CBSE Questions for Class 12 Medical Biology Molecular Basis Of Inheritance Quiz 2 - MCQExams.com

The process of formation of mRNA from DNA is known as
  • Transformation
  • Translation
  • Transcription
  • Translocation
  • Relication
In genetic code, $$61$$ codons code for $$20$$ different types of amino acids. This is called.
  • Colinearity
  • Commaless
  • Degeneracy
  • Non-ambiguity
Which of the following is an application  of human genome project?
  • Understanding of phylogenetic disorder
  • Improvement in gene therapy
  • Understanding of mutation concept
  • All of the above
Which one of the following is a stop codon ?
  • UAG
  • UAC
  • AUG
  • UCA
Which of the following enzymes is not necessary for the process of DNA replication?
  • Helicase
  • DNA polymerase
  • Ligase
  • RNA polymerase
Who discovered DNA fingerprinting?
  • Alec Jeffrey
  • Jacob Monod
  • Herbert Boyer
  • Stanley Cohen
There are 64 coders in genetic code dictionary because
  • There are 64 amino acids to be coded
  • There are 44 Meaningless and 20 codons for amino acids
  • There are 64 types of t-RNAs found in the cell
  • Genetic code is triplet
In the double helix model of DNA, what would be the distance between two consecutive base pairs?
  • 3.4 nm
  • 2 nm
  • 20 nm
  • 0.34 nm
One turn of the helix in a B-form DNA is approximately 
  • 3.4 nm
  • 2 nm
  • 20 nm
  • 0.34 nm
Which of the following statements is not true for retroviruses:
  • The gentic material in mature retroviruses in RNA
  • Retroviruses are causative agents or certain kinds of

    cancer in man
  • DNA is not present at any stage in the life cycle of

    retroviruses
  • Retroviruses carry gene for RNA-dependent DNA

    polymerase

DNA ligase helps in:      
  • Joining segments of DNA
  • Splitting or separation of two strands of DNA
  • Renaturation
  • Denaturation

The enzyme which helps to cut one strand of DNA duplex to release tension of coiling of two strands is
  • DNA ligase
  • DNA Polymerase I
  • Topoisomerase
  • Swielases (helicase or unwindases)
The mechanism of removing introns followed by joining of the exons in a defined order during transcription is called
  • Splicing
  • Tailing
  • Transformation
  • Capping
DNA replication is aided by
  • DNA polymerase only
  • DNA ligase only
  • Both DNA polymerase and ligase
  • RNA polymerase
Histone occupies the major grooves of DNA at an angle of 
  • 15$$^o$$
  • 90$$^o$$
  • 45$$^o$$ to the helix axis
  • 30$$^o$$ to the helix axis
Which one of the following is a base analogue?
  • Nitrous acid
  • Colchicine
  • 5 - bromouracil
  • Caffeine
The two polynucleotide chains in a DNA are
  • Parallel
  • Discontinuous
  • Antiparallel
  • Semiconservative
What is the name of double helix model of Watson and Crick?
  • C-DNA
  • B-DNA
  • Z-DNA
  • D-DNA
Nucleotides in the two helical strands of DNA are held together by
  • Hydrogen bond
  • Covalent bond
  • Van der Waals bond
  • Electrovalent bond
DNA repair in prokaryotes in carried out by
  • Ligase
  • DNA polymerase III
  • DNA polymerase II
  • None of the above
Who among the following did not provide experimental proof for the semiconservative model of DNA replication?
  • Meselson & Stahl
  • Cairns
  • Watson & Crick
  • Taylor

If the DNA codons are ATG ATG ATG and a cytosine base is inserted at the beginning, which of the following will result?
  • A non-sense mutation
  • CT TGA TGA TG
  • CAT GAT GAT G
  • C CTG ATG ATG
What is the width of DNA molecule?
  • 15 A$$^o$$
  • 20 A$$^o$$
  • 25 A$$^o$$
  • 34 A$$^o$$
The 3'- 5' phosphodiester linkages inside a polynucleotide chain serve to join
  • One nucleotide with the another nucleotide
  • One nucleoside with another nucleoside
  • One deoxyribose sugar with another nucleoside
  • One nitrogenous base with pentose sugar
During Meselson and Stahl's experiments, heavy DNA was distinguished from normal DNA by which type of centrifugation?
  • CsOH gradient
  • $$^{14}NH_{4}Cl$$
  • $$^{15}NH_{4}Cl$$
  • $$^{35}SO_{2}$$
  • CsCl gradient

