MOLECULAR BASIS OF INHERITANCE - PRACTICE QUESTIONS

MOLECULAR BASIS OF INHERITANCE 

1.     Genetic material should be -

        a) Ubiquitous

        b) Able to permit diversity

        c) Capable of replication

        d) All of above

2.     Complete set of chromosomes inherited as a unit from one parent is known as

        a) Karyotype                                b) Gene pool

        c) Genome                                   d) Genotype

3.     The change of non-virulent strain of the bacterium into virulent strain is called

         a)Transduction     b) Transformation

         c) Transcription    d) Translation

4.     the agent for bacterial transformation was found to be DNA by --

            a)Griffith                     b) Hershey and Chase

        c) Avery, Mc Carty and Macleod

        d) Meselson and Stahl

5.     The structure of nuclear membrane  facilitates -

        a) Organisation of spindle

        b) Synapsis of homologous  chromosomes during meiosis

        c) Nucleo - cytoplasmic exchange of material

        d) Anaphasic separation of daughter  chromosomes

6.     The chromatin thread is made up of

        a)Lipoproteins         b) phospholipids

         c) Nucleoproteins   d) Glycoproteins

7.     Solenoid is made up of --

        a) Genes                  b) Alleles

        c) Chromosomes    d) Nucleosomes

8.     Extranuclear DNA is present in-

            a) Chloroplast         b) Mitochondria

            c) Ribosome           d) Both a and b

9.     The hydrophilic nature of DNA is due to presence of -

        a) Deoxyribose sugar      b) phosphate group  

        c) Thymine base              d) Hydrogen bonds

10.   In a DNA molecule the sugars -

         a) Bond covalently to phosphate group

         b) Bond covalently to nitrogen base

         c) Bond to nitrogen base by hydrogen bond

            d) Bond to both phosphate group and  nitrogen base by covalent bonds

11.   DNA is --

            a) Right handed coiling and parallel

            b) Right handed coiling and antiparallel

            c)Left handed coiling and antiparallel

            d) Left handed coiling and parallel

12.   DNA synthesis takes place in --

            a) Interphase          b) Metaphase

        c) Anaphase          d) Telophase

13.   Which stage is known for DNA  replication?

        a) Metaphase          b) S - phase

        c) S - phase             d) G2 phase

14.   Origin of DNA replication is --

            a)One in all organisms

            b)One in prokaryotes and several in  eukaryotes

        c) One in eukaryotes and several in  prokaryotes

         d) Several in almost all organisms

15.   Which of the following is needed during DNA replication ?

            a) RNA polymerase and translocase

            b) DNA polymerase and DNA ligase

            c) DNA polymerase only

            d) DNA ligase only

16.   Ligase enzyme is used for

        a) Denaturation of DNA

        b) Splitting of DNA into small bits

        c) Joining bits of DNA

        d) Digestion of lipids

17.   DNA is believed to be the genetic material because

         a) All the body cells of an individual seem to have identical amounts and       composition of DNA

        b) The proteins are the same from cell  to cell in an individual but the DNA  differs; the DNA must be the material  that makes different tissues different.

        c) DNA is the largest type of macro -molecule found in living organisms

        d) DNA is found in the cell muscles

18.   Plasmids consist of-

         a) Circular double stranded DNA

         b) Circular single stranded DNA

         c) Straight single stranded DNA

        d) None of these

19.   Plasmids have genes for sexuality, antibiotic resistance etc. hence a plasmid is  said to be

            a) A vital gene but without it the cell  can survive

            b) An unimportant gene but necessary for survival of any cell can survive

        c) A vital gene and without it a cell cannot survive

        d) Not a vital gene, and a cell can  survive without it.

20.   RNA is polymer of --

        a) Deoxyribonucleosides             b) Ribonucleoside

        c) Deoxyribonucleotides                 d) Ribonucleotides

 21. Similarity between DNA and RNA lies in -

        a)Similar sugar

        b) Double stranded nature

        c) Being polymers of nucleotides

        d) Similar pyrimidines

22.   The correct statement is --

        a) RNA is double stranded

        b) RNA is single stranded

        c) Most cellular RNA is single stranded

        d) Both double and single RNA are  present in equal amount

23.   All the three types of RNA mainly function in -

        a) Replication      b) Synthesis of proteins

        c) Synthesis of carbohydrates

        d) Both a and c

24.   The types of RNA specifically responsible for  directing the proper sequence of amino acids in protein synthesis is

