Genetics MCQs Part 8

1) Which of the following are polymerized to form protein?
a) Amino acids
b) Muramic acid
c) Carbohydrates
d) Nucleic acid

2) Protein synthesis in an animal cell takes place
a) Only in the cytoplasm
b) In the nucleolus as well as in cytoplasm
c) In the cytoplasm as well as mitochondria
d) Only on the ribosome attached to a nucleon

3) RNA is involved in the biosynthesis of
a) Starch
b) Nucleic acid
c) Vitamins
d) Proteins

4) Information flow in living organisms occurs in the following sequence:

5) The "central dogma" of molecular biology
a) States that DNA is the template for all RNA production
b) States that DNA is a template only for DNA replication
c) States that translation precedes transcription
d) Pertains only to prokaryotes because humans are unique

6) Information transfer from RNA to DNA is
a) Transcription
b) Translation
c) Replication
d) Reverse transcription

7) Synthesis of DNA over RNA template occurs in
a) Reovirus
b) Rous sarcoma virus
c) TMV

8) Through which enzyme can RNA give rise to DNA?
a) Restriction enzyme
b) DNA polymerase
c) RNA polymerase
d) Reverse transcriptase

9) DNA is transcribed by some viral RNA using the enzyme
a) DNA polymerase
b) Reverse transcriptase
c) Endonuclease
d) Ligase

10) Reverse transcriptase is
a) RNA dependent RNA polymerase
b) DNA dependent RNA polymerase
c) DNA dependent DNA polymerase
d) RNA dependent DNA polymerase

11) Genes bring about growth and differentiation
in an organism through regulation of

a) Translocation
b) Transformation
c) Transduction and translation
d) Transcription and translation

12) The process involved in the RNA formation on the DNA template

a) Translocation
b) Transformation
c) Transduction
d) Transcription

13) Transcription of DNA is aided by
a) RNA polymerase
b) DNA polymerase
c) Exonuclease
d) Recombinase

14) The first step in the biosynthesis of a polypeptide is catalysed

a) Initiation factors (Ifs)
b) Aminoacyl-t-RNA synthetase
c) Peptidyl transferse
d) Terminal transferase

15) The enzyme aminoacyl synthetase facilitates the step of
a) Joining two neighbouring amino acids on ribosomes
b) Adoption of amino acid by a t-RNA molecule of its type
c) Insertion of aminoacyl-t-RNA into the ribosomes sites
d) Transfer of aminocyl-t-RNA from the ribosomal A-site to P-site

16) Synthesis of polypeptide over m-RNA is
a) Transcription
b) Transduction
c) Translation
d) Transformation

17) The antibiotic inhibiting translation in eukaryotes is
a) Tetracycline
b) Penicillin
c) Chloromycetin
d) Puromycin

18) The process of translation results in
a) RNA synthesis
b) Ribosomes synthesis
c) DNA synthesis
d) Protein synthesis

19) Ribosomes are attached to m-RNA to form
a) Ribosomal complex
b) Protein
c) Polyribosomes
d) None of the above

20) Which is not involved in protein synthesis?
a) Transcription
b) Initiation
c) Elongation
d) Termination

21) Which of the following is not a non-sense codon?
a) UAG
b) UGG
c) UGA
d) UAA

22) A radioisotope used to label proteins differentially from
nucleic acid is


23) The hydrolytic step leading to the release of a polypeptide
chain from a ribosome is catalyzed by

a) peptidyl transferase
b) step codons
c) release factors
d) UAA

24) Given the antisense strand DNA codon 3’TAC 5′, the anticodon that pairs with the corresponding m-RNA codon could


25) A potent inhibitor of protein synthesis that acts as
an analogue of aminoacyl-t-RNA is

a) Mitomyocin
b) Streptomycin
c) Rifampicin
d) Puromycin

26) An amino-acyl synthetase is responsible for
a) Joining an amino acid to a t-RNA
b) Attaching an amino group to an organic acid
c) Formation of a peptide bond
d) None of these

27) Specific radioactive identification of ribosomal RNA
can be achieved by using

a) Thymine
b) Cytosine
c) Guanine
d) Uracil

28) A group of three nucleotides in m-RNA that specifies
an amino acid is called a

a) Codon
b) Anticodon
c) Cistron
d) Transposon

29) The clover leaf model for t-RNA was proposed by
a) Holley
b) Lederberg
c) Nirenberg
d) Khorana

30) The distance between the nitrogenous bases of DNA is measured
in terms of

a) Morgan units
b) Angstrom units
c) Nanometers
d) Kilobases

31) Okazaki fragments appear in the course of
a) Repair of DNA
b) Hybridization of DNA
c) Replication of DNA
d) All of these

32) What is the amount of DNA in a diploid cell?
a) Variable for a given species
b) Constant for a given species
c) Same in all species of plants
d) Same in all species of animals

33) What is a gene chemically?
a) Chromosome
b) RNA molecule
c) DNA molecule
d) Nucleus

