1. : Which one of the following vitamins plays an important role in the biosynthesis of purine nucleotides?
(A) Pyridoxal-amine
(B) Niacin
(C) Cobalamine
(D) Folic Acid
2. : Which is correct about bacterial chromosome?
(A) It contains histones
(B) It is evenly distributed throughout the cell
(C) It is locally organized into nucleosome-like structures
(D) It is attached to the inner surface of the plasma membrane
3. : “PCR” technique is useful for:
(A) Hybridization of DNA
(B) Recombination of DNA
(C) Cloning of DNA
(D) All of these
4. : What is the number of hydrogen bonds existing in G-C pair?
(A) 3
(B) 2
(C) 1
(D) 4
5. : Which of the following is the base which is not existing in DNA?
(A) Uracil
(B) Adenine
(C) Guanine
(D) Thymine
6. : Which is not a pyrimidine base?
(A) Uracil
(B) Thymine
(C) Guanine
(D) Cytosine
7. : The sugar existing in DNA is:
(A) D-ribose
(B) D-glucose
(C) 3-Deoxy-D-ribose
(D) 2-Deoxy-D-ribose
8. : Which among the following is the sugar existing in RNA?
(A) D-arabinose
(B) D-ribose
(C) D-glucose
(D) Deoxyribose
9. : Which is the unit of nucleic acid having base-sugar combination?
(A) Nucleic acid
(B) Nucleotide
(C) Nucleoside
(D) None of these
10. : Cytosine, a pyrimidine base, pairs with which of the following?
(A) Thymine
(B) Guanine
(C) Adenine
(D) Any of these
11. : What is the number of hydrogen bonds holding A-T pair?
(A) 1
(B) 4
(C) 3
(D) 2
12. : Adenosine nucleoside has the base:
(A) Guanine
(B) Adenine
(C) Thymine
(D) Cytosine
13. : RNA is involved in the synthesis of which of the following?
(A) Nucleic acid
(B) Proteins
(C) Carbohydrates
(D) Fats
14. : Which of the following is the formation of daughter DNA’s from parent DNA?
(A) Translation
(B) Replication
(C) Reproduction
(D) Transcription
15. : Which of the following is the procedure of transfer of genetic message from DNA to m-RNA?
(A) Replication
(B) Translation
(C) Transference
(D) Transcription
16. : Hydrogen bonds holding the strands of nucleic acids are formed between ______ and _____.
(A) Sugar and base units
(B) Base units
(C) Sugar and phosphate units
(D) Sugar units
17. : Codon for amino acid glycine is not represented by base pair:
(A) GGA
(B) GCA
(C) GGC
(D) GGU
18. : Anticodons in t-RNA’s corresponding to different amino acids ________.
(A) Same as in codons
(B) Complimentary to codons
(C) Sometimes as Same as in codons and sometimes as Complimentary to codons
(D) Haphazard in arrangement
19. : One arm of each t-RNA terminates in the base sequence:
(A) UGU
(B) GGC
(C) CCA
(D) ACT
20. : The binding site on ribosome for t-RNA and m-RNA is offered by which of the following?
(A) Ribosomal RNA
(B) Polysome
(C) Codons
(D) DNA
21. : Biological role of nucleic acid does not include which of the following?
(A) Genetic continuity
(B) Protein synthesis
(C) Mutation
(D) Hybridization
22. : The steps involved in biosynthesis of protein includes which of the following?
(A) Transcription
(B) Translation
(C) Both of these
(D) None of these
23. : How many nucleoprotein subunits does the mammalian ribosome contain?
(A) 6
(B) 1
(C) 2
(D) 5
24. : Which is the most abundant intracellular free nucleotide?
(A) FAD
(B) ATP
(C) NADP
(D) NAD
25. : Hypoxanthine and ribose are components of _______ molecules.
(A) Adenosine
(B) Guanosine
(C) Inosine
(D) Cytidine
26. : Which are adapter molecules that translate genetic code into amino acid sequence?
(A) tRNA
(B) mRNA
(C) DNA
(D) rRNA
27. : All tRNA molecules have a common CCA sequence at the ______ termini.
(A) 4′ termini
(B) 3′ termini
(C) 3, 5′ termini
(D) All of these
28. : A prokaryotic polypeptide of 300 amino acids is encoded by how many base pairs of DNA?
(A) 100 bp
(B) 300 bp
(C) 1800 bp
(D) 900 bp
29. : AUG, the only identified codon for methionine, is important as ______.
(A) A chain initiating codon
(B) A chain terminating codon
(C) A releasing factor for peptide chain
(D) The recognition site on the tRNA
30. : The anticodon region is an important part of the structure of which of the following?
