bt0202 molecular biology unit i

7/29/2019 BT0202 Molecular Biology Unit I

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Rex Arunraj, Department of Genetic Engineering, School of Biotechnology, SRM University

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Department of Genetic EngineeringSchool of Bioengineering

SRM UniversityBT0202 Molecular Biology

Instruction#Do not write or scribble on the question booklet. Score on the coding sheet.#Return the question booklet along with the coding sheets.#Do not copy.

Choose the best answers

1. The phosphate group is joined to a ------------ sugara) Deoxyribose b) oxyribosec) 3deoxyribose d) 2deoxyribose

2. The 3 indicates the carbon present ina) Sugar b) Base c) Phosphate d) all the above

3.The base is attached to the sugar at positiona) 1 b) 2 c) 3 d) 4

4. The bond between sugar and base is calleda) peptide bond b) diester bondc) sugar bond d) glycosidic bond

5. A. Sugar and base is called as a nucleosideB. Sugar , base and glycosidic bond is called as nucleotide

a) A true, B true b) A true, B false

c) A false, B true d) A false, B false

6. Nucleoside is formed with the release ofa) energy b) water c) 2Pi d) oxygen

7. The sequence 5-AGCTAAGCT-3 inDNA is equivalent to which sequence in RNA.a) UCGAUTCGA b) UCGUUTCGAc) UCGAUUCGA d) UCGUUUCGA

8. Which of the following correctly describes A form DNA?a) Right handed, antiparallel, double helix with 10 bp/turn

b) left handed, antiparallel, double helix, with 12 bp/ turnc) Right handed, antiparallel, double helix with 11 bp/turnd) Globular form single stranded nucleic acid

9. RNA moleculas differ from DNA in all but which of the following aspects?a) kinds of purines b) kinds of pyrimidinesc) number of strands per molecule d) Type of sugar


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10. Which of the following is not a characteristic of most DNA under physiologicalconditions?

a) A pairs with T by 2 H bondsb) antipolarity of complementary chainsc) 3.4 A pitch

d) 10 bp/turn of the helix

11. The polarity of DNA chain is represented bya) 3-5 b) 1-6 c) 1-3 d) 5-3

12. The class of RNA molecules to which aminoacids are covalently bound isa) mRNA b) rRNA c) tRNA d) mtRNA

13. Adenosine is aa) Nitrogenous base b) ribonucleosidec) Ribonucleotide d) deoxyribonucleotide

14. A. % A=% T, % C =% GB. A #U, G #C

a) A true, B true b) A true, B falsec) A false, B true d) A false, B false

15. [ A +T] / [ C +G ] is ---------------------a) Zero b) onec) not always one d) none of the above

16. Which of the following is not a terminator codona) UGA b) UAA C) UAG d) UGG

17. Which of the following is not true for a B form of DNAa) 10 bp/ turn b) right handed helixc) glycosidic bond anti at C and syn at G d) vertical rise 3.2 A

18. The DNA can exist in uncommon form likea) C b) D c) D d) none of the above

19. Z conformation was named becausea) Phosphate groups are zigzagb) form present under extreme conditionsc) alternating purine and pyrimidinesd) all the above

20. In Z DNA the base pairs are flippeda) 450 b) 900 c) 1800 d) none of the above

21. Z form is less stable because


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a) they are formed under extreme conditionsb) they have alternating purines and pyrimidinesc) phosphate groups are closer to each otherd) number of bp is more per turn

22. Which is not true for the stability of Z form of DNAa) cytosine methylation makes it stableb) formation of negative supercoilingc) shallow major groove and deep minor grooved) alternating purines and pyrimidines

23. The helix pitch isa) 450 b) 900 c) 1800 d) 3600

24. mRNA cap is formed by methylation of Guanineat position

a) 1 b) 3 c) 5 d) 7

25. In a prokaryotic ribosome ------ is not a characteristic featurea) ribosome is 70 Sb) Large subunit is 60S and small subunit is 30 Sc) r RNA are 16 S, 5 S, and 23 Sd) they are present in the cytoplasm

26. Which of the following is not true for major groovea) it contains H bond donorsb) it contains van der Waals forcesc) H bond acceptord) covalent bond

