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OBJECTIVE QUESTIONS
1. The double helix model of DNA was given by
a.Watson and Crick
b.Meselson and Stahl
c.Wilkins and Franklin
d.Sutton and Baveri
2.Transcription involves
a.synthesis of RNA over the template of DNA
b.joining of amino acids into a polypeptide
c.synthesis of RNA over ribosomes
d.synthesis of DNA over the template of DNA
3.In eukaryotes, which of the following is removed from
initially transcribed
RNA before it is transported to the cytoplasm for
translation?
a.Intron
b.3 Poly A tail
c.Ribosome binding site
d.5 cap
4.Choose the incorrect statement about the genetic code
a.includes 61 codons for amino acids and 3 stop codons
b.almost universal; exactly the same in most genetic systems
c.some amino acids are coded by multiple codons
d.it is degenerate but ambiguous
5.Identify the polypeptide that would be produced as a result
of
transcribing and translating the following DNA sequence.
DNA: 3 A C C A A G T C T 5
a.arg-phg-trp
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b.arg-leg-gly
c.thr-lys-ser
d.trp-phe-arg
6.DNA ligase is
a.an enzyme that joins fragments in normal DNA replication
b.an enzyme that joins amino acids together in a polypeptide
chain
c.an enzyme that cuts ds DNA at specific sites
d.an enzyme that facilitates transcription of specific genes
7.A very Mc Cleod and Mc Carty conducted an experiment to prove
the
nature of the transforming principle. What cannot be conclueded
fromtheir experiment?
a.DNA could be involved in transformation
b.addition of proteases did not affect the sample.
c.the extraction of lipids and proteins from the principle only
slightly
reduced its activity
d.DNA-digesting enzyme, DNase, destroyed all transcription
activity
8.A genetic change involving the substitution of one base in the
DNA foranother which results in the substitution of one amino acid
in a
polypeptide for another is called as a
a.nonsense mutation
b.missense mutation
c.frame shift mutation
d.neutral mutation
9.Barbara Mclintock, the 1983 Nobel Laureate in Physiology or
Medicine,
is famous for her work on
a.rice
b.wheat
c.maize
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d.sugarcane
10. Which of the following is not true about double stranded
a.A/T is one
b.A + G = C + T
c.C/G is one
d.A + T = C + G
11. Hn RNA, also called as pre-mRNA, is
a.heteronuclear RNA
b.homonuclear RNA
c.heterogenous RNA
d.useful RNA
12. Homobox sequences
a.are involved in the regulation of patterns of development
(mophogenesis) in animals, fungi and plants.
b.are found in prokaryotes but not in eukaryotes
c.are about 1800 base pairs long
d.represent integration sites for transposable elements
13. Identify the incorrect statement
a.The repressor of the lac operon is synthesized
constitutively.
b.Regulation of lac operon by repressor is referred to as
negative
regulation.
c.Regulation of lac operon is a regulation of enzyme synthesis
by its
substrate.
d.In the presence of lactose or allolactose, the repressor is
activated
and it binds to the operator.
14. The y gene of the lac operon codes for
a.beta galactosidase
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II. Its genome is one of the smallest plant genomes
III. Genome was the first plant genome to be sequenced.
a.I and II are correct
b.I and III are correct
c.II and III are correct
d.I, II and III are correct
19. Consider the following statements that attempt to explain
why DNA
is a better storage molecule of genetic information.
I. The protein synthesizing machinery has evolved around DNA
II. DNA chemically is less reactive and structurally more stable
whencompared to RNA
III. Because of the rules of base pairing and complimentarity,
DNA can
direct its duplication while RNA cannot do so.
Of the above statements, the correct explanation is/are
a.II alone
b.I and II only
c.II and III only
d.I, II and III
20. Assuming that the level of glucose is low, constitute
expression of
the lac operon genes would result from
a.a mutation in the repressor of the lac operon in E. coli,
preventing
binding of the repressor to the operator.
b.a mutation in the repressor associated with the lac operon of
E.coli
which prevents binding of the repressor to lactose.
c.a mutation in CAP binding site
d.all of these.
21. Identify the incorrectly matched pair:
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Codon on mRNA Amino acid coded for
a.AGU Serine
b.AUU Isolelucine
c.ACA Asparagine
d.AGG Arginine
22. Mitochondrial DNA
I. Evolved from the circular genomes of the bacteria that
were
engulfed by the early ancestors of todays eukaryotic cells.
II. The two strands of mtDNA are differentiated by their
nucleotide
content with the guanine rich strand referred to as the
heavy
strand, and the cytosine rich strand referred to as the light
strand.
