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

Questions
76 If the total amount of adenine and thymine in a double-stranded DNA is 45%, the amount of guanine in this DNA will be
1 22.5%
2 27.5%
3 45%
4 55%

Answer: 27.5%
77 Number of nitrogenous bases in a Codon is
1 3
2 2
3 1
4 5

Answer: 3
78 DNA has equal number of adenine and thymine residues (A = T) and equal number of guanine and cytosine (G = C). These relationships are known as
1 Chargaff's rule
2 Coulomb's law
3 Le-Chatelier's principle
4 Van't Hoff plot

Answer: Chargaff's rule
79 RNA polymerase is only capable of catalyzing the process of ______.
1 Termination
2 Initiation
3 Elongation
4 All of the above

Answer: Elongation
80 E. coli cells with a mutated z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because
1 They cannot synthesize functional beta galactosidase
2 They cannot transport lactose from the medium into the cell
3 The lac operon is constitutively active in these cells
4 In the presence of glucose, E. coli cells do not utilize lactose

Answer: They cannot synthesize functional beta galactosidase
81 Beadle and Tatum showed that each kind of mutant bread mould they studied lacked a specific enzyme. Their experiments demonstrated that
1 Cells need specific enzymes in order to function
2 Genes are made of DNA
3 Enzymes are required to repair damage
4 Genes carry information for making proteins

Answer: Genes carry information for making proteins
82 Molecular scissors which cut DNA at specific site is
1 Pectinase
2 Polymerase
3 Restriction endonuclease
4 Ligase

Answer: Restriction endonuclease
83 A gene of operon which synthesizes a repressor protein is ______.
1 Promoter gene
2 Operator gene
3 Structural gene
4 Regulator gene

Answer: Regulator gene
84 Central dogma of protein synthesis is
1 DNA → RNA → Protein
2 DNA → DNA → Protein
3 RNA → DNA → Protein
4 DNA → protein → RNA

Answer: DNA → RNA → Protein
85 WThe region of tRNA which consists of three bases complementary to a mRNA codon is ______.
1 Codon
2 Intron
3 Anticodon
4 Interferon

Answer: Anticodon
86 Balbiani rings are the sites of
1 DNA replication
2 RNA and protein synthesis
3 Synthesis of lipids
4 Synthesis of polysaccharides

Answer: RNA and protein synthesis
87 Production of a human protein in bacteria by genetic engineering is possible because
1 Bacterial cell can carry out the RNA splicing reactions
2 The mechanism of gene regulation is identical in humans and bacteria
3 The human chromosome can replicate in bacterial cell
4 The genetic code is universal

Answer: The genetic code is universal
88 The genetic material of Rabies virus is
1 Double stranded RNA
2 Single stranded RNA
3 Double stranded DNA
4 ssDNA

Answer: Single stranded RNA
89 There are 64 codons in the genetic dictionary as
1 There are 64 amino acids to be coded
2 Genetic code has a triplet nature
3 There are 3 nonsense codons and 61 sense codons
4 There are 64 different types of t-RNA

Answer: Genetic code has a triplet nature
90 DNA sequence that code for protein are known as
1 Introns
2 Exons
3 Control regions
4 Intervening sequences

Answer: Exons

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