GATE Life Sciences (XL) 2010 Question Paper Part 5 Microbiology (Optional Paper) by Easybiologyclass

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GATELifeSciences(XL)2010(GraduateAptitudeTestinEngineering:OriginalQuestionPaper)

Microbiology(K)OptionalQuestionPaper

Questions1–10carries1markeach

1. Aelectronmicroscopehashigherresolutionascomparedtothelightmicroscope.Thisisbecause:

a. Thewavelengthofanelectronislongerthanthewavelengthoflightb. Thewavelengthofanelectronisshorterthanthewavelengthoflightc. Theelectronscanpenetratethesamplebetterd. Theyusedifferentstains

2. Bacterialcelllysisbylysozymeisduetothe:a. Hydrolysis of α‐1,4‐glycosidic bonds between theN‐acetylglucosamine and

N‐acetylmuramicacidb. Inhibitionofcellwallsynthesisc. Hydrolysisofpentapeptidebridgesd. Hydrolysisofβ‐1,4‐glcosidicbondsbetweentheN‐acetylglucosamineandN‐

acetylmuramicacid3. Therecombinationfrequenciesbetweenthreegenesx,y,andzareasfollows:

X–y=2.6%,y–z=1.4%andx–z=1.2%.Thenthegeneorderis:

a. x–z–yb. x–y–zc. y–x–zd. z–x–y

4. Amutantphenotypedue toanonsensemutationcanberescuedbyamutation intRNAgene.Thisrescueisanexampleof:

a. Inducedmutationb. Suppressormutationc. Spontaneousmutationd. Deletionmutation

5. Amestestisperformedtodetect:a. Mutagenb. pHc. nutrientstressd. salinitywww.ea

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6. WildtypeE.coliformspurplecolouredcoloniesonEMB‐lactoseplate.Thisisduetoa. IncreaseinpHofthemediumb. DecreaseinthepHofthemediumc. Secretionofpurplecolouredpigmentd. Secretionofβ‐galactosidase

7. TheresistanceofalambdalysogenicE.colitoreinfectionbylambdaismediatedby:a. BlockingentryoftheincominglambdaDNAb. DegradingtheincominglambdaDNAc. BlockingtranscriptionoftheincominglambdaDNAd. Triggeringmutationofthelambdareceptorofthehost

8. Pasteurizationofmilkiscarriedoutby:a. Boilingfor5minb. Heatingat72oCfor30minutesc. Heatingat63oCfor15minutesd. Heatingat63oCfor30minutes

9. Agrowingbacterialculturewithadoublingtimeof20minutesreachescelldensityof2X108cells/mlin3hours.Howmuchtimewouldittaketoreachthecelldensityof1X108cells/ml?

a. 200minb. 180minc. 160mind. 90min

10. Thequickestwaytodeterminebacterialgrowthintermsofviablecellsisthrough:a. Mostprobablenumber(MPN)techniqueb. Spreadplatemethodc. Pourplatemethodd. Slideculturetechnique

Questions1–10carries1markeach

11. Match the scientist from Group I with the corresponding contribution listed inGroupIIGroupI GroupIIP.RobertKoch 1.DiscoveryofendosporesQ.WalterHesse 2.DisprovedspontaneousgenerationR.LouisPasteur 3.DiscoveryofcausativeagentoftuberculosisS.FerdinandCohn 4.Useofagarassolidmedia 5.Inventionofmicroscopewww.ea

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a. P–5,Q–3,R–4,S–2b. P–3,Q–4,R–2,S–5c. P–3,Q–4,R–1,S‐5d. P–3,Q–4,R–2,S–1

12. Super‐antigenselicitaverystrongTcellresponsebecausethey:a. BindtothespecificantigenbindingsiteontheTcellreceptor(TCR)b. BindtothesiteonTcellreceptor(TCR)that isoutsidetheantigen‐specific

bindingsitec. DirectlyactivatetheTcellwithoutthehelpofantigenpresentingcellsd. Directlyinducecytokinesecretionbymacrophages

13. MHC‐Igroovecanbelocatedwithpeptidesononly8‐10aminoacidsbecause:a. MHC‐Igrooveisclosedonbothendsb. Fragmentsofonly8‐10aminoacidsaregeneratedinMHC‐Ibearingcellsc. β2‐microglobulinofMHCIpreventsthebindingoflargepeptidestoMHC‐Id. βpolypeptidesofMHC‐Ipreventsbindingof8‐10aminoacid longpeptides

toMHC‐I14. inalacOcLacZ‐/lacO+lacZ+partialdiploidofthetwolacZenzymes,onlythemutant

enzyme (lacZ‐) is synthesized constitutively. This observation shows that lacOcmutationis:

a. trans‐dominantb. trans‐recessivec. cis‐dominantd. cis‐recessive

15. Whichoneofthefollowingeventsoccursinprokaryotesbutnotineukaryotes?a. Proteinphosphorylationb. RNApolymeraseandpromoterinteractionc. Controloftranscriptionbyattenuationd. FormationofOkazakifragments

16. MatchthepathogeninGroupIwiththecorrespondingdiseaseinGroupIIGroupI GroupIIP.Bacteria 1.MeaslesQ.Virus 2.CandidiasisR.Fungi 3.MalariaS.Protozoa 4.Bovinespongiformencephalitis 5.Tuberculosisa. P–1,Q–2,R–4,S–5b. P–1,Q–4,R–2,S–3www.ea

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c. P–5,Q–1,R–4,S–2d. P–5,Q–1,R–2,S–3

17. A bacterial culture was diluted 1000 fold and 0.1 ml of this diluted sample wasspreadperplateonnutrientagar.Inatriplicaterun,thenumberofcoloniesformedis 121, 93, 86. The number of colony forming units/ml in the original bacterialcultureis:

a. 106b. 105c. 103d. 102

18. MatchthemicroorganisminGroupIwiththeapplicationinGroupIIGroupI GroupIIP.Aspergillusoryzae 1.MetaloreleachingQ.Brevibacteriumflavum 2.GlucoamylaseproducerR.Thiobacillusferroxidans 3.BreadmakingS.Saccharomycescervisiae 4.GlutamicacidproducerT.Rhizobiummeliloti 5.Penicilliumproducer 6.Symbioticnitrogenfixera.P–1,Q–6,R–4,S–5,T–2b.P–2,Q–4,R–1,S–3,T–6c.P–4,Q–1,R–6,S–3,T–5d.P–6,Q–2,R–3,S–5,T–1

19. AmutantofE.coligrowsnormallyonglucoseoronglycerolbutnotonacetate.Themostlikelymetabolicpathwaythatisdefectiveinthismutantis:

a. Glyoxalatecycleb. Hexosemonophosphateshuntc. Krebscycled. Entner–Doudoroffpathway

20. MatchtheresistancemechanisminGroupIwiththeantibioticingroupIIGroupI GroupIIP.β‐Lactamase 1.AminoglycosidesQ.Enhancedfolatemetabolism 2.PenicillinsR.Drugefflux 3.SulfadrugsS.Phosphorylationofthedrug 4.TetracyclinsT.MutantRNAPolymerase 5.Naladixicacid 6.Rifamycin

a. P–2,Q–3‐R–4,S–5,T–6b. P–3,Q–4,R–1,S–6,T–5www.ea

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c. P–2,Q–3,R–4,S–1,T–6d. P–1,Q–2,R–3,S–4,T–6

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GATE Life Sciences (XL) 2010 Question Paper Part 5 Microbiology (Optional Paper) by Easybiologyclass