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Class 12 Biology Objective In English Chapter – 6 Molecular Basis Of Inheritance
1. Uracil is related to
( A ) RNA
( B ) DNA
( C ) Both ( A ) & ( D )
( D ) None of these
Answer-( A )
2. Lac operon represents
( A ) Inducible gene system
( B ) Repressible gene system
( C ) Housekeeping gene system
( D ) All of these
Answer- ( A )
3. Synthesis of RNA on DNA template is known as
( A ) Translation
( B ) Transcription
( C ) Transduction
( D ) Replication
Answer-( B )
4. Which of the following is a wrong pair ?
( A ) G ≡ C
( B ) T = A
( C ) A = U
( D ) T = U
Answer- ( D )
5. Genes present on same locus having different expression are called :
( A ) Multiple allele
( B ) Polygene
( C ) Oncogene
( D ) Codominant gene
Answer- ( A )
6. The human chromosome with highest and least number of genes are
( A ) Chromosome 21 and Y
( B ) Chromosome 1 and X
( C ) Chromosome 1 and Y
( D ) Chromosome X & Y
Answer- ( C )
7. Which of the following phenomena was experimentally proved by Meselson & Stahl ?
( A ) Transformation
( B ) Transduction
( C ) Semi – conservative DNA replication
( D ) central dogma
Answer- ( C )
8. DNA replication takes place at which phase of cell cycle ?
( A ) G1
( B ) S
( C ) G2
( D ) M
Answer- ( B )
9. If a double stranded DNA has 20 % of cytosine , what will be the percentage of adenine in it ?
( A ) 20 %
( B ) 40 %
( C ) 30 %
( D ) 60 %
Answer- ( C )
10. During transcription , the site of DNA molecule at which RNA polymerase binds is called :
( A ) Promoter
( B ) regulator
( C ) receptor
( D ) enhancer
Answer- ( A )
11. Both deoxyribose and ribose belong to a class of sugars called :
( A ) trioses
( B ) hexoses
( C Pentoses
( D ) Polysacharies
Answer- ( C )
12. Amino acid acceptor end of tRNA lies at
( A ) 5 ‘ end
( B ) 3’end
( C ) T C loop
( D ) DHU loop
Answer- ( B )
13. During expression of an operon , RNA polymerase binds to :
( A ) Structural gerte
( B ) regulator gene
( C ) Operator
( D ) Promoter
Answer- ( D )
14. If the sequence of bases in coding strand of DNA is ATTCGATG , then the sequence of bases in mRNA will be :
( A ) TAAGCTAC
( B ) UAAGCUAC
( C ) ATTCGATG
( D ) AUUCGAUG
Answer- ( D )
15. RNA is the genetic material in
( A ) Prokaryotes
( B ) Eukaryotes
( C ) TMV
( D ) E Coil
Answer- ( C )
16. Khorana was a awarded Nobel Prize for :
( A ) Discovering DNA
( B ) Discovering RNA
( C ) Chemical synthesis of gene
( D ) Discovering DNA polymerase .
Answer- ( C )
17. Nucleosome contains :
( A ) Histone molecules
( B ) Nucleotides
( C ) Nucleoplasmin
( D ) Nuclear pore complex
Answer- ( A )
18. Continuously functional genes are :
( A ) Gene battery
( B ) Luxury genes
( C ) Mild genes
( D ) House keeping genes
Answer- ( D )
19. The ultimate source of variations is :
( A ) natural selection
( B ) sexual reproduction
( C ) mutations
( D ) hormonal actions
Answer- ( C )
20. Purine base of DNA molecule has
( A ) A and C
( B ) C and T
( C ) A and G
( D ) None of these
Answer-( C )
21. Which Nitrogenous base is not present in RNA ?
( A ) Thymine
( B ) Uracil
( C ) Adenine
( D ) Guanine
Answer-( A )
22 , which base is present in RNA but absent in DNA ?
( A ) uracil
( B ) Guanine
( c ) Cytosine
( D ) Thymine
Answer-( A )
23. Nallisomie organism will have a genetic complement of :
( A ) 2n – 1
( B ) 2n – 2
( c ) 2n + 1
( D ) 2n + 2
Answer-( B )
24. Nucleic acid are strong acids . The acidity is due to :
( A ) phosphates
( B ) sugar
( C ) nitrogen bases
( D ) H – bonds
Answer-( A )
