1. A nucleoside consists of
(A) Nitrogenous base
(B) Purine or pyrimidine base + sugar
(C) Purine or pyrimidine base + phosphorous
(D) Purine + pyrimidine base + sugar + phosphorous
2. A nucleotide consists of
(A) A nitrogenous base like choline
(B) Purine + pyrimidine base + sugar + phosphorous
(C) Purine or pyrimidine base + sugar
(D) Purine or pyrimidine base + phosphorous
3. A purine nucleotide is
(A) AMP (B) UMP
(C) CMP (D) TMP
4. A pyrimidine nucleotide is
(A) GMP (B) AMP
(C) CMP (D) IMP
5. Adenine is
(A) 6-Amino purine
(B) 2-Amino-6-oxypurine
(C) 2-Oxy-4-aminopyrimidine
(D) 2, 4-Dioxypyrimidine
6. 2, 4-Dioxypyrimidine is
(A) Thymine (B) Cystosine
(C) Uracil (D) Guanine
7. The chemical name of guanine is
(A) 2,4-Dioxy-5-methylpyrimidine
(B) 2-Amino-6-oxypurine
(C) 2-Oxy-4-aminopyrimidine
(D) 2, 4-Dioxypyrimidine
8. Nucleotides and nucleic acids concentration are often also expressed in terms of
(A) ng (B) mg
(C) meq (D) OD at 260 nm
9. The pyrimidine nucleotide acting as the high energy intermediate is
(A) ATP (B) UTP
(C) UDPG (D) CMP
10. The carbon of the pentose in ester linkage with the phosphate in a nucleotide struc- ture is
(A) C1 (B) C3
(C) C4 (D) C5
11. Uracil and ribose form
(A) Uridine (B) Cytidine
(C) Guanosine (D) Adenosine
12. The most abundant free nucleotide in mammalian cells is
(A) ATP (B) NAD
(C) GTP (D) FAD
13. The mean intracellular concentration of ATP in mammalian cell is about
(A) 1 mM (B) 2 mM
(C) 0.1 mM (D) 0.2 mM
14. The nucleic acid base found in mRNA but not in DNA is
(A) Adenine (B) Cytosine
(C) Guanine (D) Uracil
15. In RNA moleule ‘Caps’
(A) Allow tRNA to be processed
(B) Are unique to eukaryotic mRNA
(C) Occur at the 3’ end of tRNA
(D) Allow correct translation of prokaryotic mRNA
16. In contrast to eukaryotic mRNA, prokaryotic mRNA
(A) Can be polycistronic
(B) Is synthesized with introns
(C) Can only be monocistronic
(D) Has a poly A tail
17. The size of small stable RNA ranges from
(A) 0–40 nucleotides
(B) 40–80 nucleotides
(C) 90–300 nucleotides
(D) More than 320 nucleotides
18. The number of small stable RNAs per cell ranges from
(A) 10–50,000
(B) 50,000–1,00,000
(C) 1,00,000–10,00,000
(D) More than 10 lakhs
19. Molecular weight of heterogenous nuclear RNA (hnRNA) is
(A) More than 107 (B) 105 to 106
(C) 104 to 105 (D) Less than 104
20. In RNA molecule guanine content does not necessarily equal its cytosine content nor does its adenine content necessarily equal its uracil content since it is a
(A) Single strand molecule
(B) Double stranded molecule
(C) Double stranded helical molecule
(D) Polymer of purine and pyrimidine ribonucleo- tides
21. The nitrogenous base present in the RNA molecule is
(A) Thymine (B) Uracil
(C) Xanthine (D) Hypoxanthine
22. RNA does not contain
(A) Uracil (B) Adenine
(C) Thymine (D) Ribose
23. The sugar moiety present in RNA is
(A) Ribulose (B) Arabinose
(C) Ribose (D) Deoxyribose
24. In RNA molecule
(A) Guanine content equals cytosine
(B) Adenine content equals uracil
(C) Adenine content equals guanine
(D) Guanine content does not necessarily equal its cytosine content.
25. Methylated purines and pyrimidines are characteristically present in
(A) mRNA (B) hnRNA
(C) tRNA (D) rRNA
26. Thymine is present in
(A) tRNA (B) Ribosomal RNA
(C) Mammalian mRNA(D) Prokaryotic mRNA
27. The approximate number of nucleotides in tRNA molecule is
(A) 25 (B) 50
(C) 75 (D) 100
28. In every cell, the number of tRNA mole- cules is at least
(A) 10 (B) 20
(C) 30 (D) 40
29. The structure of tRNA appears like a
(A) Helix (B) Hair pin
(C) Clover leaf (D) Coil
30. Although each specific tRNA differs from the others in its sequence of nucleotides, all tRNA molecules contain a base paired stem that terminates in the sequence CCA at
(A) 3 Termini (B) 5 Termini
(C) Anticodon arm (D) 35 -Termini
31. Transfer RNAs are classified on the basis of the number of base pairs in
(A) Acceptor arm (B) Anticodon arm
(C) D arm (D) Extra arm
32. In tRNA molecule D arm is named for the presence of the base:
(A) Uridine (B) Pseudouridine
(C) Dihydrouridine (D) Thymidine
33. The acceptor arm in the tRNA molecule has
(A) 5 Base pairs (B) 7 Base pairs
(C) 10 Base pairs (D) 20 Base pairs
34. In tRNA molecule, the anticodon arm possesses
(A) 5 Base pairs (B) 7 Base pairs
(C) 8 Base pairs (D) 10 Base pairs
35. The T C arm in the tRNA molecule possesses the sequence
(A) T, pseudouridine and C
(B) T, uridine and C
(C) T, dihydrouridine and C
(D) T, adenine and C
36. Double helical structure model of the DNA was proposed by
(A) Pauling and Corey
(B) Peter Mitchell
(C) Watson and Crick
(D) King and Wooten
37. DNA does not contain
(A) Thymine (B) Adenine
(C) Uracil (D) Deoxyribose
38. The sugar moiety present in DNA is
(A) Deoxyribose (B) Ribose
(C) Lyxose (D) Ribulose
39. DNA rich in A-T pairs have
(A) 1 Hydrogen bond (B) 2 Hydrogen bonds
(C) 3 Hydrogen bonds(D) 4 Hydrogen bonds
40. In DNA molecule
(A) Guanine content does not equal cytosine content
(B) Adenine content does not equal thymine content
(C) Adenine content equals uracil content
(D) Guanine content equals cytosine content
41. DNA rich in G-C pairs have
(A) 1 Hydrogen bond (B) 2 Hydrogen bonds
(C) 3 Hydrogen bonds (D) 4 Hydrogen bonds
42. The fact that DNA bears the genetic information of an organism implies that
(A) Base composition should be identical from species to species
(B) DNA base composition should charge with age
(C) DNA from different tissues in the same organism should usually have the same base composition
(D) DNA base composition is altered with nutritional state of an organism
43. The width (helical diameter) of the double helix in B-form DNA in nm is
(A) 1 (B) 2
(C) 3 (D) 4
44. The number of base pair in a single turn of B-form DNA about the axis of the molecule is
(A) 4 (B) 8
(C) 10 (D) 12
45. The distance spanned by one turn of B- form DNA is
(A) 1.0 nm (B) 2.0 nm
(C) 3.0 nm (D) 3.4 nm
46. In a DNA molecule the thymine concen- tration is 30%, the guanosine concentra- tion will be
(A) 10% (B) 20%
(C) 30% (D) 40%
47. IN a DNA molecule, the guanosine content is 40%, the adenine content will be
(A) 10% (B) 20%
(C) 30% (D) 40%
48. An increased melting temperature of du- plex DNA results from a high content of
(A) Adenine + Guanine
(B) Thymine + Cytosine
(C) Cytosine + Guanine
(D) Cytosine + Adenine
49. A synthetic nucleotide analogue, 4-hydro- xypyrazolopyrimidine is used in the treatment of
(A) Acute nephritis
(B) Gout
(C) Cystic fibrosis of lung
(D) Multiple myeloma
50. A synthetic nucleotide analogue, used in the chemotherapy of cancer and viral infections is
(A) Arabinosyl cytosine
(B) 4-Hydroxypyrazolopyrimidine
(C) 6-Mercaptopurine
(D) 6-Thioguanine
51. Histamine is formed from histidine by the enzyme histidine decarboxylase in the presence of
(A) NAD (B) FMN
(C) HS-CoA (D) B6-PO4
52. Infantile convulsions due to lesser formation of gamma amino butyric acid from glutamic acid is seen in the de- ficiency of
(A) Glutamate-dehydrogenase
(B) Pyridoxine
(C) Folic acid
(D) Thiamin
53. Which of the following amino acids pro- duce a vasoconstrictor on decarboxyla- tion?
(A) Histidine (B) Tyrosine
(C) Threonine (D) Arginine
54. The degradation of RNA by pancreatic ribonuclease produces
(A) Nucleoside 2-Phosphates
(B) Nucleoside 5-phosphates
(C) Oligonucleosides
(D) Nucleoside 3-phosphate and oligonucleotide
55. Intestinal nucleosidases act on nucleo- sides and produce
(A) Purine base only (B) Phosphate only
(C) Sugar only (D) Purine or pyrimidine bases and sugars
56. In purine biosynthesis carbon atoms at 4 and 5 position and N at 7 position are contributed by
(A) Glycine (B) Glutamine
(C) Alanine (D) Threonine
57. N10-formyl and N5N10-methenyl tetrahy- drofolate contributes purine carbon atoms at position
(A) 4 and 6 (B) 4 and 5
(C) 5 and 6 (D) 2 and 8
58. In purine nucleus nitrogen atom at 1 position is derived from
(A) Aspartate (B) Glutamate
(C) Glycine (D) Alanine
59. The key substance in the synthesis of purine, phosphoribosyl pyrophosphate is formed by
(A) -D-ribose 5-phosphate
(B) 5-phospho -D-ribosylamine
(C) D-ribose
(D) Deoxyribose
60. In purine biosynthesis ring closure in the molecule formyl glycinamide ribosyl-5- phosphate requires the cofactors:
(A) ADP (B) NAD
(C) FAD (D) ATP and Mg++
61. Ring closure of formimidoimidazole carboxamide ribosyl-5-phosphate yields the first purine nucleotide:
(A) AMP (B) IMP
(C) XMP (D) GMP
62. The cofactors required for synthesis of adenylosuccinate are
(A) ATP, Mg++ (B) ADP
(C) GTP, Mg++ (D) GDP
63. Conversion of inosine monophosphate to xanthine monophosphate is catalysed by
(A) IMP dehydrogenase
(B) Formyl transferase
(C) Xanthine-guanine phosphoribosyl transferase
(D) Adenine phosphoribosyl transferase
64. Phosphorylation of adenosine to AMP is catalysed by
(A) Adenosine kinase
(B) Deoxycytidine kinase
(C) Adenylosuccinase
(D) Adenylosuccinate synthetase
65. The major determinant of the overall rate of denovo purine nucleotide biosynthesis is the concentration of
(A) 5-phosphoribosyl 1-pyrophosphate
(B) 5-phospho -D-ribosylamine
(C) Glycinamide ribosyl-5-phosphate
(D) Formylglycinamide ribosyl-5-phosphate
66. An enzyme which acts as allosteric reg- ulator and sensitive to both phosphate concentration and to the purine nucle- otides is
(A) PRPP synthetase
(B) PRPP glutamyl midotransferase
(C) HGPR Tase
(D) Formyl transferase
67. PRPP glutamyl amidotransferase, the first enzyme uniquely committed to purine synthesis is feed back inhibited by
(A) AMP (B) IMP
(C) XMP (D) CMP
68. Conversion of formylglycinamide ribosyl- 5-phosphate to formyl-glycinamide ribosyl-5-phosphate is inhibited by
(A) Azaserine (B) Diazonorleucine
(C) 6-Mercaptopurine (D) Mycophenolic acid
69. In the biosynthesis of purine nucleotides the AMP feed back regulates
(A) Adenylosuccinase
(B) Adenylosuccinate synthetase
(C) IMP dehydrogenase
(D) HGPR Tase
70. 6-Mercapto purine inhibits the conversion of
(A) IMP XMP
(B) Ribose 5 phosphate PRPP
(C) PRPP 5-phospho -D-ribosylamine
(D) Glycinamide ribosyl 5-phosphate formylg- lycinamide ribosyl-5-phosphate
71. Purine biosynthesis is inhibited by
(A) Aminopterin (B) Tetracyclin
(C) Methotrexate (D) Chloramphenicol
72. Pyrimidine and purine nucleoside bio- synthesis share a common precursor:
(A) PRPP (B) Glycine
(C) Fumarate (D) Alanine
73. Pyrimidine biosynthesis begins with the formation from glutamine, ATP and CO2, of
(A) Carbamoyl aspartate
(B) Orotate
(C) Carbamoyl phosphate
(D) Dihydroorotate
74. The two nitrogen of the pyrimidine ring are contributed by
(A) Ammonia and glycine
(B) Asparate and carbamoyl phosphate
(C) Glutamine and ammonia
(D) Aspartate and ammonia
75. A cofactor in the conversion of dihydro- orotate to orotic acid, catalysed by the enzyme dihydroorotate dehydrogena- se is
(A) FAD (B) FMN
(C) NAD (D) NADP
76. The first true pyrimidine ribonucleotide synthesized is
(A) UMP (B) UDP
(C) TMP (D) CTP
77. UDP and UTP are formed by phosphory- lation from
(A) AMP (B) ADP
(C) ATP (D) GTP
78. Reduction of ribonucleotide diphosphates (NDPs) to their corresponding deoxy ribonucleotide diphosphates (dNDPs) involves
(A) FMN (B) FAD
(C) NAD (D) NADPH
79. Conversion of deoxyuridine monophos- phate to thymidine monophosphate is catalysed by the enzyme:
(A) Ribonucleotide reductase
(B) Thymidylate synthetase
(C) CTP synthetase
(D) Orotidylic acid decarboxylase
80. d-UMP is converted to TMP by
(A) Methylation (B) Decarboxylation
(C) Reduction (D) Deamination
81. UTP is converted to CTP by
(A) Methylation (B) Isomerisation
(C) Amination (D) Reduction
82. Methotrexate blocks the synthesis of thymidine monophosphate by inhibiting the activity of the enzyme:
(A) Dihydrofolate reductase
(B) Orotate phosphoribosyl transferase
(C) Ribonucleotide reductase
(D) Dihydroorotase
83. A substrate for enzymes of pyrimidine nucleotide biosynthesis is
(A) Allopurinol (B) Tetracylin
(C) Chloramphenicol (D) Puromycin
84. An enzyme of pyrimidine nucleotide bio- synthesis sensitive to allosteric regulation is
(A) Aspartate transcarbamoylase
(B) Dihydroorotase
(C) Dihydroorotate dehydrogenase
(D) Orotidylic acid decarboxylase