III. Is advantageous for evolutionary studies because it is
inherited
only through the female parent and thus evolves in a way
that
allows trees of relationship to be easily constructed
a.I, II and III are correct
b.I and II are correct
c.I and III are correct
d.II and III are correct
23. Caenorhabditis elegansis a
a.Free-living non-pathogenic nematode
b.Symbiont non-pathogenic nematode
c.Free-living pathogenic nematode
d.Parasitic pathogenic nematode
24. The inducer/s of the lac operon is/are
a.lactose
b.glucose
c.galactose
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d.all of these
25. Twin studies in humans are useful because
a.they allow more refined estimates of chromosome location to
be
made
b.twins have a greater likelihood of being heterozygous
c.they allow improved expressions of genes
d.they allow genetic as opposed to environmental influences
on
variation in a trait to be estimated
26. The deleterious allele associated with sickle cell anaemia
is found
in higher frequencies than expected in certain human
populations. That
means it is selected by nature here. What can be the reason for
this?
a.random mating
b.superior fitness of heterozygotes in areas where malaria
was
present
c.migration of individuals with the allele into other
populations
d.a high mutation rate at that specific gene
27. The lac i gene is the regulator of the lac operon. i in lac
i refers to
a.inducer
b.inhibitor
c.initial
d.intermediate
28. Most new mutations appear to be
a.beneficial
b.neutral or deleterious
c.favorably selected by the nature
d.dominant
29. Which of the following strands of DNA would be the
complement
stand to G-C-A-T-C-G?
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a.C-G-T-A-G-C
b.G-G-A-T-G-C
c.A-A-C-G-A-T
d.T-T-G-C-T-A
30. Who proposed the semiconservative mode of replication of
DNA?
a.Meselson and Stahl
b.Watson and Crick
c.Hershey and Chase
d.Wlikins and Franklin
31. In Hershey and Chase experiment , the DNA of the phage
waslabelled with
a.35S
b.32P
c.18O
d.14C
32. Genetic information in a DNA molecule is coded in the
a.sequence of nucleotides
b.base pairings
c.proportion of each base present
d.the turning pattern of the helix
33. In prokaryotes, the predominant site for control of gene
expression
is the
a.transcription initiation
b.processing level
c.transport of mRNA
d.translational level
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34. In bacteria, an example of ribozyme is
a.5s rRNA
b.23s rRNA
c.18s rRNA
d.16s rRNA
35. The site of protein synthesis is the
a.SER
b.RER
c.Ribosomes
d.Golgi
36. The diploid number of chromosomes in chimpanzees is 48.
How
many DNA molecules are in the genome of a chimpanzee cell before
it
begins meiosis?
a.48
b.96
c.24
d.12
37. A section of SN that contains the genetic code for a
single
polypeptide and functions as a hereditary unit and is flanked by
the start
codon and the stop codon, is called a
a.codon
b.cistron
c.translation unit
d.anticodon
38. The untranslated regions (UTRs)
a.are located on the rRNA
b.are present only on the 3 end of the mRNA
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c.are absent in the eukaryotes
d.are required for efficient translation
39. At the end of the translation, a release factor binds to
the
a.stop codon
b.ribosome
c.transfer RNA
d.last elongation factor
40. How many tRNAs are there for stop codons?
a.0
b.1
c.2
d.3
41. The two-dimensional structure of a tRNA molecule
resembles
a.english alphabet L
b.a clover leaf
c.a beta pleated sheet
d.a double helix
42. What forms the genetic basis of the proof that genetic code
is
triplet and read in a contiguous manner?
a.Some point mutations do not change the amino acid coded
for
b.A doublet or a singlet code would code for too few amino acids
than
required
c.A frameshift insertion of three bases does not change the read
in
frame
d.Most of the spontaneous mutations are lethal and recessive
43. The enzymatic synthesis of RNA in a template independent
manner
requires
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a.RNA polymerase
b.DNA polymerase
c.Polynucleotide phosphorylase
d.Translocase
44. A transcription unit does not include
a.Operator
b.Promoter
c.Structural gene
d.Terminator
45. What defines a template strand and a coding strand in
transcription?
a.the complementary base pairing
b.presence of promoter in transcription unit
c.presence of terminator in transcription unit
d.presence of structural genes in the transcription unit
46. A gene is defined as a DNA sequence coding for
a.mRNA
b.rRNA
c.tRNA
d.all of these
47. A split gene in eukaryotes consists of
a.Introns only
b.Exons only
c.Both introns and exons
d.Neither introns nor exons
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48. The phase of the cell cycle associated with the replication
of DNA is
a.G 1 phase
b.G 2 phase
c.S phase
d.M phase
49. Identify the incorrect statement:
a.Deoxyibonucleoside triphosphates act as a substrate for
DNA
polymerization as well as provide energy for polymerization
b.In transcription, unlike translation, only one of the two
strands is
transcribed completely along its entire length
c.The replication of DNA does not initiate randomly at any place
in
the DNA
d.There is a single DNA-dependent RNA polymerase that
catalyses
transcription of all types of RNA in bacteria
50. The culture in Meselson-stahl setup would contain equal
amounts
of hybrid DNA and light DNA after the DNA has been allowed to
replicate
for
a.20 minutes
b.40 minutes
c.60 minutes
d.80 minutes
