CBSE Questions for Class 12 Medical Biology Molecular Basis Of Inheritance Quiz 16 - MCQExams.com

The relative percentages of nitrogenous bases of the genetic material isolated from various species (P, Q, R, S and T) are listed in the following table.
SpeciesAdenineGuanineThymineCytosineUracil
P$$21$$$$29$$$$21$$$$29$$$$0$$
Q$$29$$$$21$$$$29$$$$21$$$$0$$
R$$21$$$$21$$$$29$$$$29$$$$0$$
S$$21$$$$29$$$$0$$$$29$$$$21$$
T$$21$$$$29$$$$0$$$$21$$$$29$$

Choose the correct statement from the following.
  • Species P, Q and R contain single-stranded DNA; S and T cannot contain double-stranded RNA
  • Species P, Q and R contain double-stranded RNA; species S and T contain single-stranded RNA
  • Species P, Q and R cannot contain single-stranded DNA; species S contains single-stranded RNA; species T contains double-stranded RNA
  • Species P and Q contain double-stranded DNA; species R contains single-stranded DNA; species S contains double-stranded RNA; species T contains single-stranded RNA
Transcription unit
  • starts with TATA box
  • starts-with pallendrous regions and ends with rho factor
  • starts with promoter region and ends in terminator region
  • starts with CAAT region
Match column I with column II and select the correct option from the-given codes.
Column I
(Codons)
Column II
(Translated amino acid)
A.UUU(i)Serine
B.GGG(ii)Methionine
C.UCU(iii)Phenylalanine
D.CCC(iv)Glycine
E.AUG(v)Proline
  • A-(iii), B-(iv),C-(i), D-(v), E-(ii)
  • A-(iii), B-(i),C-(iv), D-(v), E-(ii)
  • A-(iii), B-(iv),C-(v), D-(i), E-(ii)
  • A-(ii), B-(iv),C-(i), D-(v), E-(iii)
Choose the correct answer from the alternatives given :
Watson and Crick (1953) proposed DNA double helix model and won the Nobel Prize; their model of DNA was based on
(i) X-ray diffraction studies of DNA done by Wilkins and Franklin
(ii) Chargaffs base equivalence rule
(iii) Griffiths transformation experiment
(iv) Meselson and Stahls experiment.
  • (i), (ii) and (iv)
  • (i) and (ii)
  • (iii) and (iv)
  • (i), (ii), (iii) and (iv)
Choose the correct answer from the alternatives given :
Other than DNA polymerase, which are the enzymes involved in DNA synthesis?
  • Topoisomerase
  • Helicase
  • RNA primase
  • All of these
Choose the correct answer from the alternatives given :
Match column I with column II and select the correct option from the given codes.
Column I
(Scientists)
Column II
(Discoveries)
A.Alec Jeffreys(i)Lac operon
B.F. Sanger(ii)Annotated DNA sequences
C.Jacob and Monod(iii)DNA fingerprinting
D.Avery, MacLeod and McCarty(iv)Transforming principle
  • A - (ii), B - (iii), C - (iv), D - (i)
  • A - (iii), B - (ii), C - (i), D - (iv)
  • A - (iii), B - (ii), C - (iv), D - (i)
  • A - (i), B - (ii), C - (iii), D - (iv)
Choose the correct answer from the alternatives given :
Read the following statements.
(i) One codon codes for only one amino acid.
(ii) Some amino acids are coded by more than one codon.
(iii) The, sequence of triplet nitrogenous bases in DNA or mRNA corresponds to the amino acid sequence in the polypeptide chain.
Give suitable terms for the characteristics of genetic code as per the above statements.
  • Degeneracy - (i), Colinearity - (ii), Unambiguous - (iii)
  • Degeneracy - (iii) , Colinearity - (ii) , Unambiguous - (i)
