195;Harrison19th/2681,18th/3456,236]
Refsumdiseaseisarareautosomalrecessivedisordercausedbya
deficiencyofa-hydroxylase"(Lippincott4th/195)
ismainlyusedforfattyacidsthathaveamethylgroupatbeta-
carbon,whichblockbeta-oxidation.Thisprocessoccurmainlyin
endoplasmicreticulum&somealsoinperoxisomes.
Refsum'sdiseaseisarareneurologicdisorderduetoametabolic
foundindairyproductsandruminantfatandmeat.Phytanicacidis
thoughttohavepathologicaleffectsonmembranefunction,protein
prenylation,andgeneexpression"(Harper30th/231,28th/191)
Refsumdiseasecanmanifestininfancytoearlyadulthoodwiththe
(3)cerebellarataxia,and(4)elevatedCSFproteinconcentration.
Refsumdiseaseisgeneticallyheterogeneousbutautosomal
recessiveinnature.ClassicalRefsumdiseasewithchildhoodor
earlyadultonsetiscausedbymutationsinthegenethatencodes
Refsumdiseaseistreatedbyremovingphytanic
precursors(phytols:fishoils,dairyproducts,andruminantfats)
fromthediet.
116.Groupofallelesthatarecloselylinked
togetherasaclusteris/are:
a)Idiotype
b)Haplotype
c)Genotype
e)None
CorrectAnswer-B
Ans.(B)Haplotype([RefsHarrison19th/435,18th/497,505;
Robbins9th/195,8th/177])
haplotypes,whichcontainvaryingnumbersofcontiguoussingle
nucleotidepolymorphismsonthesamechromosomethatarein
linkagedisequilibrium&henceinheritedtogetherasacluster
Ahaplotypereferstoagroupofallelesthatarecloselylinked
Haplotypesareusefulfortrackingthetransmissionofgenomic
segmentswithinfamiliesandfordetectingevidenceofgenetic
recombination,ifthecrossovereventoccursbetweenthealleles.
117.Whichofthefollowingistrueregarding
pathway
a)Homologousrecombinationrequirealonghomologous
sequencetoguiderepair
b)Non-homologousend-joiningdoesnotrequirealong
c)HomologousrecombinationrepairsDNAbeforethecell
d)Non-homologousend-joiningrepairsDNAbeforethecellenters
mitosis
e)Non-homologousendjoiningisprominentDSBrepair
CorrectAnswer-A:B:C:E
Ans:a.Homologus...,b.Non-homologous...,c.Homologous...,
e.Non-homologous...[RefHarper30th/389-91,
Satyanarayan3rd/532;Robbins9th/430-31,8th/302;http:
Non-homologousendjoining(NHEJ)isthepredominanttypeofDSB
repairinmammaliancells,asopposedtolowereukaryotes.
DSBinDNAaredangerous;Theyresultingeneticrecombination
whichmayleadtochromosomaltranslocation,brokenchromosome
recombinationornon-homologousendjoining;Homologous
recombinationoccursinyeastswhileinmammals,non-homologous
endjoiningdominates
Double-StrandBreaksRepairMechanism
1. Double-strandbreakscanberepairedthroughhomologous
recombinationorthroughnon-homologousendjoining(NHEJ).
2. NHEJisaDNArepairmechanismwhich,unlikehomologous
recombination,doesnotrequirealonghomologoussequenceto
guiderepair.
double-strandbreaksislargelydeterminedbythephaseofcell
cycle.HomologousrecombinationrepairsDNAbeforethecellenters
mitosis(Mphase).
4. DNAdouble-strandbreaks(DSB)arepresumedtobethemost
5. Homologousrecombination(HR),single-strandannealing,andnon-
homologousendjoiningareconsideredtobethepathwaysfor
repairingDSB.
118.Whichofthefollowingenzyme(s)
a)DNAligase
b)DNAHelicase
c)Peptidase
d)Peptidyltransferase
CorrectAnswer-D
Ans:d.Peptidyltransferase
[RefHarper30th/422-24,28th/359-66,323;Lippincott4th/438-42;
Chatterjea&Shinde7th/248-501
Amino-acyl-t-RNAsynthetase:Enzymerequiredforactivationof
aminoacids,Peptidesynthetase(peptidyltransferase)
TheNH2ofnewaminoacylt-RNA(AI)in'A'sitecombinewiththe
-COOHgroupofMet-t-RNAoccupyingthe'P'site.Thereactionis
aminoacids
TheNH2ofnewaminoacylt-RNA(AI)in'A'sitecombinewiththe
-COOHgroupofMet-t-RNAoccupyingthe'P'site.Thereactionis
catalyzedbypeptidyltransferase.``peptidasesdegradesproteins
Protein
function
DNA
Deoxynucleotide
polymerization
Processiveunwindingof
Helicases
Helicases
Relievetorsionalstrain
Topoisomerases thatresultsfromhelicase-
inducedunwinding
InitiatessynthesisofRNA
primers
Single-strand
Preventpremature
bindingproteins
Sealsthesinglestrand
nickbetweenthenascent
DNAligase
Okazakichainand
strand
119.Allaretrueregardingepigenetics
mechanismexcept:
a)Non-heritable
c)Hereditary
d)MethylationofDNA
e)Xchromosomeinactivation
CorrectAnswer-A
Epigeneticsisdefinedasthestudyofheritablechemical
modificationofDNAorchromatinthatdoesnotaltertheDNA
sequenceitself.Exampleofsuchmodificationincludemethylationof
DNA&themethylationeracetylationofhistones.
regulationoftissuespecificgeneexpression,X-chromosome
inactivation&genomicimprinting.
Anepigeneticmodificationreferstoachangeinthe
genome,heritablebycellprogeny,thatdoesnotinvolveachangein
femalecellsisanexampleofanepigeneticsilencingthatprevents
geneexpressionfromtheinactivatedchromosome.
120.Trueaboutpeptidebondformation:
a)TheNH2groupofnewaminoacylt-RNAatAsitecombinewith
b)TheNH2groupofnewaminoacylt-RNAat'P'sitecombine
withthe-COOHgroupofMet-t-RNAoccupyingthe'Asite
c)Reactioniscatalyzedbypeptidyltransferase
d)Peptidebondformationrequireenergy
CorrectAnswer-A:C
Ans:a.TheNH2andc.Reaction...[RefHarper30th/422-25,
28th/359-66;Lippincott4th/438-42;Chatterjeate?Shinde7th/248-
501]
outanucleophilicattackontheesterifiedcarboxylgroupofthe
peptidyl-tRNAoccupyingthePsite(peptidylorpolypeptidesite).At
initiation,thissiteisoccupiedbyaminoacyl-tRNAmet'.
Thisreactioniscatalyzedbyapeptidyltransferase,acomponent
exampleofribozymeactivityandindicatesanimportant--and
previouslyunsuspected--directroleforRNAinproteinsynthesis.
Becausetheaminoacidontheaminoacyl-tRNAisalready
"activatornofurtherenergysourceisrequiredforthisreaction.The
tRNAintheAsite.
121.AllaretrueaboutDNAmethylation
except:
a)Itusuallyoccursinthecytosine
c)Roleingenomicimprinting
d)Noroleincarcinogenesis
e)Essentialfornormaldevelopment
CorrectAnswer-D
Harrison19th/101e-4,18th/668,679;Robbins9th/319-20,893,
8th/306;Satyanarayan3rd/359,572;Lippincott4th/460-62;
ChatterjeaShinde7th/346,426;en.wikipedia.org/wiki/
DNA_methylation]
methylcytosine.AmajorportionofCG(about20%)inhumanDNA
existsinmethylatedform.
InDNA,methylationusuallyoccursintheCpGislands,aCGrich
region,upstreamofthepromoterregion.Inhumans,DNA
methyltransferases.
DNAmethylationstablyaltersthegeneexpressionpatternincells
suchthatcellscan"rememberwheretheyhavebeen"ordecrease
geneexpression
associatedwithanumberofkeyprocessesincludinggenomic
imprinting,X-chromosomeinactivation,suppressionofrepetitive
elements,andcarcinogenesis.
Adenineorcytosinemethylationispartoftherestrictionmodification
methylatedperiodicallythroughoutthegenome.
Withinthebacterium,methylationprotectsthehostDNAfrom
cleavagebyitsownrestrictionenzyme.UnmethylatedforeignDNA
isnotprotectedfromcleavage.
122.AllaretrueregardingUreacycleexcept:
a)Ureaformedfromammonia
b)Ratelimitingenzymeisornithinetranscarbamoylase
c)RequireEnergyexpenditure
d)Malateisbyproductofureacycle
CorrectAnswer-B:D
Ans:b.Ratelimiting...,d.Malate...[RefHarrison19th/434e3-5,
18th/3216,3219;17th/2472-74;Harper30th/290-96,
28th/243;Shinde7th/450-51;Vasudevan5th/180-81]
fromaspartate.Carbonatomissuppliedfromcarbondioxide.
Rate-limitingenzyme(pacemakerenzyme)ofUreacycle:
CarbamoylphosphatesynthetaseI(CPSIIisinvolvedinpyrimidine
synthesis)"(Harper28th/245).
(nottoohardthere)
Rate-limitingenzymeofGlycogenlysis:Glycogenphophorylase
(phophorylasebreaksphosphatebond,whichmeansactivated
glycogenreleasesalotofenergy)
dehydrogenase(badtolosethisinRBCs)
Rate-limitingenzymeofdenovopyrimidinesynthesis:Carbamoyl
phosphatesynthaseII(CPSIisinvolvedinureacycle)
123.Whichofthefollowingistrueregarding
a)Dietaryphenylalaninerestrictionisusedintreatment
b)OccurduetodeficiencyofPhenyalaninehydroxylaseenzyme
c)Occurduetoincreaseactivityofphenyalaninehydroxylase
enzyme
e)Dietshouldcontainhighphenylalaninecontainingfooditems
CorrectAnswer-A:B:D
Ans:a.Dietary...,b.Occur...,d.Tyrosine...[RefHarrison
19th/434e1-3,18th/3217-18;Harper30h/304-306,28th/254;
InpatientswithPKU,tyrosinecannotbesynthesizedfrom
phenylalanine&therefore,itbecomesanessentialaminoacidthat
mustbesuppliedinthediet
Dietaryphenylalaninerestrictionisusuallyinstitutedifblood
Treatmentconsistsofaspecialdietlowinphenylalanineand
supplementedwithtyrosine,sincetyrosinebecomesanessential
aminoacidinphenylalaninehydroxylasedeficiency.
Aboutone-thirdofallpatientswithphenylketonuriaandthemajority
presentation)showincreasedtolerancetodietaryproteinsand
improvedmetaboliccontrolwhentreatedwithtetrahydrobiopterin(5-
20mg/kgperday),anessentialcofactorofphenylalanine
hydroxylase.Thisdrugshouldbeusedinadditiontodietarytherapy.
Pregnancyriskscanbeminimizedbycontinuinglifelong
phenylalanine-restricteddietsandassuringstrictphenylalanine
restriction2monthspriortoconceptionandthroughoutgestation.
124.TrueaboutDNAhyperchromatism:
a)Itisincreaseofabsorbance
c)ItoccurswhentheDNAduplexisdenatured
d)DoublestrandedDNAismorehyperchromicthanssDNA
e)None
CorrectAnswer-A:B:C
absorbanceat260nm(inaspectrophotometer)(C)Itoccurs
whentheDNAduplexisdenatured[RefHarper30th/361,
28th/303;Satyanarayan3rd/78;Lippincott4th/397-98]
Hyperchromicityistheincreaseofabsorbance(opticaldensity)ofa
DNAthatoccurswhentheDNAduplexisdenatured
Itistheincreaseofabsorbance(opticaldensity)ofamaterial.The
mostfamousexampleisthehyperchromicityofDNAthatoccurs
whentheDNAduplexisdenatured.
absorbancethandoesdoublestrandedDNA"(Lippincott
4th/397-98)
TheUVabsorptionisincreasedwhenthetwosingleDNAstrands
arebeingseparated,eitherbyheatorbyadditionofdenaturantor
Lossofhelicalstructurecanbemeasuredbyincreasein
absorbanceat260nm(inaspectrophotometer),Theopposite,a
decreaseofabsorbanceiscalledhypochromicity
Renatuartion(reannealing)istheprocessinwhichtheseparated
complementaryDNAstrandscanformadoublehelix
125.InBenedicttest,redcolouris/are
producedby:
a)Sucrose
b)Inositol
d)Lactose
e)Maltose
CorrectAnswer-C:D:E
Ans:c.Fructose,d.Lactose,e.Maltose[RefLippincott4th/84-
Inositolisalsocalledasmusclesugar.Chemicallyitishexahydroxyl
cyclohexane"(ChatterjeadShinde7th/190)
Reducingsugarscanreactwithchromogenicagents(fore.g,
Benedict'sreagentorFehling'ssolutionorBarfoed'stest)causing
sugarbecomingoxidized"(Lippincott4th/84;Satyanarayan3rd/16).
InBenedict'stest,reactionofreducingsugarwithBenedict'sreagent
produceredcolourofcuprousoxide.
126.Truestatementsare:
preventVitAdeficiencytoinfants
b)HighdoseofVitaminCmaycauserenalstone
c)VitaminEreducesriskofatherosclerosis
d)Folicaciddeficiencycausemicrocyticanaemia
CorrectAnswer-A:B:C:E
Ans:a.Vitamina....,b.High...,c.Vitamine...,e.Banana...[Ref
Harrison19th/96e1-7,18th/599;Harper30th/547-62,28th/47178;
Lippincott4th/374]
becauseascorbicacidismetabolizedtooxalate,butstoneformation
hasnotbeenfrequentlyreported"(CMDT06/1275)"Prophylaxis
againstxerophthalmia:Lactatingmothersshouldbegiven20,000
IUorallyonceatdeliveryorduringthenext2months.Thiswillraise
protectthebreastfedinfant"(Khurana5th/466)
"Folicaciddeficiencycausemegaloblasticanaemia(macrocytic)"
(Lippincott4th/374)
"Vit.Ereducestheriskofatherosclerosis"(Vasudevan5th/291)
providesabout28%ofdaily-recommendedallowance.
127.Thiaminedeficiencycause(s):
a)Glossitis
b)Polyneuropathy
d)Angularstomatitis
e)Cardiomegaly
CorrectAnswer-B:E
Ans:b.Polyneuropathy,e.Cardiomegaly[Re(Harrison
Wetberiberipresentsprimarilywithcardiovascularsymptoms,due
toimpairedmyocardialenergymetabolismanddysautonomia,and
canoccurafter3monthsofathiamine-deficientdiet.Patients
presentwithanenlargedheart,tachycardia,high-outputcongestive
Patientswithdryberiberipresentwithasymmetricperipheral
neuropathyofthemotorandsensorysystemswithdiminished
reflexes.Theneuropathyaffectsthelegsmostmarkedly,andthese
patientshavedifficultyrisingfromasquattingposition.
128.Thiamineactasco-enzymefor:
a)Transketolase
b)Pyruvatedehydrogenase
c)Alcoholdehydrogenase
d)Transaminase
CorrectAnswer-A:B
Ans:a.Transketolase,b.Pyruvate...[RefHarper30th/555,
28th/52;Chatterjea&Shinde7th/166-67]
"NAD+(byvitaminB3)actsasacoenzymeforalcohol
Pyridoxalphosphate(byvitaminpyridoxine,B6)actsascoenzyme
fortransaminaseslikeaminotransferase.
thiaminepyrophosphateactsascoenzymein:Pyruvate
dehydrogenasemn(oxidativedecarboxylation),a-oxoglutararte
(transketolationreaction),tryptophanpyrrolase,pyruvate
carboxylase(non-oxidativedecarboxylation).
129.Terminalproduct(s)ofphenylalanineis:
a)Fumarate
c)Oxaloacetate
d)Acetoacetate
e)None
CorrectAnswer-A:B:D
[RefHarper30th/285,304,29th/269,290;Lippincott6th/263,262;
Satyanarayan3rd/345-47;Vasudevan5th/202-03]
"Thepredominantmetabolismofphenylalanineoccursthrough
tyrosine.Duringthecourseofdegradation,phenylalanine&tyrosine
serveasprecursorsforthesynthesisofglucose(fumarate-Itisan
intermediateofthecitricacidcycle&canalsoserveasprecursorfor
gluconeogenesis)&fat(acetoacetate-Itisaketonebodyfromwhich
fatcanbesynthesized)".
hydroxylationofthearomaticside-chainofphenylalanineto
generatetyrosine.
Phenylalanineisfirstconvertedtotyrosine.Subsequentreactions
arethoseoftyrosine"(Harper30th/304,29th/288)"Hydroxylationof
tyrosinemerge,leadingultimatelytotheformationoffumarateer
acetoacetate.phenylalanine&tyrosineare,therefore,both
glucogenicorketogenic.
130.NADPHisproducedby:
b)Isocitratedehydrogense
c)a-ketoglutarylDehydrogense
d)SuccinateDehydrogense
e)Malatedehydrogense
Ans:a.Pyruvate...,b.Isocitrate....c.a-ketoglutaryl...,&e.
Malate...,
[RefHarper30th/169,29th/177;Lippincott6th/109-13,155;Shinde
7th/321]
Pathway Reactioncatalyzedby
ATP
formation
1.Pyruvate
5
dehydrogenase
oxidationof2NADH
2.Isocitrate
5
dehydrogenase
oxidationof2NADH
3.a-Ketoglutarate
Citric
5
dehydrogenase
oxidationof2NADH
4.Substratelevel
cycle
4.Succinatethiokinase
2
5.Succinate
5.Respiratorychain
3
dehydrogenase
6.Malate
6.Respiratorychain
5
dehydrogenase
131.FunctionofmiRNAis/are:
a)Genesilencing
b)Geneactivation
c)Transcriptioninhibition
e)BreakingofmessengerRNA
CorrectAnswer-A:D:E
Ans:a.Gene...,d.Translation...&e.Breaking...[RefHarper
30th/368,29th/351-52;Lippincott6th/459;Vasudevan5th/436]
decreasedexpressionofmRNA,eitherbyrepressionoftranslation
orbyincreaseddegradation.
miRNAbindtomatchingpiecesofmessengerRNA,turnitintoa
doublestrand&keepitfromdoingitsjob.Theprocesseffectively
miRNAsaretypically21-25nucleotidesinlengthandaregenerated
bynucleolyticprocessingoftheproductsofdistinct
genes/transcriptionunits.miRNAprecursorsaresinglestrandedbut
haveextensiveintramolecularsecondarystructure.
132.Opticallyinactiveaminoacidis/are:
a)Threonine
b)Thyronine
c)Valine
d)Glycine
CorrectAnswer-D
Ans:d.Glycine[RefVasudevan5th/20;Shinde7th/78]
Aminoacidshavinganasymmetriccarbonatomexhibitoptical
activity.Asymmetryariseswhen4differentgroupsareattachedto
Glycineisthesimplestaminoacids&hasnoasymmetriccarbon
atom&thereforeshowsnoopticalactivity.Allothersareoptically
active
Themirrorimageformsproducedwithreferencetothealphacarbon
Isoleucineerthreoninehave2opticallyactivecentres&therefore
eachhas4diastereoisomers
133.cDNAisusedingeneamplificationin
bacteriainsteadofgenomicDNA
a)Easytoreplicatebecauseofsmallsize
b)cDNAlacksintronwhereasthisispresentingenomicDNA
c)Promotorarenotfoundinbacteria
d)Completegenomecannoteasilyreplicatedinbacteria
CorrectAnswer-A:B:D
Ans:a.Easy...,b.cDNA...&d.Complete[RefHarper30th/455-
56,29th/438-39;Lippincott6th/469-70;Vasudevan5th/449]
BecausecDNAhasnointervening,itcanbeclonedintoan
bacteria";"cDNAlacksintrons&thecontrolregionsofthegene,
whereasthesearepresentingenomicDNA"(Lippincott6th/469)
"Bacterialpromotersarerelativelysimple.
cDNAlibrariescontainthoseDNAsequencesthatonlyappearas
typetoanother.AcDNAlibrarycomprisescomplementaryDNA
copiesofthepopulationofmRNAsinatissue.
cDNAprobesareusedtodetectDNAfragmentsonSouthernblot
transfersandtodetectandquantitateRNAonNorthernblot
134.Informing3Dstructureofprotein
followingcomponentshelp:
a)Hydrogenbonds
b)Aminoacidsequence
d)Chaperon
e)allofthese
CorrectAnswer-E
Ans:(E)allofthese[RefHarper30th/39-41,29th/36-40;
The3-dimensionalarrangementofproteinstructureisreferredtoas
tertiarystructure.Thistypeofarrangementensuresstabilityofthe
molecule.Besidesthehydrogenbonds,disulfidebonds,ionic
interactions(electrostaticbonds)&hydrophobicinteractionsalso
Theunique3dimensionalstructureofthenativeconformationis
determinedbyitsprimarystructure,thatis,itsaminoacidsequence,
Interactionsb/wtheaminoacidsidechainsguidethefoldingofthe
polypeptidechaintoformsecondary,tertiary&(sometimes)
conformationoftheprotein.
Inaddition,aspecializedgroupofproteinnamedchaperonesis
requiredfortheproperfoldingofmanyspeciesofproteins.
135.Testusedforproteinis/are:
b)Southernblot
c)ELISA
d)CHIPessay
e)Dotblotting
Ans:a.Westernblot,c.ELISAd.CHIPessay
[RefHarper30th/457,29th/439;Lippincott6th/484,473,485;
Satyanarayan3rd/589]
Westernblot-Measuresproteinamount
136.Whichofthefollowingdiseaseoccurs
duetoDNAmoleculerepairdefect:
a)Krabe'sdisease
b)Angelmannsyndrome
d)Marfansyndrome
e)Ataxiatelangiectasia
CorrectAnswer-C:E
Ans:c.Xeroderma...,e.Ataxia...[RefHarper30th/390,29th/374,
17th/395]
Angelmannsyndromeresultsfromgeneticdisorderthatresultsfrom
defectingenethatencodesubiquitin";"Marfansyndrome:Itis
causedbymutationingeneforfibrillin";"Krabbedisease:dueto13
XerodermaPigmentosum(XP):Anautosomalrecessivegenetic
disease;morethan10genesareinvolved;Theclinical
syndromeincludesmarkedsensitivitytosunlight(ultraviolet)with
subsequentformationofmultipleskincancersandpremature
2000-fold.
137.FullformofLCATis:
a)Lecithincholesterolacyltransferase
b)Lecithincholineacyltransferase
d)Lecithincholinealcoholtransferase
e)LecithinCoAtransferase
CorrectAnswer-A
Ans:a.Lecithincholesterol...[RefHarper30th/272,29th/242,
PlasmaLCATIsResponsibleforVirtuallyAllPlasmaCholesteryl
EsterinHumans(Harper29th/256).LCATactivityisassociatedwith
HDLcontainingapoA-I.AscholesterolinHDLbecomesesterified,it
createsaconcentrationgradientanddrawsincholesterolfrom
reversecholesteroltransport.
Thisprotein,associatedwithHDL,isfoundinplasmaofhumansand
manyotherspecies.Itfacilitatestransferofcholesterylesterfrom
HDLtoVLDL,IDL,andLDLinexchangefortriacylglycerol,relieving
138.Whichvitamindeficiencycause
dementia:
a)VitaminA
b)VitaminC
d)VitaminB1
e)Nicotinicacid
CorrectAnswer-C:D:E
Ans:c.Vitamin...,d.Vitamin...&e.Nicotinic...[RefLippincott
Niacinornicotinicaciddeficiencycausespellagra.Thesymptomof
pellagraprogressthroughthethreeDs:dermatitis,diarrhea
&dementia"
Niacinpellagra:pigmentedrashofsun-exposedareas,brightred
FolateMegaloblasticanemia,atrophicglossitis,depression,T
homocysteine
VitaminMegaloblasticanemia,lossofvibratoryandposition
B12sense,abnormalgait,dementia,impotence,lossofbladder
VitaminCScurvy:petechiae,ecchymosis,coiledhairs,inflamed
andbleedinggums,jointeffusion,poorwoundhealing,fatigue
VitaminAXerophthalmia,nightblindness,Bitot'sspots,follicular
hyperkeratosis,impairedembryonicdevelopment,immune
139.Whichofthefollowingorgancannotuse
ketonebody:
a)Brain
b)RBC
d)Heart
e)Liver
CorrectAnswer-A:E
Ans:a.Brain,e.Liver[RefHarper30th/150,211-12,29th/161,
Ketonebodiescanbeusedbyextrahepatictissuesuchasskeletal&
cardiacmuscle,intestinalmucosa&renalcortex.Eventhebraincan
useketonebodiestohelpmeetitsenergyneedsifthebloodlevels
risesufficiently.
extrahepatictissues.Theheartmuscle&renalcortexpreferthe
ketonebodiestoglucoseasfuel.Tissuelikeskeletalmuscle&brain
canalsoutilizetheketonebodiesasalternatesourcesofenergy,if
glucoseisnotavailable.
a)AdenineandGuanine
b)GuanineandCytosine
c)CytosineandAdenine
d)ThymineandCytosine
--- Content provided by FirstRanker.com ---
e)NoneCorrectAnswer-D
Ans:(D)CytosineandAdenine
InDNAandRNA,Pyrimidinebasesformhydrogenbondswiththeir
complementarypurines.