34) RNA requires for the protein synthesis
a) m-RNA
b) t-RNA
c) r-RNA
d) All of these

35) Which of the following terms is used to specify protein
synthesis from m-RNA?

a) Transformation
b) Translation
c) Transduction
d) Transcription

36) To determine the three-dimensional structure of DNA,
Watson and Crick took the help of

a) Tissue culture
b) X-ray diffraction
c) Autoradiography
d) Electrophoresis

37) The genetic transformation experiments on Diplococcus
pneumoniae gave the first undoubted evidence that

a) DNA is made of nucleotides
b) DNA is the genetic material
c) Chromosomes are made of DNA
d) RNA is synthesized from a DNA template

38) Transcription is the transfer of genetic information

a) Chromosome to cytoplasm
b) tRNA to mRNA
c) DNA to mRNA
d) mRNA to rRNA

39) The chemical knives of DNA are
a) Ligases
b) Endonucleases
c) Transcriptases
d) Polymerases

40) Restriction endonucleases are
a) Present in mammalian cells for degeneration of DNA when the cell dies
b) Used in genetic engineering for fighting two DNA molecules
c) Synthesized by bacteria as part of their defence mechanism
d) Used for in vitro DNA synthesis

41) Recombinant DNA is achieved by cleaving the pro-DNA

a) Ligase
b) Primase
c) Exonuclease
d) Restriction endonuclease

42) The DNA of Escherichia coli is
a) Double-stranded and circular
b) Double-stranded and linear
c) Single-stranded and linear
d) Single-stranded and circular

43) A circular DNA molecule occurs in
a) Viruses
b) Bacteria, chloroplasts and mitochondria
c) Bacteria and chloroplasts only
d) Bacteria only

44) Wilkins showed by X-ray diffraction that the diameter of
the DNA helix was


45) How many base pairs are found in one turn of DNA?
a) 11
b) 10
c) 9
d) 12

46) Isotopes used for proving semiconservative replication


47) Bacterial transformation was discovered by
a) Avery et al
b) Beadle and Tatum
c) Robert Brown
d) Har Gobind Khorana

48) A sequence of three consecutive bases in a t-RNA
molecule which specially binds to a complementary
codon sequence in m-RNA is known as

a) Triplet
b) Anticodon
c) Non-sense codon
d) Termination codon

49) Which type of DNA is found in bacteria?
a) Membrane bound DNA
b) Circular free DNA
c) Straight DNA
d) Helical DNA

50) The genetic code of nuclear and mitochondrial DNA is
a) Similar
b) Different
c) Not worked out so far
d) DNA is not found in mitochondria

51) The wobble hypothesis was given by
a) R.W. Holley
b) H.G. Khorana
c) M. Nirenberg
d) F.H.C. Crick

52) Which of the following RNAs picks up specific amino
acids from the amino acid pool in the cytoplasm to the ribosome
during protein synthesis?

a) m-RNA
b) r-RNA
c) t-RNA
d) all of these

53) Which of the following terms is not concerned with
genetic recombination in bacteria?

a) Transformation
b) Translation
c) Transduction
d) Conjugation

54) The function of the nucleolus is the synthesis of
a) r-RNA
b) m-RNA
c) t-RNA
d) DNA

55) Nucleic acids were discovered by
a) Watson and Crick
b) Khorana
c) Wilkins
d) Friedrich Miescher

56) What is the type of coiling in DNA?
a) Right-handed
b) Left-handed
c) Opposite
d) Zig-zag

57) Prokaryotic genetic material possesses
a) Neither DNA not histomes
b) DNA but no histones
c) Either DNA or histones
d) Both DNA and histones

58) Who discovered reverse transcription?
a) Beadle and Tatum
b) Temin and Baltimore
c) Har Gobind Khorana
d) Watson and Crick

59) A gene that takes part in the synthesis of a polypeptide is a
a) Structural gene
b) Regulator gene
c) Operator gene
d) Promoter gene

60) The components of an operon are
a) Operator, promoter and regulator genes
b) Regulator, promoter, operator and structural genes
c) Operator, regulator and structural genes
d) Regulator, promoter and structural genes.

61) The lactose operon of Escherichia coli is
a) Monocistronic
b) Inducible
c) Repressible
d) Both b and c

62) The tryptophan operon of Escherichia coli is
a) Monocistronic
b) Inducible
c) Unregulated
d) Repressible

63) A corepressor binds with a/an
a) Promoter gene
b) Operator gene
c) Aporepressor
d) Regulator gene

64) The external supply of tryptophan in Escherichia coli brings about
a) Switching off of the tryptophan operon
b) Switching on of the tryptophan operon
c) Switching off of the lac operon
d) Switching on of the lac operon

65) The essential components of the eukaryotic cistron are
a) Introns
b) Exons
c) Opersons
d) Operator and regulator regions.