            a) Ribosomal RNA b) Messenger RNA

        c) Chromosomal RNA d) None of the above

25.   If the sequence of bases in DNA is ATC GCT CCA then the sequence of  bases in m- RNA produced from it will be--

        a) AAG CGT CCT  b) AUG CGU CCA

        c) UAG CGA GGU d) TAU CUT UUA

26.   The triple code is read from ---

        a) 5'  ---->  3' direction  b) 3' ---->  5' direction

        c) At any point                        d) In any direction

27.   UAA, UAG and UGA are

        a) Starting codons           b) Degenerate codons

        c) Non - overlapping codons

        d) Non - senses codons

28.   The termination codon is -

         a) UAG (Amber)      b) UAA (ochre)

         c) UGA (opal)         d) All of these

29.   In a codon, wobbling is generally  restricted to -

        a) First nitrogen base

        b) Second nitrogen base

        c) Third nitrogen base

        d) Aromatic amino aids

30.   Which of the following is translated completely?

        1] AUG  UGA  UUA  AAG  AAA

        2] AUG  AUA  UUG  CCC  UGA

        3] AGU CCC  AGA  CUC  UAA

        4] AUG  UAC  AGU  AAC  UAG

        a) 1and 2               b) 2 and 3

        c) 2 and 4              d) 3 and 4

31.   In protein synthesis, polymerization of amino acids involves three steps. Which one of the following is not involved in it -?

        a)Elongation          b) Transcription

        c) Termination        d) Initiation

32.   Transcription is process of -

        a) m- RNA formation over DNA

        b) Protein synthesis over ribosome

        c) Digestion by lysosomes

        d) Formation of mitochondrion

33.   The portion of DNA which contains information for an entire polypeptide is called -

        a) Cistron              b) Muton

        c) Recon               d) Operon

34.   Enzyme useful for synthesis of m - RNA transcription is

        a) RNA - polymerase b) DNA - polymerase

        c) Ligase                               d) Non - sense strand

35.   Arrangement of amino acids by t-RNA  according to the information present on m- RNA is called

        a) Transcription      b) Translocation

        c) Translation         d) Transformation

36.   The initiation of polypeptide chain requires

        a)Initiation factors   b) GTP

        c) Either a or b        d)Both a and b

37.   Prokaryotic 70S ribosome break into 

        a) 40S and 30S      b) 50S and  30S

        c) 45S and 25S      d) 50S and 20S

38.   In protein synthesis loaded t-RNA

        enter the ribosome from A site except

        a) t- RNA carrying methionine

        b) t- RNA carrying serine

        c) t- RNA carrying arginine

        d) t- RNA carrying tryptophan

39.   According to most recent studies each chromosome consists of

        a) A single double helical DNA

        b) Variable number of DNA

        c) Many small linked DNA

        d) Small wrapped DNA helices

40.   The substance that acts as connecting link between two generations is

        a) Ribonucleic acid         b)Nucleoplasm

        c) Deoxyribonucleic  acid

        d) Ribonucleic acid +Deoxyribonucleic acid

41.   The chromosomes are generally stained by

        a) Aniline blue      b) Gentian violet

        c) Acetocarmine   d) Erythrosine

42.   The number of coils formed by the DNA  molecule around a protein core for forming a nucleosome

        a) 2            b)  2   c)2       d) 1

43.   Ribose is

        a) Monosaccharide  b) Disaccharide

        c) Polysaccharide    d) None of the above

44.   Due to coiling of the DNA molecule, vertically running grooves are formed. Such grooves are

        a)Two major and one minor

        b) One major and two minor

        c) Two major and two minor

        d) One major and one minor

45.   The term plasmid was introduced by

        a) Jacob                 b) Wollman

        c) Lederberg         d) Tatum 

46.   The extra genomic DNA segments of bacteria   are known as....

        a) Episomes                     b) Plasmid

        c) Lederberg          d) Tatum

47.   Exact replication of DNA is possible due to

        a) Genetic code          b) Mitosis

        c) Base pairing rule

        d) DNA enclosed in a membrane

48.   Polysome do not contain

        a) m- RNA             b) t- RNA

        c) r - RNA              d) DNA

49.   Gram stain is

        a) A strain produced out of gram seed

        b) A trade marks

        c) A staining technique developed by  the Danish Scientist Gram

        d) Chemical to differentiate of bacteria

50.   In DNA replication, the primer is

        a) A small deoxyribonucleotide polymer

        b) Small ribonucleotide polymer

        c) Helix destabilising protein

        d) Enzyme taking part in joining nucleotides to their complementary  template bases