--- Content provided by FirstRanker.com ---
Thus,inDNA,thepurinesadenine(A)andguanine(G)pairupwiththepyrimidinesthymine(T)andcytosine(C),respectively.
InRNA,thecomplementofadenine(A)isuracil(U)insteadof
thymine(T),sothepairsthatformareadenine:uraciland
guanine:cytosine.
--- Content provided by FirstRanker.com ---
Twotypesofbasesarefoundinnucleotides:(i)purinesand(ii)pyrimidines.
1. Purines:TwomajorpurinebasesfoundbothinDNAsaswellas
RNAsare(i)adenine(A)and(ii)guanine(G).
2. Pyrimidines:Threemajorpyrimidinebasesare(i)cytosine(C),(ii)
--- Content provided by FirstRanker.com ---
Uracil(U)and(iii)Thymine(T).CytosineanduracilarefoundinRNAsandcytosineandthyminearefoundinDNAs.Uracilisnot
foundinDNAsQandthymineisnotfoundinRNAs.
Ref:RodwellV.W.(2011).Chapter32.Nucleotides.InD.A.Bender,
K.M.Botham,P.A.Weil,P.J.Kennelly,R.K.Murray,V.W.Rodwell
--- Content provided by FirstRanker.com ---
(Eds),Harper'sIllustratedBiochemistry,29e2.Majorcontributiontowards
gluconeogenesisisby?
a)Lactate
b)Glyerol
--- Content provided by FirstRanker.com ---
c)Ketonesd)Alanine
e)None
CorrectAnswer-D
Di.e.Alanine
--- Content provided by FirstRanker.com ---
3.Whichofthefollowingisnotapyrimidine
base?
a)Cytosine
b)Uracil
c)Guanine
--- Content provided by FirstRanker.com ---
d)Thyminee)Adenine
CorrectAnswer-C
Ans.is'c'i.e.,Guanine
PurinesPyrimidines
--- Content provided by FirstRanker.com ---
AdenineCytosineGuanineUraciI
Thymine
Bothpurines(adenineandguanine)arefoundbothinDNA&RNA.
Amongpyrimidines-
--- Content provided by FirstRanker.com ---
LiCytosineanduracilarefoundinRNA(thymineisnotfoundinRNA).
CytosineandthyminearefoundinDNA(uracilisnotfoundinDNA).
InDNA,adenineisalwayspairedwiththyminebytwohydrogen
bonds;andguaninealwayspairedwithcytosinebythreehydrogen
--- Content provided by FirstRanker.com ---
bonds.4.Glycogenstoragedisorderis-
a)Niemann?Pickdisease
b)Gaucherdisease
c)Tay-Sacksdisease
--- Content provided by FirstRanker.com ---
d)Pompe'sdiseasee)McArdlesdisease
CorrectAnswer-D
GlycogenstoragediseasetypeII,alsocalledPompedisease,is
anautosomalrecessivemetabolicdisorder[1]whichdamages
--- Content provided by FirstRanker.com ---
muscleandnervecellsthroughoutthebody.Itiscausedbyanaccumulationofglycogeninthelysosomeduetodeficiencyofthe
lysosomalacidalpha-glucosidaseenzyme.Itistheonlyglycogen
storagediseasewithadefectinlysosomalmetabolism,andthefirst
glycogenstoragediseasetobeidentified,
--- Content provided by FirstRanker.com ---
Thediseaseiscausedbyamutationinagene(acidalpha-glucosidase:alsoknownasacidmaltase)onlongarm
ofchromosome17.
Mostcasesappeartobeduetothreemutations.Atransversion(T
G)mutationisthemostcommonamongadultswiththisdisorder.
--- Content provided by FirstRanker.com ---
ThismutationinterruptsasiteofRNAsplicing.Thegeneencodesaprotein--acidalpha-glucosidase(EC3.2.1.20)
--whichisalysosomalhydrolase.Theproteinisanenzymethat
normallydegradesthealpha-1,4andalpha-1,6linkages
inglycogen,maltoseandisomaltoseandisrequiredforthe
--- Content provided by FirstRanker.com ---
degradationof1?3%ofcellularglycogen.Thedeficiencyofthisenzymeresultsintheaccumulationofstructurallynormalglycogen
inlysosomesandcytoplasminaffectedindividuals.
clinicalfeatures:
Accumulationofglycogeninlysosomes:Juvenileonsetvariant,
--- Content provided by FirstRanker.com ---
musclehypotonia,deathfromheartfailurebyage2;adultonsetvariant,muscledystrophy
5.Whichofthefollowingwillbemore
towardsthenegativepoleingel
electrophoresis?
--- Content provided by FirstRanker.com ---
a)5bpb)50kbp
c)150bp
d)550bp
e)50000bp
--- Content provided by FirstRanker.com ---
CorrectAnswer-B:EAns.is'b'i.e.,50kbp&'e'i.e.50000bp[RefVariousinternet
sites]
Ingelelectrophoresis,DNAmoleculesmovetowardspositiveendas
theyarenegativelychargedthemselves.
--- Content provided by FirstRanker.com ---
largermolecules(>500bp)moveslowlyascomparedtosmallermolecules.So,largerthemolecule,itismoretowardsthenegative
endandviseverse.
Polyacrylamidegelsareusuallyusedforproteins,andhavevery
highresolvingpowerforsmallfragmentsofDNA(5-500bp).
--- Content provided by FirstRanker.com ---
AgarosegelsontheotherhandhavelowerresolvingpowerforDNAbuthavegreaterrangeofseparation,andarethereforeused
forDNAfragmentsofusually50-20,000bpinsize,butresolutionof
over6Mbispossiblewithpulsedfieldgelelectrophoresis(PFGE)"-
wikipedia
--- Content provided by FirstRanker.com ---
6.Betagalactosidasedeficiencycauses?
a)Goucherdisease
b)Krabbe'sdisease
c)Fabry'sdisease
d)NeimannPickdisease
--- Content provided by FirstRanker.com ---
e)MetachromaticleukodystrophyCorrectAnswer-B
Ans.is'b'i.e.,Krabbe'sdisease[RefHarper30th/ep.251&
29thiep.235]
Krabbedisease,alsoknownasgloboidcellleukodystrophyor
--- Content provided by FirstRanker.com ---
galactosylceramidelipidosis,isanautosomal-recessivesphingolipidosiscausedbydeficientactivityofthelysosomal
hydrolasegalactosylceramidebeta-galactosidase(GALC).
GALCdegradesgalactosylceramide,amajorcomponentofmyelin,
andotherterminalbeta-galactose-containingsphingolipids,including
--- Content provided by FirstRanker.com ---
psychosine(galactosylsphingosine).Beta-galactosidaseisalysosomalenzymeresponsibleforcatalyzing
thehydrolysisofgangliosides.Thedeficiencyofthisenzymecan
leadto1ofthefollowingconditions:GM1gangliosidosis,Morquio
syndromeB,andgalactosialidosis.
--- Content provided by FirstRanker.com ---
7.Trueregardingphenylketoneureais?
a)Mustyorderisduetophenylalanineinsweat
b)Deficientenzymeisphenylalaninehydroxylase
c)Autosomaldominant
d)Maybeassociatedwithimpairedmentaldevelopment
--- Content provided by FirstRanker.com ---
e)InfantsarenormalatbirthCorrectAnswer-B:D:E
Ans.is'b'i.e.,Deficientenzymeisphenylalanine
hydroxylase,'d'i.e.Maybeassociatedwithimpairedmental
development&'e'i.e.Infantsarenormalatbirth
--- Content provided by FirstRanker.com ---
[RefHarper's30th/ep.304&29m/ep.288;Chatterjee5th/ep.426]InPhenylketonuriathereisinabilityofoxidationofphenylalanineinto
tyrosine.Thereisdefectivefunctionofphenylalaninehydroxylase.
Toxiclevelsofphenylalanine(andinsufficientlevelsoftyrosine)can
interferewithinfantdevelopmentinwayswhichhavepermanent
--- Content provided by FirstRanker.com ---
effects.Thediseasemaypresentclinicallywithseizures,hypopigmentation
anda"mustyodor"tothebaby'ssweatandurine(dueto
phenylacetate,acarboxylicacidproducedbytheoxidationof
phenylketone).
--- Content provided by FirstRanker.com ---
Untreatedchildrendevelopmicrocephaly,anddemonstrateprogressiveimpairmentofcerebralfunctionwhichcanleadto
intellectualdisability,behavioralproblems,andmentaldisorders.
8.Methodsthatcanbeusedtoseeprotein-
proteininteractioninclude?
--- Content provided by FirstRanker.com ---
a)Fluorescencelifeimagingb)Fluorescenceresonanceenergytransfer
c)Fluorescencepolarization
d)Fluorescencecomplementation
e)Alloftheabove
--- Content provided by FirstRanker.com ---
CorrectAnswer-EAns.is'e'i.e.,Alloftheabove[Refwiki]
Biochemicalmethods
1. Co-immunoprecipitation
2. Bimolecularfluorescencecomplementation(BiFC)
--- Content provided by FirstRanker.com ---
Biophysical&theoreticalmethods1. Bio-layerinterferometry
2. Dualpolarisationinterferometry(DPI)
3. Fluorescencepolarization/anisotropy
4. Fluorescenceresonanceenergytransfer(FRET)
--- Content provided by FirstRanker.com ---
5. Fluorescencelifetimeimagingmicroscopy(FLIM).9.Uncouplersofoxidativephosphorelation
include?
a)2,4-DNP
b)H2S
--- Content provided by FirstRanker.com ---
c)Cyanided)Thermogenin
e)Carboxin
CorrectAnswer-A:D
Ans.is'a'i.e.,2,4-DNP&'d'i.e.,Thermogenin[RefHarper
--- Content provided by FirstRanker.com ---
30thiep.132er29thlep.339;Vasudevan6thIep.234,235;ChatterjeaShinde7th/ep.132;LippincottOlep.79]
Uncouplersblockthecouplingofoxidationwithphosphorylation.
Thesecompoundsallowthetransferofreducingequivalentsin
respiratorychainbutpreventthephosphorylationofADPtoATPby
--- Content provided by FirstRanker.com ---
uncouplingthelinkagebetweenETCandphosphorylation.Uncouplersmaybe:?
1. Natural:-Thermogenin,thyroxine,longchainFAs
2. Synthetic:-2,4-dinitrophenol(2,4-DNP),2,4-dinitrocresol(2,4-
DNC),andCCCP.
--- Content provided by FirstRanker.com ---
Thermogeninisanuncouplerproteinpresentinmitochondriaofbrownadiposetissue(brownfat).
Ituncouplesoxidationandphosphorylationbyactingasachannel
forH+ionssothathydrogeniongradientcannotbuildup
10.Pyridoxineisrequiredfor?
--- Content provided by FirstRanker.com ---
a)Decarboxylationb)Carboxylation
c)Transamination
d)Transsulfuration
e)Oxidativedeamination
--- Content provided by FirstRanker.com ---
CorrectAnswer-A:C:DAns.is'a'i.e.,Decarboxylation,'c'i.e.Transamination&'d'i.e.
Transsulfuration[RefHarper's30m/ep.557&29th/ep.536,
537]
1. Transamination:PLPactsascoenzymefortransaminases.
--- Content provided by FirstRanker.com ---
2. Decarboxylation:Alldecarboxylationreactions(bydecarboxylases)requirePLP.ThusPLPisinvolvedingenerationofimportant
biogenicamines:GABA,Serotonin,Melatonin,Histamineand
catecholamines(epinephrine,norepinephrine).
Inpyridoxindeficiency,3-hydroxykinurenineaccumulatesandis
--- Content provided by FirstRanker.com ---
convertedtoalternatemetabolitexanthurenicacid(xanthurenate).Thus,xanthurenicacid(xanthurenate)excretioninurineisincreased
inpyridoxinedeficiency.Thuspyridoxinmaybeusedinxanturenic
aciduria.
11.Aminoacidsderivedfromtissuesare
--- Content provided by FirstRanker.com ---
directedtowards?a)Ammoniaformation
b)Ammoniumsalts
c)Ureacycle
d)Ureaformation
--- Content provided by FirstRanker.com ---
e)AminoacidpoolofcellsCorrectAnswer-E
Ans.is'e'i.e.,Aminoacidpoolofcells[Ref:Harper30"/ep.
298;NutritionbyPaulInsel,DonRoss,KimberleyMc?Mahon
4th/ep.242]
--- Content provided by FirstRanker.com ---
Whencellsbreakprotein,theprotein'saminoacidsreturntocirculation.Theseavailableaminoacids,foundthroughoutthebody
tissuesandfluids,arecollectivelyreferredtoasaminoacidpool.
Theavailableaminoacidswillbeutilizedforproteinsynthesis.
Othersmayhavetheiraminogroupremovedandbeusedto
--- Content provided by FirstRanker.com ---
produceenergyornonproteinsubstancessuchasglucose.12.Co-factorsrequiredforfattyacid
synthesisinhumanare?
a)ATP
b)NADPH
--- Content provided by FirstRanker.com ---
c)Biotind)Pyridoxine
e)Pentothenicacid
CorrectAnswer-A:B:C
Ans.is'a'i.e.,ATP,'b'i.e.NADPH&'c'i.e.,Biotin[RefHarper
--- Content provided by FirstRanker.com ---
30thlep.236er29th/ep.219;Lippincott4'5/ep.187]pyridoxalphosphateisneededforelongationofalreadysynthesized
fattyacids,notforsynthesisitself.
Extramitochondrial(cytoplasmic)Systemisconcernedwithdenovo
synthesisoffattyacidfromacetylCoA,andispresentincytosaol.
--- Content provided by FirstRanker.com ---
Palmiticacidissynthesized.CofactorrequirementsforfattyacidsynthesisareNADPH,ATP,
Mn+2,biotinandHCO3-(asasourceofCO2).
Themajorproductoffattyacidssynthesisispalmitate.Longerfatty
acidsareformedbyelongationreactionseitherinmicrosomes
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(endoplasmicreticulumorinmitochondria.13.AllareTruestatementsregardingOkazaki
fragmentEXCEPT?
a)RequiresDNApolymerase
b)Formsonleadingstrand
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c)Formsonlaggingstrandd)Requireshelicaseforopening
e)RequiresRNAprimer
CorrectAnswer-B
Ans.is'b'i.e.,Formsonleadingstrand[RefLippincott's5thiep.
--- Content provided by FirstRanker.com ---
399,401,406;Harper's30lep.383&250/ep.367]DNApolymerasesresponsibleforcopyingtheDNAtemplatesare
onlyableto"read"theparentalnucleotidesequencein3'-5'
direction,andtheysynthesizethenewDNAstrandsonlyin5'-3'
direction.Therefore,2newlysynthesizedchainsmustgrowin
--- Content provided by FirstRanker.com ---
oppositedirections.TheDNAchainwhichrunsinthe3'to5'directiontowardsreplication
forkascontinuedstrandiscalledleadingstrand.Thisrequiresonly
oneRNAprimer
TheDNAchainwhichrunsinthe5'to3'directionawayfromthe
--- Content provided by FirstRanker.com ---
replicationforkiscalledlaggingstrand.ItissynthesizeddiscontinuouslyandrequiresnumerousRNAprimers.
Asthereplicationforkmoves,RNAprimersaresynthesizedat
specificintervals.TheseRNAprimersareextendedbyDNA
polymeraseIIIintoshortpiecesofDNAcalledOkazaki
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fragments.14.AllaretrueregardingsatelliteDNA
EXCEPT?
a)RepeatedDNAsequencesintandem
b)Clusteredaroundcentromere
--- Content provided by FirstRanker.com ---
c)Clusteredaroundtelomeresd)Transcriptionallyactive
e)Noneoftheabove
CorrectAnswer-D
Ans.is'd'i.e.,Transcriptionallyactive[RefHarper's30"'/ep.
--- Content provided by FirstRanker.com ---
377-78;Lippincot4t5lep.461]RepetitivesequencesinDNAisalsocalled(satelliteDNA)
Theseconsistof5-500basepairlengthsrepeatedmanytimes.
Theseareoftenclusteredincentromeres(centralproteinof
chromosomeswheresisterchromatidsjoineachother)and
--- Content provided by FirstRanker.com ---
telomeres(repeatedsequenceattheendofchromosomes).Themajorityofthesesequencesaretranscriptionally
inactiveandplayastructuralrole
microsatellitesequencesmostcommonlyarefoundasdinucleotide
repeatsofACononestrandandTGontheoppositestrand.
--- Content provided by FirstRanker.com ---
Microsatelliterepeatsequencesconsistof2-6bprepeatedupto50times.TheACrepeatsequencesoccurat50000-100000locationsin
humangenome.
15.Truestatementregardingt-RNAis?
a)Containscodon
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b)Containsanti-codonc)Containsbluntends
d)Actsasaacceptorforaminoacidsinproteinsynthesis
e)Getsattachedtoribosomes
CorrectAnswer-B:D:E
--- Content provided by FirstRanker.com ---
Ans.is'b'i.e.,Containsanti-codon,'d'i.e.Actsasaacceptorforaminoacidsinproteinsynthesis&'e'i.e.Getsattachedto
ribosomes
[RepLippincoteselep.418;Harper's30'Vep.394]
tRNAistheSmallestofthethreemajorRNAShaving73to93
--- Content provided by FirstRanker.com ---
nucleotideresidues.Itcomprisesabout15%oftotalRNAinthecell.Acceptorarmconsistsofabasepairedstemthatterminatesin
thesequenceCCAatthe3'end.Thisistheattachmentsitefor
aminoacids.CCAtailisaddedduringpost-transcriptional
modification.
--- Content provided by FirstRanker.com ---
ItcontainsanticodonthatbasepairswiththecodonofcomingmRNA.Anticodonhasnucleotidesequencecomplementarytothe
codonofmRNAandisresponsibleforthespecificityofthetRNA.
ThroughTCarmtRNAgetsattachedtoribosome.
16.Examplesofchaperonincludeallexcept?
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a)Calreticulinb)Calnexin
c)Calbindin
d)BiP
e)Ubiquitin
--- Content provided by FirstRanker.com ---
CorrectAnswer-C:EAns.is'c'i.e.,Calbindin&`e'i.e.Ubiquitin[RefHarper's30th/e
p.609;Vasudevan5thlep.17]
Chaperonesarepresentinawiderangeofspeciesfrombacteriato
humans.Manysocalled'Heatshockproteins'(HSP)are
--- Content provided by FirstRanker.com ---
chaperones.Theyarealsoknown/asstressproteins.SomeChaperonesandEnzymesInvolvedinFoldingthatare
LocatedintheRoughEndoplasmicReticulumareBiP
(immunoglobulinheavychainbindingprotein),GRP94(glucose-
regulatedprotein),GRP-170,GRP-78,Calnexin,CalreticulinPDI
--- Content provided by FirstRanker.com ---
(proteindisulfideisomerase),PPI(peptidylprolylcis-transisomerase),HSP47,ERp29
17.VitaminEdeficiencyinadultcauses?
a)Hemolysis
b)PosteriorcolumnInvolvement
--- Content provided by FirstRanker.com ---
c)Peripheralneuropathyd)Hairloss
e)Impairedimmunity
CorrectAnswer-A:B:C:D:E
Ans.is'All'i.e.,a,b,c,d&e[Ref:Harper's30th/ep.553&29th/e
--- Content provided by FirstRanker.com ---
p.532,541,543]vitaminEdeficiencyarecharacterizedbyaxonaldegenerationinthe
posteriorcolumnsandaselectivelossoflargecalibremyelinated
sensoryaxonsinthespinalcordandperipheralnerves.
Subacutecombineddegenerationofspinalcord,alsoknownas
--- Content provided by FirstRanker.com ---
Lichtheim'sdisease,referstodegenerationoftheposteriorandlateralcolumnsofthespinalcordasaresultofvitaminB12
deficiency(mostcommon),vitaminEdeficiency,andcopper
deficiency.
VitaminEactiviyispresentinseveraltocopherols,themost
--- Content provided by FirstRanker.com ---
importantbeinga-,y-and8-tocopherol.a-Tocopherolisthemostabundantandistakenasthestandard.
SeleniumandvitaminEsupplementeachotherbytheiranti-oxidant
property.
Hemolyticanemia-duetooxidativedamagetoredblood
--- Content provided by FirstRanker.com ---
cells,Impairmentoftheimmuneresponse,Digestiveproblems&Malabsorptionleadingtoliverandpancreaticproblems,Dryskin
andhairloss
18.VitaminCdeficiencyisassociatedwith?
a)Decreasedimmunity
--- Content provided by FirstRanker.com ---
b)Improperwoundhealingc)Epistaxis
d)Seizures
e)Anemia
CorrectAnswer-A:B:C:E
--- Content provided by FirstRanker.com ---
Ans.is'a'i.e.,Decreasedimmunity,'b'i.e.,Improperwoundhealing,'c'i.e.,Epistaxis&`e'i.e.,Anemia[RefHarper's30thle
p.561-65;Internet]
GeneralsymptomsincludeLowgradefever,irritability,tachypnea,
digestivedisturbances,lossofappetite,weakness,weightloss,
--- Content provided by FirstRanker.com ---
vaguemyalgiasandarthritis&arthralgias.AnemiaDuetodefectinutilizationofiron&folicacid.
Dermatological:-Dryskin,Follicularhyperkeratosis,coiledhair,
splittingofhair,Poorwoundhealing
Impairedimmunityleadingrecurrentinfections,Irritabilityandother
--- Content provided by FirstRanker.com ---
psychologicsymptoms.19.Trueabouttelomeraseis?
a)DNAdependentRNApolymerase
b)RNAdependentDNApolymerase
c)Reversetranscriptaseenzyme
--- Content provided by FirstRanker.com ---
d)Increasedtelomeraseactivityisseeninsomaticcellse)Telomeraseincreasesthelongevityofcells
CorrectAnswer-B:C:E
Ans.is'b'i.e.,RNAdependentDNApolymerase,'c'i.e.Reverse
transcriptaseenzyme&`e'i.e.Telomeraseincreasesthe
--- Content provided by FirstRanker.com ---
longevityofcells[RefHarper29th/ep.358&28`"/ep.315,316;Robbin's8th/ep.40,296]
Telomeraseisareversetranscriptase(RNAdependentDNA
polymerase)andisresponsiblefortelomeresynthesisand
maintainingthelengthoftelomers(replicationofendof
--- Content provided by FirstRanker.com ---
chromosome).Thus,telomeraseprovidelongevitytothecellswhichcontainthisenzyme.
Telomeraseisabsentfrommostofthesomaticcellsandhencethey
sufferprogressivelossoftelomeresandtheyexitthecellcycle.
Senscentcellslacktelomerasesotheirtelomeresgetshortenedby
--- Content provided by FirstRanker.com ---
criticallengthandthesecellsremainsinGophase20.Whichis/arenottransportprotein?
a)Transferrin
b)Collagen
c)Ceruloplasmin
--- Content provided by FirstRanker.com ---
d)Hemoglobine)Albumin
CorrectAnswer-B
Ans.is'b'i.e.,Collagen[Ref
http://www.gastrohep.com/ebooks/rodes/Rodes_2_4_1.pdf]
--- Content provided by FirstRanker.com ---
CollagenisastructuralproteinAlbuminhascirculatingtransportproteinssuchassteroids,
thyroxine,triiodothyronine,fatsolublehormones,fattyacidstoliver,
unconjugatedbilirubin,manydrugs,Calcium,magnesium,cations&
anions.
--- Content provided by FirstRanker.com ---
CeruloplasminhasCopperHemoglobinOxygenfromlungtotisuues
Transferrinironionsintheferricform(Fe3+).
21.FullformofLCATis?
a)Lecithincholesterolacyltransferase
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b)Lecithincholesterolalkyltransferasec)Lecithincholineacetyltransferase
d)Lecithincholinealcoholtransferase
e)LecithincoAtransferase
CorrectAnswer-A
--- Content provided by FirstRanker.com ---
Ans.is'a'i.e.,Lecithincholesterolacyltransferase[RefHarper's30`Vep.272;Lippincott6thlep.234]
Lecithin-cholesterolacyltransferase(LCAT)ispresentinHDLand
esterifiesthecholesterolinHDL.MajoractivatorofLCATisApo-Al.
Apo-C1canalsoactivateLCAT.
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HDL-Cholesterolappearstobethebestindependentpredictorofcoronaryarterydisease(inverserelationship)thananyotherknown
riskfactor.ThatmeanslowHDLisamuchstrongerpredictorof
coronaryarterydiseasethanincreasedLDLcholesterolorincreased
totalcholesterol
--- Content provided by FirstRanker.com ---
Theintracellularcholesterolactivatestheintracellularenzymeacyl-CoAcholesterolacyltransferase(ACAT).Thisenzymecatalyzes
transferofanacylgroupfromafattyacidderivativetocholesterol,
resultingintheformationofesterifiedcholeserol,andthischolesterol
esterisstoredforsubsequentuse.
