NCERT - Molecular Basis of Inheritance Questions and Answers of Class 12 Biology | GkSeries

Questions
61 Link together two pieces of DNA
1 Link together two pieces of DNA
2 Cut DNA at specific locations
3 Restrict elongation of DNA
4 Restrict DNA replication

Answer: Cut DNA at specific locations
62 The sequence of structural gene in lac operon concept is
1 lac Y, lac Z, lac A
2 lac Z, lac Y, lac A
3 lac A, lac Y, lac Z
4 lac A, lac Z, lac Y

Answer: lac Z, lac Y, lac A

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63 mRNA directs the building of proteins through a sequence of
1 Introns
2 Codons
3 Exons
4 Anticodons

Answer: Codons
64 In the DNA molecule:
1 There are two strands which run antiparallel-one in 5′ → 3′ direction and other in 3′ → 5′
2 There are two strands which run parallel in the 5′ → 3′ direction
3 The proportion of Adenine in relation to thymine varies with the organism
4 The total amount of purine nucleotides and pyrimidine nucleotides is not always equal

Answer: There are two strands which run antiparallel-one in 5′ → 3′ direction and other in 3′ → 5′
65 What are those structures that appear as 'beads-on-string' in the chromosomes when viewed under electron microscope?
1 Base pairs
2 Genes
3 Nucleotides
4 Nucleosomes

Answer: Nucleosomes
66 The sections of a structural gene that are expressed are the ______.
1 Interferons
2 Neurons
3 Introns
4 Exons

Answer: Exons
67 Which one of the following techniques made it possible to genetically engineer living organisms?
1 Heavier isotope labelling
2 Hybridization
3 Recombinant DNA techniques
4 X-ray diffraction

Answer: Recombinant DNA techniques
68 The sequence of nitrogen bases in a particular region of the noncoding strand of a DNA molecule was found to be CAT GTT TAT CGC. What would be the sequence of nitrogen bases in the mRNA that is synthesized by the corresponding region of the coding strand in that DNA?
1 GUA CAA AUA GCC
2 GTA CAA ATA GCC
3 CAU GUU UAU CGG
4 CAA GAA TAU GCC

Answer: GUA CAA AUA GCC
69 Enzyme responsible for reverse transcription is :
1 Reverse transcriptase
2 DNA polymerase
3 RNA polymerase
4 RNA dependent RNA polymerase

Answer: Reverse transcriptase
70 Gel electrophoresis is used for
1 Isolation of DNA molecule
2 Cutting of DNA into fragments
3 Separation of DNA fragments according to their size
4 Construction of recombinant DNA by joining with cloning vectors

Answer: Separation of DNA fragments according to their size
71 What is not true for genetic code?
1 It is unambiguous
2 A codon in mRNA is read in a non-contiguous fashion
3 It is nearly universal
4 It is degenerate

Answer: A codon in mRNA is read in a non-contiguous fashion
72 Chromosome is made up of
1 DNA + pectin
2 RNA + DNA
3 DNA + Histone
4 Only histone

Answer: DNA + Histone
73 What would happen if in a gene encoding a polypeptide of 50 amino acids, 25th codon (UAU) is mutated to UAA
1 A polypeptide of 24 amino acids will be formed
2 A polypeptide of 25 amino acids will be formed
3 A polypeptide of 49 amino acids will be formed
4 Two polypeptides of 24 and 25 amino acids will be formed

Answer: A polypeptide of 24 amino acids will be formed
74 The anti-parallel nature of DNA refers to
1 Its charged phosphate groups
2 The opposite direction of the two strands
3 The formation of hydrogen bonds between bases from opposite strands
4 The pairing of bases on one strand with bases on the other strand

Answer: The opposite direction of the two strands
75 Protein synthesis in an animal cell occurs
1 On ribosomes presents in cytoplasm as well as in mitochondria
2 On ribosomes present in the nucleolus as well as in cytoplasm
3 Only on ribosomes attached to the nuclear envelope and endoplasmic reticulum
4 Only on the ribosomes present in cytosol

Answer: On ribosomes presents in cytoplasm as well as in mitochondria

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