51.   Topoisomerase is involved in

        a) Producing RNA primer

        b) Joining DNA segments

        c) Producing nick in DNA

        d) Synthesis of RNA

52.   The proteins having similar amino acids may differ because

        a) Amino acid sequence is different

        b) Being formed by different ribosomes

        c) They perform different functions

        d) They are formed at different times

53.   Autocatalytic function of DNA means

        a) Synthesis of RNA b) Synthesis of proteins

        c) Synthesis of DNA d) All of these

54.   A feature common to nucleus, chloroplast and mitochondria is the presence of

        a) Nucleic acid        b) Cytoplasm

        c) Cristae                 d) Lamellae

55.   A short length of DNA molecule contains 120 adenine and 120 cytosine bases . The total number of  nucleotides in this DNA fragment is

        a) 480                      b) 120

        c) 60                        d) 240

56.   The contribution of cytoplasmic DNA in the cell's total DNA is

        a) 65 to 75%           b) 45 to 50 %

        c) 1 to 5%                d) 95 to 99%

57.   The gene are made up of

        a) Histones           b) Polynucleosides

        c) Nucleosides    d) Polynucleotides

58.   Who coined the term gene ?

        a) Morgan            b) Johansen

        c) Mendel            d) Jensen

59.   Protein does not constitute genetic material because it

        a) It is not ubiquitous

        b) Does not possess diversity

        c) Does not possess ability of replication

        d) Is a small molecule

60.   The modern concept of gene is

        a) A segment of DNA capable of  crossing over

        b) A functional unit of DNA

        c) A segment of DNA

        d) A segment of chromosome

61.   Who discovered transformation in bacteria ?

        a) Griffith                   b) Meselson and Stahl

        c) Hershey and chase  d) Watson and crick

62.   The scientist who separated and  identified the chemical which showed transformation were

        a) Griffith                        b) Avery Macleod , McCarty

        c) Lederberg and Zinder

        d) Meselson and Stahl

63.   Transduction is a

        a) Transfer of genetic material from one bacterium to another through  bacteriophage

        b) Transfer of genetic material by using DNA extract

        c) Transfer of genetic material by sexual reproduction

        d) None of above

64.   Nucleic acid is composed of following elements

        a) C,  H,  O,  N,  P

        b) C,  H,  N,  Ca, P

        c) C,  H,  O,   P,  Pb

        d) C,  Fe, O,  P,  N

65.   Nucleus of bacteria is called

        a) Chromosome   b) Nucleolus

        c) Mesosome        d) Nucleoid

66.   Normally GUG specifies valine amino acid but when this is initiation codon then it specifies which one of the following amino acids.

        a) Valine                b) Threonine

        c) Methionine       d) Lysine

67.   Winding of DNA around a core of  histones result in a structure called

        a) Nucleosome         b) Nucleus

        c) Chromosomes    d) Chromonema

68.   Watson and Crick are known for their discovery that DNA

        a) Is a single stranded helix

        b) Contain deoxyribose only

        c) Is a double stranded helix

        d) Synthesis of r- RNA

69.   In nucleotide nitrogen base is attached to

        a) First carbon of sugar

        b) Third carbon of sugar

        c) Fifth carbon of sugar

        d) Fourth carbon of sugar

70.   The two strands of DNA are

        a) Similar and complementary

        b) Antiparallel and complementary

        c) Different

        d)Antiparallel and non-complementary

71.   Backbone of DNA stand is build-up of

        a) Nitrogen base phosphate and deoxyribose sugar base

        b) Alternate nitrogen base and phosphate

        c) Alternate nitrogen base and deoxyribose sugar

        d) Alternate phosphate and deoxyribose sugar

72.   Okazaki segments are

        a) DNA segment capable of free replication

        b) DNA segment formed during replication

        c) Nucleotide segments formed during transcription

         d) Segment of gene which undergo mutation and recombination

73.   Nobel Prize for the concept of  jumping gene was awarded to

        a) Korenberg         b) Mc. Lintock

        c) Khorana            d) Watson

74.   Clover leaf model for t- RNA was proposed by

        a) Holley                b) Khorana

        c) Nirenberg          d) Lederberg

75.   Genetic code determines

        a) Structure pattern of an organism

        b) Sequence of amino acid in protein chain

        c) Variation in off spring

        d) Constancy of morphological trait

76.   Out of 64 codons in genetic code  how many codons are responsible for specifying 20 amino acids

        a) 20                       b) 59

        c) 61                       d) 64

77.   The wobble effect is

        a) Lack of precision with regard to          the third base of anticodon and codon