--- Content provided by FirstRanker.com ---
22.Whichorgancannotuseketonebodies?
a)Brain
b)RBC
c)Muscle
d)Heart
--- Content provided by FirstRanker.com ---
e)LiverCorrectAnswer-B:E
Ans.is'b'i.e.,RBC&`e'i.e.,Liver[RefHarper's30th/ep.227;
Vasudevanelep.145]
LiveritselfcannotutilizeketonebodiesasitlackstheenzymeCoA-
--- Content provided by FirstRanker.com ---
transferasewhichisrequiredforactivationofketonebody.Besideliver,RBCsalsodonotutilizeketonebodies(onlyglucoseis
thesolefuelforRBCs).
Acetoacetateandp-hydroxybutyrateareusedinpreferenceto
glucoseasenergysourcebycertaintissues,e.g.heart,muscle,
--- Content provided by FirstRanker.com ---
intestinalmucosaandrenalcortex.Brainalsoswitchestousingpredominantlyacetoacetateinstarvation.
Inextrahepatictissues,acetoacetateisactivatedtoacetoacetylCoA
bysuccinyl-CoA-acetoacetateCoAtransferase(thiophorase).
23.HGPRTareinvolve,andgoutcanbea
--- Content provided by FirstRanker.com ---
feature.a)HGPRTdeficiency
b)HGPRToveractivity
c)PRPPsynthetasedeficiency
d)Glucose6-phosphatasedeficiency
--- Content provided by FirstRanker.com ---
e)GlucosephosphatedehydrogenasedeficiencyCorrectAnswer-A:D
Answer.(a)HGPRTdeficiency,(d)Glucose6-phosphatase
deficiency
[Ref:Harper30th/354-56;Satyanarayan4th/269-70,394-951
--- Content provided by FirstRanker.com ---
VonGierke'sdisease(Type1glycogenstoragedisease):HyperuricemiaoccursduetoGlucose6-phosphataseenzyme
defect.
HGPRTdeficiency(asseeninLesch-Nyhansyndrome):Increased
productionofpurines
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Glucose6-phosphatasedeficiency:Purineoverproduction.Goutisusuallyprecededandaccompaniedbyhyperurlcemta
(plasmauricacidlevel>0.4Immol/L).
Hlperuricemiaiscausedbydacreasedrenalextretlon,lncreased
productlon"orincreasedintakeoturlcacid
--- Content provided by FirstRanker.com ---
24.Hyperphenylalaninemiaoccursdueto:
a)Phenylalaninehydroxylasedeficiency
b)Phenylalaninehydroxylaseoveractivity
c)Dihydrobiopterinreductasedeficiency
d)Tyrosinehydroxylasedeficiency
--- Content provided by FirstRanker.com ---
e)DefectindihydrobiopterinbiosynthesisCorrectAnswer-A:C:E
Answer:(a)Phenylalaninehydroxylase...,(c)Dihydrobiopterin
reductase...,(e)Defectindihydrobiopterinbiosynthesis
Hyperphenylalaninemiasarisefromdefectsinphenylalanine
--- Content provided by FirstRanker.com ---
hydroxylaseitself(typeI,classicphenylketonuriaorPKU),indihydrobiopterinreductase(typesIIandIII),orindihydrobiopterin
biosynthesis(typesIVandV).Alternativecatabolitesareexcreted.
PKUiscausedbyadcficiencyotphenylalaninehydroxyl.ase,isthe
mostcommonclinicallvencounteredinbornerrorofamino
--- Content provided by FirstRanker.com ---
acidmetabolism.Hyperphenylalaninemiamayalsobecausedbydeficienciesinany
oftheseveralenzymesrequiredtosynthesizeBH4,or
indihydropteridinereductase,whichregeneratesBH4fromBH2.
BH4isalsorequiredfortyrosinehydroxylaseandtryptophan
--- Content provided by FirstRanker.com ---
hydroxylase,whichcatalyzereactionsleadingtothesynthesisofneurotransmitters,suchasserotoninandreversethecentral
nervoussystem(CNS)effectsduetodeficienciesin
neurotransmitters.
25.DuringDNAreplicationwhichbond
--- Content provided by FirstRanker.com ---
breaks:a)Phosphodiesterbonds
b)Phosphatebond
c)Hydrogenbond
d)Glycosidicbonds
--- Content provided by FirstRanker.com ---
e)NoneCorrectAnswer-C
Answer:c.Hydrogenbond[Ref:Lippincott6th/397-400;Harper
30th/381-86;Satyanarayana4th/524-29]
WhenDNAreplicates,ahelicaseenzyme"unzips"thedoublehelix,
--- Content provided by FirstRanker.com ---
breakingthehydrogenbondsthatholdittogetherinthecenterThetwostrandsofthedoublehelixseparatewhenhydrogenbonds
betweenthepairedbasesaredisrupted.Disruptioncanoccurinthe
laboratoryifthepHoftheDNAsolutionisalteredsothatthe
nucleotidebasesionize,orifthesolutionisheated.
--- Content provided by FirstRanker.com ---
26.Oxidativephoephoryletlonnotinhiblted
by:
a)Fluoride
b)2,4-dinitrophenol(DNP)
c)Oligomycin
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d)Carboxine)Ouabin
CorrectAnswer-A:D:E
Answer:(a)Fluoride,(d)Carboxin,(e)Ouabin(Ref:Harper
30th/132-33;Lippincott6th/79;Satyanarayan4th/233-34;
--- Content provided by FirstRanker.com ---
Chatterjea7th/132-341TherearethreesitesinrespiratorychainwhereATPisformedby
oxidativephosphorylation.Threesitesare-Sitel(Complex-I),Site
Il(ComplexIII)andSiteIll(ComplexIV).Complexll(Succinate
dehyfuogenaseFAD)isnotinvolvedinoxidativephosphorylation.
--- Content provided by FirstRanker.com ---
2,4-dinitrophenol(DNP)Dinitrocresol,Trifluorocarbonylcyanidephenylhydrazone,Pentachlorophenol
Aspirin(inhighdose),Highconcentrationofthermogenin,thyroxine
andlongchainfreefattyacids,Antibiotics-valinomycin,gramicidinA
andnigercinareinhibitoresofoxidativephosphorylation
--- Content provided by FirstRanker.com ---
CarboxininhibitcomplexII,whichisnotinvolvedinoxidativephosphorylation(sonotincludedinanswer)"?Chatterjea7h/134
"OuabainisacardiacglycosidethatactsbyinhibitingtheNW/IC-
ATPasesodium-potassiumionpump"-Harper30th/491
Fluoride:Itinhibitstheactivitiesofcertainenzymes.Sodium
--- Content provided by FirstRanker.com ---
fluorideinhibitsenolase(ofglycolysis)whilefluoroacetateinhibitsaconitase(ofcitricacidcycle)"-Satyanarayan4th/420.
27.TrueaboutApolipoproteii.
a)Constituteperipheralregionofplasmalipoproteins
b)DividedintoA,B,Conly
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c)ApoA-Iisthemajorproteincomponentofhighdensitylipoprotein(HDL)
d)ApoA,BandCarefurtherdivided
e)Roleinenzymeactivation
CorrectAnswer-A:C:D:E
--- Content provided by FirstRanker.com ---
Answer.(a)Constituteperipheralregionof...,(c)ApoA-Iisthemajorprotein...,(d)ApoA,BandCare...,(e)Roleinenzyme...
[Ref:Harper30th/254-55;Satyanarayan4th/318;
http://noprniscairres.in/bitstream;onlinelibrary.wiley.com]
Apolipoproteins(apo)playveryimportantrolesinthesynthesisand
--- Content provided by FirstRanker.com ---
catabolismofplasmalipoproteins,inlipidtransport,andasactivatorsofcertainenzymesassociatedwithlipidandlipoprotein
metabolism
Apolipoproteinsaretheproteincomponentofplasma
lipoproteinswhichconsistofacoreoftriglyceridesandcholesterol
--- Content provided by FirstRanker.com ---
estersandaperipheralregionofphospholipid,sphingolipidandprotein.
ApoA-Iisthemajorproteincomponentofhighdensity
lipoprotein(HDL)andaminorcomponentofchylomicronsandvery
lowdensitylipoprotein(VLDL).
--- Content provided by FirstRanker.com ---
Apolipoproteinsaredividedbystructureandfunctionintofivemajorclasses,AthroughE,withmostclasseshaving
subclasses,forexample,apolipoprotein(orapo)A-IandapoC-
II.
28.whichnNAcontalneabnormalpurineand
--- Content provided by FirstRanker.com ---
pyrimidine:a)tRNA
b)23SrRNA
c)16SrRNA
d)5SrRNA
--- Content provided by FirstRanker.com ---
e)mRNACorrectAnswer-A
Answer:a.tRNA
tRNAmoleculecontainahighpercentageofunusalbases,for
example,dihydrouracilandhaveextensiveintra-chainbasepairing
--- Content provided by FirstRanker.com ---
thatleadstocharacteristicsecondaryandtertiarystructure"-Lippincott6th/418.
ThetRNAmoleculescontainahighpercentageofunusualbases
(forexample,dihydrouracil)andhaveextensiveintrachainbase-
pairingthatleadstocharacteristicsecondaryandtertiarystructure.
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TransferRNAisuniqueamongnucleicacidsinitscontentof"unusual"bases.Anunusualbaseisanypurineorpyrimidinering
excepttheusualA,G,C,andUfromwhichallRNAsare
29.Aminoacidscontaininghydroxylgroup:
a)Threonine
--- Content provided by FirstRanker.com ---
b)Tyrosinec)Serine
d)Tryptophan
e)Valine
CorrectAnswer-A:B:C
--- Content provided by FirstRanker.com ---
Answer:(a)Threonine,(b)Tyrosine,(c)SerineLippincott6th/4Serine,threonine,andtyrosineeachcontainapolarhydroxyl
groupthatcanparticipateinhydrogenbondformation.
Thesidechainsofasparagineandglutamineeachcontainacarbon
ylgroupandanamidegroup,bothofwhichcanalsoparticipatein
--- Content provided by FirstRanker.com ---
hydrogenbonds"-30.CytochromeP45Ois/areinvolvedln:
a)Hydroxylationofxenobiotics
b)Methylationofxenobiotics
c)Deaminationreaction
--- Content provided by FirstRanker.com ---
d)Involvedinhydroxylationofsteroidse)Druginteraction
CorrectAnswer-A:C:D:E
Ans.(a)Hydroxylationofxenobiotics,(c)Deaminationreaction,
(d)Involvedinhydroxylationofsteroids,(e)Druginteraction
--- Content provided by FirstRanker.com ---
[Ref:Harper30th/584-85;KDT7th/23-26;Lippincott6th/;Satyanarayan4th/639-40]
CytochromeP450sareinvolvedinphaseI(hydroxulation)ofthe
metabolismofxenobiotics,notinphaseII.Methylationof
xenobioticsoccurinphaseIIbymethyltransferase
--- Content provided by FirstRanker.com ---
31.Componentof50Sribosomalzubunit:
a)16SRNA
b)18SRNA
c)5.8RNA
d)5SRNA
--- Content provided by FirstRanker.com ---
e)23SRNACorrectAnswer-D:E
Answerd.5SRNA,(e)23SRNA(Lippincott6th/436):
The50Ssubunitisprimarilycomposedofproteinsbutalsocontains
single-strandedRNAknownasribosomalRNA(rRNA).rRNAforms
--- Content provided by FirstRanker.com ---
secondaryandtertiarystructurestomaintainthestructureandcarryoutthecatalyticfunctionsoftheribosome.
Itincludesthe5SribosomalRNAand23SribosomalRNA.
50Sincludestheactivitythatcatalyzespeptidebondformation
(peptidyltransferreaction),preventsprematurepolypeptide
--- Content provided by FirstRanker.com ---
hydrolysis,providesabindingsitefortheG-proteinfactors(assistsinitiation,elongation,andtermination),andhelpsproteinfoldingafter
synthesis.
32.Trueaboutroleofphospholipids:
a)Celltocellrecognition
--- Content provided by FirstRanker.com ---
b)Cellsignalingc)PrecursorofSecondMessengers
d)Mediatorsofinflammation
e)Regulatemembranepermeability
CorrectAnswer-B:C:D:E
--- Content provided by FirstRanker.com ---
Answer:(b)Cellsignaling,(c)PrecursorofSecondMessengers,(d)Mediatorsofinflammation,(e)Regulate
membranepermeability
(Ref:Harper30th/212,216,253-54;Robbins9th/83-84;
Satyanarayan4th/36-37)
--- Content provided by FirstRanker.com ---
Glycoprotein(fibronectin,laminin)isinvolveincell-cellrecognitionandadhesion.
Theinositolispresentinphosphatidylinositolasthestereoisomer,
myoinositol.Phosphorylated
phosphatidylinositols(phosphoinositides)areminorcomponentsof
--- Content provided by FirstRanker.com ---
cellmembranes,butplayanimportantpartincellsignalingandmembranetrafficking.
Sphingomyelinsarealsofoundinlargequantitiesinthemyelin
sheaththatsurroundsnervefibers.Theyarebelievedtoplaya
roleincellsignalingandinapoptosis.
--- Content provided by FirstRanker.com ---
Phosphatidylinositolisthesourceofsecondmessengersinositoltriphosphateanddiacylglyceol,thatareinvovedthe
actionofsomehoromones.
33.Correctstatementaboutmembrane:
a)Phospholipidsundergorapidlateraldiffusion
--- Content provided by FirstRanker.com ---
b)Transversemovementoflipidsacrossthemembraneisfasterthanprotein
c)Hydrophobiccoreofthephospholipidbilayerremainsconstantly
inmotionbecauseofrotationsaroundthebondsoflipidtails
d)Phospholipdsthathaveonefattyacylgroup,cannotformthe
--- Content provided by FirstRanker.com ---
bilayere)Phospholipidsspanwholebilayer
CorrectAnswer-A:C:D
Ans.a)Phospholipidsundergo...,(c)Hydrophobiccoreofthe
phospholipid...,(d)Phospholipdsthathaveonefattyacyl...
--- Content provided by FirstRanker.com ---
(Ref:Harper30th/215-17,478-90;Satyanarayan4th/650-51;en.wikibooks.org]
Membranesaremainlymadeupoflipids,proteinsandsmallamount
ofcarbohydrate.Phospholipidsarethemostcommonlipidspresent
andtheyareamphipathicinnature.
--- Content provided by FirstRanker.com ---
Thehydrophobiccoreofthephospholipidbilayerisconstantlyinmotionbecauseofrotationsaroundthebondsoflipidtails.
Hydrophobictailsofabilayerbendandlocktogether.However,
becauseofhydrogenbondingwithwater,thehydrophilichead
groupsexhibitlessmovementastheirrotationandmobilityare
--- Content provided by FirstRanker.com ---
constrained.Thisresultsinincreasingviscosityofthelipidbilayerclosertothehydrophilicheads.
Thelysophosphollpi.dshaveonlyonefattyacylgroup,itcannotform
thebilayerasthepolarheadsaretoolarge,similarlycholesterolalso
cannotformbilayersastherigidfitsedringsystenxsandadditional
--- Content provided by FirstRanker.com ---
nonpolartailsaretoolarge".
34.TrueaboutChromatin,remodeling:
a)EnergyisrequiredtodisplacethehistoneoctamersfromDNA
ortranslocatethemontoneighboringDNAsegments
b)Histonemodificationsbyspecificenzyme
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c)Donotinvolveenzymesd)Aberrationsinchromatinremodelingproteinsmaybe
associatedwithcancer
e)None
CorrectAnswer-A:B:D
--- Content provided by FirstRanker.com ---
Answer:aEnergyisrequiredtodisplacethehistone...,(b)Histonemodificationsby...,(d)Aberrationsinchromatin...
[Ref:Harper30th/735,438-39;Lippincott6th/422,460;Harrison
19th/102e-7]
Chromatinremodelingisthedynamicmodificationof
--- Content provided by FirstRanker.com ---
chromatinarchitecturetoallowaccessofcondensedgenomicDNAtotheregulatorytranscriptionmachineryproteins,and
therebycontrolgeneexpression.
chromatinremodelingcomplexesdisplacethehistone
octamersfromDNAortranslocatethemontoneighboringDNA
--- Content provided by FirstRanker.com ---
segments,therebyexposingunderlyingDNAsequencestosequencespecificregulatoryfactors.
histoneacetylaseandotherenzymaticactivitiesareassociated
withthecoregulatorsinvolvedinregulationofgene
transcription.
--- Content provided by FirstRanker.com ---
Aberrationsinchromatinremodelingproteinsarefoundtobeassociatedwithhumandiseases,includingcancer.
35.Bestassessmentofproteinbinding
regionsonaDNAmoleculecanbedone
by:
--- Content provided by FirstRanker.com ---
a)DNAfootprintingb)RTPCR
c)Microarray
d)Westernblotting
e)Northernblotting
--- Content provided by FirstRanker.com ---
CorrectAnswer-AAnswer-(a)DNAfootprinting[Ref:www.biotecharticles.com;
www.biologyexams4u.comLippincott6th/473]
DNAfootprinting-Anin-vitrotechniquetofindoutprotein
bindingregionsonaDNAmolecule.Thetechniqueisalso
--- Content provided by FirstRanker.com ---
calledasDNAseIfootprinting.Thousandsofproteins(enzymes)areinteractingwithDNAinthenucleusfor
regulatingactivitieslikereplication,transcription,translation
etc.
DNAFootprintingisamoleculartechniqueusedtoidentifythe
--- Content provided by FirstRanker.com ---
specificDNAsequence(bindingsite)thatbindstoaprotein.Thistechniquemainlyusedtoidentifythetranscriptionfactors
whichbindtopromoter,enhancerorsilencerregionofgeneto
regulateitsexpression.Thereforetheregulationoftranscript
ionofagenecanbestudiedusingthismethod.
--- Content provided by FirstRanker.com ---
36.Nucleosomecontains:
a)DNA
b)RNA
c)Chromatin
d)Histone
--- Content provided by FirstRanker.com ---
e)NoneCorrectAnswer-A:D
Ans:a.DNAd.Histone[RefHarper30th/371-72;Lippincott6th/
409]
Histonesarehighlyalkalineproteinsfoundineukaryoticcellnuclei
--- Content provided by FirstRanker.com ---
thatpackageandordertheDNAintostructuralunitscallednucleosomes.
Theyarethechiefproteincomponentsofchromatin,actingas
spoolsaroundwhichDNAwinds,andplayingaroleingene
regulation.
--- Content provided by FirstRanker.com ---
WhenthehistoneoctamerismixedwithpurifieddsDNAunderappropriateionicconditions,thesamex-raydiffractionpatternis
formedasthatobservedinfreshlyisolatedchromatin.Biochemical
andelectronmicroscopicstudiesconfirmtheexistenceof
reconstitutednucleosomes.
--- Content provided by FirstRanker.com ---
Inthenucleosome,theDNAissupercoiledinalefthandedhelixoverthesurfaceofthedisk-shapedhistoneoctamer
37.EnzymeusedinDNArepairis/are:
a)DNAgyrase
b)DNApolymerase
--- Content provided by FirstRanker.com ---
c)Restrictionendonucleased)DNAligase
e)None
CorrectAnswer-B:D
Ans:b.DNApoly...,d.DNA(RefHarper30th/382,389-92;
--- Content provided by FirstRanker.com ---
Lippincott6th/411-131Whenthestrandcontainingthemismatchisidentified,an
endonucleasenicksthestrandandthemismatchednucleotide(s)
is/areremovedbyanexonuclease.
Additionalnucleotidesatthe5'-and3'-endsofthemismatchare
--- Content provided by FirstRanker.com ---
alsoremoved.Thegapleftbyremovalofthenucleotidesisfilled,usingthesisterstrandasatemplate,byaDNApolymerase.
The3'-hydroxylofthenewlysynthesizedDNAisjoinedtothe5'-
phosphateoftheremainingstretchoftheoriginalDNAstrandby
DNAligase
--- Content provided by FirstRanker.com ---
38.AllareUreacycleenzymesexcept:
a)Ornithinetranscarbamylase
b)Carbamoyl-phosphatesynthetaseI
c)Argininosuccinase
--- Content provided by FirstRanker.com ---
d)Citrullinesynthasee)Argininosuccinicacidsynthetase
CorrectAnswer-D
Answer:(D)Citrullinesynthase[RefHarper30th/290-96,
29th/274-88;Lippincott
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39.PhospholipaseA2acton:
a)Phosphoglycericacid
b)Phosphate
c)Ca+
d)Phosphatidyl-inositol
--- Content provided by FirstRanker.com ---
e)NoneCorrectAnswer-D
Ans:d.Phosphatidyl-inositol
Phospholipaseshydrolyzethephosphodiesterbondsof
phosphoglycerides,witheachenzymecleavingthephospholipidata
--- Content provided by FirstRanker.com ---
specificsite.Phospholipasesreleasemoleculesthatcanserveasmessengers
(forexample,DAGandIP3),orthatarethesubstratesforsynthesis
ofmessengers(forexample,arachidonicacid.
Phospholipasesareresponsiblenotonlyfordegrading
--- Content provided by FirstRanker.com ---
phospholipids,butalsofor"remodeling"them.Forexample,phospholipasesAlandA2removespecificfattyacidsfrom
membrane-boundphospholipids;thesecanbereplacedwith
alternativefattyacidsusingfattyacylCoAtransferase.
40.Non-polaraminoacidsare:
--- Content provided by FirstRanker.com ---
a)Prolineb)Lysine
c)Isoleucine
d)Arginine
e)Asparginine
--- Content provided by FirstRanker.com ---
CorrectAnswer-A:CAns:a.Prolinec.Isoleucine[RefHarper30th/16-22;Lippincott
6th/1-9;Satyanarayan4th/48]
AcidicandPolarsidechainsAsparticAcidGlutamicAcid
BasicandPolarsidechainsArginine,Lysine,Histidine
--- Content provided by FirstRanker.com ---
Uncharged&PolarsidechainsAsparginine,Glutamine,Serine,Threonine,Tyrosine
NonPolarAminoAcidswithNonPolarsidechainsGlycine,
Alanine,Valine,Leucine,Isoleucine,Proline.
41.Trueaboutsqualene:
--- Content provided by FirstRanker.com ---
a)Presentinsubhumanprimateonlyb)Itisoneofthemajorcarbohydratesofbody
c)Itinvolvesinthesynthesisofcholesterol
d)Itinvolvesinthesynthesisofsteroids
e)None
--- Content provided by FirstRanker.com ---
CorrectAnswer-C:DAns:(C)Itinvolvesinsynthesisofcholesterol,(D)Itinvolvesin
synthesisofsteroids
Squaleneisahydrocarbonandatriterpene,andisanaturaland
vitalpartofthesynthesisofallplantandanimalsterols,including
--- Content provided by FirstRanker.com ---
cholesterol,steroidhormones,andvitaminDinthehumanbody.Squaleneisusedincosmetics,andmorerecentlyasan
immunologicadjuvantinvaccines.
Itisanatural30-carbonorganiccompoundoriginallyobtainedfor
commercialpurposesprimarilyfromsharkliveroil(henceitsname),
--- Content provided by FirstRanker.com ---
althoughplantsources(primarilyvegetableoils)arenowusedaswell,includingamaranthseed,ricebran,wheatgerm,andolives.
Squaleneandomega2fattyacidhasunlikeomega3fishoilsmore
completeandeffectivechemicalgroups.
42.Molecularweightofproteincanbe
--- Content provided by FirstRanker.com ---
determined/estimatedby:a)SDS-PAGE
b)Gelfiltrationchromatography
c)Agarosegelelectrophoresis
d)Ultracentrifugation
--- Content provided by FirstRanker.com ---
e)FRETmicroscopyCorrectAnswer-A:B:D
Ans:(A)SDS-PAGE(B)Gelfiltrationchromatography(D)
Ultracentrifugation[RefHarper30th/28;Shinde7th/772-74;
Satyanarayan4th/725,60;Vasudevan5th/482-851
--- Content provided by FirstRanker.com ---
"SDS-PAGEiscommonlyusedformolecularweightdeterminationofproteins"(Vasudevan5th/482)
"SDS-PAGEisapopulartechniquefordeterminationofmolecular
weightofproteins"(Satyanarayan4th/725)
"Sodiumdodecylsulfate-polyacrylamidegelelectrophoresis(SDS-
--- Content provided by FirstRanker.com ---
PAGE)isareliablemethodfordeterminingthemolecularweight(MW)ofanunknownprotein".
"Thegelfiltrationchromatographytechniqueisusedfor"Separation
ofproteinmolecules,purificationofproteins&molecularweight
determinations"Ultracentrifugationisanindispensabletoolforthe
--- Content provided by FirstRanker.com ---
isolationofsubcellularorganelles,proteins,&nucleicacids.Inaddition,thistechniqueisalsoemployedindeterminationof
molecularweightofmacromolecules\
43.GelusedinRNAelectrophoresis:
a)Agarosegel
--- Content provided by FirstRanker.com ---
b)Polyacrylamideplaingelc)PolyacrylamideSDS(Sodiumdodecylsulphate)impregnated
Polyacrylamidegel
d)A&C
e)None
--- Content provided by FirstRanker.com ---
CorrectAnswer-AAns:a.Agarosegel
SeparationofRNAinagarosegelsisusedforanumberofdifferent
purposes,includingNorthernblotstomonitorRNAexpression
levels,checkingRNAintegrityandsizeselectionofRNAforcloning
--- Content provided by FirstRanker.com ---
experiments.SeparationofRNAbasedonfragmentlengthrequiresconditions
thataredifferentfromDNAanalysis.