85 An enzyme of pyrimidine nucleotides biosynthesis regulated at the genetic level by apparently coordinate repression and derepression is
(A) Carbamoyl phosphate synthetase
(B) Dihydroorotate dehydrogenase
(C) Thymidine kinase
(D) Deoxycytidine kinase
86. The enzyme aspartate transcarbamoy- lase of pyrimidine biosynthesis is inhibit- ed by
(A) ATP (B) ADP
(C) AMP (D) CTP
87. In humans end product of purine cata- bolism is
(A) Uric acid (B) Urea
(C) Allantoin (D) Xanthine
88. In humans purine are catabolised to uric acid due to lack of the enzyme:
(A) Urease (B) Uricase
(C) Xanthine oxidase (D) Guanase
89. In mammals other than higher primates uric acid is converted by
(A) Oxidation to allantoin
(B) Reduction to ammonia
(C) Hydrolysis to ammonia
(D) Hydrolysis to allantoin
90. The correct sequence of the reactions of catabolism of adenosine to uric acid is
(A) Adenosinehypoxanthinexanthineuric acid
(B) Adenosinexanthineinosineuric acid
(C) Adenosineinosinehypoxanthine xanthine uric acid
(D) Adenosinexanthineinosinehypo- xanthine uric acid
91. Gout is a metabolic disorder of catabolism of
(A) Pyrimidine (B) Purine
(C) Alanine (D) Phenylalanine
92. Gout is characterized by increased plasma levels of
(A) Urea (B) Uric acid
(C) Creatine (D) Creatinine
93. Lesch-Nyhan syndrome, the sex linked recessive disorder is due to the lack of the enzyme:
(A) Hypoxanthine-guanine phosphoribosyl transferse
(B) Xanthine oxidase
(C) Adenine phosphoribosyl transferase
(D) Adenosine deaminase
94. Lesch-Nyhan syndrome, the sex linked, recessive absence of HGPRTase, may lead to
(A) Compulsive self destructive behaviour with elevated levels of urate in serum
(B) Hypouricemia due to liver damage
(C) Failure to thrive and megaloblastic anemia
(D) Protein intolerance and hepatic encephalop- athy
95. The major catabolic product of pyrim- idines in human is
(A) -Alanine (B) Urea
(C) Uric acid (D) Guanine
96. Orotic aciduria type I reflects the deficien- cy of enzymes:
(A) Orotate phosphoribosyl transferase and orotidylate decarboxylase
(B) Dihydroorotate dehydrogenase
(C) Dihydroorotase
(D) Carbamoyl phosphate synthetase
97. Orotic aciduria type II reflects the deficien- cy of the enzyme:
(A) Orotate phosphoribosyl transferase
(B) Orotidylate decarboxylase
(C) Dihydroorotase
(D) Dihydroorotate dehydrogenase
98. An autosomal recessive disorder, xanthi- nuria is due to deficiency of the enzymes:
(A) Adenosine deaminase
(B) Xanthine oxidase
(C) HGPRTase
(D) Transaminase
99. Enzymic deficiency in -aminoisobutyric aciduria is
(A) Adenosine deaminase
(B) Xanthine oxidase
(C) Orotidylate decarboxylase
(D) Transaminase
100. Polysomes lack in
(A) DNA (B) mRNA
(C) rRNA (D) tRNA
101. Genetic information flows from
(A) DNA to DNA
(B) DNA to RNA
(C) RNA to cellular proteins
(D) DNA to cellular proteins
102. Genetic code is
(A) Collection of codon
(B) Collection of amino acids
(C) Collection of purine nucleotide
(D) Collection of pyrimidine nucleotide
103. Degeneracy of genetic code implies that
(A) Codons do not code for specific amino acid
(B) Multiple codons must decode the same amino acids
(C) No anticodon on tRNA molecule
(D) Specific codon decodes many amino acids
104. Genetic code is
(A) Overlapping (B) Non-overlapping
(C) Not universal (D) Ambiguous
105. mRNA is complementary to the nucleotide sequence of
(A) Coding strand (B) Ribosomal RNA
(C) tRNA (D) Template strand
106. In DNA replication the enzyme required in the first step is
(A) DNA directed polymerase
(B) Unwinding proteins
(C) DNA polymerase
(D) DNA ligase
107. The smallest unit of DNA capable of cod- ing for the synthesis of a polypeptide is
(A) Operon (B) Repressor gene
(C) Cistron (D) Replicon
108. Termination of the synthesis of the RNA molecule is signaled by a sequence in the template strand of the DNA molecule, a signal that is recognized by a termination protein, the
(A) Rho () factor (B) factor
(C) factor (D) factor
109. After termination of the synthesis of RNA molecule, the core enzymes separate from the DNA template. The core enzymes then recognize a promoter at which the syn- thesis of a new RNA molecule commenc- es, with the assistance of
(A) Rho () factor (B) factor
(C) factor (D) factor
110. In the process of transcription in bacterial cells
(A) Initiation requires rho protein
(B) RNA polymerase incorporates methylated bases in correct sequence
(C) Both the sigma unit and core enzymes of RNA polymerase are required for accurate promotor site binding
(D) Primase is necessary for initiation
111. The correct statement concerning RNA and DNA polymerases is
(A) RNA polymerase use nucleoside diphosphates
(B) RNA polymerase require primers and add bases at 5’ end of the growing polynucleotide chain
(C) DNA polymerases can add nucleotides at both ends of the chain
(D) All RNA and DNA polymerases can add nucleotides only at the 3’ end of the growing polynucleotide chain
112. The eukaryotic nuclear chromosomal DNA
(A) Is a linear and unbranched molecule
(B) Is not associated with a specific membranous organelle
(C) Is not replicated semiconservatively
(D) Is about of the same size as each prokaryotic chromoses
113. The function of a repressor protein in an operon system is to prevent synthesis by binding to
(A) The ribosome
(B) A specific region of the operon preventing transcription of structural genes
(C) The RNA polymerase
(D) A specific region of the mRNA preventing translation to protein
114. All pribnow boxes are variants of the sequence:
(A) 5–TATAAT –3 (B) 5–GAGCCA –3
(C) 5–UAACAA –3 (D) 5–TCCTAG –3
115. 5’-Terminus of mRNA molecule is capped with
(A) Guanosine triphosphate
(B) 7-Methylguanosine triphophate
(C) Adenosine triphosphate
(D) Adenosine diphosphate
116. The first codon to be translated on mRNA is
(A) AUG (B) GGU
(C) GGA (D) AAA
117. AUG, the only identified codon for methio- nine is important as
(A) A releasing factor for peptide chains
(B) A chain terminating codon
(C) Recognition site on tRNA
(D) A chain initiating codon
118. In biosynthesis of proteins the chain terminating codons are
(A) UAA, UAG and UGA
(B) UGG, UGU and AGU
(C) AAU, AAG and GAU
(D) GCG, GCA and GCU
119. The formation of initiation complex during protein synthesis requires a factor:
(A) IF-III (B) EF-I
(C) EF-II (D) IF-I
120. The amino terminal of all polypeptide chain at the time of synthesis in E. coli is tagged to the amino acid residue:
(A) Methionine (B) Serine
(C) N-formyl methinine (D) N-formal serine
121. Initiation of protein synthesis begins with binding of
(A) 40S ribosomal unit on mRNA
(B) 60S ribosomal unit
(C) Charging of tRNA with specific amino acid
(D) Attachment of aminoacyl tRNA on mRNA
122. Initiation of protein synthesis requires
(A) ATP (B) AMP
(C) GDP (D) GTP
123. The enzyme amino acyl tRNA synthetase is involved in
(A) Dissociation of discharged tRNA from 80S ribosome
(B) Charging of tRNA with specific amino acids
(C) Termination of protein synthesis
(D) Nucleophilic attack on esterified carboxyl group of peptidyl tRNA
124. In the process of activation of amino acids for protein synthesis, the number of high energy phosphate bond equivalent utilised is
(A) 0 (B) 1
(C) 2 (D) 4
125 Translation results in a product known as
(A) Protein (B) tRNA
(C) mRNA (D) rRNA
126. In the process of elongation of chain binding of amino acyl tRNA to the A site requires
(A) A proper codon recognition
(B) GTP
(C) EF-II
(D) GDP
127. The newly entering amino acyl tRNA into A site requires
(A) EF-II (B) Ribosomal RNA
(C) mRNA (D) EF-I
128. The -amino group of the new amino acyl tRNA in the A site carries out a nucleo- philic attack on the esterified carboxyl group of the peptidyl tRNA occupying the P site. This reaction is catalysed by
(A) DNA polymerase
(B) RNA polymerase
(C) Peptidyl transferase
(D) DNA ligase
129. The nucleophilic attack on the esterified carboxyl group of the peptidyl-tRNA occupying the P site and the -amino group of the new amino acyl tRNA, the number of ATP required by the amino acid on the charged tRNA is
(A) Zero (B) One
(C) Two (D) Four
130. Translocation of the newly formed peptidyl tRNA at the A site into the empty P site involves
(A) EF-II, GTP
(B) EF-I, GTP
(C) EF-I, GDP
(D) Peptidyl transferase, GTP
131. In eukaryotic cells
(A) Formylated tRNA is important for initiation of translation
(B) Cyclohexamide blocks elongation during translation
(C) Cytosolic ribosomes are smaller than those found in prokaryotes
(D) Erythromycin inhibits elongation during translation
132. The mushroom poison amanitin is an inhibitor of
(A) Protein synthesis (B) mRNA synthesis
(C) DNA synthesis (D) Adenosine synthesis
133. Tetracylin prevents synthesis of polypep- tide by
(A) Blocking mRNA formation from DNA
(B) Releasing peptides from mRNA-tRNA complex
(C) Competing with mRNA for ribosomal binding sites
(D) Preventing binding of aminoacyl tRNA
134. In prokaryotes, chloramphenicol
(A) Causes premature release of the polypeptide chain
(B) Causes misreading of the mRNA
(C) Depolymerises DNA
(D) Inhibits peptidyl transferase activity
135 Streptomycin prevents synthesis of poly- peptide by
(A) Inhibiting initiation process
(B) Releasing premature polypeptide
(C) Inhibiting peptidyl transferase activity
(D) Inhibiting translocation
136. Erythromycin acts on ribosomes and in- hibit
(A) Formation of initiation complex
(B) Binding of aminoacyl tRNA
(C) Peptidyl transferase activity
(D) Translocation
137. The binding of prokaryotic DNA depen- dent RNA polymerase to promoter sites of genes is inhibited by the antibiotic:
(A) Puromycin (B) Rifamycin
(C) Terramycin (D) Streptomycin
138. The gene which is transcribed during repression is
(A) Structural (B) Regulator
(C) Promoter (D) Operator
139 The gene of lac operon which has constitu- tive expression is
(A) i (B) c
(C) z (D) p
140. The minimum effective size of an operator for lac repressor binding is
(A) 5 base pairs (B) 10 base pairs
(C) 15 base pairs (D) 17 base pairs
141 To commence structural gene transcrip- tion the region which should be free on lac operation is
(A) Promoter site (B) Operator locus
(C) Y gene (D) A gene
142. In the lac operon concept, a protein mole- cule is
(A) Operator (B) Inducer
(C) Promoter (D) Repressor
143. The catabolite repression is mediated by a catabolite gene activator protein (CAP) in conjunction with
(A) AMP (B) GMP
(C) cAMP (D) Cgmp
144. The enzyme DNA ligase
(A) Introduces superhelical twists
(B) Connects the end of two DNA chains
(C) Unwinds the double helix
(D) Synthesises RNA primers
145. Restriction endonucleases
(A) Cut RNA chains at specific locations
(B) Excise introns from hnRNA
(C) Remove Okazaki fragments
(D) Act as defensive enzymes to protect the host bacterial DNA from DNA of foreign organisms
146. The most likely lethal mutation is
(A) Substitution of adenine for cytosine
(B) Insertion of one nucleotide
(C) Deletion of three nucleotides
(D) Substitution of cytosine for guanine
147. In the following partial sequence of mRNA, a mutation of the template DNA results in a change in codon 91 to UAA. The type of mutation is
88 89 90 91 92 93 94
GUC GAC CAG UAG GGC UAA CCG
(A) Missene (B) Silent
(C) Nonsense (D) Frame shit
148. Restriction endonucleases recognize and cut a certain sequence of
(A) Single stranded DNA
(B) Double stranded DNA
(C) RNA
(D) Protein
149. Positive control of induction is best described as a control system in which an operon functions
(A) Unless it is switched off by a derepressed repressor protein
(B) Only after a repressor protein is inactivated by an inducer
(C) Only after an inducer protein, which can be inactivated by a corepressor, switches it on
(D) Only after an inducer protein, which is activated by an inducer, switch it on
150. Interferon
(A) Is virus specific
(B) Is a bacterial product
(C) Is a synthetic antiviral agent
(D) Requires expression of cellular genes
151. Repressor binds to DNA sequence and regulate the transcription. This sequence is called
(A) Attenuator (B) Terminator
(C) Anti terminator (D) Operator
152. Okazaki fragment is related to
(A) DNA synthesis (B) Protein synthesis
(C) mRNA formation (D) tRNA formation
153. The region of DNA known as TATA BOX is the site for binding of
(A) DNA polymerase
(B) DNA topoisomerase