        b) Instability of DNA molecule when unbound

        c) Instability of pairing when purine  pairs with another purine

        d) Undulating movement of m- RNA

78.   Which of the following is proper  sequence in  protein  synthesis ?

        a)Translation t- RNA amino acid  complex - peptide chain

        b) t - RNA amino acid complex - peptide chain - transcription

        c) t- RNA amino acid complex -  peptide chain - initiation

        d) Transcription- t- RNA amino acid

79.   Which is the correct sequence of code. transfer involve in the formation of polypeptide ?

        a) DNA -  t-RNA  -  r-RNA  -  m-RNA

        b) t-RNA -  DNA  -  m-RNA  -  r-RNA

        c) m-RNA  -  t-RNA  -  DNA  -  Amino acid

        d) DNA  - m- RNA  -  t-RNA  - Amino acid

80.   The core of nucleosome is made up of

        a) H3, H2A, H2B, H1      b) H1, H2A, H2B, H4

        c) H1, H2A, H2B, H3, H4 d) H2A, H2B, H3, H4

81.   A plasmid is a

        a) Bacteriophage

        b) DNA molecule incorporated in the bacterial chromosome

        c) DNA molecule present in  mitochondria

        d) A small circular DNA molecule  capable of self-replication

82.   Those enzymes which break specific nucleotide sequences are called as

        a) Nucleases        b) Endonucleases

        c) Exonucleases   d) Restriction enzymes

83.   The m- RNA sequence AUG CAG GAU ACG recognises four amino acids and

         this character to the code is referred to as

        a) Degeneracy                             b) Universality

        c) Non - ambiguity          d) Comma lessness

84.   During transcription base sequence in RNA is complementary to one  strand of DNA except for the substitution

        a) A  for G                                               b) U  for  C

        c) U for  T                                                d) C  for  T

85.   Which one is an amino acid ?

        a) CH2-CH - NH2COOH

        b) NH2CH2CH2 COOH

        c) CH3-CHNH2COCI

        d) CH3-CH2-COH3

86.   the unidirectional flow of information  is carried out from DNA to RNA to  protein referred to as the

        a)Central dogma of molecular biology

        b) Circular flow of information

        c) Reverse central dogma

        d) None of these

87.   Wobble hypothesis was proposed by

        a) Niren burg                               b) Korn burg

        c) Crick                                                    d) None

88.   In the protein synthesis t- RNA  carrying the amino acid enter from which site of ribosome

        a) a- site                                                   b) P - site

        c) Anticodon site                         d) Recognition site

89.   The function of non-sense codon is

        a) To release polypeptide chain from t- RNA

        b) To from an in specified amino acid

        c) To terminate the message of protein synthesis

        d) To convert a sense DNA into non-sense DNA

90.   Which is correct sequence according to mole.wt.

        a) t-RNA - DNA -  t- RNA

        b) r-RNA - DNA -  t- RNA

        c) DNA - r- RNA - DNA

        d) t- RNA - r-RNA - DNA

91.   Sigma factor is component of ......

        a) DNA ligase    b) DNA polymerase e

        c) RNA polymerase

        d) Dissociation factor

92.   An episomes is

        a) A genetic particle which can exist in either cytoplasm or in DNA

        b) A segment of DNA capable of an independent replication

        c) A segment of DNA deleted as a result of mutation

        d) None of these

93.   Which one of the following is the  most specific region on t- RNA?

        a) Amino acid attachment site

        b) Amino acid recognition site

        c) Codon recognition site

        d) Ribosome recognition site

94.   There are 64 codons in genetic code dictionary because

        a) There are 64 types of t-RNA found  in cell

        b) There are 44 meaningless and 20 codons for amino acid

        c) There are 64 amino acids to be  coded

        d) Genetic code is triplet

95.   Dr hargovind Khurana has been  awarded noble prize for researches in

        a) Artificial DNA synthesis

        b) Artificial RNA synthesis

        c) Genetic code               d) Amino acid

96.   The protein which unwind DNA molecule  during replication are  called as

        a)Topoisomerases                       b) Helicases

        c) Primases                                  d) All of these

97.   The genes that keep on changing  their location on chromosome are

        a) Pleiotropic genes         b) Jumping genes

        c) Duplicate genes                       d) Split genes

98.   During protein synthesis the correct  amino acid is brought to the ribosome and inserted in correct sequence in the growing  polypeptide chain by