  • Degeneracy - (ii) , Colinearity - (iii) , Unambiguous - (i)
  • Degeneracy - (i) , Colinearity (ii) , Unambiguous - (iii)
Select the correct option that correctly fill the blanks i - iv
I. Less than (i) of genome represents structural genes that code for proteins.
II. Chemical substance that binds with repressor and convert it into a non-DNA binding State is (ii).
III. In prokaryotes, during replication RNA primer is removed by (iii) whereas in eukaryotes it is removed by (iv).
  • (i) - 5%, (ii) regulator, (iii) - DNA polymerase II, (iv) - DNA polymerase $$\beta$$
  • (i) - 10%, (ii) - regulator, (iii) - DNA polymerase I, (iv) - DNA polymerase $$\alpha$$
  • (i) - 2%, (ii) inducer, (iii) - DNA polymerase I, (iv) - DNA polymerase $$\beta$$
  • (i) - 50%, (ii) inducer, (iii) - DNA polymerase III, (iv) - DNA polymerase $$\alpha$$
Choose the correct answer from the alternatives given :
If Meselson and Stahls experiment is continued for four generations in bacteria, the ratio of $$N^{15}$$- $$N^{15}$$, $$N^{14}$$ - $$N^{15}$$, $$N^{14}$$ - $$N^{14}$$  containing DNA in the fourth generation would be
  • 1:1:0
  • 1:4:0
  • 0:1:3
  • 0:1:7
DNA is a polymer of nucleotides which are linked to each other by 3-5 phosphodiester bond. To prevent polymerisation of nucleotides, which of the following modifications would you choose?
  • Replace purines with pyrimidines.
  • Remove/Replace 3 OH group in deoxyribose.
  • Remove/Replace 2 OH group with some other group in deoxyribose.
  • Both (b) and (c).
The promoter site and the terminator site for transcription are located at
  • 3 (downstream) end and 5 (upstream) end, respectively of the transcription unit
  • 5 (upstream) end and 3 (downstream) end, respectively of the transcription unit
  • the 5 (upstream) end
  • the 3 (downstream) end.
Which of the following statements are correct?
(i) RNA polymerase I transcribes rRNAs.
(ii) RNA polymerase II transcibes snRNAs.
(iii) RNA polymerase III transcibes hnRNA,
(iv) RNA polymerase II transcribes hnRNA.
  • (i) and (ii)
  • (i) and (iii)
  • (i), (ii) and (iv)
  • (i) and (iv)
Which of the following statements regarding human genome is incorrect?
  • Human genome consists of $$3 \, \times \, 10^9$$ bp and about 20,500 genes.
  • The average gene size is 3000 bop and dystrophin is the largest known human gene.
  • Chromosome 1 contains maximum (2968) number of genes and Y-chrbmosome has the least (231) number of genes.
  • Repeated (or repetitive) sequences are not present in human genome.
Choose the correct answer from the alternatives given :
A DNA template plus primer with the structure
3 P - TG C GAATTAG C GACAT - P5
5 P - ATCGGTACGACGCTTAAC OH 3
(where P = a phosphate group) is placed in an in vitro DNA synthesis system containing $$Mg^{2+}$$, an excess of the four deoxyribonucleoside triphosphates, etc. and a mutant form of E. Coli DNA polymerase I that lacks 5 $$\rightarrow$$ 3 exonuclease activity. The 5 $$\rightarrow$$ 3 polymerase and. 3 $$\rightarrow$$ 5 exonuclease activities of this aberrant enzyme are identical to those of normal E. Coli DNA polymerase I. It simply has no 5 $$\rightarrow$$ 3 exonuclease activity. What will be the structure of the final product?
  • 3P-TGCGAATTAGCGACAT- P 5