(C) DNA dependent RNA polymerase
(D) Polynucleotide phosphorylase
154. Reverse transcriptase is capable of synthesising
(A) RNA DNA (B) DNA RNA
(C) RNA RNA (D) DNA DNA
155. A tetrovirus is
(A) Polio virus (B) HIV
(C) Herpes virus (D) Tobacco mosaic virus
156. Peptidyl transferase activity is located in
(A) Elongation factor
(B) A charged tRNA molecule
(C) Ribosomal protein
(D) A soluble cytosolic protein
157. Ultraviolet light can damage a DNA strand causing
(A) Two adjacent purine residue to form a covalently bounded dimer
(B) Two adjacent pyrimidine residues to form covalently bonded dimer
(C) Disruption of phosphodiesterase linkage
(D) Disruption of non-covalent linkage
158. Defective enzyme in Hurler’s syndrome is
(A) -L-diuronidase
(B) Iduronate sulphatase
(C) Arylsulphatase B
(D) C-acetyl transferase
159. Presence of arginine can be detected by
(A) Sakaguchi reaction
(B) Million-Nasse reaction
(C) Hopkins-Cole reaction
(D) Gas chromatography
160. A nitrogenous base that does not occur in mRNA is
(A) Cytosine (B) Thymine
(C) Uracil (D) All of these
161. In nucleotides, phosphate is attached to sugar by
(A) Salt bond (B) Hydrogen bond
(C) Ester bond (D) Glycosidic bond
162. Cyclic AMP can be formed from
(A) AMP (B) ADP
(C) ATP (D) All of these
163. A substituted pyrimidine base of pharma- cological value is
(A) 5-Iododeoxyuridine
(B) Cytisine arabinoside
(C) 5-Fluorouracil
(D) All of these
164 The ‘transforming factor’ discovered by Avery, McLeod and McCarty was later found to be
(A) mRNA (B) tRNA
(C) DNA (D) None of these
165. In DNA, the complementary base of adenine is
(A) Guanine (B) Cytosine
(C) Uracil (D) Thymine
166. In DNA, three hydrogen bonds are formed between
(A) Adenine and guanine
(B) Adenine and thymine
(C) Guanine and cytosine
(D) Thymine and cytosine
167. Left handed double helix is present in
(A) Z-DNA (B) A-DNA
(C) B-DNA (D) None of these
168. Nuclear DNA is present in combination with
(A) Histones (B) Non-histones
(C) Both (A) and (B) (D) None of these
169. Number of guanine and cytosine residues is equal in
(A) mRNA (B) tRNA
(C) DNA (D) None of these
170. Alkalis cannot hydrolyse
(A) mRNA (B) tRNA
(C) rRNA (D) DNA
171. Codons are present in
(A) Template strand of DNA
(B) mRNA
(C) tRNA
(D) rRNA
172. Amino acid is attached to tRNA at
(A) 5’-End (B) 3’-End
(C) Anticodon (D) DHU loop
173. In prokaryotes, the ribosomal subunits are
(A) 30 S and 40 S (B) 40 S and 50 S
(C) 30 S and 50 S (D) 40 S and 60 S
174. Ribozymes are
(A) Enzymes present in ribosomes
(B) Enzymes which combine the ribosomal subunits
(C) Enzymes which dissociate
(D) Enzymes made up of RNA
175. The smallest RNA among the following is
(A) rRNA (B) hnRNA
(C) mRNA (D) tRNA
176. The number of adenine and thymine bases is equal in
(A) DNA (B) mRNA
(C) tRNA (D) rRNA
177. The number of hydrogen bonds between adenine and thymine in DNA is
(A) One (B) Two
(C) Three (D) Four
178. The complementary base of adenine in RNA is
(A) Thymine (B) Cystosine
(C) Guanine (D) Uracil
179. Extranuclear DNA is present in
(A) Ribosomes
(B) Endoplasmic reticulum
(C) Lysosomes
(D) Mitochondria
180. Mitochondrial DNA is present in
(A) Bacteria (B) Viruses
(C) Eukaryotes (D) All of these
181. Ribothymidine is present in
(A) DNA (B) tRNA
(C) rRNA (D) hnRNA
182. Ten base pairs are present in one turn of the helix in
(A) A-DNA (B) B-DNA
(C) C-DNA (D) Z-DNA
183. Transfer RNA transfers
(A) Information from DNA to ribosomes
(B) Information from mRNA to cytosol
(C) Amino acids from cytosol to ribosomes
(D) Proteins from ribosomes to cytosol
184. Ceramidase is deficient in
(A) Fabry’s disease (B) Farber’s disease
(C) Krabbe’s disease (D) Tay-Sachs disease
185. Ceramide is present in all of the following except
(A) Plasmalogens (B) Cerebrosides
(C) Sulphatides (D) Sphingomyelin
186. Nucleotides required for the synthesis of nucleic acids can be obtained from
(A) Dietary nucleic acids and nucleotides
(B) De novo synthesis
(C) Salvage of pre-existing bases and nucleosides
(D) De novo synthesis and salvage
187. De novo synthesis of purine nucleotide occurs in
(A) Mitochondria (B) Cytosol
(C) Microsmes (D) Ribosomes
188. The nitrogen atoms for de novo synthesis of purine nucleotides are provided by
(A) Aspartate and glutamate
(B) Aspartate and glycine
(C) Aspartate, glutamine and glycine
(D) Aspartate, glutamate and glycine
189 For de novo synthesis of purine nucle- otides, glycine provides
(A) One nitrogen atom
(B) One nitrogen and one carbon atom
(C) Two carbon atoms
(D) One nitrogen and two carbon atoms
190. For de novo synthesis of purine nucle- otides, aspartate provides
(A) Nitrogen 1 (B) Nitrogen 3
(C) Nitrogen 7 (D) Nitrogen 9
191. In the purine nucleus, carbon 6 is contrib- uted by
(A) Glycine (B) CO2
(C) Aspartate (D) Glutamine
192. 5-Phosphoribosyl-1-pyrophosphate is required for the synthesis of
(A) Purine nucleotides (B) Pyrimidine nucleotides
(C) Both (A) and (B) (D) None of these
193. Inosine monophophate is an intermediate during the de novo synthesis of
(A) AMP and GMP (B) CMP and UMP
(C) CMP and TMP (D) All of these
194. Xanthosine monophosphate is an intermediate during de novo synthesis of
(A) TMP (B) CMP
(C) AMP (D) GMP
195. In the pathway of de novo synthesis of purine nucleotides, all the following are allosteric enzymes except
(A) PRPP glutamyl amido transferase
(B) Adenylosuccinate synthetase
(C) IMP dehydrogenase
(D) Adenylosuccinase
196. All of the following enzymes are unique to purine nucleotide synthesis except
(A) PRPP synthetase
(B) PRPP glutamyl amido transferase
(C) Adenylosuccinate synthetase
(D) IMP dehydrogenase
197. PRPP synthetase is allosterically inhibited by
(A) AMP (B) ADP
(C) GMP (D) All of these
198. An allosteric inhibitor of PRPP glutamyl amido transferase is
(A) AMP (B) ADP
(C) GMP (D) All of these
199. An allosteric inhibitor of adenylosuccinate synthetase is
(A) AMP (B) ADP
(C) GMP (D) GDP
200. An allosteric inhibitor of IMP dehydroge- nase is
(A) AMP (B) ADP
(C) GMP (D) GDP
201. GMP is an allosteric inhibitor of all the following except
(A) PRPP synthetase
(B) PRPP glutamyl amido synthetase
(C) IMP dehydrogenase
(D) Adenylosuccinate synthetase
202. AMP is an allosteric inhibitor of
(A) PRPP synthetase
(B) Adenylosucciante synthetase
(C) Both (A) and (B)
(D) None of these
203. The first reaction unique to purine nucleo- tide synthesis is catalysed by
(A) PRPP synthetase
(B) PRPP glutamyl amido transferase
(C) Phosphoribosyl glycinamide synthetase
(D) Formyl transferase
204. Free purine bases which can be salvaged are
(A) Adenine and guanine
(B) Adenine and hypoxanthine
(C) Guanine and hypoxanthine
(D) Adenine, guanine and hypoxanthine
205. The enzyme required for salvage of free purine bases is
(A) Adenine phosphoribosyl transferase
(B) Hypoxanthine guanine phosphoribosyl transferase
(C) Both (A) and (B)
(D) None of these
206. Deoxycytidine kinase can salvage
(A) Adenosine
(B) Adenosine and deoxyadenosine
(C) Adenosine and guanosine
(D) Adenine and adenosine
207. Adenosine kinase can salvage
(A) Adenosine
(B) Adenosine and deoxyadenosine
(C) Adenosine and guanosine
(D) Adenine and adenosine
208. Salvage of purine bases is regulated by
(A) Adenosine phosphoribosyl transferase
(B) Hypoxanthine guanine phosphoribosyl transferase
(C) Availability of PRPP
(D) None of these
209. The available PRPP is used preferentially for
(A) De novo synthesis of purine nucleotides
(B) De novo synthesis of pyrimidine nucleotides
(C) Salvage of purine bases
(D) Salvage of pyrimidine bases
210. The end product of purine catabolism in man is
(A) Inosine (B) Hypoxanthine
(C) Xanthine (D) Uric acid
211. The enzyme common to catabolism of all the purines is
(A) Adenosine deaminase
(B) Purine nucleoside phosphorylase
(C) Guanase
(D) None of these
212. Uric acid is the end product of purine as well as protein catabolism in
(A) Man (B) Fish
(C) Birds (D) None of these
213. Daily uric acid excretion in adult men is
(A) 2–6 mg (B) 20–40 mg
(C) 150–250 mg (D) 40–600 mg
214. Dietary purines are catabolised in
(A) Liver (B) Kidneys
(C) Intesitnal mucosa (D) All of these
215. De novo synthesis of pyrimidine nucle- otides occurs in
(A) Mitochondria (B) Cytosol
(C) Microsomes (D) Ribosomes
216. An enzyme common to de novo synthesis of pyrimidine nucleotides and urea is
(A) Urease
(B) Carbamoyl phosphate synthetase
(C) Aspartate transcarbamoylase
(D) Argininosuccinase
217. The nitrogen atoms of pyrimidine nucleus are provided by
(A) Glutamate
(B) Glutamate and aspartate
(C) Glutamine
(D) Glutamine and aspartate
218. The carbon atoms of pyrimidine nucleus are provided by
(A) Glycine and aspartate
(B) CO2 and aspartate
(C) CO2 and glutamate
(D) CO2 and glutamine
219. Nitrogen at position 1 of pyrimidine nu- cleus comes from
(A) Glutamine (B) Glutamate
(C) Glycine (D) Aspartate
220. Nitrogen at position 3 of pyrimidine nu- cleus comes from
(A) Glutamine (B) Glutamate
(C) Glycine (D) Aspartate
221. The carbon atom at position 2 of pyrimi- dine nucleus is contributed by
(A) CO2 (B) Glycine
(C) Aspartate (D) Glutamine
222. Aspartate contributes the following carbon atoms of the pyrimidine nucelus:
(A) C2 and C4 (B) C5 and C6
(C) C2, C4 and C6 (D) C4, C5 and C6
223. The first pyrimidine nucleotide to be formed in de novo synthesis pathway is
(A) UMP (B) CMP
(C) CTP (D) TMP
224. Conversion of uridine diphosphate into deoxyuridine diphosphate requires all the following except
(A) Ribonucleotide reductase
(B) Thioredoxin
(C) Tetrahydrobiopterin
(D) NADPH
225. Amethopterin and aminopterin decrease the synthesis of
(A) TMP (B) UMP
(C) CMP (D) All of these
226. For synthesis of CTP and UTP, the amino group comes from
(A) Amide group of Asparagine
(B) Amide group of glutamine
(C) -Amino group of glutamine
(D) -Amino group of glutamate
227. CTP synthetase forms CTP from
(A) CDP and inorganic phosphate
(B) CDP and ATP
(C) UTP and glutamine
(D) UTP and glutamate
228. For the synthesis of TMP from dump, a coenzyme is required which is
(A) N10- Formyl tetrahydrofolate
(B) N5- Methyl tetrahydrofolate
(C) N5, N10- Methylene tetrahydrofolate
(D) N5- Formimino tetrahydrofolate
229. All the enzymes required for de novo synthesis of pyrimidine nucleotides are cytosolic except
(A) Carbamoyl phosphate synthetase
(B) Aspartate transcarbamoylase
(C) Dihydro-orotase
(D) Dihydro-orotate dehydrogenase
230. During de novo synthesis of pyrimidine nucleotides, the first ring compound to be formed is
(A) Carbamoyl aspartic acid
(B) Dihydro-orotic acid
(C) Orotic acid
(D) Orotidine monophosphate
231. Tetrahydrofolate is required as a coen- zyme for the synthesis of
(A) UMP (B) CMP
(C) TMP (D) All of these
232. All of the following statements about thioredoxin reductase are true except:
(A) It requires NADH as a coenzyme
(B) Its substrates are ADP, GDP, CDP and UDP
(C) It is activated by ATP
(D) It is inhibited by dADP
233. De novo synthesis of pyrimidine nucle- otides is regulated by
(A) Carbamoyl phosphate synthetase
(B) Aspartate transcarbamoylase
(C) Both (A) and (B)
(D) None of these
234. Cytosolic carbamoyl phosphate synthe- tase is inhibited by
(A) UTP (B) CTP
(C) PRPP (D) TMP
235. Cytosolic carbamoyl phosphate syn- thetase is activated by
(A) Glutamine (B) PRPP
(C) ATP (D) Aspartate
236. Aspartate transcarbamoylase is inhibited by
(A) CTP (B) PRPP
(C) ATP (D) TMP
237. The following cannot be salvaged in hu- man beings:
(A) Cytidine (B) Deoxycytidine
(C) Cytosine (D) Thymidine
238. -Aminoisobytyrate is formed from ca- tabolism of
(A) Cytosine (B) Uracil
(C) Thymine (D) Xanthine
239. Free ammonia is liberated during the catabolism of
(A) Cytosine (B) Uracil
(C) Thymine (D) All of these
240. -Alanine is formed from catabolism of
(A) Thymine
(B) Thymine and cytosine
(C) Thymine and uracil
(D) Cytosine and uracil
241. The following coenzyme is required for catabolism of pyrimidine bases:
(A) NADH (B) NADPH
(C) FADH2 (D) None of these
242. Inheritance of primary gout is
(A) Autosomal recessive
(B) Autosomal dominant
(C) X-linked recessive
(D) X-linked dominant
243. The following abnormality in PRPP synthetase can cause primary gout:
(A) High Vmax
(B) Low Km
(C) Resistance to allosteric inihbition.