         a) Base pairing between DNA and m-RNA

         b) Base pairing between m- RNA codon and anticodon in t- RNA

        c) Interaction between two anticodons

         d) Interaction between two triplets’ codons

99.   Polysomes are

        a) Cell organelles in prokaryotes

        b) Ribosomes attached to messenger

        c) Cell organelles in eukaryotes

        d) Chain of nucleosomes

100. Which of the function is not performed by DNA?

        a) Synthesis of protein

        b) Transmission of hereditary character

        c) Synthesis of carbohydrates

        d) Replication

101. RNA is a genetic material in

        a) All viruses          b) Some viruses

        c) Bacteria              d) Prokaryotes

102. the first amino acid in any  polypeptide chain in prokaryotes is

        a) Formylated arginine    b) Lysine

        c) Formylated methionine

        d) Methionine

103. Purines of DNA / RNA are

        a) Uracil and guanine

        b) Uracil and cytosine

        c) Adenine and guanine

        d) Cytosine and Guanine

104. Ribosome are made up of

        a) DNA only              b) RNA only

        c) r- RNA + protein  d) DNA + protein

105. Mark the correct statement

        a) Histones are acidic proteins

        b) Histones stimulate genetic activity

        c) Both of these    d) None of these 

106.     The codon which specify same amino acid                    ( Eg. CAU and CAC) are called

        a) synonyms         b) Start signal

        c) Anonyms           d) Stop signal

107.     The hereditary material in Tobacco  Mosaic Virus is a :

        a) Double - stranded DNA

        b) Single - stranded RNA

        c) single - stranded DNA

        d) Double - stranded RNA

108. Which of  the following are associated  with      bacterial chromo-some ?

        a) Linear DNA       b) Histones

        c) Plasmids          d) All the three

109. What is the genetic material in influenza virus

        a) RNA                

        b) Single- stranded linear DNA

        c) Double - stranded linear DNA

        d) Circular DNA

110.     Which of the following nucleotide sequences has 4 pyrimidine bases ?

        a) GCUAGACAA    b) UAGCGGUAA

        c) GATCAATGC      d) Both a and b

111. The phenomenon of transformation in Diplococcus pneumoniae was  discovered by

        a) Avery, Macleod and Mc Carty

        b) Griffith

        c) Hershey and Chase    d) Morgan

112. A nucleoside is

        a) A pentose sugar + a nitrogen base

        b) A nucleotide minus phosphate

        c) A pentose sugar + a phosphate

        d) Both a and b

113.     In the polynucleotide strands of the  nucleic acids, the nucleotides are joined by the

        a) Peptide linkage       b) H - bonds

        c) High energy phosphatic bond

        d) Phosphodiester bonds

114.     Kornberg and Thomas  proposed

        a) The nucleosome solenoid model

        b) That RNA is the genetic material in  some viruses

        c) The term 'gene' for 'factor'

        d) that the prokaryotic DNA is circular

115.     DNA nucleotide differs from RNA nucleotide in

        a) Having Uracil as a pyrimidine base                        

        b) Having Ribose sugar

        c) Having Deoxyribose sugar

        d) All the above three

116.     Each complete helix (spiral) of eukaryotic DNA has    

        a) Ten pairs of nucleotides 

        b) Ten nucleotides in each strand

        c) Ten base pairs

        d) All the above three

117.     In a DNA double helix, the distance

         between the two strands is

        a) 34  Ao                                                    b) 20   Ao . c

        c) 3.4  Ao              d)  15  Ao

118. Double stranded RNA is present in

        a) Bacterium E.coli   b) Reovirus

        c) Chloroplast            d) TMV

119. RNA plays major role in the  synthesis of

        a) Amino acids         b) Nucleotides

            c) Ribosomes          d) Enzymes

120.     If a DNA has 20 Adenine and 30 Cytosine bases.  What will be the             total number of purine bases in the given sample ?