ThemostfrequentlyuseddenaturantsforRNAagarosegel
electrophoresisareformaldehyde,formaldehyde/formamide,and
--- Content provided by FirstRanker.com ---
glyoxalplusDMSO.ThemostefficientRNAdenaturantismethylmercuryhydroxide.
Becauseofthehazardsassociatedwiththisdenaturant,itisthe
leastusedsystemforRNA
44.Whichoffollowingreleases/provide
--- Content provided by FirstRanker.com ---
energy:a)ConversionofADPtoATP
b)Breakingofhighenergybondtolowenergybond
c)Conversionofpyruvatetolactate
d)Electricalgradientacrossinner&outersideofmitochondria]
--- Content provided by FirstRanker.com ---
membranee)Passageofe-throughFADinelectrontransportchain
CorrectAnswer-B:D:E
Ans:(B)Breakingofhigh...(D)Electricalgradientacross...(E)
Passageofe-throughFAD....
--- Content provided by FirstRanker.com ---
Inabsenceof0xygenpyruvateisreducedtolacticacid(withoutproducingATP).Inanaerobicglycolysis,pyruvateactsasa
temporaryH-store.
Itdehydrogenation(oxidizes),thereducedNADH+H+backto
oxidizedNAD+,sothatglycolysiscancontinueevenintheabsence
--- Content provided by FirstRanker.com ---
of02.Inpresenceof02,lacticacidcanbeoxidizedintopyruvicacidagain.
ElectrontransportiscoupledtothephosphorylationofADPbythe
transport("pumping")ofprotons(H+)acrosstheinnermitochondrial
membranefromthematrixtotheintermembranespaceat
--- Content provided by FirstRanker.com ---
ComplexesI,III,andIV.Thisprocesscreatesanelectricalgradient(withmorepositive
chargesontheoutsideofthemembranethanontheinside)anda
pHgradient(theoutsideofthemembraneisatalowerpHthanthe
inside).
--- Content provided by FirstRanker.com ---
Theenergygeneratedbythisprotongradientissufficienttodrive
ATPsynthesis.Thus,theprotongradientservesasthecommon
intermediatethatcouplesoxidationtophosphorylation.
45.Restrictionendonucleasecleaves:
a)dsDNA
--- Content provided by FirstRanker.com ---
b)RNAc)Histone
d)Protein
e)ssDNA
CorrectAnswer-A
--- Content provided by FirstRanker.com ---
Ans:a.dsDNARestrictionendonucleases(restrictionenzymes),which
cleavedouble-stranded(ds)DNAintosmaller,moremanageable
fragments,hasopenedthewayforDNAanalysis"
Restrictionenzyme(REorRestrictionEndonuclease)isanenzyme
--- Content provided by FirstRanker.com ---
thatcleavedouble-strandedDNAQatspecificrecognitionnucleotideknownasrestrictionsitesQ
ThecutDNAfragmentsbyREmayhavestickyends(cohesive
ends)?orbluntsends?dependingonthemechanismusedby
enzyme
--- Content provided by FirstRanker.com ---
DNAfragmentswithstickyendsareparticularlyusefulforrecombinantDNAexperiments(hybridorchimericDNAmolecules)
Restrictionenzymeisnamedaccordingtotheorganismfromwhich
itwasisolated
46.Trueaboutgeneticcode:
--- Content provided by FirstRanker.com ---
a)FollowMendelianlawb)Itistotalnumberofchromosomeinthebody
c)Itisnucleotidesequencewhichcodesforaminoacids
d)ItcodesforDNA
e)None
--- Content provided by FirstRanker.com ---
CorrectAnswer-CAns:c.Itisnucleotidesequencewhichcodesforaminoacids
MendelianGeneticsiswidelyregardedasthecornerstoneof
classicalgenetics.Itisasetofprimarybeliefsrelatingtothe
transmissionofhereditarycharacteristicsfromparentorganismsto
--- Content provided by FirstRanker.com ---
theiroffspringThegeneticcodeisadictionarythatidentifiesthecorrespondence
betweenasequenceofnucleotidebasesandasequenceofamino
acids.
TheNucleotideSequenceofanmRNAMoleculeConsistsofa
--- Content provided by FirstRanker.com ---
SeriesofCodonsThatSpecifytheAminoAcidSequenceoftheEncodedProtein
47.Whichofthefollowingisfeature(s)of
diabeticketoacidosis:
a)Decreasedtriglyceridelevel
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b)Increasedfattyacidlevelc)TLipoprotein
d)Decreasedketonebodies
e)HighAniongapacidosis
CorrectAnswer-B:C:E
--- Content provided by FirstRanker.com ---
Ans:(B)Increasedfattyacidlevel(C)TLipoprotein(E)HighAniongapacidosis[RefHarper30th/231;Lippincott6th/339,
345;Satyanarayan4th/481,682;Harrison19th/2417-18]
DKAischaracterizedbyhyperglycemia,ketosis,andmetabolic
acidosis(increasedaniongap)alongwithanumberofsecondary
--- Content provided by FirstRanker.com ---
metabolicderangements,Leukocytosis,hypertriglyceridemia,andhyperlipoproteinemiaarecommonlyfoundaswell
Increasedlacticacidproductionalsocontributestotheacidosis.The
increasedfreefattyacidsincreasetriglycerideandVLDLproduction.
VLDLclearanceisalsoreducedbecausetheactivityofinsulin-
--- Content provided by FirstRanker.com ---
sensitivelipoproteinlipaseinmuscleandfatisdecreased.Hypertriglyceridemiamaybesevereenoughtocausepancreatitis.
Reducedinsulinlevels,incombinationwithelevationsin
catecholaminesandgrowthhormone,increaselipolysisandthe
releaseoffreefattyacids.Normally,thesefreefattyacidsare
--- Content provided by FirstRanker.com ---
convertedtotriglyceridesorvery-low-densitylipoprotein(VLDL)intheliver.
48.Secondmessengeris/are:
a)Ca2+
b)DNA
--- Content provided by FirstRanker.com ---
c)Histoned)cDNA
e)None
CorrectAnswer-A
Ans:a.Ca2+[RefHarper30th/501,91-92,179,343;Lippincott
--- Content provided by FirstRanker.com ---
6th/94-951Nucleotides,suchascyclicadenosinemono-phosphate(cAMP)and
cyclicguanosinemonophosphate(cGMP),serveassecond
messengersinsignaltransductionpathways.
Twoofthemostwidelyrecognizedsecondmessengersystemsare
--- Content provided by FirstRanker.com ---
thecalciumlphosphatidylinositolsystem,andtheadenylylcyclasesystem,whichisparticularlyimportantinregulatingthepathwaysof
intermediarymetabolism.
49.Nucleicacidamplificationtechniquesare:
a)PCR
--- Content provided by FirstRanker.com ---
b)RealtimePCRc)DNACloning
d)NextgenerationDNAsequencing
e)None
CorrectAnswer-A:B
--- Content provided by FirstRanker.com ---
Ans:a.PCR...,b.Realtime....[RefHarper30th/458;Robbins9th/180;Lippincott6th/479;Harrison19th/150e-7;http://link.
springer.corn]
Real-timePCRautomatesthelaboriousprocessofamplificationby
quantitatingreactionproductsforeachsampleinevery
--- Content provided by FirstRanker.com ---
Cycle.Thereareseveralmethodsforamplification(copying)ofsmall
numbersofmoleculesofnucleicacidtoreadilydetectablelevels.
TheseNAATsincludePCR,LCR,stranddisplacementamplification,
andself-sustainingsequencereplication.
--- Content provided by FirstRanker.com ---
Theamplifiednucleicacidcanbedetectedafterthereactioniscompleteor(inreal-timedetection)asamplificationproceeds.The
sensitivityofNAATsisfargreaterthanthatoftraditionalassay
methodssuchasculture.
50.Whichofthefollowingis/aretrueabout
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pHofsolution:a)Absoluteconcentrationofacid&salt
b)Relativeconcentrationofacid&saltinsolution
c)IncreaseoftemperatureincreasespH
d)AriseinH+concentrationdecreasespH
--- Content provided by FirstRanker.com ---
e)NoneCorrectAnswer-B:D
Ans:(B)Relativeconcentration...,(D)AriseinH*concentra
tion....
"WhenpHmeasuredatroomtemperaturethereisnodirect
--- Content provided by FirstRanker.com ---
correlationbetweenpHandtemperature.AriseinH+concentrationdecreasespHwhileafallinH+
concentrationincreasespH.ThereverseistrueforOH-
concentration
Theratioofsalttoacidconcentration-Actualconcentrationsofsalta
--- Content provided by FirstRanker.com ---
acidinabuffersolutionmaybevaryingwidely,withnochangeinpH,solongastheratiooftheconcentrationsremainsthesame
51.Truestatement(s)aboutMagnetic-
activatedcellsorting:
a)Itisamethodtoseparatespecificcellfromcomplexmixture
--- Content provided by FirstRanker.com ---
b)Fluorescentdyesareusesc)Antibody-coatedmagneticnanoparticlesareused
d)Antibodiesusedarespecificforcertaincellsurfacemarkers
e)Magneticfieldisapplied
CorrectAnswer-A:C:D:E
--- Content provided by FirstRanker.com ---
Ans:(A)Itisamethod...,(C)Antibody-coatedmagnetic...,(D)Antibodiesusedare...,(E)Magneticfieldisappli...
MACS,isaproceduredevelopedbyMiltenyiBiotectoseparatecells
fromcomplexmixturesusingantibody-coatedmagneticnano
particles.
--- Content provided by FirstRanker.com ---
Theantibodiesarespecificforcertaincellsurfacemarkers,eitherexpressedonyourpopulationofinterest(positiveselection),or
expressedonundesiredcelltypes(negativeselection).
Afteraddingtheantibody-coatedbeadstothecellmixtureand
incubating,thesuspensionisaddedtoaspecialsingle-use
--- Content provided by FirstRanker.com ---
separationcolumnaffixedtoamagnet,towhichthebeadsstick,whileunlabeledcellsflowthrough.
52.Whichofthefollowingis/aretrueabout
Translation:
a)N-formylmethionineisfirstaminoacidinprokaryotes
--- Content provided by FirstRanker.com ---
b)UsesenergyinformofGMPc)ElongationfactorEF-1&EF-2usedinprokaryotes
d)ElongationfactorPisusedineukaryoticorganism
e)Threeinitiationfactorsarerequiredinprokaryotes
CorrectAnswer-A:E
--- Content provided by FirstRanker.com ---
Ans:a.N-formylmethionine...,e.Threeinitiation[RefHarper30th/419-23;Lippincott6th/438-42;Satyanarayan4th/554-60]
Ineukaryotes,thefirstaminoacidincorporatedismethionine(AUG
codon).Butinprokaryotes,thesamecodonattractsN-formyl
methionine,whichisthefirstaminoacid"(Vasudevan5th/432)
--- Content provided by FirstRanker.com ---
"ElongationfactorPisaprokaryoticproteintranslationfactorrequiredforefficientpeptidebondsynthesison70S
ribosomesfromfMet-tRNAfMet.Itprobablyfunctionsindirectlyby
alteringtheaffinityoftheribosomeforaminoacyl-tRNA,thus
increasingtheirreactivityasacceptorsforpeptidylStepsinProtein
--- Content provided by FirstRanker.com ---
SynthesisInprokaryotes,threeinitiationfactorsareknown(IF-1,IF-2,andIF-
3),whereasineukaryotes,thereareoverten(designatedeIFto
indicateeukaryoticorigin).EukaryotesalsorequireATPforinitiation.
53.TwostrandsofDNAis/areheldby:
--- Content provided by FirstRanker.com ---
a)Glycosidicbondb)Hydrogenbond
c)Covalentbond
d)Ionicbond
e)Vanderwaalforce
--- Content provided by FirstRanker.com ---
CorrectAnswer-BAnswer(b)hydrogenbond[RefHarper30th/359;Lippincott
6th/396-97;Satyanarayan4th/75]
Thetwostrandsareheldtogetherbyhydrogenbondformed
bycomplementarybasepairs"(Satyanarayan4th/75)
--- Content provided by FirstRanker.com ---
"Thebasepairsareheldtogetherbyhydrogenbonds:twobetweenAandTandthreebetweenGandC.Thesehydrogenbonds,plus
thehydrophobicinteractionsbetweenthestackedbases,stabilize
thestructureofthedoublehelix.
54.Silverstainingisdonefor:
--- Content provided by FirstRanker.com ---
a)DNAb)RNA
c)Karyotypinganalysis
d)Protein
e)Collagen
--- Content provided by FirstRanker.com ---
CorrectAnswer-A:B:C:D:EAnswer-(A)DNA(B)RNA(C)Karyotypinganalysis(D)Protein
(E)Collagen
Silverstainingisahighlysensitivemethodfordetectingproteinsand
nucleicacids(dsDNA&RNA)inpolyacrylamideslabgels.
--- Content provided by FirstRanker.com ---
Silverstainingistheuseofsilvertoselectivelyaltertheappearanceofatargetinmicroscopyofhistologicalsections;intemperature
gradientgelelectrophoresis;andinpolyacrylamidegels.
Silverstainingisthemostsensitivemethodforpermanentstaining
ofproteinsornucleicacidsinpolyacrylamidegels.
--- Content provided by FirstRanker.com ---
Histologicalcharacterization:Silverstainingaidsthevisualizationoftargetsofinterest,namelyintracellularandextracellularcellular
componentssuchasDNAandproteins,suchastypeIIIcollagen
andreticulinfibresbythedepositionofmetallicsilverparticlesonthe
targetsofinterest.
--- Content provided by FirstRanker.com ---
55.PolymeraseIIIsynthesizes:
a)Fragment28SofrRNA
b)Fragment23SofrRNA
c)Fragment5SofrRNA
d)tRNA
--- Content provided by FirstRanker.com ---
e)mRNACorrectAnswer-C:D
Ans:c.andd[RefHarper30th/395-98;Lippincott428]
"RNApolymeraseIIIsynthesizestRNA,5SrRNA,andsomesnRNA
andsnoRNA"(Lippincott428)
--- Content provided by FirstRanker.com ---
56.Non-codingRNAis/are:
a)miRNA
b)SiRNA
c)tRNA
d)mRNA
--- Content provided by FirstRanker.com ---
e)rRNACorrectAnswer-A:B:C:E
Ans:a.miRN...,b.SiRNA...,c.tRNA...,e.rRNA...,[RefHarper
30th/394-95,368;en.wikipedia.org;Lippincott6th/417]
AlleukaryoticcellshavetwomajorclassesofRNA,theprotein
--- Content provided by FirstRanker.com ---
codingRNAs,ormessengerRNAs(mRNAs),andtwoformsofabundantnon-proteincodingRNAsdelineatedonthebasisofsize:
thelargeribosomalRNAs(rRNA)andlongnoncodingRNAs
(lncRNAs)andsmallnoncodingRNAstransferRNAs(tRNA),the
smallnuclearRNAs(snRNAs)andthemicroandsilencingRNAs
--- Content provided by FirstRanker.com ---
(miRNAsandsiRNAs).ThemRNAs,rRNAsandtRNAsaredirectlyinvolvedinprotein
synthesiswhiletheotherRNAsareparticipateineithermRNA
splicing(SnRNAs)ormodulationofgeneexpressionbyaltering
mRNAfunction(mi/SiRNAs)and/orexpression(lncRNAs).These
--- Content provided by FirstRanker.com ---
RNAdifferintheirdiversity,stability,andabundanceincells57.Trueaboutsuccinatedehydrogenase
defect-
a)DeficiencyofcomplexII
b)Tumorigenesis
--- Content provided by FirstRanker.com ---
c)Defectinkrebscycled)DefectinETC
e)Mitochondrialencephalopathy
CorrectAnswer-A:B:C:D:E
ANSWER-(A)DeficiencyofcomplexII(B)Tumorigenesis
--- Content provided by FirstRanker.com ---
(C)Defectinkrebscycle(D)DefectinETC(E)Mitochondrialencephalopathy
Mitochondrialsuccinatedehydrogenase(SDH)catalysesthe
oxidationofsuccinatetofumarateintheKrebscycle(citricacid
cycle).
--- Content provided by FirstRanker.com ---
Succinatedehydrogenasecomplexismadeupoffoursubunits-(i)SDH-A;(ii)SDH-B;(iii)SDH-C;and(iv)SDH-D.
Functionsofsuccinatedehydrogenaseare:?
1. CatalysesoxidationofsuccinateorfumarateinTCAcycle/citric
acidcycle.
--- Content provided by FirstRanker.com ---
2. TransferselectronsfromsuccinatetocoenzymeQ(atcomplexII)SuccinatedehydrogenaseactsascomplexIIinETC.
DefectinSDHcausesdefectinmitochondrialETC.Whichleadsto
mitochondria!encephalopathyandmyopathy
(encephalomyopathy)ThisisduetomutationinSDHAsubunit
--- Content provided by FirstRanker.com ---
gene.MutationinSDH-B,-Cand-Dsubunitscausestumorformation,
especiallyparaganglioma/pheochromocytoma/carotidbodytumor
Thus,thesesubunitsareregardedasatumorsuppressorgene.
58.Allaretrueaboutglycosaminoglycans
--- Content provided by FirstRanker.com ---
except?a)Proteinassociatedwithglycosaminoglycansiscalledcore
proteins
b)Maybeassociatedwithconnectivetissues
c)Highlypositivelycharged
--- Content provided by FirstRanker.com ---
d)Negativelychargede)ComponentofECM
CorrectAnswer-C
Ans.is'c'i.e.,Highlypositivelycharged[RefHarper30"/ep.
786]
--- Content provided by FirstRanker.com ---
Proteoglycansarecarbohydratestowhichsmallamountofproteinisattached.Proteoglycansconsistsof95%ofcarbohydratesand5%
ofprotein.Toknowthestructureofproteoglycans,oneshouldknow
thestructureofglycosaminoglycans.
Glycosaminoglycansareheteropolysaccharide
--- Content provided by FirstRanker.com ---
(heteropolysaccharidesarepolysaccharideswhichcontaintwoormoredifferentmonosaccharideunitortheirderivatives).
Glycosaminoglycansarelinear(unbranched)polysaccharides,with
repeatingdiasaccharideunits.Eachdisaccharideunitconsistsofan
aminosugarandanacidsugar(sugaracid).
--- Content provided by FirstRanker.com ---
Glycosaminoglyclanswerefirstisolatedfrommucin,thereforetheyarealsocalledmucopolysaccharides.
Theyarenegativelycharged.
59.Mechanismsforregulatingenzyme
activityareALLEXCEPT
--- Content provided by FirstRanker.com ---
a)Covalentmodificationb)Allostericactivation
c)Competitiveinhibition
d)Inductionofgenesforenzymesynthesis
e)Repressionofgeneforinhibitionofenzymesynthesis
--- Content provided by FirstRanker.com ---
CorrectAnswer-CAns.is(c)Competitiveinhibition[Ref:Harper319`Vep.89-
94;Lippincott6"/ep.62-64;Vasudevan5thiep.42-50;Shinde
Asthenamesuggests,thereiscompetitionbetweeninhibitorand
normalsubstrateforthecatalyticbindingsiteoftheenzyme.Thisis
--- Content provided by FirstRanker.com ---
becauseboththeinhibitorandthenormalsubstratehavesimilarstructuralconfiguration.Therefore,enzymecannotdifferentiate
thesetwoandbothcanbindtotheenzyme.BothESandEI
complexesareformed.ButonlyEScanformproduct.
60.Truestatementare-
--- Content provided by FirstRanker.com ---
a)Alllipidarefatb)Linoleicacidisessentialfattyacid
c)Hydrogenationconvertsunsaturatedfattyacidtosaturated
fattyacid
d)Rancidityoffoodisduetolipidperoxidation
--- Content provided by FirstRanker.com ---
e)Hydrolysisoffatbyacidissaponification.CorrectAnswer-B:C:D
Ans.is"B"i.e.,Linoleicacidisessentialfattyacid;"C"
Hydrogenationconvertsunsaturatedfattyacidtosaturated
fattyacid;'d'i.e.,Rancidityoffoodisduetolipid
--- Content provided by FirstRanker.com ---
peroxidation[RefLippincott6"Iep.181-1821.Thethreepolyunsaturatedfattyacids(PUFAs),namely,linoleicacid
linolenicacidandarachidonicacidarecalledessentialfattyacids.
theyarecalledessentialfattyacidsbecausehumanbeingsrequire
thesefattyacidsbutcannotsynthesizethem.
--- Content provided by FirstRanker.com ---
Additionofhydrogenatomstounsaturatedfattyacidreferstohydrogenation.Itreducesthenumberofdoublebondsin
unsaturatedfats,Ashydrogenationreducesnumberofdouble
bonds,unsaturatedfattyacidsmaygetconvertedtosaturatedfatty
acid,ifalldoublebondsarereduced.
--- Content provided by FirstRanker.com ---
Theunpleasantodorandtaste,developedbynaturalfatsuponaging,isreferredtoas"rancidity".Ranciditymaybedueto
hydrolysis(bylipase)oroxidationoffat.
61.Truestatement(s)aboutlipiddigestion
andabsorption-
--- Content provided by FirstRanker.com ---
a)Micellesplayanimportantroleinlipidsabsorptionb)Absorptionoflong-chainfattyacidsisgreatestintheupper
partsofthesmallintestine
c)Bileacidhasnoroleinfatabsorption
d)Fattyacidsafterabsorptionarereesterifiedtotriglycerides
--- Content provided by FirstRanker.com ---
intheenterocytese)Gastriclipaseisthemajorenzyme
CorrectAnswer-A:B:D
Ans.is'a'i.e.,Micellesplayanimportantroleinlipids
absorption;'b'i.e.,Absorptionoflong-chainfattyacidsis
--- Content provided by FirstRanker.com ---
greatestintheupperpartsofthesmallintestine;&'d'Le.,Fattyacidsafterabsorptionarereesterifiedtotriglyceridesinthe
enterocytes[RefGanong251h/ep.481-83;Harper..30thlep.
253-54;Guyton12thIep.421-23;Lippincott6th/ep.1761.
Micellesformationistheprocessinwhichdigestedfats(FFAsand
--- Content provided by FirstRanker.com ---
monoglycerides)areincorporatedintomuchsmallerdroplets(micelles)sothattheycanbeabsorbedmoreefficiently.Thus,
micellesformationhelpsinabsorptionofdigestedfats.
Fatdigestionessentiallybeginsintheduodenumwithentryof
pancreaticandbiliarysecretions.Pancreaticjuicecontainslipase
--- Content provided by FirstRanker.com ---
(pancreaticlipase),themostimportantenzymeforfatdigestion.Thepancreaticlipasedigeststriglycerides(triacylglycerols)intofreefatty
acidsand2-monoglycerides(2-monoacylglycerols).
Afterfatdigestion,fattyacidsandmonoglyceridesareabsorbedin
thesmallintestine,especiallyinthejejunumandsomeamountalso
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inileum.Insidetheenterocyte,fattyacidsandmonoglyceridesagainformtriglycerides.
62.Gluconeogenesisisfavouredinfasting
stateby-
a)ActivationofpyruvatecarboxylasebyacetylCoA
--- Content provided by FirstRanker.com ---
b)Increasedconversionofphosphoenolpyruvatetopyruvatebyactivationofpyruvatekinase
c)Increasedfattyacidoxidationinliver
d)Hydrolysisoffructosel,6-bisphosphatebyfructosel,6-
bisphosphatase
--- Content provided by FirstRanker.com ---
e)NoneCorrectAnswer-A:C:D
Ans.is'a'i.e.,Activationofpyruvatecarboxylasebyacetyl
CoA;'c'i.e.,Increasedfattyacidoxidationinliver;'d'i.e.,
Hydrolysisoffructose1,6-bisphosphatebyfructose1,6-
--- Content provided by FirstRanker.com ---
bisphosphatase,[Ref:Satyanarayan4thiep.258-63;Harper30thiep.188;
Lippincott6fVep.117-123;Shinde7m/ep.347]
Theactivationofpyruvatecarboxylaseandreciprocalinhibitionof
PDHcomplexbyacetyl-CoAderivedfromtheoxidationoffattyacids
--- Content provided by FirstRanker.com ---
explaintheactionoffattyacidoxidationinsparingtheoxidationofpyruvateandinstimulatinggluconeogenesis.
