🐒 Molecular Genetics - Part - I 🐒

12th Standard Molecular Genetics Part I- Exam Code MQGN01
Name/பெயர்


Ref.Number/தேர்வு எண்


Class-Section/வகுப்பு-பிரிவு


1) Hershey and Chase experiment with bacteriophage showed that
  a)   Protein gets into the bacterial cells
  b)   DNA is the genetic Material
  c)   DNA contains radioactive sulphur
  d)   Viruses undergo transformaton

2) DNA and RNA are similar with respect to
  a)   Thymine as nitrogen base
  b)   A Single - stranded helix shape
  c)   Nucelotide conatining sugars, nitrogen bases and phosphates
  d)   The same sequence of nucleotides for the amino acid phenyl alanine


3) A mRNA molecules is produced by
  a)   Replication
  b)   Transcription
  c)  Duplication
  d)   Translation


4) The total number of nitrogenous bases in human genome is estimated to be about
  a)   3.5 Million
  b)   35,000
  c)   35 Million
  d)   3.1 billion


5) E.Coli cell grown on ¹⁵N medium are transferred to ¹⁴N medium and allowed to grow for two generations. DNA extracted from these cells is ultracentrifuged in a cesium chloride density gradient. What density distribution of DNA would you expect in this experiments?
  a)   One High and one low density band.
  b)   One intermediate desnsity band
  c)   One High and intermediate density band
  d)   One low and one intermediate density band


6) What is the basis for the the difference in the synthesis of the leading and lagging strand of DNA molecules?
  a)   Orign of replication occurs only at the 5' end of the molecules
  b)   DNA ligase works only in the 3' ----> 5' direction
  c)   DNA Polymerase can join new nucleotides only to the 3' end of the growing stand.
  d)   Helicases and single -strand binding proteins that work at the 5' end.


7) Which of the following is the correct sequence of event with reference to the central dogma?
  a)   Transcription, Tanslation, Replication
  b)   Transcription, Replication, Translation
  c)   Duplication, Translation, Transcription
  d)   Replication, Transcription, Translation


8) Which of the following statements about DNA replication is not correct?
  a)   Unwinding of DNA molecule occurs as hydrogen bonds break
  b)   Replication occurs as each base is paired with another exactly like it
  c)   Process is known as semi conservative replication because one old strand is conserved in the new molecule
  d)   Complementary basepairs are held together with hydrogen bonds


9) Which of the following statement is not true about DNA replication in eukaryotes?
  a)   Replication begins at a single origin of replicaton
  b)   Replication is bidirectional from the origins
  c)   Replication occurs at about 1 million base pairs per minute
  d)   There are numerous different bacterial chromosomes, with replication occuring in each at the same time


10) The first codon to be deciphered was .......... which codes for .............
  a)   AAA, proline
  b)   GGG, alaine
  c)   UUU, Phenylalanine
  d)   TTT,arginine


11) Meselson and Stahl's experiment proved
  a)   Transduction
  b)   Transformation
  c)   DNA is the genetic material
  d)   Semi-conservative nature of DNA replication


12) Ribosomes are composed of two subunits; the smaller subunit of a ribosome has a binding site for ....... and the larger subunit has two binding sites for two .........
  a)   mRNA, tRNA
  b)   DNA, RNA
  c)   RNA, DNA
  d)   all the above


13) An operon is a
  a)   Protein that suppresses gene expression
  b)   Protein that accelerates gene expression
  c)   Cluster of structural genes with related function
  d)   Gene that switched other genes on or off


14) When lactose is present in the culture medium
  a)   Transcription of lac y, lac z, lac a genes occurs
  b)   Repressor is unable to bind to the the operator
  c)   Repressor is able to bind to the operator
  d)   Both (a) and (b) are correct


15) The association of histone H1 with a nucleosome indicates
  a)   Transcription is occuring
  b)   DNA replicaion is occuring
  c)   The DNA is condensed into chromatin fibre
  d)   The DNA double helix is exposed


16) Which of the following is not required for any of the techniques of DNA fingerprinting available at present
  a)   Zinc finger analysis
  b)   Restriction enzymes
  c)   DNA-DNA hybridization
  d)   Polymerase chain reaction

17) The okazaki fragments in DNA chain growth
  a)   Result in Transcription
  b)   Polymerise in the 3' to 5' direction and forms replication fork
  c)   Prove semi conservative nature of DNA replication
  d)   Polymerises 5' to 3' direction

18) Satellite DNA is important because it
  a)   codes for proteins needs in cell cycles
  b)   Shows high degree of polymorphism in Population and also the same degree of polymorphism in an individual, which is heritable from parents to children
  c)   Does not code for protein and is same in all members of the population
  d)   Codes for enzymes needed for DNA replication

19) Reverse transcriptase is
  a)   RNA dependent RNA polymerase
  b)   DNA dependent RNA Polymerase
  c)   DNA dependent DNA Polymerase
  d)   RNA dependent DNA Polymerase

20) During translation initiation in prokaryotes, a GTP molecules is needed in
  a)   association of 30s, mRNA with formyl met tRNA
  b)   association of 50s subunit of ribosome with initiation complex
  c)   fromation of formyl met tRNA
  d)   Binding of 30s subunit of ribosome with mRNA


Exam results are displayed in Result Notic Board

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