(D) All of these
244. All the following statements about primary gout are true except
(A) Its inheritance is X-linked recessive
(B) It can be due to increased activity of PRPP synthetase
(C) It can be due to increased activity of hypox- anthine guanine phosphoribosyl transferase
(D) De novo synthesis of purines is increased in it
245. All of the following statements about uric acid are true except
(A) It is a catabolite of purines
(B) It is excreted by the kidneys
(C) It is undissociated at pH above 5.8
(D) It is less soluble than sodium urate
246. In inherited deficiency of hypoxanthine guanine phosphoribosyl transferase
(A) De novo synthesis of purine nucleotides is decreased
(B) Salvage of purines is decreased
(C) Salvage of purines is increased
(D) Synthesis of uric acid is decreased
247. All of the following statements about uric
acid are true except
(A) It can be formed from allantoin
(B) Formation of uric acid stones in kidneys can
be decreased by alkalinisation of urine
(C) Uric acid begins to dissociate at pH above 5.8
(D) It is present in plasma mainly as monosodium
urate
248. All of the following statements about
primary gout are true except
(A) Uric acid stones may be formed in kidneys
(B) Arthritis of small joints occurs commonly
(C) Urinary excretion of uric acid is decreased
(D) It occurs predominantly in males
249. All of the following statements about
allopurinol are true except
(A) It is a structural analogue of uric acid
(B) It can prevent uric acid stones in the kidneys
(C) It increases the urinary excretion of xanthine and hypoxanthine
(D) It is a competitive inhibitor of xanthine oxidase
250. Orotic aciduria can be controlled by
(A) Oral administration of orotic acid
(B) Decreasing the dietary intake of orotic acid
(C) Decreasing the dietary intake of pyrimidines
(D) Oral administration of uridine
251. All of the following occur in orotic aciduria except
(A) Increased synthesis of pyrimidine nucleotides
(B) Increased excretion of orotic acid in urine
(C) Decreased synthesis of cytidine triphosphate
(D) Retardation of growth
252. Inherited deficiency of adenosine deami- nase causes
(A) Hyperuricaemia and gout
(B) Mental retardation
(C) Immunodeficiency
(D) Dwarfism
253. Complete absence of hypoxanthine gua- nine phospharibosyl transferase causes
(A) Primary gout (B) Immunodeficiency
(C) Uric acid stones (D) Lesh-Nyhan syndrome
254. Increased urinary excretion of orotic acid can occur in deficiency of
(A) Orotate phosphoribosyl transferase
(B) OMP decarboxylase
(C) Mitochondrial ornithine transcarbamoylase
(D) Any of the above
255. All of the following can occur in Lesch-
Nyhan syndrome except
(A) Gouty arthritis
(B) Uric acid stones
(C) Retarted growth
(D) Self-mutiliating behaviour
256. Inherited deficiency of purine nucleoside phosphorylase causes
(A) Dwarfism (B) Mental retardation
(C) Immunodeficiency (D) Gout
257. Deoxyribonucleotides are formed by reduction of
(A) Ribonucleosides
(B) Ribonucleoside monophosphates
(C) Ribonucleoside diphosphates
258. (D)
An Ribonucleoside triphosphates
alternate substrate for orotate
phosphoribosyl transferase is
(A) Allopurinol (B) Xanthine
(C) Hypoxanthine (D) Adenine
259. Mammals other than higher primates do not suffer from gout because they
(A) Lack xanthine oxidase
(B) Lack adenosine deaminase
(C) Lack purine nucleoside phosphorylase
(D) Possess uricase
260. Hypouricaemia can occur in
(A) Xanthine oxidase deficiency
(B) Psoriasis
(C) Leukaemia
(D) None of these
261. Synthesis of DNA is also known as
(A) Duplication (B) Replication
(C) Transcription (D) Translation
262. Replication of DNA is
(A) Conservative (B) Semi-conservative
(C) Non-conservative (D) None of these
263. Direction of DNA synthesis is
(A) 5’ 3’ (B) 3’ 5’
(C) Both (A) and (B) (D) None of these
264. Formation of RNA primer:
(A) Precedes replication
(B) Follows replication
(C) Precedes transcription
(D) Follows transcription
265. Okazaki pieces are made up of
(A) RNA (B) DNA
(C) RNA and DNA (D) RNA and proteins
266. Okazaki pieces are formed during the synthesis of
(A) mRNA (B) tRNA
(C) rRNA (D) DNA
267. After formation of replication fork
(A) Both the new strands are synthesized disconti- nuously
(B) One strand is synthesized continuously and the other discontinuously
(C) Both the new strands are synthesized continuously
(D) RNA primer is required only for the synthesis of one new strand
268. An Okazaki fragment contains about
(A) 10 Nucleotides
(B) 100 Nucleotides
(C) 1,000 Nucleotides
(D) 10,000 Nucleotides
269. RNA primer is formed by the enzyme:
(A) Ribonuclease (B) Primase
(C) DNA polymerase I (D) DNA polymerase III
270. In RNA, the complementary base of ade- nine is
(A) Cytosine (B) Guanine
(C) Thymine (D) Uracil
271. During replication, the template DNA is unwound
(A) At one of the ends (B) At both the ends
(C) At multiple sites (D) Nowhere
272. During replication, unwinding of double helix is initiated by
(A) DNAA protein (B) DnaB protein
(C) DNAC protein (D) Rep protein
273. For unwinding of double helical DNA,
(A) Energy is provided by ATP
(B) Energy is provided by GTP
(C) Energy can be provided by either ATP or GTP
(D) No energy is required
274. Helicase and DNAB protein cause
(A) Rewinding of DNA and require ATP as a source of energy
(B) Rewinding of DNA but do not require any source of energy
(C) Unwinding of DNA and require ATP as a source of energy
(D) Unwinding of DNA but do not require any source of energy
275. The unwound strands of DNA are held apart by
(A) Single strand binding protein
(B) Double strand binding protein
(C) Rep protein
(D) DNAA protein
276. Deoxyribonucleotides are added to RNA primer by
(A) DNA polymerase I
(B) DNA polymerase II
(C) DNA polymerase III holoenzyme
(D) All of these
277. Ribonucleotides of RNA primer are re- placed by deoxyribonucleotides by the enzyme:
(A) DNA polymerase I
(B) DNA polymerase II
(C) DNA polymerase III holoenzyme
(D) All of these
278. DNA fragments are sealed by
(A) DNA polymerase II
(B) DNA ligase
(C) DNA gyrase
(D) DNA topoisomerase II
279. Negative supercoils are introduced in DNA by
(A) Helicase
(B) DNA ligase
(C) DNA gyrase
(D) DNA polymerase III holoenzyme
280. Reverse transcriptase activity is present in the eukaryotic:
(A) DNA polymerase
(B) DNA polymerase
(C) Telomerase
(D) DNA polymerase II
281. DNA polymerase III holoenzyme possesses
(A) Polymerase activity
(B) 3’5’ Exonuclease activity
(C) 5’3’ Exonuclease and polymerase activities
(D) 3’5’ Exonuclease and polymerase activities
282. DNA polymerase I possesses
(A) Polymerase activity
(B) 3’5’ Exonuclease activity
(C) 5’3’ Exonuclease activity
(D) All of these
283. 3’5’ Exonuclease activity of DNA polymerase I
(A) Removes ribonucleotides
(B) Adds deoxyribonucleotides
(C) Corrects errors in replication
(D) Hydrolyses DNA into mononucleotides
284. All of the following statements about RNA-dependent DNA polymerase are true except:
(A) It synthesizes DNA using RNA as a template
(B) It is also known as reverse transcriptase
(C) It synthesizes DNA in 5’3’ direction
(D) It is present in all the viruses
285. Reverse transcriptase catalyses
(A) Synthesis of RNA
(B) Breakdown of RNA
(C) Synthesis of DNA
(D) Breakdown of DNA
286. DNA A protein can bind only to
(A) Positively supercoiled DNA
(B) Negatively supercoiled DNA
(C) Both (A) and (B)
(D) None of these
287. DNA topoisomerase I of E. coli catalyses
(A) Relaxation of negatively supercoiled DNA
(B) Relaxation of positively supercoiled DNA
(C) Conversion of negatively supercoiled DNA into positively supercoiled DNA
(D) Conversion of double helix into supercoiled DNA
288. In mammalian cell cycle, synthesis of DNA occurs during
(A) S phase (B) G1 phase
(C) Mitotic Phase (D) G2 phase
289. Melting temperature of DNA is the tempera- ture at which
(A) Solid DNA becomes liquid
(B) Liquid DNA evaporates
(C) DNA changes from double helix into supercoiled DNA
(D) Native double helical DNA is denatured
290. Melting temperature of DNA is increased by its
(A) A and T content (B) G and C content
(C) Sugar content (D) Phosphate content
291. Buoynat density of DNA is increased by its
(A) A and T content (B) G and C content
(C) Sugar content (D) None of these
292. Relative proportions of G and C versus A and T in DNA can be determined by its
(A) Melting temperature
(B) Buoyant density
(C) Both (A) and (B)
(D) None of these
293. Some DNA is present in mitochondria of
(A) Prokaryotes (B) Eukaryotes
(C) Both (A) and (B) (D) None of these
294. Satellite DNA contains
(A) Highly repetitive sequences
(B) Moderately repetitive sequences
(C) Non-repetitive sequences
(D) DNA-RNA hybrids
295. Synthesis of RNA and a DNA template is known as
(A) Replication (B) Translation
(C) Transcription (D) Mutation
296. Direction of RNA synthesis is
(A) 5 3’ (B) 3 5’
(C) Both (A) and (B) (D) None of these
297. DNA-dependent RNA polymerase is a
(A) Monomer (B) Dimer
(C) Trimer (D) Tetramer
298. DNA-dependent RNA polymerase requires the following for its catalytic activity:
(A) Mg++ (B) Mn++
(C) Both (A) and (B) (D) None of these
299. The initiation site for transcription is recognized by
(A) Subunit of DNA-dependent RNA polymerase
(B) Subunit of DNA-dependent RNA polymerase
(C) Sigma factor
(D) Rho factor
300. The termination site for transcription is recognized by
(A) Subunit of DNA-dependent RNA polymerase
(B) Subunit of DNA-dependent RNA polymerase
(C) Sigma factor
(D) Rho factor
301. Mammalian RNA polymerase I synthesises
(A) mRNA (B) rRNA
(C) tRNA (D) hnRNA
302. Mammalian RNA polymerase III synthesises
(A) rRNA (B) mRNA
(C) tRNA (D) hnRNA
303. In mammals, synthesis of mRNA is catalysed by
(A) RNA polymerase I (B) RNA polymerase II
(C) RNA polymerase III(D) RNA polymerase IV
304. Heterogeneous nuclear RNA is the precursor of
(A) mRNA (B) rRNA
(C) tRNA (D) None of these
305. Post-transcriptional modification of hnRNA involves all of the following except
(A) Addition of 7-methylguanosine triphosphate cap
(B) Addition of polyadenylate tail
(C) Insertion of nucleotides
(D) Deletion of introns
306. Newly synthesized tRNA undergoes post- transcriptional modifications which include all the following except
(A) Reduction in size
(B) Methylation of some bases
(C) Formation of pseudouridine
(D) Addition of C-C-A terminus at 5’ end
307. Post-transcriptional modification does not occur in
(A) Eukaryotic tRNA (B) Prokaryotic tRNA
(C) Eukaryotic hnRNA (D) Prokaryotic mRNA
308. A consensus sequence on DNA, called TATA box, is the site for attachment of
(A) RNA-dependent DNA polymerase
(B) DNA-dependent RNA polymerase
(C) DNA-dependent DNA polymerase
(D) DNA topoisomerase II
309. Polyadenylate tail is not present in mRNA synthesising
(A) Globin (B) Histone
(C) Apoferritin (D) Growth hormone
310. Introns are present in DNA of
(A) Viruses (B) Bacteria
(C) Man (D) All of these
311. A mammalian DNA polymerase among the following is
(A) DNA polymerase
(B) DNA polymerase I
(C) DNA polymerase II
(D) DNA polymerase IV
312. Mammalian DNA polymerase is located in
(A) Nucleus (B) Nucleolus
(C) Mitochondria (D) Cytosol
313. Replication of nuclear DNA in mammals is catalysed by
(A) DNA polymerase
(B) DNA polymerase
(C) DNA polymerase
(D) DNA polymerase III
314. Primase activity is present in
(A) DNA polymerase II
(B) DNA polymerase
(C) DNA polymerase
(D) DNA polymerase
315. The mammalian DNA polymerase involved in error correction is
(A) DNA polymerase
(B) DNA polymerase
(C) DNA polymerase
(D) DNA polymerase
316. Novobicin inhibits the synthesis of
(A) DNA (B) mRNA
(C) tRNA (D) rRNA
317. Ciprofloxacin inhibits the synthesis of
(A) DNA (B) mRNA
(C) tRNA (D) rRNA
