#4 Biology Class 12 Chapter 4- Molecular Basis of Inheritance MHTCET / NEET MCQ
(1) Griffith worked on .......... .
(a) Bacteriophage
(b) Drosophila
(c) Frog eggs
(d) Streptococci
Answer-
(d) Streptococci
(2) The molecular knives of DNA are .......... .
(a) Ligases
(b) Polymerases
(c) Endonucleases
(d) Transcriptase
Answer-
(c) Endonucleases
(3) Translation occurs in the .......... .
(a) Nucleus
(b) Cytoplasm
(c) Nucleolus
(d) Lysosomes
Answer-
(b) Cytoplasm
(4) T he enzyme required for transcription is .......... .
(a) DNA polymerase
(b) RNA polymerase
(c) Restriction enzyme
(d) RNase
Answer-
(b) RNA polymerase
(5) T ranscription is the transfer of genetic information from .......... .
(a) DNA to RNA
(b) t-RNA to m-RNA
(c) DNA to m-RNA
(d) m-RNA to t-RNA
Answer-
(a) DNA to RNA
(6) Which of the following is NOT part of protein synthesis ?
(a) Replication
(b) Translation
(c) Transcription
(d) All of these
Answer-
(a) Replication
(7) I n the RNA molecule, which nitrogen base is
found in place of thymine ?
(a) Guanine
(b) Cytosine
(c) Thymine
(d) Uracil
Answer-
(d) Uracil
(8) H ow many codons are needed to specify three amino acids ?
(a) 3
(b) 6
(c) 9
(d) 12
Answer-
(a) 3
(9) Which out of the following is NOT an example of inducible operon ?
(a) Lactose operon
(b) Histidine operon
(c) Arabinose operon
(d) Tryptophan operon
Answer-
(d) Tryptophan operon
(10) Place the following event of translation in the correct sequence
i. Binding of met-t-RNA to the start codon.
ii. C ovalent bonding between two amino acids.
iii. Binding of second t-RNA.
iv. Joining of small and large ribosome subunits.
(a) iii, iv, i, ii
(b) i, iv, iii, ii
(c) iv, iii, ii, i
(d) ii, iii, iv, i
Answer-
(b) i, iv, iii, ii
(11) How many of the following characteristics are shown by R-strain of Streptococcus pneumoniae ?
Avirulent, Smooth, Pathogenic, Capsulated
(a) One
(b) Two
(c) Three
(d) Four
Answer-
(a) One
(12) Griffith obtained .......... from the blood of the dead mice.
(a) dead S-strain bacteria
(b) live R-strain bacteria
(c) dead R-strain bacteria
(d) live S-strain bacteria
Answer-
(d) live S-strain bacteria
(13) O swald T. Avery, Colin M. MacLeod and Maclyn McCarty demonstrated that .......... .
(a) transformation of live S-strain bacteria into R-strain type was because of DNA of bacteria of S-strain.
(b) the transforming substance was either a protein or RNA.
(c) only DNA was able to transform harmless R-strain into virulent S-strain.
(d) when DNA isolated from S-strain bacteria, was digested with DNase, the transformation occurred.
Answer-
(c) only DNA was able to transform harmless R-strain into virulent S-strain
(14) Which of the following was NOT observed in Hershey and Chase experiment ?
(a) Viruses grown in the presence of radioactive sulphur, had radioactive protein but not radioactive DNA.
(b) Radioactive ‘P’ remained in suspension.
(c) Only radioactive ‘P’ was found inside the bacterial cells in the pellet.
(d) Viruses grown in the presence of radioactive phosphorus contained radioactive DNA but not radioactive proteins.
Answer-
(b) Radioactive ‘P’ remained in suspension.
(15) E nzymes like .......... and DNA topoisomerase-I, play important role in maintaining super-coiled state in rokaryotic
DNA.
(a) DNA ligase
(b) DNA gyrase
(c) RNA polymerase
(d) N one of these
Answer-
(b) DNA gyrase
(16) Histone octamer of nucleosome has two molecules, each of .......... proteins.
(a) H2A, H2B, H3 and H4
(b) H2A, H2B, H3 and H1
(c) H2A, H2B, H3A and H3B
(d) H1A, H2B, H3A and H4
Answer-
(a) H2A, H2B, H3 and H4
(17) Select the CORRECT statement.
(a) E uchromatin is mainly located near centromere and telomeres.
(b) H eterochromatin replicates at faster rate than euchromatin.
(c) H eterochromatin has 2 to 3 times more DNA than in the euchromatin.
(d) H eterochromatin is lightly stained region of chromonema.
Answer-
(c) H eterochromatin has 2 to 3 times more DNA than in the euchromatin
(18) A DNA molecule in which both strands have 14N is allowed to replicate in an environment containing 15N. What will be the exact number of DNA molecules that contain the 14N after three replications ?
(a) One
(b) Two
(c) Four
(d) Eight
Answer-
(b) Two
(19) A s the base sequence present on one strand of DNA decides the base sequence of other strand, this strand is considered as .......... .
(a) descending strand
(b) leading strand
(c) lagging strand
(d) complementary strand
Answer-
(d) complementary strand
(20) I n prokaryotes, .......... recognizes the promoter sequence.
(a) alpha factor
(b) rho factor
(c) theta factor
(d) sigma factor
Answer-
(d) sigma factor
(21) I f the base sequence in DNA is 5'AAAA 3', then the base sequence in m-RNA is ......... .