Thereciprocalrelationshipbetweenthesetwoenzymesaltersthe
metabolicfateofpyruvateasthetissuechangesfromcarbohydrate
oxidation(glycolysis)togluconeogenesisduringthetransitionfrom
--- Content provided by FirstRanker.com ---
thefedtofastingstate.Fructose-2-6-bisphosphateisformedbyphosphorylationoffructose-
6-phosphatebyphosphofructokinase-2.Thisenzymeisa
bifunctionalenzymethatalsohasfructose-2,6-bisphosphatase
activitywhichisresponsibleforbreakdownoffructose-2,6-
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bisphosphatasebacktofructose-6-phosphate.Thisbifunctionalenzymeisunderallostericcontroloffructose-6
phosphatewhichstimulatesphosphofructokinase-2activityand
inhibitsfructose-2,6-bisphosphataseactivity.
63.AIIaretrueaboutHexose
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monophosphatepathway(HMP)except-a)ProduceNADPHinoxidativephaseofpathway
b)DoesnotproduceATP
c)Occursintestes,ovaries,placentaandadrenalcortex
d)Producesribose5-phosphateinoxidativephaseofpathway
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e)Glucose6-phosphatedehydrogenaseenzymeisinvolvedCorrectAnswer-D
Ansis.'d'i.e.,Producesribose5-phosphateinoxidativephase
ofpathway[RefHarper30thiep.196-200;Lippincottelep.145;
Satyanarayan4thIep.270-71]
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HMPshuntisamulticyclicprocessinwhich3moleculesofglucose-6-phosphategiveriseto3moleculesofCO,and3moleculesof5-
carbonsugars(ribulose-5-phosphate).
Thelatterarerearrangedtogenerate2moleculesofglucose-6-
phosphate(throughfructose-6-phosphate)and1molecule
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glyceraldehyde-3-phosphate.HMPshuntdoesnotgenerateATP.HMPshuntoccursinthecytosol.Itishighlyactiveinliver,adipose
tissue,adrenalcortex,lens,cornea,lactating(butnotthe
nonlactating)mammarygland,Gonads(testis,ovary)and
erythrocytes.Activityofthispathwayisminimalinmuscleandbrain,
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wherealmostalloftheglucoseisdegradedbyglycolysis.64.Post-translationmodificationofprotein
includesallexcept:
a)Removalofpeptide
b)5'capping
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c)Intronsplicingd)Proteinfolding
e)Covalentmodification
CorrectAnswer-B:C
Ans.isB.,5'capping&`ci.e.,intronsplicing[Ref;
--- Content provided by FirstRanker.com ---
Satyanarayan4thiep.561-62;Harper30`lep426;Lippincott0-4p.443-441
5'cappingandintronsplicingarepost-transcriptionalmodification
(notpost-translationalmodification.
Thisisthefirstprocessingreaction.5'-endofmRNAiscappedwith
--- Content provided by FirstRanker.com ---
7-methylguansosine.Thiscaphelpsininitiationoftranslation(proteinsynthesis)and
stabilizesthestructureofmRNAbyprotectingfrom5'-exonuclease
Removalofintrons(splicing):?Eukaryoticgenescontainsome
codingsequenceswhichcodeforproteinandsomeinterveningnon-
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codingsequenceswhichdonotcodeforprotein.65.Whichofthefollowingisnottrueabout
transcription
a)SynthesisofprecursorsforthelargeandsmallribosomalRNAs
b)FormationoftRNAtranscript
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c)RNApolymeraseIIisresponsibleforthesynthesisofprecursorsforthelargeribosomalRNAs
d)RNApolymeraseIisresponsibleforthesynthesissmall
ribosomalRNAs
e)BindingofRNApolymeraseonDNA
--- Content provided by FirstRanker.com ---
CorrectAnswer-C:DAns.is'c'i.e.,RNApolymeraseIIisresponsibleforthe
synthesisofprecursorsforthelargeribosomalRNAs;&'d'i.e.,
RNApolymeraseIisresponsibleforthesynthesissmall
ribosomalRNAs.
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[Ref:Harrion19th/ep.427-28;Satyanarayan4thiep.546,566-68]RNA,eukaryoteshavethreedifferentRNApolymerases:I,II,II
RNApolymeraseI:Itcatalyzesthesynthesisoflargeribosomal
RNA(rRNA),i.e.28SrRNA,18SrRNAand5.8SrRNA.
TheserRNAsarecodedonclass-Igene,i.e.classIgeneis
--- Content provided by FirstRanker.com ---
transcribedbyrRNA.rRNAsarenottranslatedintoprotein.RNApolymeraseII:?ItcatalyzesthesynthesisofmRNA,small
nuclearRNA(sn-RNA)andmiRNA.Theseproductsarecodedby
classIIgene,i.e.classIIgeneistranscribedbymRNA.ClassII
genedifferfromclassIandIIIinthatoneofitstranscribedproducts
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(mRNA)istranslatedintoproteinRNApolymeraseIII:?ItcatalyzesthesynthesisoftRNAand5S
rRNA.TheseproductsarecodedbyclassIIIgene.
BesidesthesethreenuclearRNApolymerases,inaeukaryoticcell,
afourthtypeofRNApolymeraseisfoundinmitochondrialmatrix
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knownasmitochondrialRNApolymerase(mtRNAP).SimilartoprokaryoticRNApolymerase,mtRNAPcatalyzesthesynthesisofall
thethreetypesofRNA,i.e.mRNA,tRNAandrRNA
66.Ultravioletradiationexposurecancauses
DNAdamageby-
--- Content provided by FirstRanker.com ---
a)Pyrimidinedimersformationb)DNAbreakage
c)Thyminedimerformation
d)AcetylationofDNA
e)MethylationofDNA
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CorrectAnswer-A:CAns.is'a'Pyrimidinedimersformation;&'c'i.e.,Thyminedimer
formation[RefHarper30/ep.761;Lippincott0/ep.412]
UVraysexposureresultsincovalentjoiningoftwoadjacent
pyrimidines(usuallythymine)toformpyrimidinedimers(thymine-
--- Content provided by FirstRanker.com ---
thyminedimersorcyclobutanepyrimidinedimers).Cytosine-thymineandcytosine-cytosinedimersarealsoformedbutatslower
rates.
Ultravialet(UV)radiations:-Inducedimerizationofadjacent
pyrimidinestoproducepyrimidinedimers.
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67.TrueaboutDNAphotolyase-
a)RepairdamagecausedbyUVlight
b)Foundonlyinhuman
c)Usevisiblelight
d)Breakspyrimidinedimers
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e)NoneCorrectAnswer-A:C:D
Ans.is'a'i.e.,RepairdamagecausedbyUVlight;'c'i.e.,Use
visiblelight;&'d'Breakspyrimidinedimer[Ref:PankajNaikp.
496]
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NearlyallcellscontainaphotoreactivatingenzymecalledDNAphotolyase.ItisaDNArepairenzymewhichbindtothedamaged
regionofDNAandgetexcitedbylightenergyabsorbedbyN5,N'?-
methenyltetrahydrofolate,whichisboundtothephotolyase.The
processiscalledphotoreactivation.
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Theactivationrequiresvisiblelight,preferentiallyfromtheviolet/blueendofthespectrum.
Theexcitedphotolyasethencleavesthedimerintooriginalbases.
Theseenzymesoccurinalmostalllivingorganismsexposedto
sunlight,theonlyexceptionbeingplacentalmammalslikehumans
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andmice.Theircatalyticmechanismemploysthelight-driveninjectionofanelectronintotheDNAlesiontotriggerthecleavageof
cyclobutane-pyrimidinedimers.
PhotolyaseisparticularlyimportantinrepairingUVinduceddamage
inplants.Thephotolyasemechanismisnolongerworkingin
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humansandotherplacentalmammalswhoinsteadrelyonthelessefficientnucleotideexcisionrepairmechanism.
68.TrueaboutDNAGyrase-
a)AtypeoftopoisomeraseI
b)AtypeoftopoisomeraseII
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c)ActoncircularDNAd)Overcometheproblemofsupercoils
e)None
CorrectAnswer-B:C:D
Ans.is'b'i.e.,AtypeoftopoisomeraseIL;"c'i.e.,Acton
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circularDNA;'d',Overcometheproblemofsupercoils[RefLippincottetc401;StayanarayanxlaVep.528J
TopoisomeraseI4Removesnegativesupercoiling.
TopoisomeraseIIRelaxespositivesupercoilsandformsnegative
supercoilingbycondensation.ofchromosome.
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TopoisomeraseIIICanintroducesinglestrandbreaksduringrecombinationthatarerequiredforDNAtobeexchanged.
69.Whichofthefollowingenzymesofurea
cycleis/arenotpresentinmitochondria?
a)Carbamoylphosphatesynthetase-1[CPS-1]
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b)Arginasec)Arginosuccinase
d)Arginosuccinatesynthase
e)Ornithinetranscarbamylase
CorrectAnswer-B:C:D
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Ans.is'b'i.e.,Arginase,'c'i.e.,Arginosuccinase&'d'i.e.Arginosuccinatesynthase[RefHarper's30th/ep.291]
Ammoniaisultimatelydisposedofbyformationofureaby"Kreb's
Henseleitureacycle"intheliver.
Ureacycletakesplacebothinmitochondriaandcytosol.
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Firsttworeactionsofureacycleoccurinthemitochondria,andremainingreactionsoccursincytosol
Argininosuccinatesynthasecatalyzestheformationof
argininosuccinatefromcitrullineandaspartate.Thisreaction
requiresIATP,but2highenergyphosphatebondsareconsumedas
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ATPisconvertedtoAMP+PPi.Theaminogroupofaspartateprovidesoneofthetwonitrogenatomsthatappearinurea(The
otheroneisprovidedbyammoniaNH4).
Argininosuccinatelyase(argininosuccinase)catalysesthecleavage
ofargininosuccinateintoarginineandfumarate.Fumarateentersin
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TCAcycle.Arginasecatalysestheformationofureafromargininebyhydrolytic
cleavageofargininetoyieldureaandornithine.Ornithineisthus
regeneratedandcanentermitochondriatoinitiateanotherroundof
theureacycle.
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70.Regulatoryenzymesofglycolysisare-
a)Phosphofructokinase
b)Pyruvatekinase
c)BPGkinase
d)Hexokinase
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e)Glucose-6-phosphataseCorrectAnswer-A:B:D
Ans.'a'i.e.,Phosphofructokinase,'b'i.e.,Pyruvatekinase&'d'
i.e.,Hexokinase[RefHarper's30thlep.170-177]
Glycolysisisregulatedat3stepswhichareirreversible.These
--- Content provided by FirstRanker.com ---
reactionsarecatalyzedbyfollowingkeyenzymes:(1)Hexokinaseandglucokinase,(2)PhosphofructokinaseI,and(3)Pyruvate
kinase.
Hexokinaseisfoundinmostofthetissueexceptliverandcomes
intoplaywhenbloodglucoseislow.Itisnotaffectedbyfeedingor
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insulinorstarvation.Hexokinaseisnotspecificforglucosemetabolism,itisalsoinvolvedinmetabolismoffructoseand
galactose.
PhosphofructokinaseIisthemajorregulatoryenzymeofglycolysis.
Itcatalyzesthe3rdreactionofglycolysis,i.e.,fructose-6-P-a
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Fructose1,6bis-P.Thisreactionisirreversibleandisthe"rate-limitingstep"forglycolysis.
Itisallostericallyactivatedby:Fructose-6-phosphate,fructose2,6-
bisphophate,AMP,ADP,K.andphosphate.Itisallosterically
inhibitedby:ATP,citrate,Ca+2,Mg+2,andlowpH.
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Phosphofructokinaseisaninducibleenzymethatincreasesitssynthesisinresponsetoinsulinanddecreasesinresponseto
glucagon.
PyruvatekinaseisenzymethatcatalyzesconversionofPEPto
pyruvate.Pyruvatekinaseisaninducibleenzymethatincreasesin
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concentrationwithhighinsulinlevelanddecreaseswithglucagon.Itisactivatedbyfructose-1,6bisphosphateandinactivatedbyATP
andalanine.
71.Whichofthefollowingis/areto-6fatty
acid(s)
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a)Linoleicacidb)Arachidinicacid
c)Gammalinolenicacid
d)Alphalinolenicacid
e)Oleicacid
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CorrectAnswer-A:B:CAns.is'a'i.e.,Linoleicacid,'b'i.e.,Arachidinicacid&'c'i.e.,
Gammalinolenicacid[Ref:Harper's30thlep.2141
Linoleicacid(18carbon:Chemicalformula'aCH,-(CH,),-CH=CH
-CH2-CH=CH-(CH2)7-COOH
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C-SystemC:18:2:6,9'12orC:18:2:9,12,i.e.18carbonfattyacidwith2doublebondsat915(betweenC-9andC-10)and12'(betweenC-
12andC-13)positionswhennumberingisstartedfromcarboxyl
carbon.
co-systemC:18:2:w-6,9,i.e.18carbonfattyacidwith2double
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bondsat6th(betweenC-6andC-7)and9'(betweenC-9andC-10)positionswhennumberingisstartedfromterminalmethylcarbon.So
linoleicacidisco-6fattyacid,asthefirstdoublebondisat6th
positioninco-systemclassification.
Arachidonicacid(20carbon)ChemicalformulaC20H32O2
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72.Nonreducingsugarsareallexcept-
a)Glucose
b)Maltose
c)Sucrose
d)Fructose
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e)GalactoseCorrectAnswer-A:B:D:E
Ans.is'a'i.e.,Glucose;b'i.e.,Maltose;'d'i.e.,Fructose&`e'
i.e.,Galactose[RepDineshPuri3"'/elep.24]
Reducingsugarsaresugarswhichhavefreealdehydeorketone
--- Content provided by FirstRanker.com ---
grouptheirintheirstructure.Becauseofthepresenceoffreealdehydeorketonegroup,theycanreducecertainheavymetallic
cationsinanalkalimediumandintheprocesstheythemselvesget
oxidizedtoamixtureofsugaracids.
Glucoseandgalactosehavefreealdehydegroupatcarbon-1,and
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fructosehasfreeketonegroupatcarbon-2.Thus,reducingendofglucoseandgalactoseiscarbon-1andoffructoseiscarbon-2.
Sucrose(disaccharideofglucoseandfructose)isformeddueto
formationofa-glycosidicbondbetweencarbon-1ofglucoseand
carbon-2offructose(Glucose-al2-Fructose).Thus,reducing
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endofbothglucose(carbon-1)andfructose(carbon-2)areinvolvedinglycosidicbondformationandthereforelosttheirreducing
property.Hence,sucroseisanon-reducingdisaccharide.
73.ApointegratedinHDLis-
a)ApoAl
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b)ApoEc)ApoD
d)ApoB48
e)ApoB100
CorrectAnswer-A:B:C
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Ans.is'a'i.e.,ApoAl;'b'i.e.,ApoE;&'c'i.e.,ApoD[RefHarper's30th/ep.257,255;Chatterjee6th/ep.382]
Apo-A1isfoundinHDL,Chylomicrons,siteofsynthesiisLiver,
intestine,andfunctioninMajorstructuralproteinofHDL,major
activatorofLCAT.
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Apo-E(argininerich),foundin-Chylomicrons,chylomicron,siteofsynthesis-liver,functionasMediatesuptakeofchylomicron
remnantsandIDLbyLDLreceptorsinliver.
Apo-D--foundinHDL-Spleen,brain,testes,adrenal
74.Poorwoundhealinginvitamin'C'
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deficiencyisduetoallexcept-a)Inhibitionofcollagensynthesis
b)Defectivecollagensynthesis
c)Defectivepost-translationalmodificationofcollagen
d)Defectivehydroxylation
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e)DefectinantioxidantsystemCorrectAnswer-A
Ans.is"a"Inhibitionofcollagensynthesis
Ascorbicacid(VitaminC)isalsocalledantiscorbuticfactor.Itisvery
heatlabile,especiallyinbasicmedium.Ascorbicaciditselfisan
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activeform.MaximumamountofvitaminCisfoundinadrenalcortex.
Ascorbicacidfunctionsasareducingagentandscavangeroffree
radicals(antioxidant).Itsmajorfunctionsare
1. vitaminCisessentialfortheconversionofprocollagentocollagen,
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whichisrichinhydroxyprolineandhydroxylysine.Throughcollagensynthesis,itplaysaroleintheformationofmatrixofbone,cartilage,
dentineandconnectivetissue.
2. VitaminCisrequiredforpost-translationalmodificationby
hydroxylationofprolineandlysineresiduesconvertingtheminto
--- Content provided by FirstRanker.com ---
hydroxyprolineandhydroxylysine.75.MicroSatelliteinstabilityisseenin?
a)Huntington'sdisease
b)Lynchsyndrome
c)Spinocerebellarataxia
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d)HNPCCe)Colorectalcancer
CorrectAnswer-A:B:C:D:E
Ans.is'a'i.e.,Huntington'sdisease;'b'i.e.,Lynchsyndrome;
'c'i.e.,Spinocerebellarataxia;'d'i.e.,HNPCC;&'e'i.e.,
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Colorectalcancer[RefTextbookofgeneticcounsellingp.712]Microsatelliteinstabilityisgeneticinstabilityinshortnucleotide
repeats(microsatellites)duetohighmutationrateasaresultof
defectsinmismatchrepairofDNA.
Sometimesreplicationerrorsescapetheproofreadingfunction
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duringDNAsynthesiscausingamismatchofoneofseveralbases.Theseerrorsarerepairedlater.
Animportantpointisthattherepairsystemmustbeableto
discriminatebetweentheparent(template)strandandthenew
daughterstrandbecauseitisthebaseonthedaughterstrandparent
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thatisincorrectsoneedstobeexcised.Methylgrouponparentstrandattachedtoadenine(methylated
adenine)nearthemismatchservesasatagbywhichtherepair
systemidentifies.
SeveralNeurologicaldiseasearecharacterizedbymicrosatellite
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sequenceinstabilityincludingHuntington'sdisease,myotonicdystrophy,Fragile-Xsyndrome,Friedreich'sataxiaand
spinocerebellarataxia.
76.UDP-glucoseisusedfor-
a)Glycogensynthesis
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b)Galactosemetabolismc)Bilirubinmetabolism
d)Gangliosidesynthesis
e)Heparinsynthesis
CorrectAnswer-A:B:C:E
--- Content provided by FirstRanker.com ---
Ans.is'a'i.e.,Glycogensynthesis;'b'i.e.,Galactosemetabolism;'c'i.e.,Bilirubinmetabolism;&`e'i.e.,Heparin
synthesis[RefBasicmedicalbiochemistryp.475]
UDP-glucoseisderivedfromglucose-6-phosphateviaglucose-l-
phosphate.
--- Content provided by FirstRanker.com ---
ThemajorfateofUDP-glucoseisthesynthesisofglycogen.OtherusesofUDP-glucoseare-
1. Inuronicacid(glucoronicacid)cycletogenerateUDPglucuronate.
2. Galactosemetabolism
Glycosylationofproteins,lipidsandproteoglycans.
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UDPglucuronate(whichisderivedfromUDPglucose)isusedfor:-1. Conjugationofbilirubin,benzoicacid,sterols,estrogenanddrugs.
2. Biosynthesis
77.ComplementaryDNAdiffersfromgenomic
DNAin-
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a)Hascodedsegmentsb)Hasintrons
c)Hasonlyexons
d)Usesreversetranscriptase
e)Larger
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CorrectAnswer-A:C:DAns.is'a'i.e.,Hascodedsegments;'c'i.e.,Hasonlyexons;&
'd'i.e.,Usesreversetranscriptase.[Ref:Lehninger5"Yep.940-
9601
Collectionofcloned(recombinant)DNAfragmentsiscalledDNA
--- Content provided by FirstRanker.com ---
libraryorshotguncollection.DNAlibrariesmaybeoftwotypes?1)Genomiclibrary:-
TheentiregenomicDNA(bothexonsandintrons)ofanorganismis
cutintosmallpiecesbyrestrictionendonucleases.
Eachandeveryfragmentisthenclonedwithsuitablevector.These
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recombinantclonesarethencollected.2)ComplementaryDNA(cDNA)library:-
IncDNAlibraryonlyexonsarerepresented.Itisconstructedsoas
toincludeonlythosegenesthatareexpressed.
cDNAlibraryismorespecializedandexclusiveDNAlibrary.
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ThemRNAsfromanorganismisextractedandcomplementarydoublestrandedDNAs(cDNAs)areproducedfromthesemRNAsby
reversetranscriptase.TheresultingDNAfragmentsarethen
insertedintoasuitablevectorandcloned
78.Whichofthefollowingenzymeshave
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proofreadingfunctioninPCR[PolymeraseChainReaction]
a)Taqpolymerase
b)PFUPolymerase
c)Thermosthermophilus
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d)Thermalflavus(Replinase)e)T-7polymerase
CorrectAnswer-B:E
Ans.is'b'i.e.,PFUPolymerase;&'e'i.e.,T-7polymerase[Ref
TextbookofPCRbyMikeMcPherson]
--- Content provided by FirstRanker.com ---
TheuseofhighfidelityDNApolymerasesinPCRisessentialforreducingtheintroductionofamplificationerrorsinPCRproducts.
SeveralthermostableDNApolymeraseswith3'5'exonuclease-
dependentproofreadingactivityhavebeenintroducedforhigh.
PfuDNApolymeraseDerivedfromPyrococcusfusarious.
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PwoDNApolymeraseIsolatedfromPyrococcuswoesei.KODHiFiDNApolymeraseIsolatedfromThermococcus
Kodakaraensis.
T7DNApolymerase.
79.EnzymesrequiredformRNAsynthesis
--- Content provided by FirstRanker.com ---
is/are?a)RNApolymeraseI
b)RNApolymeraseII
c)Primase
d)Topoisomerase
--- Content provided by FirstRanker.com ---
e)LigaseCorrectAnswer-B
Ans.is'b'i.e.,RNApolymeraseII[RefHerper's30"'/ep.390-
400]
ItcatalyzesthesynthesisofmRNA,smallnuclearRNA(sn-RNA)
--- Content provided by FirstRanker.com ---
andmiRNA.TheseproductsarecodedbyclassIIgene,i.e.classIIgeneis
transcribedbymRNA.
ClassIIgenedifferfromclassIandIIIinthatoneofitstranscribed
products(mRNA)istranslatedintoprotein.
--- Content provided by FirstRanker.com ---
80.WhichDNApolymerasehas/have
proofreadingactivity-
a)DNApolymeraseI
b)DNApolymeraseII
c)DNApolymerasea
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d)DNApolymerasee)DNApolymerasey
CorrectAnswer-A:B:D
Ans.is'a'i.e.,DNApolymeraseI;'b'i.e.,DNApolymeraseII;&
'd'i.e.,DNApolymerase
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DNApolymeraseI-possessesthreedifferentcatalyticactivities:?
1. 5'3'exonucleaseactivity,Polymeraseactivity(5'3'
polymeraseactivity),3'5'exonucleaseactivity,
2. DNApolymeraseI:-Helpsingapfillingandsynthesisbetween
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okazakifragmentsoflaggingstrand,andreplacesribonucleotidesofRNAprimerbydeoxyribonucleotides.Ithas(i)3'5'exonuclease
activity,(ii)5'3'exonucleaseactivityand(iii)polymerase(5'3'
polymerase)activity.
3. DNApolymeraseI:-Helpsingapfillingandsynthesisbetween
--- Content provided by FirstRanker.com ---
okazakifragmentsoflaggingstrand,andreplacesribonucleotidesofRNAprimerbydeoxyribonucleotides.Ithas(i)3'5'exonuclease
activity,(ii)5'3'exonucleaseactivityand(iii)polymerase(5'
3'polymerase)activity.
4. DNApolymeraseII:-Helpsin(i)proofreading(3'?5'exonuclease
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activity),and(ii)DNArepair.5. DNApolymeraseIII:-Itisthemainenzymethatsynthesizes
prokaryoteDNA,i.e.,synthesisofleadingandlaggingstrand.Ithas
(i)513'polymerase(orsimplypolymerase)activityforDNA
synthesis,and(ii)3'-->51exonucleaseactivityforproofreading.
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81.30SribosomeINTERACTSwithall
except?
a)mRNA
b)ATP
c)GTP
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d)Initiatingfactore)Elongatingfactor
CorrectAnswer-B:E
ANS-'b'i.e.,ATP;&'e'i.e.,Elongatingfactor[RefDineshPurl
Yalep.482,483]
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INIATIATIONprocessbeginsbyformationof30Sinitiationcomplexbetween30Sribosomalsubunit,mRNAandformylmettRNA.GTP
servesassourceofenergy.Threeinitiationfactors(IF1,IF2,IF3)
arealsorequiredforformationofthiscomplex.
Thenthereisformationof70Sinitiationcomplexbyjoiningof50S
--- Content provided by FirstRanker.com ---
and30Ssubunits.Inthiscomplex,initiatortRNAoccopiesP-siteontheribosome.`A'-siteisstillempty.
Elongationfactors:EF-Tu,EF-Ts,EF-G.