318. Ciprofloxacin inhibits
(A) DNA topisomerase II
(B) DNA polymerase I
(C) DNA polymerase III
(D) DNA gyrase
319. Rifampicin inhibits
(A) Unwinding of DNA
(B) Initiation of replication
(C) Initiation of translation
(D) Initiation of transcription
320. Actinomycin D binds to
(A) Double stranded DNA
(B) Single stranded DNA
(C) Single stranded RNA
(D) DNA-RNA hybrid
321. DNA contains some palindromic sequences which
(A) Mark the site for the formation of replication forks
(B) Direct DNA polymerase to turn back to replicate the other strand
(C) Are recognized by restriction enzymes
(D) Are found only in bacterial DNA
322. Introns in genes
(A) Encode the amino acids which are removed during post-translational modification
(B) Encode signal sequences which are removed before secretion of the proteins
(C) Are the non-coding sequences which are not translated
(D) Are the sequences that intervene between two genes
323. All of the following statements about post-transcriptional processing of tRNA are true except
(A) Introns of some tRNA precursors are removed
(B) CCA is added at 3 end
(C) 7-Methylguanosine triphosphate cap is added at 5 end
(D) Some bases are methylated
324. -Amanitin inhibits
(A) DNA polymerase II of prokaryotes
(B) DNA polymerase of eukaryotes
(C) RNA polymerase II of eukaryotes
(D) RNA-dependent DNA polymerase
325. Ciprofloxacin inhibits the synthesis of
(A) DNA in prokaryotes
(B) DNA in prokaryotes and eukaryotes
(C) RNA in prokaryotes
(D) RNA in prokaryotes and eukaryotes
326. All of the following statements about bacterial promoters are true except
(A) They are smaller than eukaryotic promoters
(B) They have two consensus sequences upstream from the transcription star site
(C) TATA box is the site for attachment of RNA polymerase
(D) TATA box has a high melting temperature
327. All of the following statements about eukaryotic promoters are true except
(A) They may be located upstream or down stream from the structural gene
(B) They have two consensus sequences
(C) One consensus sequence binds RNA polymerase
(D) Mutations in promoter region can decrease the efficiency of transcription of the structural gene
328. In sanger’s method of DNA sequence determination, DNA synthesis is stopped by using
(A) 1, 2- Dideoxyribonucleoside triphosphates
(B) 2, 3- Dideoxyribonucleoside triphosphates
(C) 2, 4- Dideoxyribonucleoside triphosphates
(D) 2, 5 – Dideoxyribonucleoside triphosphates
329. tRNA genes have
(A) Upstream promoters
(B) Downstream promoters
(C) Intragenic promoters
(D) No promoters
330. All of the following statements about tRNA are true except
(A) It is synthesized as a large precursor
(B) It is processed in the nucelolus
(C) It has no codons or anticodons
(D) Genes for rRNA are present in single copies
331. Anticodons are present on
(A) Coding strand of DNA
(B) mRNA
(C) tRNA
(D) rRNA
332. Codons are present on
(A) Non-coding strand of DNA
(B) hnRNA
(C) tRNA
(D) None of these
333. Nonsense codons are present on
(A) mRNA (B) tRNA
(C) rRNA (D) None of these
334. Genetic code is said to be degenerate be- cause
(A) It can undergo mutations
(B) A large proportion of DNA is non-coding
(C) One codon can code for more than one amino acids
(D) More than one codons can code for the same amino acids
335. All the following statements about genetic code are correct except
(A) It is degenerate (B) It is unambigous
(C) It is nearly universal(D) It is overlapping
336. All of the following statements about nonsense codons are true except
(A) They do not code for amino acids
(B) They act as chain termination signals
(C) They are identical in nuclear and mitochondrial DNA
(D) They have no complementary anticodons
337. A polycistronic mRNA can be seen in
(A) Prokaryotes (B) Eukaryotes
(C) Mitochondria (D) All of these
338. Non-coding sequence are present in the genes of
(A) Bacteria (B) Viruses
(C) Eukaryotes (D) All of these
339. Non-coding sequences in a gene are known as
(A) Cistrons (B) Nonsense codons
(C) Introns (D) Exons
340. Splice sites are present in
(A) Prokaryotic mRNA (B) Eukaryotic mRNA
(C) Eukaryotic hnRNA (D) All of these
341. The common features of introns include all the following except
(A) The base sequence begins with GU
(B) The base sequence ends with AG
(C) The terminal AG sequence is preceded by a purine rich tract of ten nucleotides
(D) An adenosine residue in branch site partici- pates in splicing
342. A splice some contains all the following except
(A) hnRNA (B) snRNAs
(C) Some proteins (D) Ribosome
343. Self-splicing can occur in
(A) Some precursors of rRNA
(B) Some precursors of tRNA
(C) hnRNA
(D) None of these
344. Pribnow box is present in
(A) Prokaryotic promoters
(B) Eukaryotic promoters
(C) Both (A) and (B)
(D) None of these
345. Hogness box is present in
(A) Prokaryotic promoters
(B) Eukaryotic promoters
(C) Both (A) and (B)
(D) None of these
346. CAAT box is present in
(A) Prokaryotic promoters 10 bp upstream of transcription start site
(B) Prokaryotic promoters 35 bp upstream of transcription start site
(C) Eukaryotic promoters 25 bp upstream of transcription start site
(D) Eukaryotic promoters 70–80 bp upstream of transcription start site
347. Eukaryotic promoters contain
(A) TATA box 25bp upstream of transcription start site
(B) CAAT box 70-80 bp upstream of transcription start site
(C) Both (A) and (B)
(D) None of these
348. All the following statements about tRNA are correct except
(A) A given tRNA can be charged with only one particular amino acid
(B) The amino acid is recognized by the anticodon of tRNA
(C) The amino acid is attached to end of tRNA
(D) The anticodon of tRNA finds the comple- mentary codon on mRNA
349. All the following statements about charging of tRNA are correct except
(A) It is catalysed by amino acyl tRNA synthetase
(B) ATP is converted into ADP and Pi in this reaction
(C) The enzyme recognizes the tRNA and the amino acid
(D) There is a separate enzyme for each tRNA
350. All the following statements about recognition of a codon on mRNA by an anticodon on tRNA are correct except
(A) The recognition of the third base of the codon is not very precise
(B) Imprecise recognition of the third base results in wobble
(C) Wobble is partly responsible for the degeneracy of the genetic code
(D) Wobble results in incorporation of incorrect amino acids in the protein
351. The first amino acyl tRNA which initiates translation in eukaryotes is
(A) Mehtionyl tRNA
(B) Formylmethionyl tRNA
(C) Tyrosinyl tRNA
(D) Alanyl tRNA
352. The first amino acyl tRNA which initiates translation in prokaryotes is
(A) Mehtionyl tRNA
(B) Formylmethionyl tRNA
(C) Tyrosinyl tRNA
(D) Alanyl tRNA
353. In eukaryotes, the 40 S pre-initiation complex contains all the following initiation factors except
(A) eIF-1A (B) eIF-2
(C) eIF-3 (D) eIF-4
354. Eukaryotic initiation factors 4A, 4B and 4F bind to
(A) 40 S ribosomal subunit
(B) 60 S ribosomal subunit
(C) mRNA
(D) Amino acyl tRNA
355. The codon which serves as translation start signal is
(A) AUG (B) UAG
(C) UGA (D) UAA
356. The first amino acyl tRNA approaches 40 S ribosomal subunit in association with
(A) eIF-1A and GTP (B) eIF-2 and GTP
(C) eIF-2C and GTP (D) eIF-3 and GTP
357. eIF-1A and eIF-3 are required
(A) For binding of amino acyl tRNA to 40 S ribosomal subunit
(B) For binding of mRNA to 40 S ribosomal subunit
(C) For binding of 60 S subunit to 40 S subunit
(D) To prevent binding of 60 S subunit to 40 S subunit
358. eIF-4 A possesses
(A) ATPase activity (B) GTPase activity
(C) Helicase activity (D) None of these
359. eIF-4 B
(A) Binds to 3’ chain initiation codon on mRNA
(B) Binds to 3’ end of mRNA
(C) Binds to 5’ end of mRNA
(D) Unwinds mRNA near its 5’ end
360. Peptidyl transferase activity is present in
(A) 40 S ribosomal subunit
(B) 60 S ribosomal subunit
(C) eEF-2
(D) Amino acyl tRNA
361. After formation of a peptide bond, mRNA is translocated along the ribosome by
(A) eEF-1 and GTP
(B) eEF-2 and GTP
(C) Peptidyl transferase and GTP
(D) Peptidyl transferase and ATP
362. Binding of formylmehtionyl tRNA to 30 S ribosomal subunit of prokaryotes is inhibited by
(A) Streptomycin (B) Chloramphenicol
(C) Erythromycin (D) Mitomycin
363. Tetracyclines inhibit binding of amino acyl tRNAs to
(A) 30 S ribosomal subunits
(B) 40 S ribosomal subunits
(C) 50 S ribosomal subunits
(D) 60 S ribosomal subunits
364. Peptidyl transferase activity of 50 S ribosomal subunits is inhibited by
(A) Rifampicin (B) Cycloheximide
(C) Chloramphenicol (D) Erythromycin
365. Erythromycin binds to 50 S ribosomal sub unit and
(A) Inhibits binding of amino acyl tRNA
(B) Inhibits Peptidyl transferase activity
(C) Inhibits translocation
(D) Causes premature chain termination
366. Puromycin causes premature chain termination in
(A) Prokaryotes (B) Eukaryotes
(C) Both (A) and (B) (D) None of these
367. Diphtheria toxin inhibits
(A) Prokaryotic EF-1 (B) Prokaryotic EF-2
(C) Eukaryotic EF-1 (D) Eukaryotic EF-2
368. The proteins destined to be transported out of the cell have all the following features except
(A) They possess a signal sequence
(B) Ribosomes synthesizing them are bound to endoplasmic reticulum
(C) After synthesis, they are delivered into Golgi apparatus
(D) They are tagged with ubiquitin
369. SRP receptors involved in protein export are present on
(A) Ribosomes
(B) Endoplasmic reticulum
(C) Golgi appartus
(D) Cell membrane
370. The signal sequence of proteins is cleaved off
(A) On the ribosomes immediately after synthesis
(B) In the endoplasmic reticulum
(C) During processing in Golgi apparatus
(D) During passage through the cell membrane
371. The half-life of a protein depends upon its
(A) Signal sequence
(B) N-terminus amino acid
(C) C-terminus amino acid
(D) Prosthetic group
372. Besides structural genes that encode proteins, DNA contains some regulatory sequences which are known as
(A) Operons (B) Cistrons
(C) Cis-acting elements (D) Trans-acting factors
373. Inducers and repressors are
(A) Enhancer and silencer elements respectively
(B) Trans-acting factors
(C) Cis-acting elements
(D) Regulatory proteins
374. cis-acting elements include
(A) Steroid hormones (B) Calcitriol
(C) Histones (D) Silencers
375. Silencer elements
(A) Are trans-acting factors
(B) Are present between promoters and the structural genes
(C) Decrease the expression of some structural genes
(D) Encode specific repressor proteins
376. trans-acting factors include
(A) Promoters (B) Repressors
(C) Enhancers (D) Silencers
377. Enhancer elements have all the following features except
(A) They increase gene expression through a promoter
(B) Each enhancer activates a specific promoter
(C) They may be located far away from the promoter
(D) They may be upstream or downstream from the promoter
378. Amplification of dihydrofolate reductase gene may be brought about by
(A) High concentrations of folic acid
(B) Deficiency of folic acid
(C) Low concentration of thymidylate
(D) Amethopterin
379. Proteins which interact with DNA and affect the rate of transcription possess the following structural motif:
(A) Helix-turn-helix motif
(B) Zinc finger motif
(C) Leucine zipper motif
(D) All of these
380. Lac operon is a cluster of genes present in
(A) Human beings (B) E. coli
(C) Lambda phage (D) All of these
381. Lac operon is a cluster of
(A) Three structural genes
(B) Three structural genes and their promoter
(C) A regulatory gene, an operator and a promoter
(D) A regulatory gene, an operator, a promoter and three structural genes
382. The regulatory i gene of lac operon
(A) Is inhibited by lacotse
(B) Is inhibited by its own product, the repressor protein
(C) Forms a regulatory protein which increases the expression of downstream structural genes