    5 P -ATCG GTAC GACG CTTAATCG CTGTA-OH 3
  • 3 P -T6CGAATTGGCGACAT- P 5

    5 P -ATCG GTACGAC GCTTAAC C G CTGTA-OH 3
  • 3HOTGCGAATTAGCGACAT P 5

    5-ATCG GTAC GACG CTTAATCG CTGTA - P 3
  • 3 P TGCGAATTAGCGACAT P 5

    5 P -ACGCTTAATCGCTGTA-OH3
How many amino acids will be coded by the mRNA sequence - 5 CCCUCAUAGUCAUAC3 if a adenosine residue is inserted after 12th nucleotide?
  • Five amino acids
  • Six amino acids
  • Two amino acids
  • Three amino acids
The enzyme polynucleotide phosphorylase randomly assembles nucleotides into a polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine triphosphate, how many types artificial  $$mRNA$$ 3 nucleotide codons would be possible?
  • $$3$$
  • $$4$$
  • $$8$$
  • $$16$$
During autocatalysis of DNA, which one of the following provide free OH group and is also used to anchor for addition of new DNA nucleotides? 
  • DNA polymerase
  • Ligase
  • RNA primer
  • Topoisomerase
If the sequence if the nitrogenous bases on template strand is ATCTGGCGT, what would be the sequence of mRNA transcribed from it?
  • AUCACCGCU
  • UUCUGGCGU
  • UAGACCGCA
  • AUGUCCGCU
How many amino acids will be coded by the sequence if the 14$$^{th}$$ base of given mRNA, converts to G?
5' AUG UUU CUC UAG CCG 3'
  • Three
  • Five
  • Four
  • Two
Which one of the incorrect statement regarding DNA polymerase III?
  • It is used to ligate any DNA fragment
  • Can directly bind to ori site
  • It is isolated from a virus
  • All of (A), (B) and (C)
Which of the following enzyme creates a homonucleotide overhang at the $$3'$$-OH end of the DNA? It can also make blunt ends sticky by adding poly AA and poly TT.
  • Terminal Transferase
  • Methylase
  • Alkaline phosphatase
  • DNA Pol III
Analysis of DNA of an organism revealed the following characters. Mark the option that is not likely to be true if the organism is a cat. 
  • The double helix is antiparallel & a linear molecule
  • 20 bases comprising of a mixture of deoxyribonucleotide phosphates (dNTPs) were found in a single $$360^o$$ turn of helix
  • 17 % of the nitrogenous bases were shown to be cysteines
  • Uracil was lacking but guanine was 17 %
If DNA was made of $$6$$ nucleotides instead of $$4$$, what are the total number of triplet codons  possible?
  • $$24$$
  • $$18$$
  • $$64$$
  • $$216$$
In E.coli, complete DNA replication requires ____ mins.
  • 38 hours
  • 20 minutes
  • 40 minutes
  • 3 minutes
DNA strands are anti parallel because of
  • H-bonds
  • Phosphodiester bonds
  • Disulphide bonds
  • Peptide bonds
Choose the incorrect statement regarding DNA structure.
  • Base stacking destabilise DNA double helical structure.
  • Each chain in DNA constitute sugar-phosphate backbone
  • Two chains are coiled in right handed fashion
  • The pitch of the helix has roughly 10 bp.
A couple claimed in court that a child belonged to them. Their claim can be true if the DNA fingerprint pattern of the child shows:
  • $$50\%$$ bands similar to father and $$50\%$$ similar to another DNA fingerprint pattern
  • $$100\%$$ similarity to both the parents DNA fingerprint as both contribute equally to zygote formation
  • $$100\%$$ similarity to mother's DNA fingerprint because of material inhentance
  • $$100\%$$ similarity to father's DNA fingerprint due to large number of mitochondria in sperm
DNA fingerprinting can't be performed without:
  • Restriction endonucleases
  • Agarose
  • Monoclonal antibodies
  • Both (a) and (b)
Which of the following is not associated with DNA fingerprinting?
  • Southern blotting
  • Gel electrophoresis
  • Restriction digestion
  • DNA sequencing
Find the odd one out
  • Transcription
  • Transduction
  • Translocation
  • Mutation
Join properly Column-I and Column-II.
Column IColumn II
(A) UUU$$(1)$$ Lysin
(B) GGC$$(2)$$ Stop codon
(C) AAA$$(3)$$ Phenyl Alanine
(D) UAA$$(4)$$ Glycine
  • a-$$2$$, b-$$3$$, c-$$4$$, d-$$1$$
  • a-$$4$$, b-$$3$$, c-$$1$$, d-$$2$$
  • a-$$1$$, b-$$4$$, c-$$3$$, d-$$2$$
  • a-$$3$$, b-$$4$$, c-$$1$$, d-$$2$$
If the length of DNA strand is $$ { 68A }^{ \circ  }$$ then, what will be the number of nucleotides present in DNA molecule
  • 20
  • 40
  • 60
  • 80
Which of the following is not include in transcription unit?
  • Promoter region
  • Terminator region
  • Structural gene
  • Replicon
The whole genome of Escherichia coli having $$4.6\times 10^6$$ bp will be replaced in?
  • $$2$$ minutes
  • One hour
  • $$40$$ minutes
  • $$38$$ minutes
A codon has a sequence of A, and specifies a particular B that is to be incorporated into a C. What are A, B, and C?
  • 3 bases, amino acid, and carbohydrate
  • 3 acids, carbohydrate, and protein
  • 3 bases, protein, and amino acid
  • 3 bases, amino acid, and protein
The technique of DNA fingerprint is superior to conventional fingerprint because it can:
  • Be generated more rapidly and is inexpensive
  • Generate unique fingerprint for each finger
  • Compare the whole DNA sequence of two individuas
  • Differences between polymorphic DNA sequences among individuals
Which of the following statement is incorrect about DNA fingerprinting?
  • It is used to identify racial groups.
  • Show high degree of polymorphism.
  • It is used to detect sex during fetal development.
  • It is used in medico-legal suits.
Which of the following is codons codes for proline.
  • CCC, CCU, CCG
  • UCC, UGU, CCU
  • CUG, CUU, CUA
  • CGC, CGG, CCA
The nucleic acid synthesis takes place in 
  • 3-5 direction
  • 5’-3’ direction
  • 4’-3’ direction
  • 6’-3’ direction
Which of the following statements is correct
  • Adenine pairs with thymine through one H-bond
  • Adenine pairs with thymine through three H-bonds
  • Adenine does not pair with thymine
  • Adenine pairs with thymine through two H-bonds
If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNAdouble helix in a typical mammalian cell is $$6.6 \times 10^9$$ bp, then the length of the DNA is approximately: 
  • 2.5 meters
  • 2.2 meters
  • 2.7 meters
  • 2.0 meters
0:0:1


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