This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 12 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 12 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. The two nucleotides are linked by A) 3-5 phosphodiester bond. B) 3-5 hydrogen bond. C) 5-3 phosphodiester bond. D) 5-3 hydrogen bond. Show Answer Correct Answer: A) 3-5 phosphodiester bond. 2. Which of the following is incorrect regarding repeated sequences A) It is directly involved in coding functions. B) It makes the large portion of the genome. C) It helps to study the chromosome structure. D) It helps to study the evolution. Show Answer Correct Answer: A) It is directly involved in coding functions. 3. At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork:3' C C T A G G C T G C A A T C C 5'An RNA primer is formed starting at the red T of the template. Which of the following represents the primer sequence? A) 5' G C C T A G G 3'. B) 5' A C G U U A G G 3'. C) 3' G C C T A G G 5'. D) 5' A C G T T A G G 3'. Show Answer Correct Answer: B) 5' A C G U U A G G 3'. 4. Select the correct term to complete:Heterochromatin is ..... active. A) Transcriptionally active. B) Transcriptionally inactive. C) Translationally active. D) Replicationally active. Show Answer Correct Answer: B) Transcriptionally inactive. 5. Which of the following is incorrect regarding introns A) They do not appear in mature or processed RNA. B) They are intervening sequences. C) They are expressed in mature RNA. D) None of the above. Show Answer Correct Answer: C) They are expressed in mature RNA. 6. Which of the following is a genetic RNA? A) RNA present in plant viruses. B) Hn-RNA. C) MRNA. D) RRNA. Show Answer Correct Answer: A) RNA present in plant viruses. 7. The bioactive substance which removes clots from blood vessels is A) Statins. B) Streptokinase. C) Butyric acid. D) Cyclosporin A. Show Answer Correct Answer: B) Streptokinase. 8. In DNA you find which type(s) of bond******A. Phosphodiester******B. Phosphoester******C. Hydrogen******D. Glycosidic bond A) C, D. B) A, B, C, D. C) A, B, C. D) B, C, D. Show Answer Correct Answer: B) A, B, C, D. 9. In 1957, Meselson and Stahl concluded from their studies that A) DNA replicates dispersively. B) DNA does not replicate. C) DNA replicates semiconservatively. D) DNA replicates conservatively. Show Answer Correct Answer: C) DNA replicates semiconservatively. 10. Which of the following is required as inducer for the expression of lac operon? A) Lactose. B) Galactose and Lactose. C) Glucose. D) Galactose. Show Answer Correct Answer: A) Lactose. 11. Genetic information is passed onto the next generation through: A) DNA replication. B) Protein synthesis. C) All the above. D) None of the above. Show Answer Correct Answer: A) DNA replication. 12. To make protein with 178 amino acid from eukaryotic gene having 1350 bp, the length of initial and processed mRNA transcript would respectively be A) 1350 b, 537 b. B) 640 b, 52 b. C) 670 b, 540 b. D) 1350 b, 1350 b. Show Answer Correct Answer: A) 1350 b, 537 b. 13. Purines found both in DNA and RNA are A) Guanine and cytosine. B) Cytosine and thymine. C) Adenine and guanine. D) Adenine and thymine. Show Answer Correct Answer: C) Adenine and guanine. 14. The enzyme involved in amino acid activation is A) ATP synthase. B) Aminoacyl tRNA synthetase. C) Aminoacyl rRNA synthetase. D) Aminoacyl mRNA synthetase. Show Answer Correct Answer: B) Aminoacyl tRNA synthetase. 15. Which of the following molecules functions to transfer information from one generation to the next? A) TRNA. B) DNA. C) Proteins. D) MRNA. Show Answer Correct Answer: B) DNA. 16. In biochemical explanation of transformation, process of transformation of R-strain of Streptococcus did not get affected by all the following enzymes, except A) DNase. B) Protease. C) RNase. D) Lipase. Show Answer Correct Answer: A) DNase. 17. What role does the enzyme DNA ligase play during DNA replication A) Cleaves nucleotides. B) Opens the helix. C) Maintains the helix. D) Joins nucleotides. Show Answer Correct Answer: D) Joins nucleotides. 