(a) 5'UUUU 3'
(b) 3'UUUU 5'
(c) 5'AAAA 3'
(d) 3'TTTT 5'
Answer-
(c) 5'AAAA 3'
(22) During capping, methylated guanosine triphosphate is added to 5 end of .......... .
(a) m-RNA
(b) t-RNA
(c) hnRNA
(d) r-RNA
Answer-
(c) hnRNA
(23) If each codon has two nucleotides, then there will be .......... codons, which can encode for only .......... different types of amino acids.
(a) 16, 16
(b) 16, 20
(c) 20, 16
(d) 64, 64
Answer-
(a) 16, 16
(24) What would happen if in a gene encoding a polypeptide of 50 amino acids, 25th codon (UAU ) is mutated to UAA?
(a) A polypeptide of 24 amino acids is formed.
(b) T wo polypeptides of 24 and 25 amino acids will be formed.
(c) A polypeptide of 49 amino acids is formed.
(d) A polypeptide of 25 amino acids is formed.
Answer-
(a) A polypeptide of 24 amino acids is formed.
(25) A strand of DNA has following base sequence – 3 AAAAGTGAATA GTGA 5. On transcription it produces an m-RNA. Which of the following anticodon of t-RNA recognizes the third codon of this m-RNA ?
(a) AAA
(b) CUG
(c) AAG
(d) CTG
Answer-
(c) AAG
(26) Polynucleotide chain consisting of only CUA repeats will give polypeptide chain with only one amino acid .......... .
(a) tryptophan
(b) leucine
(c) serine
(d) methionine
Answer-
(b) leucine
(27) S elect the INCORRECT statement.
(a) Dr. Khorana prepared polyribonucleotides chains with known repeated sequences of two or three nucleotides by
using synthetic DNA.
(b) M. Nirenberg and Matthaei synthesized artificial m-RNA which was a homopolymer of uracil ribonucleotides.
(c) E nzyme polynucleotide phosphorylase polymerizes RNA with defined sequences in a template-dependent manner.
(d) E vidence for triplet nature of geneticcode, was given by Crick (1961) using “frame-shift mutation”.
Answer-
(c) E nzyme polynucleotide phosphorylase polymerizes RNA with defined sequences in a template-dependent manner.
(28) .......... is/are based on complementarity principle.
(a) Replication and translation
(b) Replication and transcription
(c) Translation
(d) Only replication
Answer-
(b) Replication and transcription
(29) C ysteine has .......... codons, while isoleucin has .......... codons.
(a) two, three
(b) three, two
(c) two, four
(d) four, two
Answer-
(a) two, three
(30) Out of 64 codons, only 61 code for the 20 different amino acids. This is known as .......... of genetic code.
(a) non-ambiguity
(b) overlapping nature
(c) ambiguity
(d) degeneracy
Answer-
(d) degeneracy
(31) Mutation that results in Sickle-cell anaemia is a .......... .
(a) deletion
(b) frame-shift mutation
(c) point mutation
(d) insertion
Answer-
(c) point mutation
(32) I nitiator charged t-RNA occupies the ..........of ribosome first.
(a) A-site
(b) P-site
(c) E -site
(d) either A-site or P-site
Answer-
(b) P-site
(33) I t takes .......... for formation of peptide bond.
(a) 10 seconds
(b) 0.1 second
(c) less than 0.1 second
(d) 60 seconds
Answer-
(c) less than 0.1 second
(34) A nticodon and codon bind by .......... .
(a) glycosidic bond
(b) hydrogen bond
(c) phosphodiester bond
(d) none of these
Answer-
(b) hydrogen bond
(35) The UTRs are present at .......... .
(a) 5'-end, before start codon and at 3-end,after stop codon of m-RNA
(b) 5'-end, before start codon and at 3-end, after stop codon of t-RNA
(c) only at 3'-end, after stop codon of m -RNA
(d) only at 5'-end, before start codon of m-RNA
Answer-
(a) 5'-end, before start codon and at 3'-end, after stop codon of m-RNA
(36) The action of structural genes is regulated by .......... site with the help of a ..........protein.
(a) operator, inducer
(b) operator, repressor
(c) regulator, repressor
(d) regulator, induce
Answer-
(b) operator, repressor
(37) R epressor protein is produced by the action of .......... .
(a) gene z
(b) gene y
(c) gene i
(d) gene o
Answer-
(c) gene i
(38) S elect the correct pair.
(a) Gene z – Transacetylase
(b) Gene y – Beta-galactocidase
(c) Gene a – Beta-galactoside permease
(d) Gene I – Repressor
Answer-
(d) gene I – repressor
(39) S tructural genomics involves .......... of genome.
(a) mapping
(b) sequencing
(c) analysis
(d) all of these
Answer-
(d) all of these
(40) T he technique of transferring DNA fragments separated on agarose gel to a synthetic nitrocellulose membrane is known as .......... .
(a) Southern blotting
(b) Autoradiography
(c) Southern hybridization
(d) None of these
Answer-
(a) Southern blotting
(41) S equence of various steps in DNA fingerprinting is .......... .
i. Southern blotting,
ii. Restriction digestion,
iii. Agarose gel electrophoresis,
iv. DNA isolation,
v. Photography,
vi. Selection of DNA probe,
vii. Hybridization
(a) iv, iii, ii, i, v, vi, vii
(b) iv, v, iii, i, vi, vii, ii
(c) iv, ii, iii, i, vi, vii, v
(d) ii, iii, iv, i, vi, vii, v
Answer-
(c) iv, ii, iii, i, vi, vii, v