(A) rRNA
(B) mRNA
(C) tRNA
(D) hnRNA
31. : The chief end product of purine catabolism in man is _____.
(A) Urea
(B) Ammonia
(C) Uric acid
(D) Allantoin
32. : DNA can be denatured by which of the following?
(A) Alkali
(B) Acid
(C) Heat
(D) All of these
33. : The chemical name 2-amino-6-oxypurine is for ____.
(A) Guanine
(B) Xanthine
(C) Adenine
(D) Hypoxanthine
34. : The four nitrogen atoms in purine ring are derived from which of the following?
(A) Aspartate and Glutamine
(B) Aspartate and Glycine
(C) Aspartate, Glycine and Glutamine
(D) Aspartate, Glycine and Ammonia
35. : Each turn of DNA structure has a pitch in ____nm.
(A) 3.4
(B) 2.4
(C) 2.7
(D) 4.5
36. : Which statement is correct about histones?
(A) Their amino acid sequences are highly variable among organisms
(B) They are positively charged proteins
(C) They do not undergo any covalent modifications
(D) All of these
37. : The chemical name of thymine would be:
(A) 2, 4-dioxy-5-methylpyrimidine
(B) 2-oxy-4-aminopyrimidine
(C) 2,4-dioxypyrimidine
(D) None of these
38. : The N atoms at position 3 and 9 of purine base are derived from the amide nitrogen____
(A) Glutamate
(B) Glutamine
(C) Asparagine
(D) A
39. : Posttranscriptional modification of tRNA involves adding of which of the following?
(A) CCA at 5′ end
(B) Poly A tail at the 3′ end
(C) CCA at 3′ end
(D) 7-methyloguanosine to the 5′ end
40. : The end product of purine catabolism is ________ in other mammals, excluding man.
(A) Uric acid
(B) Ammonia
(C) Allantoin
(D) Creatinine
41. : The transfer-RNA approximately molecule comprises how many nucleotides?
(A) 74-95
(B) 70-84
(C) 93-105
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42. : Histones are:
(A) Acidic chromosomal proteins
(B) Basic proteins associated with
(C) Acidic polysomal proteins RNA
(D) Basic proteins associated with DNA
43. : The structural stability of the double helix of DNA is largely the result of which of the following?
(A) Hydrogen bonding between adjacent purine bases
(B) Hydrogen bonding between stacked purine and pyrimidine bases
(C) The energy released due to the turning of the nucleic acid molecule
(D) Hydrogen bonding between purine and pyrimidine bases of the two chains
44. : A mature mRNA could be lengthier than its precursor pre-mRNA due to which of the following?
(A) Polyadenylation
(B) Splicing
(C) 5′-end capping
(D) None of these
45. : Which processes does not happen in the nucleus of eukaryotes?
(A) Polyadenylation
(B) Translation
(C) Pre-mRNA splicing
(D) 5′-end capping of mRNAs
46. : How many energy bonds are helpful and used up during the elongation step in protein synthesis?
(A) One
(B) Four
(C) Three
(D) Two
47. : mRNA is a complimentary copy of which?
(A) 5′-3′ strand of DNA
(B) Antisense strand of DNA
(C) Coding strand of DNA
(D) tRNA
48. : For DNA-dependent RNA synthesis
(A) A RNA template and DNA primer are required
(B) A DNA template and RNA primer are required
(C) A DNA template and DNA primer are required
(D) Only the DNA template is required
49. : Which statements regarding a double-helical of DNA is correct?
(A) All hydroxyl groups of pentoses are involved in linkages
(B) Bases are parallel to the long axis
(C) both the strands are identical
(D) Both the strands are parallel
50. : Which is NOT correct regarding eukaryotic mRNA?
(A) They are translated sequentially over their length
(B) They are derived from precursor RNAs
(C) They have poly A tails at their 3′ ends
(D) They have 7-methyl GTP caps at their 5′ ends
51. : Translocate is an enzyme required in the process of:
(A) DNA replication
(B) RNA synthesis
(C) Initiation of protein synthesis
(D) Elongation of peptides
52. : Nonsense codons bring about ________.
(A) Amino acid activation
(B) Initiation of protein synthesis
(C) Termination of protein synthesis
(D) Elongation of polypeptide chains
53. : Which is not a component of polysomes?
(A) Proteins
(B) tRNA
(C) mRNA
(D) DNA
54. : In which way are the genomes of prokaryotes and eukaryotes similar?
(A) Both have genes that are precisely collinear with the amino acid sequences
(B) Both have chromosome(s) that are longer than the cell
(C) Both have satellite DNA
(D) Both have multiple chromosomes
55. : Which is NOT CORRECT about genetic code?
