Class 12 Biology MCQs Chapter – 6
61. The specific sequence of DNA recognized by Restriction Endonuclease are
( A ) Palindromic nucleotide sequence
( B ) VNTR
( C ) Minisatellite
( D ) All of these
Answer-( A )
62. 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 )
63. GAATTC is recognition site for which restriction endonuclease ?
( A ) Hind III
( B ) Eco R I
( c ) Bam 1
( D ) Hae III
Answer-( B )
64. Synthesis of DNA from RNA is explained by
( A ) Central dogma reverse
( B ) reverse transcription
( C ) Teminism
( D ) All of these
Answer-( D )
65. 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 )
66. 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 )
67. 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 )
68. Regulation of gene expression occurs at the level
( A ) transcripte 1
( B ) processing / splicing
( C ) translation
( D ) all of these
Answer-( D )
69. Estimated number of genes in human beings is :
( A ) 3000
( B ) 80,000
( C ) 30,000
( D ) 3 x 10⁹
Answer-( C )
70. In a DNA strand the nucleotides are linked together by :
( A ) glycosidic bonds
( B ) phosphodiester bond
( C ) peptide bond
( D ) hydrogen bond
Answer-( B )
71. 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 )
72. Nitrogenous base absent in DNA is :
( A ) A
( B ) C
( C ) T
( D ) U
Answer- ( D )
73. 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 )
74. Which of the following is the odd one out in RNA ?
( A ) Adenine
( B ) Guanine
( C ) Thymine
( D ) Cytosine
Answer-( C )
75. In DNA molecule , cytosine is always attached to :
( A ) thymine
( B ) uracil
( C ) guanine
( D ) cytosine
Answer-( C )
76. DNA can be tested by :
( A ) Iodine test
( B ) Fuelgen reaction
( C ) Molish test
( D ) Millions reagent
Answer-( B )