        a) 20           b) 30         c) 50        d) 100  

121.The experimental proof for the semi conservative replication of DNA by  using nitrogen 14N and 15N was  provided by

        a) Nirenberg and Mathai

        b) Kornberg and Thomas

        c) Nirenberg and Khorana

        d) Meselson and Stahl

122.  Which one of the following helps to unwind   DNA double helix in front of  the replication fork during DNA replication ?

        a) DNA helicase

        b) DNA polymerase - I

        c) DNA ligase                              d) DNA synthetase

123. During DNA replication, the formation of new DNA strand always takes place

        a) In 3' -----> 5' direction of template strand

        b) In 5' -----> 3' direction of the new strand

        c) In 5' -----> 3' direction of the lagging template strand 

        d) Both a and b

124.  The formation of new strand on the      DNA template can be initiated only by the

         a) RNA primer         b) DNA primer

         c) DNA polymerase    

         d) DNA endonuclease

125.  The octamer core of nucleosome  contains two molecules each of the  following histones 

        a) H2A, H2B, H3 and H4

        b) H1, H2A, H2B, H3

        c) H1, H2A, H2B, H4

        d) H1, H2B, H3, H4 

126. Extrachromosomal circular mini -          DNA which can be incorporated in    the main chromosomal DNA is called

        a) Daughter DNA     b) Adapter DNA

        c) Episome               d) Lysosome

127. q  mode of replication is seen in

        a) All prokaryotes     b) All eukaryotes

        c) In bacteria             d) In plant viruses

128.     Maximum formation of m - RNA occurs in

        a) Cytoplasm            b) Nucleolus

        c) Nucleoplasm        d) Ribosome

129.     The m-RNA language is also known as

        a) Cryptogram            b) Cryptogam

        c) Cryptoanalysis    d) All the above

130.     A, G, C and U are known as the         alphabets of the m-RNA language .In the formation of the 64 codons in the dictionary of genetic code, these alphabets are to be used in the following sequence

        a) A,G,C,U,               b) A,U,G,C,

        c) U,C,A,G,               d) U,A,G,C,

131.  The genetic code of triplets was  confirmed by

        a) Gamow                            b) Khorana

        c) Kornberg and Sinsheimar  d) Crick

132.     In the dictionary of genetic code, how many codons signify different amino acids required for protein synthesis?

        a) 64.       b) 61.        c) 60.           d) 63.

133.  The Wobble hypothesis was proposed by:

        a) Watson and Crick           b) Khorana.

        c) Nirenberg and Ochoa.             d) Crick

134.     Point out the odd one from the following :

        a) UAC.    b) UAG    c) UAA   d) UGA.

135.     DNA generally acts  as a template for :

        a) Protein, DNA, RNA.      

        b) Only protein and DNA

        c) Only DNA and RNA.  

        d) Only DNA.

136. Reading from 3' end of DNA template, if the sequence of the bases on DNA strand is A-T-G, what would be the sequence of bases in the complementary anticodon reading from 3'end of  the t-RNA?

        a) U- A- C                       b) A- U- G

        c) A-T- G                         d) T- A- C

137.     In the AA - t RNA complex, the amino acid is bound to the t RNA at the

        a) 3' end with C - C - A base sequence

        b) 5' end with C - C - A base sequence

        c) 3' end with G nucleotide

        d) 5' end with G nucleotide

138.  Activation of amino acid during protein  synthesis uses energy from

        a)GTP                       b) ATP  

        c) ADP                      d) AMP

139.     There are 64 codons in the dictionary of genetic code, because genetic code is

        a)Degenerate                               b) Universal

        c) Wobble                                                d) Triplet

140. Dose not consume ATP energy.

        a) Amino acid activation  

        b) Translocation

        c) Translocation

        d) Aminoacyl I - t RNA complex `binding to  A- site

141.     A small segment of eukaryote DNA contains 75 guanine and 75 thymine bases. The total number of nucleotides in this segment of DNA is

        a) 75                               b) 150     

        c) 300                             d) 450

142. Suppose a complete polypeptide chain contains 100 amino acid molecules. How many nitrogen bases will be involved in the genetic code on the m- RNA for the formation and release of such polypeptide chain

        a)100       b) 300       c) 303        d)306

143.     Which one of the following is the cause of  the wobble phenomenon ?

        a) Over crowing of amino acid during     protein synthesis

        b) Interference of extra codons on m- RNA.

        c) Non- availability of proper t-RNA    `molecules.

        d) Degeneracy of the genetic code.