(A) There may be as many as six codons for a single amino acid
(B) There are different codons for initiating methionine and internal methionine
(C) All the 64 possible codons are helpful and used during translation
(D) The arrangement of the genetic code table is Non-Random
56. : Reverse transcriptase enzyme catalyzes
(A) Formation of RNA using DNA template
(B) Peptidyl transformation
(C) DNA hybridization
(D) RNA directed DNA polymerization
57. : Where does protein synthesis take place predominantly in mammalian secretory cells?
(A) Endoplasmic reticulum
(B) Nucleolus
(C) Nucleus
(D) Lysosomes
58. : DNA ligase:
(A) Transfers AMP to the 5′ phosphate group at a nick
(B) Catalyzes the formation of a phosphodiester bond between 3’ and 5′ ends
(C) Fills in gaps
(D) Provides the phosphate group needed to form a phosphodiester bond
59. : When double-stranded DNA is slowly warmed at 85°C?
(A) The hydrogen bonding between G-C pairs breaks before that between A-T
(B) The absorbance at 260 nm increases
(C) Purine bases are cleaved from deoxyribose
(D) The viscosity of DNA increases
60. : The term “Transforming factors” has been helpful and used for _______ ?
(A) DNA
(B) RNA
(C) tRNA
(D) None of these
61. : An accurate DNA replication needs all of the following, EXCLUDING
(A) A RNA primer
(B) DNA ligase
(C) 5′-3′ exonuclease activity
(D) A free 5′-OH
62. : The purine nucleotides act as components of: factor
(A) Coenzyme A
(B) Fibrin stabilizing
(C) CTP
(D) All of these
63. : Approximately how many mg of uric acid is synthesized in a normal man in 24 hours?
(A) 200-300
(B) 500-600
(C) 400-500
(D) 300-400
64. : Which is correct about DNA gyrase?
(A) It underwinds DNA supercoils decreasing linking number
(B) It introduces positive supercoiling of DNA upstream of the fork
(C) It is a type II topoisomerase
(D) All of these
65. : Promoters:
(A) Are required for elongation of transcription
(B) Are recognized by RNA polymerases in a sequence-dependent manner
(C) Are encoded by the DNA template strand
(D) Tend to be G-C rich
66. : Which is correct about reverse transcriptase?
(A) Its activity can be detected only in cells infected with retroviruses
(B) It has a low error rate
(C) It does not require a primer to initiate synthesis
(D) None of these
67. : The normal function of restriction endonucleases is to:
(A) Excise introns from hnRNA
(B) Polymerize nucleotides to form RNA
(C) Remove proteins from Okazaki fragments
(D) Protect bacteria from foreign DNA
68. : The E.coli RNA polymerase binding to the promoter site is inhibited by:
(A) Rifampicin
(B) Streptomycin
(C) Aureomycin
(D) Terramycin
69. : Which is NOT a purine base?
(A) Guanine
(B) Adenine
(C) Cytosine
(D) None of these
70. : Hydrolysis of nucleoprotein results in the formation of which of the following?
(A) Proteins
(B) Nucleic acids
(C) Both A and B
(D) They do not hydrolyze
71. : Complete hydrolysis of nucleotides results in the formation of which of the following?
(A) Heterocyclic bases
(B) A phosphate ion
(C) A pentose
(D) All of these
72. : Which proteins unwind the two parental DNA strands in E.coli?
(A) DNA gyrase
(B) Primase
(C) SSB protein
(D) Helicase
73. : PCR can be helpful and used for:
(A) Cloning DNA fragments from mummies
(B) As a forensic tool
(C) Detection of viral infection
(D) All of these
74. : Foot-printing technique is helpful and used to:
(A) Detect the single base pair defect
(B) Detect the protein binding site
(C) Identify the TATA and Pribnow boxes
(D) Detect the restriction endonuclease sites
75. : Which nucleotide is helpful and used for epimerization of galactose to glucose?
(A) CTP
(B) GTP
(C) UTP
Answer: (C) UTP
76. : Which compound is structural analogue of hypoxanthine and competitively inhibits xanthine oxidase?
(A) Ara C
(B) 5-Fluorouracil
(C) 5-phosphoribosylpyrophosphate (PRPP)
(D) Allopurinol
77. : Which is correct for ‘Alternative splicing’?
(A) Gives rise to different arrangements of genomic DNA
(B) Results in distinct proteins with a number of common domains
(C) Needs different U1 snRNAs
(D) Results from different proteolytic processing events
78. : Which is not existing in both E.coli and human mRNA?
(A) Polyadenylation signals
(B) Shine-Dalgarno sequence
(C) Initiation codons
(D) None of these