The enzyme that breaks Hydrogen bonds between the 2 strands of a DNA molecule is 
  • Helicase
  • Topoisomerase
  • Ligase
  • Polymerase
Genetic code consists of
  • 4 codons, each with two nucleotides
  • 16 codons, each with four nucleotides
  • 64 codons, each with two nucleotides
  • 64 codons, each with three nucleotides
Purines possess nitrogen at which position?
  • 1, 2, 4 and 6 position
  • 1, 3, 5 and 7 position
  • 1, 3, 7 and 9 position
  • 1, 2, 6 and 8 position
The codons causing chain termination (stop codons) are 
  • TAG, TGA
  • GAT, AGT
  • AGT, TAG, UGA
  • UAG, UGA, UAA
When more than one codon codes for the same amino acid, what is this called?
  • Universal nature of genetic code
  • Redundancy of genetic code
  • Punctuation in genetic code
  • Continuous nature of genetic code
Khorana got the Nobel prize for
  • DNA synthesis
  • Genetic code
  • Protein synthesis
  • Enzyme synthesis
Which of the following statement is not true for genetic code?
  • A codon in mRNA is read in a non-contiguous fashion.
  • It is nearly universal.
  • It is degenerate.
  • It is unambiguous.
Set of three bases (codon) in the genetic code represent ____.
  • Protein
  • Amino acid
  • Plasmid
  • Nucleic acid
All the terminator codons begin with which nitrogenous base?
  • Adenine
  • Uracil
  • Guanine
  • Cytosine

There are 64 types of codons in genetic code dictionary because
  • There are 64 types of tRNA's found in cell.
  • There are 44 meaningless and 20 codons for amino acids.
  • There are 64 amino acids for coding.
  • Genetic code is triplet.
Assumption that genetic code is a triplet was suggested by?
  • Gamow
  • Beadle and Tatum
  • S. Brenner
  • Nirenberg and Matthaei
Code of a mature mRNA and the protein synthesized from it are
  • Coplanar
  • Collinear
  • Nonlinear
  • Irregular
Which one of the following pairs is correctly matched?
  • Ribosomal RNA - carries aminoacids to the site of protein synthesis
  • Transcription - process by which protein is synthesized
  • Translation - process by which mRNA carries the information from nucleus to the ribosome
  • Anticodon - site of tRNA molecule that contains complementary bases to the triple code on the mRNA
Which one of the following is common to both prokaryotes and eukaryotes?
  • Endoplasmic reticulum
  • Histones
  • Mitochondria
  • Genetic code
  • None of the above
Out of 64 codons, 61 codons code for 20 types of amino acid. What is it called as?
  • Wobbling of codon
  • Overlapping of gene
  • University of codons
  • Degeneracy of genetic code
A sequence of how many nucleotides in messenger RNA makes a codon for an amino acid?
  • One
  • Two
  • Three
  • Four
Genetic code is a translation of the language of
  • RNA into that of proteins
  • Proteins into that of RNA
  • Amino acids into that of RNA
  • RNA into that of DNA

Which of the following is the simplest amino acid?
  • Tyrosine
  • Asparagine
  • Glycine
  • Alanine
What is an anticodon?
  • Paired triplet of bases on messenger RNA
  • Unpaired triplet of bases on rRNA
  • Paired triplet of bases on rRNA
  • An unpaired triplet of bases in an exposed position of tRNA

Which of the following are a diamino and dicarboxylic amino acid?
  • Cystine
  • Lysine
  • Cysteine
  • Aspartic acid
The number of triplet codons having all the three bases same in 64 triplet codons is
  • 2
  • 4
  • 6
  • 8

The process by which DNA of nucleus passes genetic information to mRNA is called
  • Translocation
  • Transcription
  • Translation
  • Transportation
A triplet codon represents
  • A sequence of three nitrogen bases on mRNA
  • A sequence of three nitrogen bases in tRNA
  • A sequence of three bases in rRNA
  • The presence of only three bases in mRNA
The one aspect which is not a salient feature of genetic code is, its 
  • Specificity
  • Degeneracy
  • Ambiguity
  • Relativity

Which one of the following statement is not correct?
  • Cysteine is coded by UGU and UGC codons.
  • Tyrosine is coded by UAU and UAC codons.
  • UAA codon codes for lysine.
  • UGG codon codes for tryptophan.
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