144.     The following are the codon -anticodon         pairs. Identify the pair showing effect of the degeneracy of genetic code

        a) AUG - UAC               b) UUA - AAG

        c) AAC - UUG               d) GUG - CAC

145. 'Genome' represents

        a) Total number of chromosomes in a cell.

        b) Total number of genes presents on a chromosome compliment.

        c) Total number of genes presents on all the chromosome compliment

        d) Total number of genes presents on  the diploid set of chromosomes.

146.     DNA duplication occurs during

        a)Mitosis only                b) Meiosis only

        c)Meiosis- I only  

        d) Meiosis-II and mitosis

147.  The anticodon on t-RNA which can   identify specific codon on m- RNA is also Known as

        a) Genetic code                           b) Triplet

        c) Nodoc                                                  d) Codon

148. The degeneracy of genetic code and economy of number of t- RNA in a cell can be explained by

        a) Watson and Crick model        

        b) Chargaff’s rule

        c) Wobble hypothesis           

        d) Lyon hypothesis

149.  Who provided the first clear evidence to establish DNA as the genetic material?

        a) Avery, Macleod and Mc Carty

        b) Hershey and Chase

        c) Lederberg and Zinder

        d) Franki - Conrai and Singer

150. Double stranded DNA is presents in

        a) M 13 phage      b) f d phage

        c) Reovirus                      d) Bacterium E. coli.

151.     The octamer core of nucleosome is made of a total of 8 molecules of

        a) 8 types of histones 

        b)4 types of histones

        c) one type of histones

        d)Two types of histones

152.     Suppose a particular segment of a DNA is 100 base pairs long then it

        a) Be 340 Ao  long  

        b)contain 100 nucleotides

        c) Contain 100 bases        

        d) All of these

153.     Suppose a molecule of m- RNA contains 25 Adenine and 25 Guanine bases. Then it must

        a) Be 100 nucleotides long

        b) Contain 25 uracil and 25 cytosine bases

        c) Be 50 base pairs long

        d) None of these

154.     If  a DNA strand is 340 Ao long, then is should contain

        a) 340 bases            b) 100 nucleotide

        c) Contain a N- base     d) All of these

155.     A nucleoside phosphate

        a) Contains a pentose sugar

        b) Is a nucleotide

        c) Contain a N- base.            

        d) All of these

156. A bacterium containing 100% N15 nitrogen bases is allowed to replicate in a medium containing N14 bases. After one round of duplication, the result would be

        a) all individuals would be identical parents

        b) all individuals would be radioactive but the percentage of radioactivity in DNA would be 50%

        c) only 50% individuals would be radioactive

        d) all individuals would be similar to parents but different among themselves.

157. A bacterium E. coli with completely radioactive DNA was allowed to replicate in a non-radioactive medium for two generations. What % of the bacteria should contain radioactive DNA?

        a) 100%      b) 50%      c) 25%     d) 12.5%

158.     If one wants to obtain precise information regarding the exact time and location of synthesis of new DNA, which of the following methods would be most effective for such study ?

        a) Electron microscopy   b) Carbon dating

        c) Isolating and extracting DNA after regular intervals and estimating DNA among

        d) Using radioactive precursors of nucleic acids

159)     Experiments using N15 (heavy nitrogen) to confirm the semiconservative replication of DNA were carried out by

        a) Meselson and Stahl  b) Hershey and Chase

        c) Beadle and Tatum    d) Watson and Crick

160)     In an E.coli cell, according to the operon theory, an operator gene combines with

        a) inducer gene to 'switch on' structural gene transcription

        b) regulator gene to 'switch off' structural gene transcription

        c) regulator protein to 'switch off' structural gene transcription

        d) regulator protein to 'switch on' structural gene transcription

161)     According to operon concept, the regulatory gene regulates biochemical reaction in a cell by

        a) inhibiting transcription

        b) inactivating enzymes

        c) inactivating substrate

        d) inhibiting migration of mRNA

162)     Lac operon is related to the

        a) synthesis of enzyme of lactose anabolism

        b) synthesis of enzyme of lactose catabolism

        c) synthesis of lac by lac insect

        d) degradation of lac in the body of lac-insect

163)     The lac operon requires a 'helper' protein which, by binding to the promoter and by facilitating the attachment of RNA polymerase, accelerates the rate of transcription. The protein is

        a) amino acid activating enzyme

        b) essential metabolite

        c) inactive repression protein

        d) catabolite activator protein

164)     Addition of lactose in a culture of E.coli induces enzymes.... to breakdown the lactose into glucose and galactose.