(D) Is constitutively expressed
383. RNA polymerase holoenzyme binds to lac operon at the following site:
(A) i gene (B) z gene
(C) Operator locus (D) Promoter region
384. Trancription of z, y and a genes of lac operon is prevented by
(A) Lactose (B) Allo-lactose
(C) Repressor (D) cAMP
385. Transcription of structural genes of lac operon is prevented by binding of the repressor tetramer to
(A) i gene (B) Operator locus
(C) Promoter (D) z gene
386. The enzymes encoded by z, y and a genes of lac operon are inducible, and their inducer is
(A) Lactose
(B) Allo-lactose
(C) Catabolite gene activator protein
(D) All of these
387. Binding of RNA polymerase holoenzyme to the promoter region of lac operon is facilitated by
(A) Catabolite gene activator protein (CAP)
(B) cAMP
(C) CAP-cAMP complex
(D) None of these
388. Lactose or its analogues act as positive regulators of lac operon by
(A) Attaching to i gene and preventing its expression
(B) Increasing the synthesis of catabolite gene activator protein
(C) Attaching to promoter region and facilitating the binding of RNA polymerase holoenzyme
(D) Binding to repressor subunits so that the repressor cannot attach to the operator locus
389. Expression of structural genes of lac operon is affected by all the following except
(A) Lactose or its analogues
(B) Repressor tetramer
(C) cAMP
(D) CAP-cAMP complex
390. The coding sequences in lac operon include
(A) i gene
(B) i gene, operator locus and promoter
(C) z, y and a genes
(D) i, z, y and a genes
391. Mutations can be caused by
(A) Ultraviolet radiation
(B) Ionising radiation
(C) Alkylating agents
(D) All of these
392. Mutations can be caused by
(A) Nitrosamine (B) Dimethyl sulphate
(C) Acridine (D) All of these
393. Nitrosamine can deaminate
(A) Cytosine to form uracil
(B) Adenine to form xanthine
(C) Guanine to form hypoxanthine
(D) All of these
394. Exposure of DNA to ultraviolet radiation can lead to the formation of
(A) Adenine dimers (B) Guanine dimers
(C) Thymine dimers (D) Uracil dimers
395. Damage to DNA caused by ultraviolet radiation can be repaired by
(A) uvr ABC excinuclease
(B) DNA polymerase I
(C) DNA ligase
(D) All of these
396. Xeroderma pigmentosum results from a defect in
(A) uvr ABC excinuclease
(B) DNA polymerase I
(C) DNA ligase
(D) All of these
397. All the following statements about xeroderma pigmentosum are true except
(A) It is a genetic disease
(B) Its inheritance is autosomal dominant
(C) uvr ABC excinuclease is defective in this disease
(D) It results in multiple skin cancers
398. Substitution of an adenine base by guanine in DNA is known as
(A) Transposition (B) Transition
(C) Transversion (D) Frameshift mutation
399. Substitution of a thymine base by adenine in DNA is known as
((A) Transposition (B) Transition
(C) Transversion (D) Frameshift mutation
400. A point mutation results from
(A) Substitution of a base
(B) Insertion of a base
(C) Deletion of a base
(D) All of these
401. Substitution of a base can result in a
(A) Silent mutation (B) Mis-sense mutation
(C) Nonsense mutation (D) All of these
402. A silent mutation is most likely to result from
(A) Substitution of the first base of a codon
(B) Substitution of the third base of a codon
(C) Conversion of a nonsense codon into a sense codon
(D) Conversion of a sense codon into a nonsense codon
403. The effect of a mis-sense mutation can be
(A) Acceptable (B) Partially acceptable
(C) Unacceptable (D) All of these
404. Amino acid sequence of the encoded protein is not changed in
(A) Silent mutation
(B) Acceptable mis-sense mutation
(C) Both (A) and (B)
(D) None of these
405. Haemoglobin S is an example of a/an
(A) Silent mutation
(B) Acceptable mis-sense mutation
(C) Unacceptable mis-sense mutation
(D) Partially acceptable mis-sense mutation
406. If the codon UAC on mRNA changes into UAG as a result of a base substitution in DNA, it will result in
(A) Silent mutation
(B) Acceptable mis-sense mutation
(C) Nonsense mutation
(D) Frameshift mutation
407. Insertion of a base in a gene can cause
(A) Change in reading frame
(B) Garbled amino acid sequence in the encoded protein
(C) Premature termination of translation
(D) All of these
408. A frameshift mutation changes the reading frame because the genetic code
(A) Is degenerate
(B) Is overlapping
(C) Has no punctuations
(D) Is universal
409. Suppressor mutations occur in
(A) Structural genes (B) Promoter regions
(C) Silencer elements (D) Anticodons of tRNA
410. Suppressor tRNAs can neutralize the effects of mutations in
(A) Structural genes (B) Promoter regions
(C) Enhancer elements (D) All of these
411. Mutations in promoter regions of genes can cause
(A) Premature termination of translation
(B) Change in reading frame of downstream structural gene
(C) Decreased efficiency of transcription
(D) All of these
412. Mitochondrial protein synthesis is inhibited by
(A) Cycloheximide (B) Chloramphenicol
(C) Diptheria toxin (D) None of these
413. All of the following statements about puromycin are true except
(A) It is an alanyl tRNA analogue
(B) It causes premature termination of protein synthesis
(C) It inhibits protein synthesis in prokaryotes
(D) It inhibits protein synthesis in eukaryotes
414. Leucine zipper motif is seen in some helical proteins when leucine residues appear at every
(A) 3rd position (B) 5th position
(C) 7th position (D) 9th position
415. Zinc finger motif is formed in some proteins by binding of zinc to
(A) Two cysteine residues
(B) Two histidine residues
(C) Two arginine residues
(D) Two cysteine and two histidine residues or two pairs of two cysteine residues each
416. Restriction endonucleases are present in
(A) Viruses (B) Bacteria
(C) Eukaryotes (D) All of these
417. Restriction endonucleases split
(A) RNA
(B) Single stranded DNA
(C) Double stranded DNA
(D) DNA-RNA hybrids
418. Restriction endonucleases can recognise
(A) Palindromic sequences
(B) Chimeric DNA
(C) DNA-RNA hybrids
(D) Homopolymer sequences
419. All of the following statements about restriction endonucleases are true except:
(A) They are present in bacteria
(B) They act on double stranded DNA
(C) They recognize palindromic sequences
(D) They always produce sticky ends
420. Which of the following is a palindromic sequence
(A) Southern blotting (B) Northern blotting
(C) Both (A) and (B) (D) None of these
427. An antibody probe is used in
(A) Southern blotting (B) Northern blotting
(C) Western blotting (D) None of these
428. A particular protein in a mixture can be detected by
(A)
(B)
(C)
(D)
5 ATGCAG 3
3 TACGTC 5
5 CGAAGC 3
3 GCTTCG 5
A) Southern blotting (B) Northern blotting
(C) Western blotting (D) None of these
429. The first protein synthesized by recom- binant DNA technology was
421. In sticky ends produced by restriction endonucleases
(A) The 2 strands of DNA are joined to each other
(B) The DNA strands stick to the restriction endonuclease
(C) The ends of a double stranded fragment are overlapping
(D) The ends of a double stranded fragment are non overlapping
422. All of the following may be used as ex- pression vectors except
(A) Plasmid (B) Bacteriophage
(C) Baculovirus (D) E. coli
423. A plasmid is a
(A) Single stranded linear DNA
(B) Single stranded circular DNA
(C) Double stranded linear DNA
(D) Double stranded circular DNA
424. Fragments of DNA can be identified by the technique of
(A) Western blotting (B) Eastern blotting
(C) Northern blotting (D) Southern blotting
425. A particular RNA in a mixture can be identified by
(A) Western blotting (B) Eastern blotting
(C) Northern blotting (D) Southern blotting
426. A radioactive isotope labeled cDNA probe is used in
(A) Streptokinase
(B) Human growth hormone
(C) Tissue plasminogen activator
(D) Human insulin
430. For production of eukaryotic protein by recombinant DNA technology in bacteria, the template used is
(A) Eukaryotic gene (B) hnRNA
(C) mRNA (D) All of these
431. Monoclonal antibodies are prepared by cloning
(A) Myeloma cells (B) Hybridoma cells
(C) T-Lymphocytes (D) B-Lymphocytes
432. Myeloma cells are lacking in
(A) TMP synthetase
(B) Formyl transferase
(C) HGPRT
(D) All of these
433. Hybridoma cells are selected by culturing them in a medium containing
(A) Adenine, guanine, cytosine and thymine
(B) Adenine, guanine, cytosine and uracil
(C) Hypoxanthine, aminopterin and thymine
(D) Hypoxanthine, aminopterin and thymidine
434. Myeloma cells and lymphocytes can be fused by using
(A) Calcium chloride (B) Ethidium bromide
(C) Polyethylene glycol (D) DNA polymerase
435. Trials for gene therapy in human beings were first carried out, with considerable success, in a genetic disease called
(A) Cystic fibrosis
(B) Thalassemia
(C) Adenosine deaminase deficiency
(D) Lesch-Nyhan syndrome
436. Chimeric DNA
(A) Is found in bacteriophages
(B) Contains unrelated genes
(C) Has no restriction sites
(D) Is palindromic
437. Which of the following may be used as a cloning vector?
(A) Prokaryotic plasmid (B) Lambda phage
(C) Cosmid (D) All of these
438. The plasmid pBR322 has
(A) Ampicillin resistance gene
(B) Tetracycline resistance gene
(C) Both (A) and (B)
(D) None of these
439. Lambda phage can be used to clone DNA fragments of the size
(A) Upto 3 kilobases (B) Upto 20 kilobases
(C) Upto 45 kilobases (D) Upto 1,000 kilobases
440. DNA fragments upto 45 kilobases in size can be cloned in
(A) Bacterial plasmids
(B) Lambda phage
(C) Cosmids
(D) Yeast artificial chromosomes
441. A cosmid is a
(A) Large bacterial plasmid
(B) Viral plasmid
(C) Hybrid of plasmid and phage
(D) Yeast plasmid
442. Polymerase chain reaction can rapidly amplify DNA sequences of the size
(A) Upto 10 kilobases (B) Upto 45 kilobases
(C) Upto 100 kilobases(D) Upto 1,000 kilobases
443. The DNA polymerase commonly used in polymerase chain reaction is obtained from
(A) E. coli (B) Yeast
(C) T.aquaticus (D) Eukaryotes
444. Base sequence of DNA can be determined by
(A) Maxam-Gilbert method
(B) Sanger’s dideoxy method
(C) Both (A) and (B)
(D) None of these
445. From a DNA-RNA hybrid, DNA can be obtained by addition of
(A) DNA B protein and ATP
(B) Helicase and ATP
(C) DNA topoisomerase I
(D) Alkali
446. Optimum temperature of DNA polymerase of T. aquaticus is
(A) 30°C (B) 37°C
(C) 54°C (D) 72°C
447. In addition to Taq polymerase, poly- merase chain reaction requires all of the following except
(A) A template DNA
(B) Deoxyribonucleoside triphosphates
(C) Primers
(D) Primase
448. DNA polymerase of T. aquaticus is preferred to that of E. coli in PCR because
(A) It replicates DNA more efficiently
(B) It doesn’t require primers
(C) It is not denatured at the melting temperature of DNA
(D) It doesn’t cause errors in replication
449. Twenty cycles of PCR can amplify DNA:
(A) 220 fold (B) 202 fold
(C) 20 x 2 fold (D) 20 fold
450. Transgenic animals may be prepared by introducing a foreign gene into
(A) Somatic cells of young animals
(B) Testes and ovaries of animals
(C) A viral vector and infecting the animals with the viral vector
(D) Fertilised egg and implanting the egg into a foster mother
451. Yeast artificial chromosome can be used to amplify DNA sequences of the size
(A) Upto 10 kb (B) Upto 45 kb
(C) Upto 100 kb (D) Upto 1,000 kb
452. DNA finger printing is based on the presence in DNA of
(A) Constant number of tandem repeats
(B) Varibale number of tandem repeats
(C) Non-repititive sequences in each DNA
(D) Introns in eukaryotic DNA
453. All the following statements about restriction fragment length polymor- phism are true except
(A) It results from mutations in restriction sites
(B) Mutations in restriction sites can occur in coding or non-coding regions of DNA