82.Components/genesinvolvedinRISC
complex-
--- Content provided by FirstRanker.com ---
a)Pashab)MiRNA
c)rRNA
d)Drosha
e)Dicernuclease
--- Content provided by FirstRanker.com ---
CorrectAnswer-A:B:D:EAns.is'a'i.e.,Pasha;'b'i.e.,MiRNA;'d'i.e.,Drosha;&'e'i.e.,
Dicernuclease[RefTextbookofmolecularbiologyp.7121]
RNA-inducedsilencingcomplex(RISC)isamultiproteincomplex
thatincorporatesonestrandofadoublestrandedsmallinterfering
--- Content provided by FirstRanker.com ---
RNA(siRNA)orsinglestrandedmicroRNA(miRNA).RISCusesthesiRNAormiRNAasatemplateforrecognizing
complementarymRNA.
OnceRISCfindscomplementarystrandofmRNA(withhelpof
miRNAorsiRNA),itactivatesRNAasetocleave(degrade)mRNA.
--- Content provided by FirstRanker.com ---
TheRISC-loadingcomplex(RLC)istheessentialstructurerequiredtoloaddsRNAfragmentsintoRISCinordertotargetmRNA.The
RLCconsistsofdicer,thehumanimmunodeficiencyvirus
transactivatingresponseRNA-bindingprotein(TRBP)and
Argonuate2.
--- Content provided by FirstRanker.com ---
AnuclearRNAasespecificfordsRNAcalledDroshaactswithanucleards-RNAbindingprotiencalledDGCRinhuman(Pashain
Dorsophila)andcleavesthehairpinregionoutoflongprecursor
RNAgeneratingapre-miRNA.
83.30SribosomeCONSISTofallexcept-
--- Content provided by FirstRanker.com ---
a)mRNAb)ATP
c)GTP
d)InitiatingfactorandElongatingfactor
e)None
--- Content provided by FirstRanker.com ---
CorrectAnswer-EAns.isNone[RefLippincates5th/ep.436]
Ribosomesarelargecomplexesofr-RNAandproteinswithone
largeandonesmallsubunits.
Thesmallsubunitbindsm-RNA,thusguidinginteractionbetween
--- Content provided by FirstRanker.com ---
m-RNAcodonandanticodonoft-RNAtoreadthegeneticinformationwithexiquisitefidelity.Hencesmallsubunitis
responsibleforaccuracy,whereasthelargesubunitcatalyzes
theformationofpeptidebond.
Ribosomesarecomposedoftwounequalsubunits.
--- Content provided by FirstRanker.com ---
Eukaryotic(80S)ribosomeismadeupof60Sand40Ssubunits.Prokaryotic(70S)ribosomeismadeof50Sand30Ssubunits.
60Ssubunitofeukaryotescontains5SrRNA,5.8SrRNA,28S
rRNAandmorethan50polypeptides.40Ssubunitcontains18S
rRNAandabout30polypeptidechains.
--- Content provided by FirstRanker.com ---
84.Whichofthefollowingisrequiredfor
unwindingofDNA-
a)Helicase
b)Primase
c)SSBP
--- Content provided by FirstRanker.com ---
d)Ligasee)Topoisomerase
CorrectAnswer-A
Ans.is'a'i.e.,Helicase[Ref:Harper's30thlep.383&29thp.367]
protein
--- Content provided by FirstRanker.com ---
functionDNApolymerases Deoxynucleotidepolymerization
Helicases
ProcessiveunwindingofDNA
Relievetorsionalstrainthatresults
--- Content provided by FirstRanker.com ---
Topoisomerasesfromhelicaseinducedunwinding
DNAprimase
InitiatessynthesisofRNAprimers
Single-strand
--- Content provided by FirstRanker.com ---
Preventprematurereanneallingofbindingproteins
dsDNA
Sealsthesinglestrandnick
betweenthenascentchainand
--- Content provided by FirstRanker.com ---
DNAligaseOkazakifragmentsonlagging
strand
85.Trueaboutcollagen:
a)Doublehelixstructure
--- Content provided by FirstRanker.com ---
b)Singlehelixstructurec)Triplehelixstructure
d)-pleatedstructure
e)Componentofconnectivetissueofbody
CorrectAnswer-C:E
--- Content provided by FirstRanker.com ---
Ans:c.Triplehelix...,e.Component....[RefHarper30th/46-47,627-32;Lippincott6th/43-48;Vasudevan5th/254-55]
Incollagen,thecollagenhelix,ortype-2helix,isamajorshapein
secondarystructure
Allcollagenhaveatriplehelicalstructure.
--- Content provided by FirstRanker.com ---
Astrikingcharacteristicofcollagenisoccurrenceofglycineresidueateverythirdpositionoftriplehelicalportionofachain.
Thisrepeatingstructure,representedas(Gly-x-y)n,isanabsolute
requirementfortheformationofthetriplehelix.
300nmlongand1.5nmindiameter,itismadeupofthree
--- Content provided by FirstRanker.com ---
polypeptidestrands(calledalphachains),eachpossessingtheconformationofaleft-handedhelix(itsnameisnottobeconfused
withthecommonlyoccurringalphahelix,aright-handedstructure).
Thesethreeleft-handedhelicesaretwistedtogetherintoaright-
handedcoiledcoil,atriplehelixor"superhelix"
--- Content provided by FirstRanker.com ---
Collagen,themajorcomponentofmostconnectivetissues,constitutesapproximately25%oftheproteinofmammals.
Itprovidesanextracellularframeworkforallmetazoananimalsand
existsinvirtuallyeveryanimaltissue.Atleast28distincttypesof
collagenmadeupofover30distinctpolypeptidechains(each
--- Content provided by FirstRanker.com ---
encodedbyaseparategene)havebeenidentifiedinhumantissues.86.Atisoelectricpoint(p1)netchargeof
aminoacisis:
a)-1
b)+1
--- Content provided by FirstRanker.com ---
c)-2d)+1
e)0
CorrectAnswer-E
Ans:e.0...[RefHarper30th/201]
--- Content provided by FirstRanker.com ---
Isoelectricpoint(pI)isapHinwhichnetchargeofaminoacidiszero"(Harper30th/20)
"Isoelectricpoint(pI)isapHinwhichnetchargeofaminoacidis
zero.Incaseofproteinsisoelectricpointmostlydependsonseven
chargedaminoacids:glutamate(6-carboxylgroup),aspartate(13-
--- Content provided by FirstRanker.com ---
carboxylgroup),cysteine(thiolgroup),tyrosine(phenolgroup),histidine(imidazolesidechains),lysine(c-ammoniumgroup)and
arginine(guanidiniumgroup).
87.HexosaminidaseAdeficiencycauses:
a)Niemann-pick
--- Content provided by FirstRanker.com ---
b)Tay-Sachsdiseasec)Hurlersyndrome
d)Gaucher'sdisease
e)Krabbe'sdisease
CorrectAnswer-B
--- Content provided by FirstRanker.com ---
Ans:b.Tay-Sachsdisease[RefsHarper30th/251;Lippincott6th/212;Harrison19th/432e,433e
HexosaminidaseAdeficiencyisanenzymedeficiencythatcauses
brainandothernervecellstodie,whichcanleadtosevere
neurologicalandmentalproblems.
--- Content provided by FirstRanker.com ---
HexosaminidaseA(HEXA)deficiencyiscausedbyadeficiencyinanenzymecalledbeta-hexosaminidaseA.Thisenzymehelpsbreak
downaparticularfattyacidcalledGM2ganglioside.
Withoutadequateamountsoffunctionalenzymes,GM2ganglioside
willbuildupinnervecellsandcausethemtodie.
--- Content provided by FirstRanker.com ---
ThereareseveralformsofHEXAdeficiency,includingacuteinfantile(Tay-Sachsdisease),juvenile,chronic,oradult-onsetforms.
88.Mitchondrialmatrixcontainsenzymesof:
a)Pyruvatedehydrogenase
b)TCAcycleenzyme
--- Content provided by FirstRanker.com ---
c)AcylCoAsynthetased)ATPsynthase
e)-oxidationenzymes
CorrectAnswer-A:B:D
Ans:a.Pyruvatedehydrogenase,b.TCAcycleenzyme,d.ATP
--- Content provided by FirstRanker.com ---
synthaseMatrixoftheMitochondrionisgel-likesolutionintheinteriorof
mitochondriais50%protein.Thesemoleculesincludetheenzymes
responsiblefortheoxidationofpyruvate,aminoacids,fattyacids(by
n-oxidation),andthoseofthetricarboxylicacid(TCA)cycle.
--- Content provided by FirstRanker.com ---
Thesynthesisofglucose,urea,andhemeoccurpartiallyinthematrixofmitochondria.Inaddition,thematrixcontainsNAD+and
FAD(theoxidizedformsofthetwocoenzymesthatarerequiredas
hydrogenacceptors)andADPandPi,whichareusedtoproduce
ATP.
--- Content provided by FirstRanker.com ---
89.Whichofthefollowinggroup(s)are
presentinnaturalaminoacids:
a)Imidazolegroup
b)Tetrapyrrolegroup
c)Indolegroup
--- Content provided by FirstRanker.com ---
d)Guanidiniumgroupe)Ketogroup
CorrectAnswer-A:B:C:D
Ans:a.Imidazole...,b.Tetrapyrrole...,c.Indole...,d.
Guanidinium(RefHarper30th/20-23;Lippincott6th/I-11;
--- Content provided by FirstRanker.com ---
Vasudevan5th/19]Imidazolegroup:Histidine,Betacarboxylgroup:Asparticacid
(Vasudevan5th/19)Gammacarboxylgroup:Glutamicacid
(Vasudevan5th/19)?-aminogroup:Lysine(Vasudevan5th/19).
SpecialgroupsinAminoacidsVasudevan5th/17:Benzenegroup-
--- Content provided by FirstRanker.com ---
PhenylalanineIndolegroupin-TryptophanPyrrolidinegroup-ProlineGuanidiniumgroup-ArgininePhenolgroup-Tyrosine
90.Whichofthefollowingvitamindeficiency
causetriadofmentalconfusion,
ophthalmoplegia&ataxia:
--- Content provided by FirstRanker.com ---
a)VitB2b)VitB1
c)VitB6
d)VitC
e)Vit.B12
--- Content provided by FirstRanker.com ---
CorrectAnswer-BAns:b.VitBl[RefLippincott6th/378-79;Harrison19th/96e,
18th/594-96;Harper30th/555-56,28th/468]
Classically,Wernicke'sencephalopathyischaracterizedbythetriad
ofophthalmoplegia,ataxia,andmentalconfusion,butconfusion&a
--- Content provided by FirstRanker.com ---
staggeringgaitareperhapsmostcommon"-SynopsisofPsychaitryby(Kaplan11th/796-799)
Thiaminedeficiencyinitsearlystageinducesanorexiaand
nonspecificsymptoms(e.g.,irritability,decreaseinshort-term
memory).
--- Content provided by FirstRanker.com ---
Alcoholicpatientswithchronicthiaminedeficiencyalsomayhavecentralnervoussystem(CNS)manifestationsknownasWernicke's
encephalopathy,whichconsistsofhorizontalnystagmus,
ophthalmoplegia(duetoweaknessofoneormoreextraocular
muscles),cerebellarataxia,andmentalimpairment
--- Content provided by FirstRanker.com ---
91.Whichofthefollowingenzyme(s)is/are
involvedingluconeogenesis:
a)Pyruvatecarboxylase
b)Phosphoenolpyruvatecarboxykinase
c)Phosphofructokinase-1
--- Content provided by FirstRanker.com ---
d)Glucose6-phosphatasee)Pyruvatedehydrogenase
CorrectAnswer-A:B:D
Ans:a.Pyruvatecarboxylase,b.Phosphoenolpyruvate
carboxykinase,d.Glucose6-phosphatase,[RefHarper
--- Content provided by FirstRanker.com ---
30th/188;Lippincott6th/117-122;Harper28th/165-68;Lippincott4th/329J]
glucose-6-phosphatase,fructose-1,6-bisphosphatase,andPEP
carboxykinase/pyruvatecarboxylase.
92.Gelusedinelectrophoresisis/are:
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a)Agarosegelb)Polyacrylamideplaingel
c)PolyacrylamideSDS(Sodiumdodecylsulphate)impregnated
Polyacrylamidegel
d)alloftheabove
--- Content provided by FirstRanker.com ---
e)NoneCorrectAnswer-D
Ans.d-alloftheabove[www.lonza.com/go/literature/2043;
Shinde7th/7741]
SeparationofRNAinagarosegelsisusedforanumberofdifferent
--- Content provided by FirstRanker.com ---
purposes,includingNorthernblotstomonitorRNAexpressionlevels,checkingRNAintegrityandsizeselectionofRNAforcloning
experiments.SeparationofRNAbasedonfragmentlengthrequires
conditionsthataredifferentfromDNAanalysis.
Theseincludesamplepreparation,theuseofsampleandgel
--- Content provided by FirstRanker.com ---
denaturants,electrophoresisbuffers,andvisualization.ThepurposeoftheexperimentandthesizeoftheRNAbeingseparatedarethe
primarydriversindeterminingwhichdenaturingsystemtouse.
ThemostfrequentlyuseddenaturantsforRNAagarosegel
electrophoresisareformaldehyde,formaldehyde/formamide,and
--- Content provided by FirstRanker.com ---
glyoxalplusDMSO.93.Whichofthefollowingmethod(s)is/are
usedfordetectionofnucleicacid:
a)Northernblotting
b)Southernblotting
--- Content provided by FirstRanker.com ---
c)Westernblottingd)Microarray
e)ELISA
CorrectAnswer-A:B:D
Ans:a.Northern...,b.Southern"',d'Microarray'
--- Content provided by FirstRanker.com ---
SampleTechnique
GelUsed Purpose
Analysed
Southern
--- Content provided by FirstRanker.com ---
DNA?Yes
DetectDNAchanges
blot
Northern
--- Content provided by FirstRanker.com ---
RNA?Yes
MeasuresmRNAamounts&size
blot
Western
--- Content provided by FirstRanker.com ---
Protein?Yes
Measuresproteinamount
blot
ASO
--- Content provided by FirstRanker.com ---
DNA?No
DetectsDNAmutations?
RNAor
MeasuresmanymRNAlevelsat
--- Content provided by FirstRanker.com ---
MicroarrayNo
cDNA
onetime
Proteins?
--- Content provided by FirstRanker.com ---
Detectsproteins(antigens)orELISA
or
No
antibodies?
--- Content provided by FirstRanker.com ---
antibodiesMeasuresabundance,distribution,
posttranslai.iurimodifications,
Proteomics Proteins?
Yes
--- Content provided by FirstRanker.com ---
functions&interactionsofcellularproteins
interactionsofcellularproteins
94.Mucopolysacchidosis,whichisa
lysosomalstoragedisease,occursdueto
--- Content provided by FirstRanker.com ---
abnormalityin:a)Hydrolaseenzyme
b)Dehydorgenaseenzyme
c)Lipaseenzyme
d)Phosphatase
--- Content provided by FirstRanker.com ---
e)Acetyl-CoAcarboxylaseCorrectAnswer-A
Ans:a.Hydrolaseenzyme[RefHarper30th/638-39,29th/589,
599,600;Lippincott6th/163-64J
Themucopolysaccharidosesarehereditarydiseasescausedbya
--- Content provided by FirstRanker.com ---
deficiencyofanyoneofthelysosomalhydrolasesnormallyinvolvedinthedegradationofheparansulfateand/ordermatansulfate
Theyareprogressivedisorderscharacterizedbyaccumulationof
glycosaminoglycansinvarioustissues,causingarangeof
symptoms,suchasskeletalandextracellularmatrixdeformities,and
--- Content provided by FirstRanker.com ---
mentalretardation.Childrenwhoarehomozygousforanyoneofthesediseasesare
apparentlynormalatbirth,thengraduallydeteriorate.Insevere
cases,deathoccursinchildhood.
Diagnosisisconfirmedbymeasuringthepatient'scellularlevelof
--- Content provided by FirstRanker.com ---
thelysosomalhydrolases.BonemarrowandcordbloodtransplantshavebeenusedtotreatHurlerandHuntersyndrome
95.Sulphurofcysteinarenotused/utilizedin
bodyforthefollowingprocess/product:
a)Helpinconversionofcyanidetothiocyanate
--- Content provided by FirstRanker.com ---
b)Thiosulphateformationc)Introductionofsulphuratominmethionine
d)Disulfidebondformationb/wtwoadjacentpeptide
e)None
CorrectAnswer-C
--- Content provided by FirstRanker.com ---
Ans:c.Introductionofsulphuratominmethionine,[RefHarper30th/301-02,313-14,29th/285-86;Lippincott6th/263-68;Shinde
7th/471-73,578;Vasudevan5th/191;Satyanarayan3rd/361]
TheH2Sderivedfromthecysteinemaybeoxidizedtosulfites&
thiosulfateserfurtheroxidizedtosulfate.
--- Content provided by FirstRanker.com ---
Cysteinetransaminatestoformbetamercaptopyruvicacid&finallypyruvate.ThebetamercaptopyruvatecantransferStoCNtoform
thiocynate(SCN).
ThesulphurmayberemovedeitherasH2Sorelementalsulphuror
assulfite,Cysteineondecarboxylationgivesbetamercapto
--- Content provided by FirstRanker.com ---
ethanolamine.ThisisusedforsynthesisofcoenzymeA.Formationofcysteineisbyusingthecarbonskeletoncontributedby
serine&sulphuroriginatingfrommethionine.
96.Whichoneofthefollowingstatements
aboutproteinstructureiscorrect:
--- Content provided by FirstRanker.com ---
a)Proteinsconsistingofonepolypeptidecanhavequaternarystructure
b)Theformationofadisulfidebondinaproteinrequiresthatthe
twoparticipatingcysteineresiduesbeadjacenttoeachotherin
theprimarysequenceoftheprotein
--- Content provided by FirstRanker.com ---
c)Thestabilityofquaternarystructureinproteinsismainlyaresultofcovalentbondsamongthesubunits
d)Thedenaturationofproteinsalwaysleadstoirreversiblelossof
secondaryandtertiarystructure
e)Theinformationrequiredforthecorrectfoldingofaproteinis
--- Content provided by FirstRanker.com ---
containedinthespecificsequenceofaminoacidsalongthepolypeptidechain
CorrectAnswer-E
Ans:e.Theinformationrequiredforthecorrect...[RefHarper
3001/36-41,29th/36-40;Lippincott6th/24,13-20]
--- Content provided by FirstRanker.com ---
Thecorrectfoldingofaproteinisguidedbyspecificinteractionsbetweenthesidechainsoftheaminoacidresiduesofthe
polypeptidechain
Thetwocysteineresiduesthatreacttoformthedisulfidebondmay
beagreatdistanceapartintheprimarystructure(oronseparate
--- Content provided by FirstRanker.com ---
polypeptides),butarebroughtintocloseproximitybythethree-dimensionalfoldingofthepolypeptidechain.Denaturationmay
eitherbereversibleorirreversible.
Quaternarystructurerequiresmorethanonepolypeptidechain.
Thesechainsassociatethroughnoncovalentinteractions"
--- Content provided by FirstRanker.com ---
Primarystructuresarestabilizedbycovalentpeptidebonds.Higherordersofstructurearestabilizedbyweakforces--multiplehydrogen
bonds,salt(electrostatic)bonds,andassociationofhydrophobicR
groups.
Proteindenaturationresultsintheunfoldinganddisorganizationof
--- Content provided by FirstRanker.com ---
theprotein'sstructure,whicharenotaccompaniedbyhydrolysisofpeptidebonds.Denaturationmaybereversibleor,morecommonly,
irreversible.
97.Trueaboutretinol:
a)Formpartofrhodopsin
--- Content provided by FirstRanker.com ---
b)Transportedfromintestinetoliverbyviachylomicronsc)Activelytakepartinvisualcycle
d)Implicatedingrowth&differentiationoftissue
e)Notformedbyretinoicacid
CorrectAnswer-B:D:E
--- Content provided by FirstRanker.com ---
Ans:b.Transportedfromintestinetoliverbyviachylomicrons,d.Implicatedingrowth&differentiationoftissue,&e.Not
formedbyretinoicacid,
[RefHarper30th/547-51,29th/526-28;Lippincott6th/381-83;
Shinde7th/152-56;Vasudevan5th/284-86]
--- Content provided by FirstRanker.com ---
Retinoicacidisproducedbyoxidationofretinal.However,retinoicacidcannotgiverisetotheformationofretinalorretinol"
Retinoicacidisimplicatedingrowth&differentiationoftissue,itis
necessaryforthereproductivesystem.Retinol
actslikeasteroidhormoneincontrollingtheexpressionofcertain
--- Content provided by FirstRanker.com ---
genes.ThismayaccountfortherequirementofVitAfornormalreproduction
Retinylesterspresentinthedietarehydrolyzedintheintestinal
mucosa,releasingretinolandfreefattyacids.Retinolderivedfrom
estersandfromthecleavageandreductionofcarotenesisre-
--- Content provided by FirstRanker.com ---
esterifiedtolong-chainfattyacidsintheintestinalmucosaandsecretedasacomponentofchylomicronsintothelymphaticsystem.
Retinylesterscontainedinchylomicronremnantsaretakenupby,
andstoredin,theliver.
retinolisreleasedfromtheliverandtransportedtoextrahepatic
--- Content provided by FirstRanker.com ---
tissuesbytheplasmaretinolbindingprotein(RBP).
98.Inprolongfastingglycerolisformedfrom
triglyceride.Whichofthefollowing
statement(s)is/aretrueregarding
glycerol:
--- Content provided by FirstRanker.com ---
a)Usedinsynthesisofchylomicronb)Itisdirectlyusedbytissuesforenergyneeds
c)Itisformedduetoincreasedactivityoflipoproteinlipase
d)Itisformedduetoincreasedactivityofhormonesensitive
lipase
--- Content provided by FirstRanker.com ---
e)GlycerolactsasasubstrateforgluconeogenesisintheliverCorrectAnswer-D:E
Ans:d.Itisformedduetoincreasedactivityofhormone
sensitivelipase,&e.Glycerolactsasasubstratefor
gluconeogenesisintheliver,[RefHarper30th/262,149,
--- Content provided by FirstRanker.com ---
29th/160-61;Lippincott6th/331,178,190].Fasting:Inadiposetissuethedecreaseininsulinandincreasein
glucagonresultsininhibitionoflipogenesis,inactivationof
lipoproteinlipase,andactivationofintracellularhormone-sensitive
lipase.
--- Content provided by FirstRanker.com ---
Thisleadstoreleasefromadiposetissueofincreasedamountsofglycerol(whichisasubstrateforgluconeogenesisintheliver)and
freefattyacids,whichareusedbyliver,heart,andskeletalmuscle
astheirpreferredmetabolicfuel,thereforesparingglucose.
TheglycerolproducedfromTAGdegradationisusedasa
--- Content provided by FirstRanker.com ---
gluconeogenicprecursorbytheliver.LipolysisIsControlledbyHormone-SensitiveLipase,whichis
?activatedbyACTH,TSH,glucagon,epinephrine,norepinephrine,
andvasopressinandinhibitedbyinsulin,prostaglandinE1and
nicotinicacid
--- Content provided by FirstRanker.com ---
Activityofthehormone-sensitivelipaseisincreasedbyfastingandstressanddecreasedbyfeedingandinsulin.Conversely,feeding
increasesandfastingandstressdecreasetheactivityoflipoprotein
lipase
99.Pyruvatedehydrogenasecomplexuses
--- Content provided by FirstRanker.com ---
followingcoenzymes/cofactors:a)Biotin
b)Lipoicacid
c)NAD
d)FMN
--- Content provided by FirstRanker.com ---
e)TPPCorrectAnswer-B:C:E
Ans:b.Lipotic.acid.,c.NAD&e.TPP(RefHarper30th/172-74,
29th/174-75;Lippincott6th/109-11;Satyanarayan3rd/253-54]
PyruvateDehydrogenaseComplex(PDH)Satyanarayan
--- Content provided by FirstRanker.com ---
3rd/253-54Itisfoundonlyinmitochondria,HighactivityofPDHarefoundin
cardiacmuscle&kidney
TheenzymePDHrequiresfivecofactors(coenzymes)namely-TPP,
lipoamide(itcontainslipoicacidlinkedtoc-aminogroupoflysine),
--- Content provided by FirstRanker.com ---
FAD,coenzymeA&NAD+,PDHisinhibitedbyarsenitePyruvatedehydrogenaseirreversiblyconvertspyruvate,theend
productofglycolysis,intoacetylCoA,amajorfuelfortheTCAcycle
andthebuildingblockforfattyacidsynthesis.
ThePDHcomplexcontainsfivecoenzymesthatactascarriersor
--- Content provided by FirstRanker.com ---
oxidantsfortheintermediatesofthereactions.Elrequiresthiaminepyrophosphate(TPP),E2requireslipoicacidandCoA,andE3
requiresFADandNAD+.
