The document discusses various topics in molecular biology and microbial genetics. It includes multiple choice questions about the central dogma of biology, genetic code, Griffith's experiment demonstrating that DNA is the genetic material, DNA polymerase, semi-conservative replication proposed by Watson and Crick, DNA gyrase, definition of a holoenzyme, Okazaki fragments, helicases, replication origins, replication bubbles, mutagens like alkylating agents, DNA repair mechanisms like photoreactivation and SOS repair, definitions of mutations, types of base changes like transitions and transversions, and point mutations.

1. MOLECULAR BIOLOGY & MICROBIAL GENETICS
1.The central dogmastatementisusuallywrittenas
(a)Protein-mRNA-DNA (b)DNA-mRNA-Protein
(c)mRNA-Protein-DNA (d)mRNA-DNA-Protein
2.A base sequence correspondingtoa particularaminoacidis
(a)Geneticcode (b)Anticodon
(c)Codon (d)tRNA
3.GriffithdevelopedthatDNA isthe geneticmaterial withanobservationin
(a)1928 (b)1945
(c)1944 (d)1952
4.Nucleotide monomersare addedone byone to the endof a growingstrandby an enzyme called
(a)Reverse transcriptase (b)DNA gyrase
(c)DNA helicase (d)DNApolymerase
5.The semiconservative mode wasfirstproposedby
(a)OswaldAvery (b)Watsonand Crick
(c)HersheyandChase (d)ColinMacLeod
6.An enzyme whichisable toproduce negative superhelicityin E.coliis
(a)DNA gyrase (b)Topoisomerases
(c)DNA polymerase (d)DNA helicase
7.The smallestaggregate havingenzymaticactivityiscalled
(a)Holoenzyme (b)DNA ligase
(c)Core enzyme (d)DNA primase
8.The fragmentswhichpropertiespredictedbythe discontinuousmodelis
(a)Replicationfork (b)Leadingstrand
(c)SSBprotein (d)Okazaki fragment
9.Helix-unwindingisaccomplishedbyenzymescalled
(a)Helicases (b)DNA Ligase
(c)DNA Primase (d)DNA Gyrase
10.Double-strandedDNA moleculesinitiate aroundof replicationata unique base sequence called
(a)Initiation (b)Replicationorigin

2. (c)SSBprotein (d)Replicationfork
11.The leadingstranddisplacesthe unreplicatedparentalstrand,the bubble iscalled
(a)Replicationbubble (b)Displacementloop
(c)Stranddisplacement (d)Rollingcircle replication
12.Noxiouschemicalscalled
(a)Depurination (b)Non-alkylatingagents
(c)Alkylatingagents (d)Solidifyingagents
13.Liquid-holdingrecoveryisknowntobe amanifestationof ageneral phenomenoncalled
(a)Dark repair (b)Photoreactivationrepair
(c)SOSrepair (d)Excisionrepair
14.Which isan enzymaticcleavage of thymine dimers?
(a)Recombination (b)Photoreactivation
(c)SOSrepair (d)Excisionrepair
15.Which includesabypasssystemthatallowsDNA chaingrowthacross damagedsegmentsatthe
cost of fidelityof replication?
(a)Darkrepair (b)Photoreactivationrepair
(c)SOSrepair (d)Excisionrepair
16.What refers toany change inthe base sequence of DNA?
(a)Mutation (b)Gene mapping
(c)Deletionmapping (d)Complementation
17.What isa physical agentor a chemical agentthatcausesmutations?
(a)Mutagenesis (b)Mutagen
(c)Pointmutation (d)Missensemutation
18.A base change that doesnotchange the pyrimidine-purineorientationiscalled
(a)Transversion (b)Reversion
(c)Transition (d)Depurination
19.A reverse mutantiscalled
(a)Deletion (b)Mapping
(c)Revertant (d)Transition
20.Mutation occurs inspecificsite iscalled
(a)Pointmutation (b)Frame shiftmutation

3. (c)Backmutation (d)Site specificmutation