(C) It is inherited in Mendelian fashion
(D) It can be used to diagnose any genetic disease
454. Inborn errors of urea cycle can cause all the following except
(A) Vomiting (B) Ataxia
(C) Renal failure (D) Mental retardation
455. Hyperammonaemia type I results from congenital absence of
(A) Glutamate dehydrogenase
(B) Carbamoyl phosphate synthetase
(C) Ornithine transcarbamoylase
(D) None of these
456. Congenital deficiency of ornithine transcarbamoylase causes
(A) Hyperammonaemia type I
(B) Hyperammonaemia type II
(C) Hyperornithinaemia
(D) Citrullinaemia
457. A ketogenic amino acid among the fol- lowing is
(A) Leucine (B) Serine
(C) Threonine (D) Proline
458. Carbon skeleton of the following amino acid can serve as a substance for gluconeogenesis
(A) Cysteine (B) Aspartate
(C) Glutamate (D) All of these
459. N-Formiminoglutamate is a metabolite of
(A) Glutamate (B) Histidine
(C) Tryptophan (D) Methionine
460. Methylmalonyl CoA is a metabolite of
(A) Valine (B) Leucine
(C) Isoleucine (D) All of these
461. Homogentisic acid is formed from
(A) Homoserine (B) Homocysteine
(C) Tyrosine (D) Tryptophan
462. Maple syrup urine disease results from absence or serve deficiency of
(A) Homogentisate oxidase
(B) Phenylalanine hydroxylase
(C) Branched chain amino acid transaminase
(D) None of these
463. Which of the following is present as a marker in lysosomal enzymes to direct them to their destination?
(A) Glucose-6-phosphate
(B) Mannose-6-phosphate
(C) Galactose-6-phosphate
(D) N-Acetyl neuraminic acid
464. Marfan’s syndrome results from a mutation in the gene coding:
(A) Collagen (B) Elastin
(C) Fibrillin (D) Keratin
465. All the following statements about fibronectin are true except
(A) It is glycoprotein
(B) It is a triple helix
(C) It is present in extra cellular matrix
(D) It binds with integrin receptors of cell
466. Fibronectin has binding sites for all of the following except
(A) Glycophorin (B) Collagen
(C) Heparin (D) Integrin receptor
467. Fibronectin is involved in
(A) Cell adhension (B) Cell movement
(C) Both (A) and (B) (D) None of these
468. Glycoproteins are marked for destruction by removal of their
(A) Oligosaccharide prosthetic group
(B) Sialic acid residues
(C) Mannose residues
(D) N-terminal amino acids
469. Glycophorin is present in cell membranes of
(A) Erythrocytes (B) Platelets
(C) Neutrophils (D) Liver
470. Selectins are proteins that can recognise specific
(A) Carbohydrates (B) Lipids
(C) Amino acids (D) Nucleotides
471. Hunter’s syndrome results from absence of
(A) Hexosaminidase A
(B) Iduronate sulphatase
(C) Neuraminidase
(D) Arylsulphatase B
472. A cancer cell is characterized by
(A) Uncontrolled cell division
(B) Invasion of neighbouring cells
(C) Spread to distant sites
(D) All of these
473. If DNA of a cancer cell is introduced into a normal cell, the recipient cell
(A) Destroys the DNA
(B) Loses its ability to divide
(C) Dies
(D) Changes into a cancer cell
474. A normal cell can be transformed into a cancer cell by all of the following except
(A) Ionising radiation
(B) Mutagenic chemicals
(C) Oncogenic bacteria
(D) Some viruses
475. Proto-oncogens are present in
(A) Oncoviruses
(B) Cancer cells
(C) Healthy human cells
(D) Prokaryotes
476. All the following statements about proto- oncogenes are true except
(A) They are present in human beings
(B) They are present in healthy cells
(C) Proteins encoded by them are essential
(D) They are expressed only when a healthy cell has been transformed into a cancer cell
477. Various oncogens may encode all of the following except:
(A) Carcinogens
(B) Growth factors
(C) Receptors for growth factors
(D) Signal transducers for growth factors
478. Ras proto-oncogene is converted into oncogene by
(A) A point mutation
(B) Chromosomal translocation
(C) Insertion of a viral promoter upstream of the gene
(D) Gene amplification
479. Ras proto-oncogene encodes
(A) Epidermal growth factor (EGF)
(B) Receptor for EGF
(C) Signal transducer for EGF
(D) Nuclear transcription factor
480. P 53 gene:
(A) A proto-oncogene
(B) An oncogene
(C) A tumour suppressor gene
(D) None of these
481. Retinoblastoma can result from a muta- tion in
(A) ras proto-oncogene
(B) erbB proto-oncogene
(C) p 53 gene
(D) RB 1 gene
482 All the following statements about retino blastoma are true except
(A) At least two mutations are required for its development
(B) One mutation can be inherited from a parent
(C) Children who have inherited one mutation develop retinoblastoma at a younger age
(D) RB 1 gene promotes the development of retinoblastoma
483. Ames assay is a rapid method for detection of
(A) Oncoviruses
(B) Retroviuses
(C) Chemical carcinogens
(D) Typhoid
484. Amplification of dihydrofolate reductase gene in a cancer cell makes the cell
(A) Susceptible to folic acid deficiency
(B) Less malignant
(C) Resistant to amethopterin therapy
(D) Responsive to amethopterin therapy
485. Conversion of a procarcinogen into a carcinogen often requires
(A) Proteolysis
(B) Microsomal hydroxylation
(C) Exposure to ultraviolet radiation
(D) Exposure to X-rays
486. The only correct statement about onco- viruses is
(A) All the oncoviruses are RNA viruses
(B) Reverse transcriptase is present in all oncoviruses
(C) Viral oncogenes are identical to human protooncogens
(D) Both DNA and RNA viruses can be oncoviruses
487. RB 1 gene is
(A) A tumour suppressor gene
(B) Oncogene
(C) Proto-oncogene
(D) Activated proto-oncogene
488. Cancer cells may become resistant to amethopterin by
(A) Developing mechanisms to destroy amethopterin
(B) Amplification of dihydrofolate reducatse gene
(C) Mutation in the dihydrofolate reductase gene so that the enzyme is no longer inhibited by amethopterin
(D) Developing alternate pathway of thymidylate synthesis
489. The major source of NH3 produced by the kidney is
(A) Leucine (B) Glycine
(C) Alanine (D) Glutamine
490. Which of these methyl donors is not a quanternary ammonium compound?
(A) Methionine (B) Choline
(C) Betain (D) Betainaldehyde
491. L-glutamic acid is subjected to oxidative deaminition by
(A) L-amino acid dehydrogenase
(B) L-glutamate dehydrogenase
(C) Glutaminase
(D) Glutamine synthetase
492. A prokaryotic ribosome is made up of
sub units.
(A) 20 S and 50S (B) 30S and 50S
(C) 30S and 60S (D) 20S and 50S
493. AN Eukaryotic ribosome is made up of
sub unit.
(A) 40S and 60S (B) 40S and 50S
(C) 40S and 80S (D) 60S and 80S
494. GTP is not required for
(A) Capping L of mRNA
(B) Fusion of 40S and 60S of ribosome
(C) Accommodation of tRNA amino acid
(D) Formation of tRNA amino acid complex
495. The antibiotic which inhibits DNA dependent RNA polymerase is
(A) Mitomycin C (B) Actinomycin d
(C) Streptomycin (D) Puromycin
496. The antibiotic which cleaves DNA is
(A) Actinomycin d (B) Streptomycin
(C) Puromycin (D) Mitomycin C
497. The antibiotic which has a structure similar to the amino acyl end of tRNA tyrosine is
(A) Actinomycin d (B) Streptomycin
(C) Puromycin (D) Mitomycin c
498. ATP is required for
(A) Fusion of 40S and 60S of ribosome
(B) Accommodation tRNA amino acid in a site of ribosome
(C) Movement of ribosome along mRNA
(D) formation of tRNA amino acid complex
499. What is the subcellular site for the bio- synthesis of proteins?
(A) Chromosomes (B) Lymosomes
(C) Ribosomes (D) Centrosomes
500. An animal is in negative nitrogen balance when
(A) Intake exceeds output
(B) New tissue is being synthesized
(C) Output exceeds intake
(D) Intake is equal to output
501. When NH3 is perfused through a dog’s liver ______ is formed, while is
formed in the birds liver.
(A) Urea, Uric acid (B) Urea, allantoin
(C) Uric acid, creatinine
(D) Uric acid, Urea
502. Aspartate amino transferase uses the following for transamination:
(A) Glutamic acid and pyruvic acid
(B) Glutamic acid and oxaloacetic acid
(C) Aspartic acid and pyruvic acid
(D) aspartic acid and keto adipic acid
503. Which among the following compounds is not a protein?
(A) Insulin (B) Hheparin
(C) Mucin (D) Pepsin
504. Almost all the urea is formed in this tissue:
(A) Kidney (B) Urethra
(C) Uterus (D) Liver
505. A polyribosome will have about individual ribosomes.
(A) 20 (B) 10
(C) 5 (D) 2
506. Progressive transmethylation of ethano- lamine gives
(A) Creatinine
(B) Choline
(C) Methionine
(D) N-methyl nicotinamide
507. Genetic information originates from
(A) Cistron of DNA
(B) Codons of mRNA
(C) Anticodons of tRNA
(D) Histones of nucleoproteins
508. The genetic code operates through
(A) The protein moiety of DNA
(B) Cistrom of DNA
(C) Nucleotide sequence of m RNA
(D) The anticodons of tRNA
509. DNA synthesis in laboratory was first achieved by
(A) Watson and crick (B) Khorana
(C) A.Kornberg (D) Ochoa
510. Among the different types of RNA, which one has the highest M.W.?
(A) mRNA (B) rRNA
(C) yeast RNA (D) tRNA
511. From DNA the genetic message is trans- cribed into this compound:
(A) Protein (B) mRNA
(C) tRNA (D) rRNA
512. This compound has a double helical structure.
(A) Deoxyribonucleic acid
(B) RNA
(C) Flavine-adevine dinucleotide
(D) Nicotinamide adamine dinucleotide
513. The structural stability of the double helix of DNA is as cribbed largely to
(A) Hydrogen bonding between adjacent purine bases
(B) Hydrophobic bonding between staked purine and pyrinuidine nuclei
(C) Hydrogen bonding between adjacent pyrimidine bases
(E) Hydrogen bonding between purine and pyrimidine bases
514. Which of the following statements about nucleic acid is most correct?
(A) Both pentose nucleic acid and deoxypentose nucleic acid contain the same pyrimidines
(B) Both pentose nucleic acid and deoxypentose nucleic acid and deoxypentose nucleic acid Contain the same purines
(C) RNA contains cytosine and thymine
(D) DNA and RNA are hydrolysed by weak alkali
515. Acid hydrolysis of ribonucleic acid would yield the following major products:
(A) d- deoxyribose, cytosine, adenine
(B) d-ribose, thymine, Guanine
(C) d-ribose, cytosine, uracil, thymine
(D) d-ribose, uracil, adenine, guanine, cytosine
516. RNA does not contain
(A) adenine (B) OH methyl cytosine
(C) d-ribose (D) Uracil
517. Which of the following statements is correct?
(A) a nucleo protein usually contain deoxy sugars of the hexose type
(B) Nucleoproteins are usually absent from the cytoplasm
(C) Nucleoproteins usually are present in the nucleus only
(D) Nucleoproteins usually occur in the nucleus and cytoplasm
518. Whcih of the following compound is present in RNA but absent from DNA?
(A) Thymine (B) Cytosine
(C) Uracil (D) Guanine
519. Nucleic acids can be detected by means of their absorption maxima near 260 nm. Their absorption in this range is due to
(A) Proteins
(B) Purines and pyrimidines
(C) Ribose
(D) Deoxyribose
520. Which of the following contains a deoxy sugar?
(A) RNA (B) DNA
(C) ATP (D) UTP
521. DNA is
(A) Usually present in tissues as a nucleo protein and cannot be separated from its protein component
(B) A long chain polymer in which the internucleotide linkages are of the diester type between C-3’ and C-5’
(C) Different from RNA since in the latter the internucleotide linkages are between C-2’ and C-5’
(D) Hydrolyzed by weal alkali (pH9 to 100°C)
522. Nobody is the name given to
(A) Ribosome (B) Microsome
(C) Centrosome (D) Nucleosome
523. Transcription is the formation of
(A) DNA from a parent DNA
(B) mRNA from a parent mRNA
(C) pre mRNA from DNA
(D) protein through mRNA
524. Translation is the formation of
(A) DNA from DNA
(B) mRNA from DNA
(C) Protein through mRNA
(D) mRNA from pre mRNA
525. Sigma and Rho factors are required for
(A) Replication (B) Transcription
(C) Translation (D) Polymerisation
526. The genine of ×174 bacteriophage is interesting in that if contains
(A) No DNA
(B) DNA with uracil
(C) Single stranded DNA
(D) Triple standard DNA
527. Okasaki fragments are small bits of
(A) RNA
(B) DNA
(C) DNA with RNA heads
(D) RNA with DNA heads
528. In addition to the DNA of nucleus there DNA is
(A) Mitochondrian
(B) Endoplasmic reticulum
(C) Golgi apparatus
(D) Plasma membrane
529. The mitochondrial DNA is
(A) Like the nuclear DNA in structure
(B) Single stranded, linear
(C) Double stranded, circular
(D) Single stranded, circular
530. A synthetic RNA having the sequence of UUUUUU (Poly U) will give a protein having poly .
(A) Alamine (B) Phenyl alanine
(C) Glycine (D) Methionine
531. Lac operon of E. coli contains is continuity.
(A) Regulator and operator genes only
(B) Operator and structural genes only
(C) Regular and structural genes only
(D) Regulator, operator and structural genes
532. A mRNA of eukaryotes can code for
(A) Only one polypeptide
(B) Two polypeptides
(C) Three polypeptides
(D) Five polypeptides
533. mRNA of prokaryotes can code for
(A) More than one polypeptide
(B) Only one polypeptide
(C) Many exons and introns
(D) Introns only
534. DNA directed RNA polymerase is
(A) Replicase
(B) Transcriptase
(C) Reverse transcriptase
(D) Polymerase III
535. RNA directed DNA polymerase is
(A) Replicase
(B) Transcriptase
(C) Reversetranscriptase
(D) Polymerase–III
Q536. RNA synthesis requires
(A) RNA primer (B) RNA template
(C) DNA template (D) DNA primer
537. The mRNA ready for protein synthesis has the cap.
(A) ATP (B) CTP
(C) GTP (D) UTP
538. mRNA ready for protein synthesis has the poly toil.