100.InconversionofpyruvatetoacetylCoA
&CO2,whichofthefollowingcoenzyme
--- Content provided by FirstRanker.com ---
isused:a)Biotin
b)Lipoicacid
c)TPP
d)Pyridoxalphosphate
--- Content provided by FirstRanker.com ---
e)TetrahydrofolateCorrectAnswer-B:C
Ans:b.Lip...&c.TPP[RefaboveQ;Harper30th/172-74,
29th/174-75;Lippincott6th/109-11;Satyanarayan3rd/253-54]
Pyruvatedehydrogenaseirreversiblyconvertspyruvate,theend
--- Content provided by FirstRanker.com ---
productofglycolysis,intoacetylCoA,amajorfuelfor,theTCAcycleandthebuildingblockforfattyacidsynthesis".(Lippincott
6th/109-10)
101.Trueaboutureacycle:
a)Nitrogenoftheureacomesfromalanine&ammonia
--- Content provided by FirstRanker.com ---
b)UsesATPduringconversionofarginosuccinatetoargininec)Onconsumptionofhighamountofprotein,excessofurea
formed
d)Occurmainlyincytoplasm
e)Synthesisofargininosuccinateconsumesenergy
--- Content provided by FirstRanker.com ---
CorrectAnswer-C:D:EAns:c.Onconsumptionofhigh...,d.Occurmainlyin
cytoplasm&e.Synthesisofarginosuccinate....[RefHarper
30th/290-96,29th/274-88;Lippincott6th/253-55;Shinde7th/450-
51;Vasudevan5th/180-811]
--- Content provided by FirstRanker.com ---
Inhealthypeople,thenormalbloodureaconcentrationis1040mg/dl.Higherproteinintakemarginallyincreasesbloodurealevel.
CitrullinePlusaspartateformsargininosuccinate,catalysedby
enzymeArgininosuccinatesynthase.ThereactionrequiresATP.
Cleavageofargininosuccinate,catalyzedbyargininosuccinase,
--- Content provided by FirstRanker.com ---
proceedswithretentionofnitrogeninarginineandreleaseoftheaspartateskeletonasfumarate(requirenoATP)".
Ureahastwoaminogroups,onederivedfromammonia&other
fromaspartate.Carbonatomissuppliedfromcarbondioxide.
102.Gangliosidescontains:
--- Content provided by FirstRanker.com ---
a)Phosphateb)Galactose
c)Sulphate
d)Serine
e)Sailicacid
--- Content provided by FirstRanker.com ---
CorrectAnswer-B:EAns:b.Galactose&e.Sailicacid[RefHarper30th/218,250-51,
29th/146,136,234;Lippincott6th/209;Vasudevan5th/78;
ChatterjeaShinde7th/45,58-61].
Agangliosideisamoleculecomposedofaglycosphingolipidwith
--- Content provided by FirstRanker.com ---
oneormoresialicacidslinkedonthesugarchain.NeuNAc,anacetylatedderivativeofthecarbohydratesialicacid,
makestheheadgroupsofgangliosidesanionicatpH7,which
distinguishesthemfromglobosides.
Gangliosidesarepresentandconcentratedoncellsurfaces,withthe
--- Content provided by FirstRanker.com ---
twohydrocarbonchainsoftheceramidemoietyembeddedintheplasmamembraneandtheoligosaccharideslocatedonthe
extracellularsurface,wheretheypresentpointsofrecognitionfor
extracellularmoleculesorsurfacesofneighboringcells.Theyare
foundpredominantlyinthenervoussystemwheretheyconstitute
--- Content provided by FirstRanker.com ---
6%ofallphospholipids.103.WhichofthefollowingRNAcontains
unusalbases:
a)mRNA
b)rRNA
--- Content provided by FirstRanker.com ---
c)tRNAd)30SRNA
e)50sRNA
CorrectAnswer-B:C
Ans:c.tRNA[RefHarper30th/pg394.
--- Content provided by FirstRanker.com ---
tRNAmoleculecontainahighpercentageofunusalbases,forexample,dihydrouracilerhaveextensiveintra-chainbasepairing
thatleadstocharacteristicsecondary6.,tertiarystructure"-
Lippincott6th/418.
ThetRNAmoleculescontainahighpercentageofunusualbases
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(forexample,dihydrouracil)andhaveextensiveintrachainbase-pairingthatleadstocharacteristicsecondaryandtertiarystructure.
EachtRNAservesasan"adaptor"moleculethatcarriesitsspecific
aminoacid--covalentlyattachedtoits3'-end--tothesiteofprotein
synthesis.Thereitrecognizesthegeneticcodesequenceonan
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mRNA,whichspecifiestheadditionofitsaminoacidtothegrowingpeptidechain
104.AllaretrueaboutstructureofDNA
except:
a)Right-handedhelix
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b)Left-handedhelixc)Phosphateformbackbone
d)Deoxyriboseformsbackbone
e)Nitrogenbasesformbackbone
CorrectAnswer-E
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Ans:e.Nitroge...[RefHarper30th/359-61,29th/354-60;Lippincott6th/395-400;Ananthanarayan9th/54)
Eachchainofdoublehelixhasabackboneofdeoxyribose&
phosphateresiduesarrangedalternately.Attachedtoeach
deoxyriboseisoneofthe4nitrogenousbases:A,G,CforT"
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Ananthanarayan9th/54ThecommonformofDNAissaidtoberight-handed.Inthetest
tube,double-strandedDNAcanexistinatleastsixforms(A-E&Z)"
Withtheexceptionofafewvirusesthatcontainsingle-stranded(ss)
DNA,DNAexistsasadoublestranded(ds)molecule,inwhichthe
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twostrandswindaroundeachother,formingadoublehelixTheAformisproducedbymoderatelydehydratingtheBform.Itis
alsoaright-handedhelix,butthereare11basepairsperturn,
andtheplanesofthebasepairsaretilted20"
awayfromtheperpendiculartothehelicalaxis..Z-DNAisa
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left-handedhelixthatcontainsabout12basepairsperturn(Note:deoxyribose-phosphatebackbone"zigzags,"hence,the
name'S"-DNA)
105.Whichofthefollowingisfalse:
a)RatioofA:T&G:Cisapproximatelyequalto1:1
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b)RatioofA:G&T:Cisapproximatelyequalto1:1c)A+T=G+C
d)A+C=G+T
e)A+G=C+T
CorrectAnswer-B:C
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Ans:b.RatioofA:G...&c.A+T=G+C(RefHarper30th/360-61;Satyanarayan3rd/73;Lippincott4th/291;Ananthanarayan
9th/54-55]
ChargaffrulestatedthatinDNAmoleculestheconcentrationof
deoxyadenosine(A)nucleotidesequalsthatofthymidine(T)
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nucleotides(A=T),whiletheconcentrationofdeoxyguanosine(G)nucleotidesequalsthatofdeoxycytidine(C)nucleotides(G=C)
Thetwostrandsofthisdouble-strandedhelixareheldbyboth,
hydrogenbondsbetweenthepurineandpyrimidinebasesofthe
respectivelinearmoleculesandbyvanderWaalsandhydrophobic
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interactionsbetweenthestackedadjacentbasepairs.Thepairingsbetweenthepurineandpyrimidinenucleotidesonthe
oppositestrandsareveryspecificandaredependentupon
hydrogenbondingofAwithTandGwithC
"Theratioofeachpairofbases(A?T)/(G+C)thoughconstantfor
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eachspecies,varieswidelyfromonebacterialspeciestoanother"-Ananthanarayan9th/54
106.Trueaboutrestrictionenzyme:
a)Alsok/arestrictionendonuclease
b)Producestickyends
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c)Candetectmutationsd)Obtainedfromvirus
e)Breaksatsugar-phosphatebond
CorrectAnswer-A:B:E
Ans:a.Alsok/a.restriction...,b.Producestickyends&e.
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Breaksatsugar-phosphatebond.[RefHarper30th/452-54,28th/388-90;Lippincott4th/465-66;Satyanarayana3rd/580]
REcanspecificallyrecognizeDNAwithparticularsequenceof4-6
mucleotidesandcleave.Therecognitionsequencesare
palindromicQ(i.e.,twofoldrotationalsymmetry"(Lippincott4th/466)
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Itisanenzymethatcleavedouble-strandedDNAQatspecificrecognitionnucleotideknownasrestrictionsitesQ.TocuttheDNA,
arestrictionenzymemakestwoincisions,onethrougheachsugar-
phosphatebackboneQ(i.e.eachstrand)oftheDNAdoublehelix.
Thisenzymecanrestrictviralreplicationsocalledrestriction
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enzymes.ThecutDNAfragmentsbyREmayhavestickyends(cohesive
ends)QorbluntsendsQdependingonthemechanismusedby
enzyme.DNAfragmentswithstickyendsareparticularlyusefulfor
recombinantDNAexperiments(hybridorchimericDNAmolecules).
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TocuttheDNA,arestrictionenzymemakestwoincisions,oncethrougheachsugar-phosphatebackbone(i.e.eachstrand)ofthe
DNAdoublehelix.
107.GenesinCpPislandisinactivatedby:
a)Methylation
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b)Metrylationc)Ubiquitisation
d)Acetylation
e)None
CorrectAnswer-A
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Ans:a.Methylation[RefLippincott6th/709;Harrison19th/101e-4,18th/668,679;Robbins9th/893;Satyanarayan3rd/359,572;
Lippincott4th/460-62;ChatterjeaShinde7th/346,426;en.
wikipedia.org/wiki/DNA_methylationj
CpGislands:Methylationofcytosinebyamethyltransferaseis
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associatedwithsilencingoftheactivitiesofcertaingene"-Lippincott6th/709
CytosineinthesequenceCGofDNAgetsmethylatedtoform5'-
methylcytosine.AmajorportionofCG(about20%)inhumanDNA
existsinmethylatedform.Ingeneral,methylationleadstolossof
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transcriptionalactivity&thusinactivationofgenes.Theroleofepigeneticcontrolmechanismsinthedevelopmentof
humancancerisunclear.However,ageneraldecreaseinthelevel
ofDNAmethylationhasbeennotedasacommonchangeincancer.
Inaddition,numerousgenes,includingsometumor-suppressor
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genes,appeartobecomehypermethylatedandsilencedduringtumorigenesis.
108.Whichofthefollowingis/aretrueabout
PCRexcept:
a)UsesheatlabileDNApolymerase
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b)UsesheatstableDNApolymerasec)IstechniqueforDNAamplification
d)UsedtoyieldmultiplecopiesofDNA
e)Reversetranscriptase-PCRisusedforquantificationofRNA
CorrectAnswer-A
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Ans:a.UsesheatlabileDNApolymerase,[RefHarper30th/458-59;Lippincott6th/479-83,5th/497-83;Chatterjeaer
Shinde7th/267-272]
SpecificityQisbasedontheuseoftwooligonucleotideprimersthat
hybridizetocomplementarysequenceonoppositestrandsofDNA&
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flankthetargetsequenceDoublestrandedDNAcanbedisruptedbyheatorhighpH,givingrisetosinglestrandedDNA.Thesingle
strandedDNAservesasatemplateforsynthesisofa
complementarystrandbyreplicatingenzymes,DNApolymerase.
EarlyPCRreactionusedanE.coliDNApolymerasethatwas
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destroyedbyeachheatdenaturationcycle.Substitutionofaheat-stableDNApolymerase(TaqpolymeraseYfromThermusaquaticus,
obviatesthisproblem&hasmadepossibleautomationofthe
reaction,sincethepolymerasereactionscanberunat70?C
109.Whichofthefollowingtechniquesare
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usedfordetectionofmutation:a)RT-PCR
b)Microarray
c)Allele-specificoligonucleotide(ASO)
d)Westrenblot
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e)DNAsequencingCorrectAnswer-A:B:C:E
Ans:a.RT-PCR,b.Microarray,c.Allele-specific
oligonucleotide(ASO)&e.DNAsequencing,
[RefLippincott6th/473;Harper30th/470,29th/483-85;Harrison
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19th/83e,443-44,18th/508,17th/406;Vasudevan5th/454-56]Mutationalanalysis:Morediscretesequencealterationsrelyheavily
ontheuseofPCR,whichallowsrapidgene
amplificationandanalysis.Moreover,PCRmakesitpossibleto
performgenetictestingandmutationalanalysiswithsmallamounts
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ofDNAextractedfromleukocytesorevenfromsinglecells,buccalcells,orhairroots.DNAsequencingcanbeperformeddirectlyon
PCRproductsoronfragmentsclonedintoplasmidvectorsamplified
inbacterialhostcells"(Harrison19th/444).
SouthernblottingcandetectDNAmutationssuchastheinsertionor
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deletionofnucleotides.Itcanalsodetectpointmutationsthatcausethelossorgainof
restrictionenzymecleavagesites.Suchmutationscausethepattern
ofbandstodifferfromthoseseenwithanormalgene.
Acomprehensiveapproachtogenome-scalestudiesconsistsof
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microarrays,orDNAchips.Usedtodeterminethegeneexpression
patternofthousandsofgenessimultaneously.Microarraysallowthe
detectionofvariationsinDNAsequenceandareusedformutational
analysisandgenotyping.
110.Whichofthefollowingtechniqueis/are
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usedinquantitificationofviralnucleicacid:
a)MALDI-TOFMS
b)Branched-chainDNA(bDNA)
c)PCR
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d)Gas-LiquidChromatographye)Biochemicalphenotyping
CorrectAnswer-B:C
Ans:(B)Branched-chainDNA(bDNA)&(C)PCR[RefHarper
29th/26;Lippincott6th/482,485;Harrison19th/150e-3-6,183e-1,
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194e-3;http://www.researchgate.net/profile/Ivo_Gut/publication/8597456_DNA_analysis_by_MALDI-TOP]
QuantitativeNAATsareavailableforHIV(PCR),cytomegalovirus
(PCR),hepatitisBvirus(PCR),andhepatitisCvirus(PCRand
TMA).
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Branched-chainDNA(bDNA)testingisanalternativetoNAAT(Nucleicacidamplificationtechniques)forquantitativenucleicacid
testing.Insuchtesting,bDNAattachestoasitedifferentfromthe
target-bindingsequenceoftheoriginalprobe.
Chemiluminescence-labeledoligonucleotidescanthenbindto
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multiplerepeatingsequencesonthebDNA.TheamplifiedbDNAsignalisdetectedbychemiluminescence.bDNAassaysforviral
loadofHIV,hepatitisBvirus,andhepatitisCvirushavebeen
approvedbytheFDA.
TheadvantageofbDNA.assaysoverPCRisthatonlyasingle
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heating/annealingstepisrequiredtohybridizethetarget-binding
probetothetargetsequenceforamplification.
111.Whichofthefollowingis/aremost
severe/dangerouschangeingene:
a)Deletion
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b)Insertionc)Mutation
d)Translocation
e)Duplication
CorrectAnswer-A:B
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Ans:a.Deletion&b.Insertion-Mostprobably[RefHarper30th/416-19;Lippincott6th/434;Harrison19th/432-34;Robbins
9th/160-61;Harshmohan7th/2551.
Deletion&Insertioncouldbepossibleanswer(Pleasegothrough
explanationgiven&otherreferencesfordecidingappropriate
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answerFrameshiftMutationsResultfromDeletionorInsertionof
NucleotidesinDNAThatGeneratesAlteredmRNAs
Thedeletionofasinglenucleotidefromthecodingstrandofagene
resultsinanalteredreadingframeinthemRNA.
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ifthreenucleotidesoramultipleofthreearedeletedfromacodingregion,thecorrespondingmRNAwhentranslatedwillprovidea
proteinfromwhichismissingthecorrespondingnumberofamino
acids.Becausethereadingframeisatriplet,thereadingphasewill
notbedisturbedforthosecodonsdistaltothedeletion.
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If,however,deletionofoneortwonucleotidesoccursjustpriortoorwithinthenormalterminationcodon(nonsensecodon),thereading
ofthenormalterminationsignalisdisturbed.Suchadeletionmight
resultinreadingthroughaterminationsignaluntilanothernonsense
codonisencountered.
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InsertionsofoneortwoornonmultiplesofthreenucleotidesintoageneresultinanmRNAinwhichthereadingframeisdistortedupon
translation,andthesameeffectsthatoccurwithdeletionsare
reflectedinthemRNAtranslation.Thismayresultingarbledamino
acidsequencesdistaltotheinsertionandthegenerationofa
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nonsensecodonatordistaltotheinsertion,orperhapsreadingthroughthenormalterminationcodon
112.TruestatementregardingLactate
dehydrogenasedeficiency:
a)Fumaratelevelincreases
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b)Exerciseintolerancec)Musclecrampsmayoccur
d)Itoperatesinanaerobiccondition
e)ItisthekeyenzymeofKrebcycle
CorrectAnswer-B:C:D
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Ans:b.Exercise...,c.Muscle...,d.Itoperate...[RefHarper30th/171,69,28th/149-151;Harrison19th/433e2;Lippincott
4th/103,111;Chatterjea&Shinde7th/313]1
FumarateisconvertedtomalatebyfumaraseenzymeinKrebcycle
(sofumaratelevelincreasesindefectiveenzymefunctioningin
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Krebscycle,notinabnormalityofglycolysisi.e.,lactatedehydrogenasedeficiency,Lactatedehydrogenasecatalyse
conversionofpyruvicacidtolacticacid.
Lactatedehydrogenasedeficiencyisaconditionthataffectshowthe
bodybreaksdownsugartouseasenergyincells,primarilymuscle
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cells.Therearetwotypesofthiscondition:lactatedehydrogenase-A
deficiency(sometimescalledglycogenstoragediseaseXI)and
lactatedehydrogenase-Bdeficiency.
Peoplewithlactatedehydrogenase-Adeficiencyexperiencefatigue,
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musclepain,andcrampsduringexercise(exerciseintolerance).113.Hyaloronicacidiscomposedof:
a)N-acetylglucosamine
b)N-acetylgalactosamine
c)Glucuronicacid
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d)N-acetylneuramicacide)Iduronicacid
CorrectAnswer-A:C
Ans:a.N-acetylandc.Glucuronic[RefHarper30th/156,159,
637,640,28th/119,534-39;Lippincott4th/159,163;Chatterjeaer
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Shinde7th/38]CompositionofHyaluronicAcid:Itiscomposedofrepeatingunitsof
N-acetylglucosamine&D-Glucuronicacid.Onhydrolysis,ityields
equimolecularquantitiesofD-Glucosamine,D-Glucuronicacid&
aceticacid.
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Hyaluronicacidispresentinbacteriaandiswidelydistributedamongvariousanimalsandtissues,includingsynovialfluid,the
vitreousbodyoftheeye,cartilage,andlooseconnectivetissues.
Hyaluronicacidisespeciallyhighinconcentrationinembryonic
tissuesandisthoughttoplayanimportantroleinpermittingcell
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migrationduringmorphogenesisandwoundrepair.Itsabilitytoattractwaterintotheextracellularmatrixandthereby"loosenitup"
maybeimportantinthisregard.
114.ThesizeofMicrosatelliterepeat
sequenceis:
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a)<1kbb)2-6bp
c)1-3kb
d)>3kb
e)5-20bp
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CorrectAnswer-BAns:b.2-6bp
sequencesof2-5bprepeatedupto50times.Mayoccurat50000-
100000locationsinthegenome"-Harper30th/377-78,28th/404
Short(2-6bp),inherited,tandemrepeatunitsofDNAoccurabout
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50,000-100,000timesinthehumangenome.Becausetheyoccurmorefrequently--andintheviewoftheroutine
applicationofsensitivePCRmethods--theyarereplacingRFLPsas
themarkerlociforvariousgenomesearches.
115.AllarefeatureofRefsumdiseaseexcept:
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a)Deficiencyofa-hydroxylaseb)Defectinpoxidation
c)Accumulationofphytanicacid
d)Peripheralneuropathy
e)Treatedbyremovingphytanicacidprecursorsfromdiet
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CorrectAnswer-BAns:b.Defectinpoxidation[RefHarper30th/231,614,28th/I91,
493;Lippincott4th/195;Harrison19th/2681,18th/3456,236]
Refsumdiseaseisarareautosomalrecessivedisordercausedbya
deficiencyofa-hydroxylase"(Lippincott4th/195)
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"Refsum'sdisease:Alphaoxidationdoesnotoccur.Alphaoxidationismainlyusedforfattyacidsthathaveamethylgroupatbeta-
carbon,whichblockbeta-oxidation.Thisprocessoccurmainlyin
endoplasmicreticulum&somealsoinperoxisomes.
Refsum'sdiseaseisarareneurologicdisorderduetoametabolic
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defectthatresultsintheaccumulationofphytanicacid,whichisfoundindairyproductsandruminantfatandmeat.Phytanicacidis
thoughttohavepathologicaleffectsonmembranefunction,protein
prenylation,andgeneexpression"(Harper30th/231,28th/191)
Refsumdiseasecanmanifestininfancytoearlyadulthoodwiththe
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classictetradof(1)peripheralneuropathy,(2)retinitispigmentosa,(3)cerebellarataxia,and(4)elevatedCSFproteinconcentration.
Refsumdiseaseisgeneticallyheterogeneousbutautosomal
recessiveinnature.ClassicalRefsumdiseasewithchildhoodor
earlyadultonsetiscausedbymutationsinthegenethatencodes
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forphytanoyl-CoAa-hydroxylase(PAHX).Refsumdiseaseistreatedbyremovingphytanic
precursors(phytols:fishoils,dairyproducts,andruminantfats)
fromthediet.
116.Groupofallelesthatarecloselylinked
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togetheratagenomiclocus&inheritedtogetherasaclusteris/are:
a)Idiotype
b)Haplotype
c)Genotype
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d)Phenotypee)None
CorrectAnswer-B
Ans.(B)Haplotype([RefsHarrison19th/435,18th/497,505;
Robbins9th/195,8th/177])
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Theentirehumangenomenowcanbedividedintoblocksknownashaplotypes,whichcontainvaryingnumbersofcontiguoussingle
nucleotidepolymorphismsonthesamechromosomethatarein
linkagedisequilibrium&henceinheritedtogetherasacluster
Ahaplotypereferstoagroupofallelesthatarecloselylinked
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togetheratagenomiclocus.Haplotypesareusefulfortrackingthetransmissionofgenomic
segmentswithinfamiliesandfordetectingevidenceofgenetic
recombination,ifthecrossovereventoccursbetweenthealleles.
117.Whichofthefollowingistrueregarding
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DNAdouble-strandbreaksrepairpathway
a)Homologousrecombinationrequirealonghomologous
sequencetoguiderepair
b)Non-homologousend-joiningdoesnotrequirealong
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homologoussequencetoguiderepairc)HomologousrecombinationrepairsDNAbeforethecell
d)Non-homologousend-joiningrepairsDNAbeforethecellenters
mitosis
e)Non-homologousendjoiningisprominentDSBrepair
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mechanisminmammalsCorrectAnswer-A:B:C:E
Ans:a.Homologus...,b.Non-homologous...,c.Homologous...,
e.Non-homologous...[RefHarper30th/389-91,
Satyanarayan3rd/532;Robbins9th/430-31,8th/302;http:
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www.ncbi.nlm.nih.gov/pubmed/20192759]Non-homologousendjoining(NHEJ)isthepredominanttypeofDSB
repairinmammaliancells,asopposedtolowereukaryotes.
DSBinDNAaredangerous;Theyresultingeneticrecombination
whichmayleadtochromosomaltranslocation,brokenchromosome
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&finallycelldeath;DSBscanberepairedbyhomologousrecombinationornon-homologousendjoining;Homologous
recombinationoccursinyeastswhileinmammals,non-homologous
endjoiningdominates
Double-StrandBreaksRepairMechanism
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1. Double-strandbreakscanberepairedthroughhomologous
recombinationorthroughnon-homologousendjoining(NHEJ).
2. NHEJisaDNArepairmechanismwhich,unlikehomologous
recombination,doesnotrequirealonghomologoussequenceto
guiderepair.
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3. WhetherhomologousrecombinationorNHEJisusedtorepairdouble-strandbreaksislargelydeterminedbythephaseofcell
cycle.HomologousrecombinationrepairsDNAbeforethecellenters
mitosis(Mphase).
4. DNAdouble-strandbreaks(DSB)arepresumedtobethemost
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deleteriousDNAlesionsastheydisruptbothDNAstrands.5. Homologousrecombination(HR),single-strandannealing,andnon-
homologousendjoiningareconsideredtobethepathwaysfor
repairingDSB.
118.Whichofthefollowingenzyme(s)
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participateinproteinsynthesis:a)DNAligase
b)DNAHelicase
c)Peptidase
d)Peptidyltransferase
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e)DNApolymeraseCorrectAnswer-D
Ans:d.Peptidyltransferase
[RefHarper30th/422-24,28th/359-66,323;Lippincott4th/438-42;
Chatterjea&Shinde7th/248-501
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EnzymeRequiredforTranslationAmino-acyl-t-RNAsynthetase:Enzymerequiredforactivationof
aminoacids,Peptidesynthetase(peptidyltransferase)
TheNH2ofnewaminoacylt-RNA(AI)in'A'sitecombinewiththe
-COOHgroupofMet-t-RNAoccupyingthe'P'site.Thereactionis
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catalyzedbypeptidyltransferase"."Peptidasesdegradesproteinstoaminoacids
TheNH2ofnewaminoacylt-RNA(AI)in'A'sitecombinewiththe
-COOHgroupofMet-t-RNAoccupyingthe'P'site.Thereactionis
catalyzedbypeptidyltransferase.``peptidasesdegradesproteins
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toaminoacids.Protein
function
DNA
Deoxynucleotide
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polymerasespolymerization
Processiveunwindingof
Helicases
Helicases
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DNARelievetorsionalstrain
Topoisomerases thatresultsfromhelicase-
inducedunwinding
InitiatessynthesisofRNA
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DNAprimaseprimers
Single-strand
Preventpremature
bindingproteins
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reannealingofdsDNASealsthesinglestrand
nickbetweenthenascent
DNAligase
Okazakichainand
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fragmentsontaggingstrand
119.Allaretrueregardingepigenetics
mechanismexcept:
a)Non-heritable
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b)AcetylationofHistonec)Hereditary
d)MethylationofDNA
e)Xchromosomeinactivation
CorrectAnswer-A
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Ans.(A)Non-heritableEpigeneticsisdefinedasthestudyofheritablechemical
modificationofDNAorchromatinthatdoesnotaltertheDNA
sequenceitself.Exampleofsuchmodificationincludemethylationof
DNA&themethylationeracetylationofhistones.