25. Which of the following is involved in transcription of tRNA , 5Sr RNA and Sn RNA of eukaryotes ?
( A ) RNA polymerase I
( B) RNA polymerase II
( C ) RNA polymerase III
( D ) All of these
Answer-( C )
26. The specific sequence of DNA recognized by Restriction Endonuclease are
( A ) Palindromic nucleotide sequence
( B ) VNTR
( C ) Minisatellite
( D ) All of these
Answer-( A )
27 Silencing of gene could be achieved through the use of
( A ) Short interfering RNA ( RNAi )
( B ) Antisense RNA
( C ) A & B both
( D ) None of these
Answer-( C )
28. GAATTC is recognition site for which restriction endonuclease ?
( A ) Hind III
( B ) Eco R I
( c ) Bam 1
( D ) Hae III
Answer-( B )
Class 12 Biology Objective In English Chapter – 6 Molecular Basis Of Inheritance
29. Synthesis of DNA from RNA is explained by
( A ) Central dogma reverse
( B ) reverse transcription
( C ) Teminism
( D ) All of these
Answer-( D )
30. In an animal cell , the process of transcription and translation occur in
( A ) nucleus only
( B ) cytoplasm only
( C ) nucleus & cytoplasm respectively
( D ) endoplasmic reticulum
Answer-( C )
31. Human genome consists of approximately
( A ) 3 × 10⁹ bp
( B ) 6 x 10⁹ bp
( C ) 20000 – 30000bp
( D ) 2.2 X 10⁴ bp
Answer-( C )
32. In some viruses , DNA is synthesizer by using RNA as template . Such DNA is called
( A ) A – DNA
( B ) B – DNA
( C ) cDNA
( D ) rDNA
Answer-( C )
33. Regulation of gene expression occurs at the level
( A ) transcripte 1
( B ) processing / splicing
( C ) translation
( D ) all of these
Answer-( D )
34. Estimated number of genes in human beings is :
( A ) 3000
( B ) 80,000
( C ) 30,000
( D ) 3 x 10⁹
Answer-( C )
35. In a DNA strand the nucleotides are linked together by :
( A ) glycosidic bonds
( B ) phosphodiester bond
( C ) peptide bond
( D ) hydrogen bond
Answer-( B )
36. In one polynucleotide strand of DNA molecule the ratio of A + T / G + C is 0.3 . What is the A + G / T + C ratio of the entire DNA molecule ?
( A ) 0.3
( B ) 0.6
( C ) 1.2
( D ) 1
Answer- ( D )
37. Nitrogenous base absent in DNA is :
( A ) A
( B ) C
( C ) T
( D ) U
Answer- ( D )
38. Ratio of DNA : RNA in prokaryotes is 1 : 2. What is this ratio in eukaryotes ?
( A ) 1 : 1
( B ) 2 : 1
( C ) 1 : 2
( D ) not fixed
Answer-( A )
39. Which of the following is the odd one out in RNA ?
( A ) Adenine
( B ) Guanine
( C ) Thymine
( D ) Cytosine
Answer-( C )
40 In DNA molecule , cytosine is always attached to :
( A ) thymine
( B ) uracil
( C ) guanine
( D ) cytosine
Answer-( C )
41. DNA can be tested by :
( A ) Iodine test
( B ) Fuelgen reaction
( C ) Molish test
( D ) Millions reagent
Answer-( B )
42. In DNA , the nitrogenous bases are :
( A ) ATUC
( B ) AUGC
( C ) UTGC
( D ) ATGC
Answer-( D )
43. Pyrimidines in DNA are :
( A ) thymine and cytosine
( B ) cytosine and guanine
( C ) adenine and uracil
( D ) adenine and thymine
Answer-( A )
44. Anticodon is associated with :
( A ) TRNA
( B ) mRNA
( C ) rRNA
( D ) genetic RNA
Answer-( A )
45. In double helix of DNA , the two DNA strands are :
( A ) coiled upon itself around a common axis
( B ) coiled around each other
( C ) coiled differently
( D ) coiled over protein sheath
Answer-( A )
46. Most abundant RNA of the cell is :
( A ) TRNA
( B ) rRNA
( C ) mRNA
( D ) tRNA threonini
Answer-( B )
47. DNA strand are antiparallel because of :
( A ) H-bonds
( B ) phospho-diester bonds
( C ) disulphide (S-S bonds)
( D ) none of the above
Answer-( B )
48. In double helix model of DNA how far is each base pair from the next ?
( A ) 34nm
( B ) 3.4 nm
( C ) 2 nm
( D ) 0.34 nm
Answer-( D )