(A) G (B) A
(C) U (D) C
539. The codon for phenyl Alanine is
(A) AAA (B) CCC
(C) GGG (D) UUU
540. Blue print for genetic information residues in
(A) mRNA (B) tRNA
(C) rRNA (D) DNA
541. Genes are
(A) RNA (B) DNA
(C) lipoproteins and (D) Chromoproteins
542. Codons are in
(A) DNA (B) mRNA
(C) tRNA (D) rRNA
543. The genetic code operates via
(A) The protein moiety of DNA
(B) The base sequences of DNA
(C) The nucleotide sequence of mRNA
(D) The base sequence of tRNA
544. Urine bases with methyl substituents occurring in plants are
(A) Caffeine (B) Theophylline
(C) Theobromine (D) All of these
545. Genetic information in human beings is stored in
(A) DNA (B) RNA
(C) Both (A) and (B) (D) None of these
546. All following are naturally occurring nucleotides except
(A) Cyclic AMP
(B) ATP
(C) DNA
(D) Inosine monophosphate
547. If the amino group and a carboxylic group of the amino acid are attached to same carbon atom, the amino acid is called as
(A) Alpha (B) Beta
(C) Gamma (D) Epsilon
548. If in a nucleic acid there are more than 8000 nucleotides it is most likely
(A) RNA (B) DNA
(C) Both (A) and (B) (D) None of these
549. Genetic information in human beings is stored in
(A) RNA (B) DNA
(C) Both (A) and (B) (D) mRNA
550. In RNA, apart from ribose and phosphate, all following are present except
(A) Adenine (B) Guanine
(C) Thymine (D) Cytosine
551. Which of the following gives a positive Ninhydrin test?
(A) Reducing sugar (B) Triglycerides
(C) -amino acids (D) Phospholipids
552. A Gene is
(A) A single protein molecule
(B) A group of chromosomes
(C) An instruction for making a protein molecule
(D) A bit of DNA molecule
553. In DNA, genetic information is located in
(A) Purine bases
(B) Pyrimidine bases
(C) Purine and pyrimidine bases
(D) sugar
554. Which one of the following is not a constituent of RNA?
(A) Deoxyribose (B) Uracil
(C) Adenine (D) Thymine
555. Which of the following are nucleo proteins?
(A) Protamines
(B) Histones
(C) Deoxy and Ribo nucleo proteins
(D) All of these
556. The total RNA in cell tRNA constitutes
(A) 1–10% (B) 10–20%
(C) 30–50% (D) 50–80%
557. Unit of genetic information:
(A) DNA (B) RNA
(C) Cistron (D) None of these
558. Anticodon sequence are seen in
(A) tRNA and transcribed DNA strand
(B) tRNA and complementary DNA strand
(C) mRNA
(D) mRNA and complementary DNA strand
559. cAMD is destroyed by
(A) Adenylate cyclase
(B) Phosphodiesterase
(C) Synthetase phosphatase
(D) Synthetase kinase
560. Restriction enzymes have been found in
(A) Humans (B) Birds
(C) Bacteria (D) Bacteriophase
561. Sulphur is not present in
(A) Thiamine (B) Lipic acid
(C) Thymine (D) Biotin
562. Which one of the following binds to specific nucleotide sequences?
(A) RNA polymerase (B) Repressor
(C) Inducer (D) Restriction
563. Using written convertion which one of the following sequences is complimentary to TGGCAGCCT ?
(A) ACC GTC GGA (B) ACC GUC GGA
(C) AGG CTG CCA (D) TGG CTC GGA
564. Ribosomes similar to those of bacterial found in
(A) Plant nucei
(B) Cardiac muscle cytoplasm
(C) Liver endoplasmic reticulum
(D) Neuronal cytoplasm
565 The mechanism of synthesis of DNA and RNA are similar in all the following ways except
(A) They involve release of pyrophosphate from each nucleotide added
(B) They require activated nucleotide precursor and Mg2+
(C) The direction of synthesis is 5’ 3’
(D) They require a primer
566. Template-directed DNA synthesis occurs in all the following except
(A) The replication fork
(B) Polymerase chain reaction
(C) Growth of RNA tumor viruses
(D) Expression of oneogenes
567. Which one of the following statements correctly describes eukaryotic DNA?
(A) They involve release of pyrophosphate from each nucleotide precussor and Mg2+
(B) The direction of synthesis is
(C) They require a primer 5’ 3’
(D) None of these
568. Which one of the following causes frame shift mutation?
(A) Transition
(B) Transversion
(C) Deletion
(D) Substitution of purine to pyrimidine
569. Catabolism of thymidylate gives
(A) -alanine
(B) -alanine
(C) -aminoisobutyrate
(D) -aminoisobutyrate
570. Glycine gives atoms of purine.
(A) C2, C3 (B) C4, C5 and N7
(C) C4, C5 and N9 (D) C4, C6 and N7
571. A common substrate of HGPRTase, APRTase and PRPP glutamyl amidotransferase is
(A) Ribose 5 phosphate
(B) Phosphoribosyl pyrophosphate
(C) Hypoxanthine
(D) Adenosine
572. Carbon 6-of purine skeleton comes from
(A) Atmospheric CO2
(B) 1 carbon carried by folate
(C) Betoine
(D) Methionine
573. Uric acid is the catabolic end product of
(A) Porphyrine (B) Purines
(C) Pyrimidines (D) Pyridoxine
574. Diphenylamine method is employed in the quantitation of
(A) Nucleic acid (B) RNA
(C) DNA (D) Proteins
575. Orcinol method is employed in the quanti- tation of
(A) Nucleic acid (B) DNA
(C) RNA (D) Proteins
576. Nucleic acid show strong absorption at one of the wavelength:
(A) 280 nm (B) 220 nm
(C) 360 nm (D) 260 nm
577. tRNA has
(A) Clover leaf structure
(B) anticodon arm
(C) poly ‘A’ tay 3’
(D) Cap at 5’ end
578. Which one of the following contributes nitrogen atoms to both purine and pyrimidine rings?
(A) Aspartate
(B) Carbanoyl phosphate
(C) Carbondioxide
(D) Tetrahydrofolate
579. The four nitrogen atoms of purines are derived from
(A) Urea and NH3
(B) NH3, Glycine and Glutamate
(C) NH3, Asparate and Glutamate
(D) Aspartate, Glutamine and Glycine
580. A drug which prevents uric acid synthesis by inhibiting the enzyme Xanthine oxi- dase is
(A) Aspirin (B) Allopurinal
(C) Colchicine (D) Phenyl benzoate
581. Glycine contributes to the following C and N of purine nucleus:
(A) C1, C2 and N7 (B) C8, C8 and N9
(C) C4, C5 and N7 (D) C4, C5 and N9
582. Insoinic acid is the biological precursor of
(A) Cytosine and Uric acid
(B) Adenylve acid and Glucine floc acid
(C) Orotic acid and Uridylic acid
(D) Adenosine acid Thymidine
583. The probable metabolic defect in gents is
(A) A defect in excretion of uric acid by kidney
(B) An overproduction of pyrimidines
(C) An overproduction of uric acid
(D) Rise in calcium leading to deposition of calcium urate
584. In humans, the principal break down product of purines is
(A) NH3 (B) Allantin
(C) Alanine (D) Uric acid
585. A key substance in the committed step of pyrimidines biosynthesis is
(A) Ribose-5-phosphate
(B) Carbamoyl phosphate
(C) ATP
(D) Glutamine
586. In humans, the principal metabolic product of pyrimidines is
(A) Uric acid (B) Allantoin
(C) Hypoxanthine (D) -alanine
587. In most mammals, except primates, uric acid is metabolized by
(A) Oxidation to allantoin
(B) Reduction to NH3
(C) Hydrolysis to allantoin
(D) Hydrolysis to NH3
588. Two nitrogen of the pyrimidines ring are obtained from
(A) Glutamine and Carbamoyl-p
(B) Asparate and Carbamoyl-p
(C) Glutamate and NH3
(D) Glutamine and NH3
589. All are true about lesch-nyhan syndrome except
(A) Produces self-mutilation
(B) Genetic deficiency of the enzyme
(C) Elevated levels of uric acid in blood
(D) Inheritance is autosomal recessive
590. Synthesis of GMP and IMP requires the following:
(A) NH3 NAD+, ATP
(B) Glutamine, NAD+, ATP
(C) NH3, GTP, NADP+
(D) Glutamine, GTP, NADP+
591. Which pathway is correct for catabolism of purines to form uric acid?
(A) GuanylateAdenylateXanthinehypo- xanthineUric acid
(B) GuanylateinosinateXanthinehypo- xanthineUric acid
(C) AdenylateInosinateXanthine hypo- xanthineUric acid
(D) AdenylateInosinatehypoxanthine XanthineUric acid
592. Polysemes do not contain
(A) Protein (B) DNA
(C) mRNA (D) rRNA
593. The formation of a peptide bond during the elongation step of protein synthesis results in the splitting of how many high energy bonds?
(A) 1 (B) 2
(C) 3 (D) 4
594. Translocase is an enzyme required in the process of
(A) DNA replication
(B) RNA synthesis
(C) Initiation of protein synthesis
(D) Elongation of peptides
595. Nonsense codons bring about
(A) Amino acid activation
(B) Initiation of protein synthesis
(C) Termination of protein synthesis
(D) Elongation of polypeptide chains
596. Which of the following genes of the E.coli “Lac operon” codes for a constitutive protein?
(A) The ‘a’ gene (B) The ‘i’ gene
(C) The ‘c’ gene (D) The ‘z’ gene
597. In the process of transcription, the flow of genetic information is from
(A) DNA to DNA (B) DNA to protein
(C) RNA to protein (D) DNA to RNA
598. The anticodon region is an important part of the structure of
(A) rRNA (B) tRNA
(C) mRNA (D) hrRNA
599. The region of the Lac operon which must be free from structural gene transcription to occur is
(A) The operator locus
(B) The promoter site
(C) The ‘a’ gene
(D) The ‘i’ gene
600. Another name for reverse transcriptase is
(A) DNA dependent DNA polymerase
(B) DNA dependent RNA polymerase
(C) RNA dependent DNA polymerase
(D) RNA dependent RNA polymerase
601. In the ’lac operon’ concept, which of the following is a protein?
(A) Operator (B) Repressor
(C) Inducer (D) Vector
602. Degeneracy of the genetic code denotes the existence of
(A) Base triplets that do not code for any amino acids
(B) Codons consisting of only two bases
(C) Codons that include one or more of the unusual bases
(D) Multiple codons for a single amino acid
603. The normal function of restriction endonuc- leases is to
(A) Excise introns from hrRNA
(B) Polymerize nucleotides to form RNA
(C) Remove primer from okazaki fragments
(D) Protect bacteria from foreign DNA
604. In contrast to Eukaryotic mRNA, pro- karyotic mRNA is characterized by
(A) Having 7-methyl guanosine triphosphate at the 5’ end
(B) Being polycystronic
(C) Being only monocystronic
(D) Being synthesized with introns
605. DNA ligase of E. coli requires which of the following co-factors?
(A) FAD (B) NAD+
(C) NADP+ (D) NADH
606. Which of the following is transcribed during repression?
(A) Structural gene (B) Promoter gene
(C) Regulator gene (D) Operator gene
607. mRNA is complementary copy of
(A) 5-3 strand of DNA+
(B) 3-5 strand of DNA
(C) Antisense strand of DNA
(D) tRNA
608. Synthesis of RNA molecule is terminated by a signal which is recognised by
(A) -factor (B) -factor
(C) -factor (D)
609. The binding of prokaryotic DNA depen- dent RNA polymerase to promoter sits of genes is inhibited by the antibiotic:
(A) Streptomycin (B) Rifamcin
(C) Aueromycin (D) Puromycin
610. In E. coli the chain initiating amino acid in protein synthesis is
(A) N-formyl methionine(B) Methionine
(C) Serine (D) Cysteine
611. Amanitin the mushroom poison inhibits
(A) Glycoprotein synthesis
(B) ATP synthesis
(C) DNA synthesis
(D) mRNA synthesis
612. How many high-energy phosphate bond equivalents are required for amino acid activation in protein synthesis?
(A) One (B) Two
(C) Three (D) Four
613. Translation results in the formation of
(A) mRNA (B) tRNA
(C) rRNA (D) A protein molecule
614. Elongation of a peptide chain involves all the following except
(A) mRNA (B) GTP
(C) Formyl-Met-tRNA (D) Tu, TS and G factors
615. The ‘rho’ () factor is involved
(A) To increase the rate of RNA synthesis
(B) In binding catabolite repressor to the promoter region
(C) In proper termination of transcription
(D) To allow proper initiation of transcriptide
616. In the biosynthesis of c-DNA, the joining enzyme ligase requires
(A) GTP (B) ATP
(C) CTP (D) UTP
617. Which one of the following binds to specific nucleotide sequences that are
upstream and most distant from the start site?
(A) RNA polymerase (B) Repressor
(C) Inducer (D) Restriction
618. Using written convention which one of the following sequences is complimentary to TGGCAGCCT?
(A) ACCGTCGGA (B) ACCGUCGGA
(C) AGGCTGCCA (D) TGGCTCGGA
619. Ribosomes similar to those of bacteria found in
(A) Plant nuclei
(B) Cardiac muscle cytoplasm
(C) Liver endoplasmic reticulum
(D) Neuronal cytoplasm
620. The mechanism of synthesis of DNA and RNA are similar to all the following ways except
(A) They involve release of pyrophosphate from each nucleotide added
(B) They require activated nucleotide precursor and Mg2+
(C) The direction of synthesis is
(D) They require a primer
621. Template-directed DNA synthesis occurs in all the following except
(A) The replication fork
(B) Polymerase chain reaction
(C) Growth of RNA tumor viruses
(D) Expression of oncogenes