66) The segments of mRNA removed during splicing are
a) Introns
b) Exons
c) Promoter regions
d) Integrator regions

67) A cistron is a
a) Functional unit of DNA
b) Functional unit of RNA
c) Nonfunctional unit of DNA
d) Nonfunctional unit of RNA

68) Housekeeping genes
a) Produce antibodies
b) Constantly operate for cellular activity
c) Form hormones
d) Function only at the time of reproduction

69) The term gene was coined by
a) Nirenberg
b) Khorana
c) Kornberg
d) Johannsen

70) The segment of DNA which participates in crossing over is known as a
a) Muton
b) Recon
c) Cistron
d) Replicon

71) The prokaryotic genetic system possesses
a) DNA but no histones
b) Either DNA or histones
c) Both DNA and histones
d) Neither DNA nor histones

72) A gene is a
a) Segment of DNA
b) Segment of chromosome
c) Functional unit of DNA
d) DNA segment capable of crossing over

73) The functional unit of a gene that specifies synthesis of one polypeptide is a
a) Codon
b) Cistron
c) Recon
d) Muton

74) A regulator gene controls chemical synthesis (operon concept) by
a) Inhibiting transcription of mRNA
b) Inhibiting enzymes
c) Inhibiting passage of mRNA
d) Inhibiting substrate enzyme reaction

75) In the operon concept, the operator gene combines with a
a) Regulator protein to switch off structural gene transcription
b) Regulator protein to switch on structural gene transcription
c) Inducer to switch off structural gene transcription
d) Regulator gene to switch off structural gene transcription.

76) The biologically functional tyrosine suppressor tRNA of Escherichia coli synthesised by Khorana in 1979 had
a) 333 nucleotides
b) 312 nucleotide pairs
c) 207 nucleotide pairs
d) 77 nucleotide pairs

77) In viruses, the nucleic acid is
a) DNA
b) RNA
c) Both A or B
d) Either A or B

78) Coliphage

a) Double strand DNA
b) Double strand RNA
c) Single strand DNA
d) Single strand RNA

79) A bacterial nucleoid has
a) One double stranded DNA
b) Many double stranded DNAs
c) One single stranded DNA
d) Two single stranded DNAs

80) The tool used in recombinant DNA technology is
a) Plasmid
b) Plastid
c) Ribosome
d) Mutation

81) In Rous Sarcoma Virus information flow is

82) A gene which synthesises a repressor protein is a
a) Operator gene
b) Structural gene
c) Promoter gene
d) Regulator gene

83) The term bacteriophage was coined by
a) De Herelle
b) Ivanowsky
c) Stanley
d) Twort

84) Genes connected with cancer are
a) Cancer genes
b) Carcinoma genes
c) Oncogenes
d) Sex-linked genes

85) A homozygous red flowered pea plant is crossed with homozygous white-flowered pea plant. The offspring would be
a) 50 % red flowered
b) 50 % pink flowered
c) All pink flowered
d) All red flowered

86) Mendel’s law applies only when
a) The first pair of contrasting characters is dependent upon other pairs
b) The parents are pure breeding
c) The characters are linked
d) F1 in monohybrid cross shows two types of individuals

87) How many types of genetically different gametes will be produced by a heterozygous plant having the genotype AABbcc ?
a) Two
b) Four
c) Six
d) Eight

88) In heredity, the genes are obtained from the
a) Father
b) Mother
c) Father and mother
d) None of these

89) The number of chromatids at metaphase is
a) One in mitosis and two in meiosis
b) Two in mitosis and four in meiosis
c) Two in mitosis and one in meiosis
d) Two both in mitosis and meiosis

90) The polytene chromosomes were discovered for the first time in
a) Chironomus
b) Fruitfly
c) Housefly
d) Mosquito

91) The point at which the polytene chromosomes appear to be attached together is known as the
a) Centriole
b) Chromocentre
c) Centromere
d) Chromomere

92) Two genes situated very close together on the chromosome show
a) High crossing over frequency
b) No crossing over
c) Infrequent crossing over
d) Only double crossing over can occur

93) Two dominant nonallelic genes are 50 map units apart. Linkage is
a) Complete
b) Absent
c) Trans type
d) Cis type

94) Identify the agent which causes mutation
a) Cosmic rays
b) Crossing over
c) Gamma rays
d) Colchicine

95) The protein which helps to open the DNA double helix in front of the replication fork is
a) DNA gyrase
b) DNA ligase
c) DNA topisomerase
d) DNA polymerase I

96) Which purine base is found in RNA?
a) Uracil
b) Guanine
c) Thymine
d) Cytosine

97) If the sequence of bases in DNA is ATTC- GATG, then the sequence of the bases in its transcript will be

98) Radio tracer techniques show that DNA is in the
a) Multi-helix stage
b) Double-helix stage
c) Single-helix stage
d) None of these

99) The hereditary material present in the bacterium E. coli is
a) Single stranded DNA
b) RNA
c) Double stranded DNA
d) Protein

100) The nucleotide arrangement in DNA can be seen by
a) Light microscopy
b) Electron microscopy
c) Ultracentrifugation
d) X-ray crystallography


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