Class 12 Biology Objective In English Chapter – 6 Molecular Basis Of Inheritance
49. How many nucleotides are found in one spiral of B DNA ?
( A ) 5
( B ) 10
( C ) 20
( D ) 25
Answer-( C )
50. If DNA has 10 spirals, the length of DNA will be :
( A ) 34 Å
( B ) 340 Å
( C ) 640 Å
( D ) 64 Å
Answer-( B )
51. The basic unit (monomer) of a nucleic acid molecule is :
( A ) nucleoside
( B ) nucleotide
( C ) nitrogenous base
( D ) pentose sugar
Answer-( B )
52. RNA differs from DNA in nature of :
( A ) sugar and purines
( B ) sugar and pyrimidines
( C ) purines and phosphate
( D.) sugar and phosphate
Answer-( B )
53. Nitrogen base is attached to pentose sugar in a nucleoside at carbon atom :
( A )1
( B ) 2
( C ) 3
( D ) 5
Answer-( A )
54. Which one is a nucleotide ?
( A ) Uridylic acid
( B ) Thymidine
( C ) Cytosine
( D ) Glutamic acid
Answer-( A )
55. Which RNA is short lived :
( A ) mRNA
( B ) TRNA
( C.) rRNA
( D ) SnRNA
Answer-( A )
56. Hydrogen bonds present between cytosine and guanosine are :
( A ) 2
( B ) 3
( C ) 1
( D ) 4
Answer-( B )
57. The terminal (stop) condon is :
( A )UAG (Amber)
( B )UAA (Ochre)
( C )UGA (Opal)
( D ) All of these
Answer-( D )
58. There are 100 amino acids. How many types of proteins can be formed by triplet genetic code ?
( A ) 20¹⁰⁰
( B ) (100)²⁰
( C )100 x 20 x 3
( D )100 x 3
Answer-( A )
59. Of 64 codons in a genetic code,how many codons are responsible for specifying 20 types of amino acids :
( A ) 61
( B ) 64
( C ) 20
( D ) 59
Answer-( A )
60. The initiation codon in protein synthesis is :
( A ) AUG
( B ) GUG
( C )met
( D ) AUG and GUG
Answer-( B )
61. The genetic code occurs in :
( A ) rRNA
( B ) TRNA
( C ) rDNA
( D ) mRNA
Answer-( D )
62. Two genes present near by on a chromosome will have :
( A ) Double crossing over
( B ) No crossing over
( C ) Hardly any crossing over
( D ) Regular crossing over
Answer-( C )
63. Exchange of segments between non- homologous chromosomes is called:
( A ) Crossing over
( B ) Inversion
( C ) Duplication
( D ) Translocation
Answer-( D )
64. Complete linkage has been reported
in :
( A ) Maize
( B ) Human female
( C ) Female Drosophilla
( D ) Male Drosophilla
Answer-( D )
65. Genes are made up of :
( A ) Lipoprotein
( B ) Nucleosides
( C ) Polynucleotides
( D ) Histones
Answer-( C )
66. Triplet UUU codes for :
( A ) Leucine
( B ) Methionine
( C )Phenylalanine
( D ) Glycine
Answer-( C )
67. In gene mutation, adenine is replaced by guanine. It is :
( A ) Frame-shift mutation
( B )Transcription
( C ) Transition
( D ) Transversion
Answer-( C )
68. A segment of DNA that reads the same forward and backward is called:
( A ) palindromic DNA
( B ) Plasmimic DNA
( C ) complementary DNA
( D ) copy DNA
Answer-( A )
69. Purines of RNA are :
( A ) guanine and adenline
( B )uracil and thymine
( C ) adenine and cytosine
( D )uracil and guanine
Answer-( A )
70. Which one is correct for RNA ?
( A ) [A] = [U]
(B) [G] = [C]
( C ) [A] not equal [U]
( D ) [A] + [G]
Answer-( C )
71. Which is recognition site of tRNA ?
( A ) Anticodon
( B ) Loop I
( C ) Loop IV
( D ) 3-OH end
Answer-( A )
72. RNA is synthesized on :
( A ) both strands of DNA
( B ) on sense strand of DNA
( C ) on complementary strand of DNA
( D ) on c DNA
Answer-( B )
73. If codon in DNA is AAA. What will be the anticodon for it :
( A )U U U
( B ) AAA
( C ) TTT
( D ) AUG
Answer-( B )
74. DNA fragments are joined by :
( A ) Ligase
( B ) Polymerase
( C ) Helicase
( D ) Gyrase
Answer-( A )
75. DNA and RNA differ by :
( A ) Nitrogen bases and sugars
( B ) Nitrogen bases and phosphate groups
( C ) Number of C-atoms in sugars
( D )Sugar and phosphate groups
Answer-( A )
76. Who discovered DNA polymerase
( A ) Okazaki
( B ) Kornberg
( C ) Meselson and Stahl
( D )Watson and Crick
Answer-( B )