27. Which of the following molecules functions to transfer information from the nucleusto the cytoplasm?

a) DNA b) mRNA c) tRNA d) proteins

28. mRNA will form hybrids only with the coding strand of DNA becausea) DNA will not reanneal at high temperaturesb) denatured DNA will not reanneal after it is dilutedc) RNA:DNA hybridization follows the base-pairing rules

d) DNA will not reanneal at low temperatures

29. The regions of DNA in a eukaryotic gene that encode a polypeptide product are calleda) hnRNAs b) exons c) leader sequences d) introns

30. What is added to the 3'-end of many eukaryotic mRNAs after transcription?a) introns b) a poly A tail c) the trinucleotide 5'-CCA d) cap


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31. A messenger acid is 336 nucleotides long, including the initiator and terminationcodons. The number of amino acids in the protein translated from this mRNA is

a) 333 b) 336 c) 111 d) 112

32. Frederick Griffith accidentally discovered transformation when attempting to develop

a vaccine for pneumonia. He injected mice with samples from S-strain (virulent)and/or R-strain (nonvirulent) pneumococci bacteria (Streptococcus pneumoniae) .Which of the following results is NOT consistent with Griffith's experiments?

a) injected S-strain; mouse dies.b) injected R-strain; mouse lives.c) injected heat-killed S-strain; mouse lives.d) injected mixture of heat-killed S-strain and live R-strain; mouse lives.

33. Which scientists first gave experimental evidence that DNA is the genetic material?a) Avery, MacLeod, and McCarty who repeated the transformation experimentsof Griffith, and chemically characterized the transforming principle.

b) Garrod, who postulated that Alcaptonuria, or black urine disease, was due to adefective enzymec) Watson and Crick who gave a model for the structure of DNAd) Hershy and Chase experiments

34. In a double stranded molecule of DNA, the ratio of purines : pyrimidines is:a) variable b) determined by the base sequence in RNAc) always 1:1 e) determined by the purines in the sense strand of DNA

35. Which of the following molecules does not form part of DNA?a) purine b) pyrimidine c) deoxyribose d) amino acid

36. The transcription of DNA to a molecule of messenger RNA occurs:a) on the ribosomes b) in the cytosolc) in the nucleus d) only during cell division

37. Codons are composed ofa) triplet sequences of nucleotide bases in mRNAb) triplet sequences of nucleotide bases in DNAc) triplet sequences of amino acids in polypeptide chainsd) triplet sequences of deoxyribose sugars in DNA

39. If, in Griffith's experiment, a mixture of heat-killed smooth bacteria and living rough

bacteria were injected into a mouse, it would be expected to __________.a) kill the mouse b) cause transfectionc) cause transduction d) have no effect on it

40. If Hershey and Chase found only 35S in the bacterial cells, they would conclude that__________.a) protein is the genetic materialb) DNA and protein together serve as the genetic material


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c) DNA is the genetic materiald) no conclusion is possible

41. RNA differs from DNA in all of the following ways except __________.a) thymine

b) Sugarc) Functionsd) 5 3 orientations of strand

42. Which of the following is true of transfer RNA?a) It is responsible for correct positioning of amino acids in a polypeptide.b) It serves as the site of protein synthesis.c) It functions in transcription, translation and replication.d) It is an important component of ribosomes.

43. Which of the following is most similar to the Watson-Crick helix?

a) B-DNA b) A-DNA c) C-DNA d) Z-DNA

44. Which of the following is NOT a characteristic of DNA?a) antiparallel b) composed of nucleotidesc) complementary d) contains ribose

45. A:C base pairing is not feasible not because of the following reasona) H bond acceptor of adenine lieopposite toH bond acceptor of cytosineb) Noplace for an water moleculec) H bond donor of adenine lieopposite toH bond donorof cytosined) structural difference

46. Which of the following contain most of the chemical information for interactiona) major groove b) minor groovec) Phosphate group d) Sugar

47. Which of the following is a characteristic feature of T:A base pair in the major groovea) MADA b) ADAM c) AADH d) HDAA

48. Which of the following do not describe B-DNA - the Watson-Crick Modela) Major groove wide and deep b) Minor groove narrow and deepc) anti glycosidic bonds d) DNA under dehydrating conditions.

49. Hoogsteen pairingis best described bya) form triplex DNAb) long stretches of either purines orpyrimidinesc) involves N-7, N6 and O6 atoms of the purine ringd) all the above

50. DNA duplexes can be melted or denatured bya) temperature b) pH c) ionic strength d) All the above

bt0202 molecular biology unit i

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