        a) b-galactosidase and transacetylase

        b) transacetylase and permease

        c) b-galactosidase, permease, transacetylase

        d) None of the above

165)     A regulatory gene produces some kind of protein through its mRNA that control the activity of the operator gene, which signals the formation of specific enzymes required for the metabolic breakdown of the food. How does that protein regulate the activity of the operator gene ?

        a) The repressor protein produced after combining with an inducer activates the operator gene

        b) The repressor protein produced after combining with a corepressor activates the operator gene

        c) the catabolic activator protein (CAP) produced activates the operator gene

        d) The mutated repressor protein produced activates the operator gene

166)     If following is the sequences of nucleotides in mRNA, predict the sequence of amino acids coded by it

        AUG UUU UUC UUC UUU UUU UUC

        a) Met-Phe-Phe-Phe-Phe-Phe-Phe

        b) Met-Phe-Leu-Leu-Phe-Phe-Phe

        c) Ser-Leu-Phe-Leu-Phe-Leu-Phe

        d) Arg-Leu-Leu-Leu-Leu-Leu

167)     After crossing two plants, the progenies are found to be male sterile. The phenomenon is found to be maternally inherited and is due to some gene, which reside in

        a) nucleus chloroplast     b) chloroplast

        c) mitochondria               d) cytoplasm

168)     Genetic code translates the language of

        a) RNA into that of proteins

        b) proteins into that of RNA

        c) amino acids that into that of RNA

        d) RNA into that of DNA

169)     Sigma factor is a component of

        a) DNA ligase      b) DNA polymerase

        c) RNA polymerase) Dissociation factor

170)     Genes for antibiotic resistance are located in

        a) plasmid                        b) nucleus

        c) chromosome    d) plastid

171)     Producing a giant mouse in the laboratory was possible through the

        a) gene mutation b) gene duplication

        c) gene synthesis d) gene manipulation

172) The smallest unit of genetic material, which when mutated produces a phenotypic effect, is

        a) recon                b) muton

        c) nucleic acid     d) cistron

173) Replication of DNA in eukaryotes commences from

        a) one end of chromatid extending to the other end

        b) the centromeres to either of the ends of chromatids

        c) several sites along the DNA of the chromatid simultaneously

        d) both ends of the chromatid simultaneously

174)     In split genes, the coding sequences are

        a) exons                           b) introns

        c) cistrons                                    d) operons

175)     The translation step in the process of protein synthesis, which is the conversion of the language of nucleic acids into that of proteins, is made by a form of

        a) mRNA                         b) rRNA

        c) tRNA               d) template DNA

176)     Which one of the following statements is incorrect ?

        Mutagens can be

        a) analogues of bases

        b) agents that make bases labile and permit substitution

        c) substances that interfere with the fidelity of nucleic acid replication

        d) agents that catalyse or retard chemical reactions

177)     TMV infects a variety of plants, including Zinnia (family - Compositae) and tobacco (family - Solanaceae). When TMV-RNA is used for infection, the amino acid sequence of the coat protein of the progeny is the same whether the host of Zinnia or tobacco. This proves that the genetic code is

        a) degenerate                   b) universal

        c) unidirectional              d) non-overlapping

178)     Amino acids polymerise at the ribosome

        a) amino group of the first amino acid (methionine) with the carboxyl group of the second, producing a peptide bond and releasing a molecule of water

        b) carboxyl group of the first amino acid (methionine) with that of the second, producing a peptide bond and releasing a molecule of water

        c) carboxyl group of the first amino acid (methionine) with the amino group of the second, producing a peptide bond and releasing a molecule of water

        d) amino group of the first amino acid (methionine) with that of the second, producing a peptide bond and releasing a molecule of water.

179)     The gene, which produces mRNA has specific start and stop signals, which have the same structure whether they are read from left to right to left. This is because

        a) the base sequence is the same either way

        b) they have the same base repeated many times

        c) they have only one base

        d) they have only one codon

180)     Which of the following is not true for an anticodon?

        a) It consists of three nucleotides

        b) It is the basic unit of the genetic code

        c) It extends from one end of a tRNA molecule

        d) It may pair with more than one codon, especially if it has the base inosine in its third position.