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

Questions
106 The RNA polymerase holoenzyme transcribes:
1 the promoter, structural gene and the terminator region
2 the promoter, and the
3 the structural gene and the terminator regions
4 the structural gene only.

Answer: the structural gene and the terminator regions
107 To initiate translation, the mRNA first binds to:
1 The smaller ribosomal sub-unit
2 The larger ribosomal sub-unit
3 The whole ribosome
4 No such specificity exists.

Answer: The smaller ribosomal sub-unit

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108 Repressor proteins are coded for by ______ genes.
1 Structural
2 Operator
3 Promoter
4 Regulator

Answer: Regulator
109 The organelles in the cell where protein synthesis occurs are ______.
1 Endoplasmic reticulum
2 lNuceus
3 Ribosomes
4 mRNA

Answer: Ribosomes
110 PCR and Restriction Fragment Length Polymorphism are the methods fo
1 DNA sequencing
2 Genetic fingerprinting
3 Study of enzymes
4 Genetic transformation

Answer: Genetic fingerprinting
111 What is antisense technology?
1 RNA polymerase producing DNA
2 A cell displaying a foreign antigen used for synthesis of antigens
3 Production of somaclonal variants in tissue cultures
4 When a piece of RNA that is complementary in sequence is used to stop expression of a specific gene

Answer: When a piece of RNA that is complementary in sequence is used to stop expression of a specific gene
112 A DNA segment which serves as a kind of “on-off switch” for transcription is a/an ______.
1 Regulator gene
2 Structural gene
3 Promoter
4 Operator

Answer: Operator
113 Which one of the following does not follow the central dogma of molecular biology?
1 Pea
2 Mucor
3 HIV
4 Chlamydomonas

Answer: HIV
114 In some viruses, DNA is synthesised by using RNA as template. Such a DNA is called
1 A-DNA
2 B-DNA
3 c DNA
4 r DNA

Answer: c DNA
115 Discontinuous synthesis of DNA occurs in one strand, because:
1 DNA molecule being synthesised is very long
2 DNA dependent DNA polymearse catalyses polymerisation only in one direction (5’ → 3’)
3 it is a more efficient process
4 DNA ligase has to have a role

Answer: DNA dependent DNA polymearse catalyses polymerisation only in one direction (5’ → 3’)
116 Both deoxyribose and ribose belong to a class of sugars called:
1 trioses
2 hexoses
3 pentoses
4 polysaccharides

Answer: pentoses
117 Which of the following statements is the most appropriate for sickle cell anaemia?
1 It cannot be treated with iron supplements
2 It is a molecular disease
3 It confers resistance to acquiring malaria
4 All of the above

Answer: All of the above
118 Who amongst the following scientists had no contribution in the development of the double helix model for the structure of DNA?
1 Rosalind Franklin
2 Maurice Wilkins
3 Erwin Chargaff
4 Meselson and Stahl

Answer: Meselson and Stahl
119 Which of the following steps in transcription is catalysed by RNA polymerse?
1 Initiation
2 Elongation
3 Termination
4 All of the above

Answer: Elongation
120 While analysing the DNA of an organism a total number of 5386 nucleotides were found out of which the proportion of different bases were: Adenine = 29%, Guanine= 17%, Cytosine = 32%, Thymine = 17%. Considering the Chargaff’s rule it can be concluded that:
1 it is a double stranded circular DNA
2 It is single stranded DNA
3 It is a double stranded linear DNA
4 No conclusion can be drawn

Answer: No conclusion can be drawn

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