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Epigeneticmodificationiscriticalfornormaldevelopmentincluding-regulationoftissuespecificgeneexpression,X-chromosome
inactivation&genomicimprinting.
Anepigeneticmodificationreferstoachangeinthe
genome,heritablebycellprogeny,thatdoesnotinvolveachangein
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theDNAsequence.TheinactivationofthesecondXchromosomeinfemalecellsisanexampleofanepigeneticsilencingthatprevents
geneexpressionfromtheinactivatedchromosome.
120.Trueaboutpeptidebondformation:
a)TheNH2groupofnewaminoacylt-RNAatAsitecombinewith
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the-COOHgroupofMet-t-RNAoccupyingthe'P'siteb)TheNH2groupofnewaminoacylt-RNAat'P'sitecombine
withthe-COOHgroupofMet-t-RNAoccupyingthe'Asite
c)Reactioniscatalyzedbypeptidyltransferase
d)Peptidebondformationrequireenergy
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e)NoneCorrectAnswer-A:C
Ans:a.TheNH2andc.Reaction...[RefHarper30th/422-25,
28th/359-66;Lippincott4th/438-42;Chatterjeate?Shinde7th/248-
501]
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Thea-aminogroupofthenewaminoacyl-tRNAintheAsitecarriesoutanucleophilicattackontheesterifiedcarboxylgroupofthe
peptidyl-tRNAoccupyingthePsite(peptidylorpolypeptidesite).At
initiation,thissiteisoccupiedbyaminoacyl-tRNAmet'.
Thisreactioniscatalyzedbyapeptidyltransferase,acomponent
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ofthe28SRNAofthe60Sribosomalsubunit.Thisisanotherexampleofribozymeactivityandindicatesanimportant--and
previouslyunsuspected--directroleforRNAinproteinsynthesis.
Becausetheaminoacidontheaminoacyl-tRNAisalready
"activatornofurtherenergysourceisrequiredforthisreaction.The
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reactionresultsinattachmentofthegrowingpeptidechaintothetRNAintheAsite.
121.AllaretrueaboutDNAmethylation
except:
a)Itusuallyoccursinthecytosine
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b)Canaltersthegeneexpressionpatternincellsc)Roleingenomicimprinting
d)Noroleincarcinogenesis
e)Essentialfornormaldevelopment
CorrectAnswer-D
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Ans:(D)Noroleincarcinogenesis[RefHarper30th/438;Harrison19th/101e-4,18th/668,679;Robbins9th/319-20,893,
8th/306;Satyanarayan3rd/359,572;Lippincott4th/460-62;
ChatterjeaShinde7th/346,426;en.wikipedia.org/wiki/
DNA_methylation]
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CytosineinthesequenceCGofDNAgetsmethylatedtoform5'-methylcytosine.AmajorportionofCG(about20%)inhumanDNA
existsinmethylatedform.
InDNA,methylationusuallyoccursintheCpGislands,aCGrich
region,upstreamofthepromoterregion.Inhumans,DNA
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methylationiscarriedoutbyagroupofenzymescalledDNAmethyltransferases.
DNAmethylationstablyaltersthegeneexpressionpatternincells
suchthatcellscan"rememberwheretheyhavebeen"ordecrease
geneexpression
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DNAmethylationisessentialfornormaldevelopmentandisassociatedwithanumberofkeyprocessesincludinggenomic
imprinting,X-chromosomeinactivation,suppressionofrepetitive
elements,andcarcinogenesis.
Adenineorcytosinemethylationispartoftherestrictionmodification
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systemofmanybacteria,inwhichspecificDNAsequencesaremethylatedperiodicallythroughoutthegenome.
Withinthebacterium,methylationprotectsthehostDNAfrom
cleavagebyitsownrestrictionenzyme.UnmethylatedforeignDNA
isnotprotectedfromcleavage.
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122.AllaretrueregardingUreacycleexcept:
a)Ureaformedfromammonia
b)Ratelimitingenzymeisornithinetranscarbamoylase
c)RequireEnergyexpenditure
d)Malateisbyproductofureacycle
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e)OnenitrogenofureacomesfromforaspartateCorrectAnswer-B:D
Ans:b.Ratelimiting...,d.Malate...[RefHarrison19th/434e3-5,
18th/3216,3219;17th/2472-74;Harper30th/290-96,
28th/243;Shinde7th/450-51;Vasudevan5th/180-81]
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Ureahastwoaminogroups,onederivedfromammonia&otherfromaspartate.Carbonatomissuppliedfromcarbondioxide.
Rate-limitingenzyme(pacemakerenzyme)ofUreacycle:
CarbamoylphosphatesynthetaseI(CPSIIisinvolvedinpyrimidine
synthesis)"(Harper28th/245).
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Rate-limitingenzymeofGlycogenSynthesis:Glycogensynthase(nottoohardthere)
Rate-limitingenzymeofGlycogenlysis:Glycogenphophorylase
(phophorylasebreaksphosphatebond,whichmeansactivated
glycogenreleasesalotofenergy)
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Rate-limitingenzymeofHMPShunt:Glucose-6Phosphatedehydrogenase(badtolosethisinRBCs)
Rate-limitingenzymeofdenovopyrimidinesynthesis:Carbamoyl
phosphatesynthaseII(CPSIisinvolvedinureacycle)
123.Whichofthefollowingistrueregarding
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phenylketonuria:a)Dietaryphenylalaninerestrictionisusedintreatment
b)OccurduetodeficiencyofPhenyalaninehydroxylaseenzyme
c)Occurduetoincreaseactivityofphenyalaninehydroxylase
enzyme
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d)Tyrosinemustbesuppliedindiete)Dietshouldcontainhighphenylalaninecontainingfooditems
CorrectAnswer-A:B:D
Ans:a.Dietary...,b.Occur...,d.Tyrosine...[RefHarrison
19th/434e1-3,18th/3217-18;Harper30h/304-306,28th/254;
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Lippincott4th/270-72]InpatientswithPKU,tyrosinecannotbesynthesizedfrom
phenylalanine&therefore,itbecomesanessentialaminoacidthat
mustbesuppliedinthediet
Dietaryphenylalaninerestrictionisusuallyinstitutedifblood
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phenylalaninelevelsare>300umol/L(5mg/dL).Treatmentconsistsofaspecialdietlowinphenylalanineand
supplementedwithtyrosine,sincetyrosinebecomesanessential
aminoacidinphenylalaninehydroxylasedeficiency.
Aboutone-thirdofallpatientswithphenylketonuriaandthemajority
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ofthosewithmilderforms(phenylalanine<1200umol/Latpresentation)showincreasedtolerancetodietaryproteinsand
improvedmetaboliccontrolwhentreatedwithtetrahydrobiopterin(5-
20mg/kgperday),anessentialcofactorofphenylalanine
hydroxylase.Thisdrugshouldbeusedinadditiontodietarytherapy.
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Pregnancyriskscanbeminimizedbycontinuinglifelong
phenylalanine-restricteddietsandassuringstrictphenylalanine
restriction2monthspriortoconceptionandthroughoutgestation.
124.TrueaboutDNAhyperchromatism:
a)Itisincreaseofabsorbance
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b)Measuredbyabsorbanceat260nm(inaspectrophotometer)c)ItoccurswhentheDNAduplexisdenatured
d)DoublestrandedDNAismorehyperchromicthanssDNA
e)None
CorrectAnswer-A:B:C
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Ans:(A)Itisincreaseofabsorbance(B)Measuredbyabsorbanceat260nm(inaspectrophotometer)(C)Itoccurs
whentheDNAduplexisdenatured[RefHarper30th/361,
28th/303;Satyanarayan3rd/78;Lippincott4th/397-98]
Hyperchromicityistheincreaseofabsorbance(opticaldensity)ofa
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material.ThemostfamousexampleisthehyperchromicityofDNAthatoccurswhentheDNAduplexisdenatured
Itistheincreaseofabsorbance(opticaldensity)ofamaterial.The
mostfamousexampleisthehyperchromicityofDNAthatoccurs
whentheDNAduplexisdenatured.
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'Atawavelengthof260nm,ssDNAhasahigherrelativeabsorbancethandoesdoublestrandedDNA"(Lippincott
4th/397-98)
TheUVabsorptionisincreasedwhenthetwosingleDNAstrands
arebeingseparated,eitherbyheatorbyadditionofdenaturantor
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byincreasingthepHlevel.Lossofhelicalstructurecanbemeasuredbyincreasein
absorbanceat260nm(inaspectrophotometer),Theopposite,a
decreaseofabsorbanceiscalledhypochromicity
Renatuartion(reannealing)istheprocessinwhichtheseparated
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complementaryDNAstrandscanformadoublehelix
125.InBenedicttest,redcolouris/are
producedby:
a)Sucrose
b)Inositol
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c)Fructosed)Lactose
e)Maltose
CorrectAnswer-C:D:E
Ans:c.Fructose,d.Lactose,e.Maltose[RefLippincott4th/84-
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85;ChatterjeaFrShinde7th/31;Satyanarayan3rd/16]Inositolisalsocalledasmusclesugar.Chemicallyitishexahydroxyl
cyclohexane"(ChatterjeadShinde7th/190)
Reducingsugarscanreactwithchromogenicagents(fore.g,
Benedict'sreagentorFehling'ssolutionorBarfoed'stest)causing
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thereagenttobereduced&coloured,withanomericcarbonofthesugarbecomingoxidized"(Lippincott4th/84;Satyanarayan3rd/16).
InBenedict'stest,reactionofreducingsugarwithBenedict'sreagent
produceredcolourofcuprousoxide.
126.Truestatementsare:
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a)VitaminAindose20,000unitmaybeusedduringlactationtopreventVitAdeficiencytoinfants
b)HighdoseofVitaminCmaycauserenalstone
c)VitaminEreducesriskofatherosclerosis
d)Folicaciddeficiencycausemicrocyticanaemia
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e)BananaisarichsourceofVit.B6CorrectAnswer-A:B:C:E
Ans:a.Vitamina....,b.High...,c.Vitamine...,e.Banana...[Ref
Harrison19th/96e1-7,18th/599;Harper30th/547-62,28th/47178;
Lippincott4th/374]
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Vit.Ctoxicity:Oxalatekidneystonesareoftheoreticconcernbecauseascorbicacidismetabolizedtooxalate,butstoneformation
hasnotbeenfrequentlyreported"(CMDT06/1275)"Prophylaxis
againstxerophthalmia:Lactatingmothersshouldbegiven20,000
IUorallyonceatdeliveryorduringthenext2months.Thiswillraise
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theconcentrationofvitaminAinthebreastmilk&therefore,helptoprotectthebreastfedinfant"(Khurana5th/466)
"Folicaciddeficiencycausemegaloblasticanaemia(macrocytic)"
(Lippincott4th/374)
"Vit.Ereducestheriskofatherosclerosis"(Vasudevan5th/291)
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"Banana:Itisaverygoodsourceofvitamin-B6(pyridoxine),providesabout28%ofdaily-recommendedallowance.
127.Thiaminedeficiencycause(s):
a)Glossitis
b)Polyneuropathy
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c)Pellagrad)Angularstomatitis
e)Cardiomegaly
CorrectAnswer-B:E
Ans:b.Polyneuropathy,e.Cardiomegaly[Re(Harrison
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19th/96e-3,18th/594-96;Harper30th/555-56,28th/468]Wetberiberipresentsprimarilywithcardiovascularsymptoms,due
toimpairedmyocardialenergymetabolismanddysautonomia,and
canoccurafter3monthsofathiamine-deficientdiet.Patients
presentwithanenlargedheart,tachycardia,high-outputcongestive
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heartfailure,peripheraledema,andperipheralneuritis.Patientswithdryberiberipresentwithasymmetricperipheral
neuropathyofthemotorandsensorysystemswithdiminished
reflexes.Theneuropathyaffectsthelegsmostmarkedly,andthese
patientshavedifficultyrisingfromasquattingposition.
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128.Thiamineactasco-enzymefor:
a)Transketolase
b)Pyruvatedehydrogenase
c)Alcoholdehydrogenase
d)Transaminase
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e)NoneCorrectAnswer-A:B
Ans:a.Transketolase,b.Pyruvate...[RefHarper30th/555,
28th/52;Chatterjea&Shinde7th/166-67]
"NAD+(byvitaminB3)actsasacoenzymeforalcohol
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dehydrogenase"(ChatterjeaShinde7th/171)Pyridoxalphosphate(byvitaminpyridoxine,B6)actsascoenzyme
fortransaminaseslikeaminotransferase.
thiaminepyrophosphateactsascoenzymein:Pyruvate
dehydrogenasemn(oxidativedecarboxylation),a-oxoglutararte
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dehydrogenasecomplex(oxidativedecarboxylation),transketolase(transketolationreaction),tryptophanpyrrolase,pyruvate
carboxylase(non-oxidativedecarboxylation).
129.Terminalproduct(s)ofphenylalanineis:
a)Fumarate
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b)AcetylCoAc)Oxaloacetate
d)Acetoacetate
e)None
CorrectAnswer-A:B:D
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Ans:a.Fumarate,b.AcetylCoA&d.Acetoacetate[RefHarper30th/285,304,29th/269,290;Lippincott6th/263,262;
Satyanarayan3rd/345-47;Vasudevan5th/202-03]
"Thepredominantmetabolismofphenylalanineoccursthrough
tyrosine.Duringthecourseofdegradation,phenylalanine&tyrosine
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areconvertedtometabolite,fumarate&acetoacetate,whichcanserveasprecursorsforthesynthesisofglucose(fumarate-Itisan
intermediateofthecitricacidcycle&canalsoserveasprecursorfor
gluconeogenesis)&fat(acetoacetate-Itisaketonebodyfromwhich
fatcanbesynthesized)".
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Phenylalaninehydroxylaseisanenzymethatcatalyzesthehydroxylationofthearomaticside-chainofphenylalanineto
generatetyrosine.
Phenylalanineisfirstconvertedtotyrosine.Subsequentreactions
arethoseoftyrosine"(Harper30th/304,29th/288)"Hydroxylationof
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phenylalanineproducetyrosine.Metabolismofphenylalanine&tyrosinemerge,leadingultimatelytotheformationoffumarateer
acetoacetate.phenylalanine&tyrosineare,therefore,both
glucogenicorketogenic.
130.NADPHisproducedby:
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a)Pyruvatedehydrogenseb)Isocitratedehydrogense
c)a-ketoglutarylDehydrogense
d)SuccinateDehydrogense
e)Malatedehydrogense
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CorrectAnswer-A:B:C:EAns:a.Pyruvate...,b.Isocitrate....c.a-ketoglutaryl...,&e.
Malate...,
[RefHarper30th/169,29th/177;Lippincott6th/109-13,155;Shinde
7th/321]
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MethodofATPPathway Reactioncatalyzedby
ATP
formation
1.Pyruvate
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1.Respiratorychain5
dehydrogenase
oxidationof2NADH
2.Isocitrate
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2.Respiratorychain5
dehydrogenase
oxidationof2NADH
3.a-Ketoglutarate
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3.RespiratorychainCitric
5
dehydrogenase
oxidationof2NADH
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acid4.Substratelevel
cycle
4.Succinatethiokinase
2
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phosphorylation5.Succinate
5.Respiratorychain
3
dehydrogenase
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oxidationof2ADH26.Malate
6.Respiratorychain
5
dehydrogenase
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oxidationof2NADH131.FunctionofmiRNAis/are:
a)Genesilencing
b)Geneactivation
c)Transcriptioninhibition
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d)Translationrepressione)BreakingofmessengerRNA
CorrectAnswer-A:D:E
Ans:a.Gene...,d.Translation...&e.Breaking...[RefHarper
30th/368,29th/351-52;Lippincott6th/459;Vasudevan5th/436]
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RNAinterferenceisamechanismofgenesilencingthroughdecreasedexpressionofmRNA,eitherbyrepressionoftranslation
orbyincreaseddegradation.
miRNAbindtomatchingpiecesofmessengerRNA,turnitintoa
doublestrand&keepitfromdoingitsjob.Theprocesseffectively
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blockstheproductionofcorrespondingprotein.miRNAsaretypically21-25nucleotidesinlengthandaregenerated
bynucleolyticprocessingoftheproductsofdistinct
genes/transcriptionunits.miRNAprecursorsaresinglestrandedbut
haveextensiveintramolecularsecondarystructure.
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132.Opticallyinactiveaminoacidis/are:
a)Threonine
b)Thyronine
c)Valine
d)Glycine
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e)SerineCorrectAnswer-D
Ans:d.Glycine[RefVasudevan5th/20;Shinde7th/78]
Aminoacidshavinganasymmetriccarbonatomexhibitoptical
activity.Asymmetryariseswhen4differentgroupsareattachedto
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thesamecarbonatomGlycineisthesimplestaminoacids&hasnoasymmetriccarbon
atom&thereforeshowsnoopticalactivity.Allothersareoptically
active
Themirrorimageformsproducedwithreferencetothealphacarbon
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atom,arecalledD&LisomersIsoleucineerthreoninehave2opticallyactivecentres&therefore
eachhas4diastereoisomers
133.cDNAisusedingeneamplificationin
bacteriainsteadofgenomicDNA
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because:a)Easytoreplicatebecauseofsmallsize
b)cDNAlacksintronwhereasthisispresentingenomicDNA
c)Promotorarenotfoundinbacteria
d)Completegenomecannoteasilyreplicatedinbacteria
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e)NoneCorrectAnswer-A:B:D
Ans:a.Easy...,b.cDNA...&d.Complete[RefHarper30th/455-
56,29th/438-39;Lippincott6th/469-70;Vasudevan5th/449]
BecausecDNAhasnointervening,itcanbeclonedintoan
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expressionvectorforthesynthesisofeukaryoticproteinsbybacteria";"cDNAlacksintrons&thecontrolregionsofthegene,
whereasthesearepresentingenomicDNA"(Lippincott6th/469)
"Bacterialpromotersarerelativelysimple.
cDNAlibrariescontainthoseDNAsequencesthatonlyappearas
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processedmessengerRNAmolecules&thesedifferfromonecelltypetoanother.AcDNAlibrarycomprisescomplementaryDNA
copiesofthepopulationofmRNAsinatissue.
cDNAprobesareusedtodetectDNAfragmentsonSouthernblot
transfersandtodetectandquantitateRNAonNorthernblot
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transfers134.Informing3Dstructureofprotein
followingcomponentshelp:
a)Hydrogenbonds
b)Aminoacidsequence
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c)Interactionbetweenaminoacidsidechainsd)Chaperon
e)allofthese
CorrectAnswer-E
Ans:(E)allofthese[RefHarper30th/39-41,29th/36-40;
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Vasudevan5th/27;Lippincott6th/18-19,22;Shinde7th/86-88]The3-dimensionalarrangementofproteinstructureisreferredtoas
tertiarystructure.Thistypeofarrangementensuresstabilityofthe
molecule.Besidesthehydrogenbonds,disulfidebonds,ionic
interactions(electrostaticbonds)&hydrophobicinteractionsalso
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contributetothetertiarystructureofprotein.Theunique3dimensionalstructureofthenativeconformationis
determinedbyitsprimarystructure,thatis,itsaminoacidsequence,
Interactionsb/wtheaminoacidsidechainsguidethefoldingofthe
polypeptidechaintoformsecondary,tertiary&(sometimes)
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quaternarystructures,whichcooperateinstabilizingthenativeconformationoftheprotein.
Inaddition,aspecializedgroupofproteinnamedchaperonesis
requiredfortheproperfoldingofmanyspeciesofproteins.
135.Testusedforproteinis/are:
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a)Westernblotb)Southernblot
c)ELISA
d)CHIPessay
e)Dotblotting
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CorrectAnswer-A:C:DAns:a.Westernblot,c.ELISAd.CHIPessay
[RefHarper30th/457,29th/439;Lippincott6th/484,473,485;
Satyanarayan3rd/589]
Westernblot-Measuresproteinamount
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ELISA-detectsproteins(antigenorantibodies)136.Whichofthefollowingdiseaseoccurs
duetoDNAmoleculerepairdefect:
a)Krabe'sdisease
b)Angelmannsyndrome
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c)Xerodermapigmentosumd)Marfansyndrome
e)Ataxiatelangiectasia
CorrectAnswer-C:E
Ans:c.Xeroderma...,e.Ataxia...[RefHarper30th/390,29th/374,
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28th/330-333;Lippincott6th/410-13;Harrison18th/496,17th/395]
Angelmannsyndromeresultsfromgeneticdisorderthatresultsfrom
defectingenethatencodesubiquitin";"Marfansyndrome:Itis
causedbymutationingeneforfibrillin";"Krabbedisease:dueto13
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?galactosidaseenzymedeficiency.XerodermaPigmentosum(XP):Anautosomalrecessivegenetic
disease;morethan10genesareinvolved;Theclinical
syndromeincludesmarkedsensitivitytosunlight(ultraviolet)with
subsequentformationofmultipleskincancersandpremature
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death,Theriskofdevelopingskincancerisincreased1000-to2000-fold.
137.FullformofLCATis:
a)Lecithincholesterolacyltransferase
b)Lecithincholineacyltransferase
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c)Lecithincholesterolalkyltransferased)Lecithincholinealcoholtransferase
e)LecithinCoAtransferase
CorrectAnswer-A
Ans:a.Lecithincholesterol...[RefHarper30th/272,29th/242,
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256;Lippincott6th/234-36]PlasmaLCATIsResponsibleforVirtuallyAllPlasmaCholesteryl
EsterinHumans(Harper29th/256).LCATactivityisassociatedwith
HDLcontainingapoA-I.AscholesterolinHDLbecomesesterified,it
createsaconcentrationgradientanddrawsincholesterolfrom
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tissuesandfromotherlipoproteins,thusenablingHDLtofunctioninreversecholesteroltransport.
Thisprotein,associatedwithHDL,isfoundinplasmaofhumansand
manyotherspecies.Itfacilitatestransferofcholesterylesterfrom
HDLtoVLDL,IDL,andLDLinexchangefortriacylglycerol,relieving
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productinhibitionofLCATactivityinHDL.138.Whichvitamindeficiencycause
dementia:
a)VitaminA
b)VitaminC
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c)VitaminB12d)VitaminB1
e)Nicotinicacid
CorrectAnswer-C:D:E
Ans:c.Vitamin...,d.Vitamin...&e.Nicotinic...[RefLippincott
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6th/379-80;Harrison19th/463]Niacinornicotinicaciddeficiencycausespellagra.Thesymptomof
pellagraprogressthroughthethreeDs:dermatitis,diarrhea
&dementia"
Niacinpellagra:pigmentedrashofsun-exposedareas,brightred
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tongue,diarrhea,apathy,memoryloss,disorientationFolateMegaloblasticanemia,atrophicglossitis,depression,T
homocysteine
VitaminMegaloblasticanemia,lossofvibratoryandposition
B12sense,abnormalgait,dementia,impotence,lossofbladder
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andbowelcontrol,Thomocysteine,MethylmalonicacidVitaminCScurvy:petechiae,ecchymosis,coiledhairs,inflamed
andbleedinggums,jointeffusion,poorwoundhealing,fatigue
VitaminAXerophthalmia,nightblindness,Bitot'sspots,follicular
hyperkeratosis,impairedembryonicdevelopment,immune
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dysfunction139.Whichofthefollowingorgancannotuse
ketonebody:
a)Brain
b)RBC
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c)Muscled)Heart
e)Liver
CorrectAnswer-A:E
Ans:a.Brain,e.Liver[RefHarper30th/150,211-12,29th/161,
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211-12;Lippincott6th/196;Vasudevan5th/1451.Ketonebodiescanbeusedbyextrahepatictissuesuchasskeletal&
cardiacmuscle,intestinalmucosa&renalcortex.Eventhebraincan
useketonebodiestohelpmeetitsenergyneedsifthebloodlevels
risesufficiently.
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Theketonebodiesareformedintheliver;buttheyareutilizedbyextrahepatictissues.Theheartmuscle&renalcortexpreferthe
ketonebodiestoglucoseasfuel.Tissuelikeskeletalmuscle&brain
canalsoutilizetheketonebodiesasalternatesourcesofenergy,if
glucoseisnotavailable.
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