18. How far is each base pair from the next one in DNA double helix model? A) 2 nm. B) 34 nm. C) 0.34 nm. D) 3.4nm. Show Answer Correct Answer: C) 0.34 nm. 19. Nitrogenous bases are attached to the sugar in the nucleic acid by A) N-glycosidic linkage. B) N-glucoamine linkage. C) N-glycophosphate bond. D) None of the above. Show Answer Correct Answer: A) N-glycosidic linkage. 20. In *E. coli*, there is a mutation in a gene called *dnaB* that alters the helicase that normally acts at the origin of replication. Which of the following events would you expect to occur as a result of this mutation? A) Additional proofreading will occur. B) Replication will occur via RNA polymerase alone. C) Replication will require a DNA template from another source. D) No replication fork will be formed. Show Answer Correct Answer: D) No replication fork will be formed. 21. Which of the following enzyme is used to join DNAfragments:- A) DNA polymerase. B) Ligase. C) Endonuclease. D) Terminase. Show Answer Correct Answer: B) Ligase. 22. Which is the energy rich molecule required for initiation of translation A) GTP. B) ATP. C) CTP. D) AMP. Show Answer Correct Answer: A) GTP. 23. In the genetic code, the number of codons that actually code for amino acids is: A) 20. B) 64. C) 3. D) 61. Show Answer Correct Answer: D) 61. 24. Within a double-stranded DNA molecule, adenine forms hydrogen bonds with thymine, and cytosine forms hydrogen bonds with guanine. What is the significance of the structural arrangement? A) It determines the type of protein produced. B) It allows variable width of the double helix. C) It determines the tertiary structure of a DNA molecule. D) It permits complementary base pairing. Show Answer Correct Answer: D) It permits complementary base pairing. 25. The failure in cell division after DNA replication cause A) Polyploidy. B) Hybridisation. C) Genetic variation. D) None of the above. Show Answer Correct Answer: A) Polyploidy. 26. Griffith finally proved that DNA is the genetic material A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 27. In E. coli, the lac operon gets A) Switched on when (a) lactose is present and it binds to the repressor. B) Repressor binds to operator. C) RNA polymerase binds to the operator. D) Lactose is present and it binds to RNA polymerase. Show Answer Correct Answer: C) RNA polymerase binds to the operator. 28. The unequivocal proof of DNA as the genetic material came from the studies on a A) Fungus. B) Bacterium. C) Bacterial virus. D) Viroid. Show Answer Correct Answer: C) Bacterial virus. 29. DNA replication turns one strand of DNA into two new strands of DNA. What percent of each new strand is the old strand? A) Half of each new DNA is the old DNA. B) The old strand of DNA was digested, so none. C) The new DNA is entirely made up of the old DNA. D) About every sixth base comes from the old DNATagsMeselson/Stahl experiment. Show Answer Correct Answer: A) Half of each new DNA is the old DNA. 30. Watson and Crick double helical DNA is a A) A DNA. B) B DNA. C) Z DNA. D) None of the above. Show Answer Correct Answer: B) B DNA. 31. HGP also focussed on identifying A) Junk DNA. B) SNPS. C) Minisatellite. D) VNTRS. Show Answer Correct Answer: B) SNPS. 32. Which is the soluble RNA? A) S rna. B) T rna. C) M rna. D) Hn rna. Show Answer Correct Answer: B) T rna. 33. The lac operon is an example of inducible operon. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 34. Arrange them on the basis of increasing size: A) Nucleotide, genome, gene, chromosome. B) Nucleotide, chromosome, gene, genome. C) Genome, chromosome, Nucleotide gene. D) Nucleotide, gene, chromosome, genome. Show Answer Correct Answer: D) Nucleotide, gene, chromosome, genome. 35. In eukaryotes, three different RNA polymerases are involved in the synthesis of a different class of RNAs namely:rRNA, tRNA, and mRNA. The RNA polymerase that is required for the synthesis of mRNA is A) RNA polymerase I. B) RNA polymerase II. C) RNA polymerase III. D) None of the above. Show Answer Correct Answer: B) RNA polymerase II. 36. MRNA bearing multiple ribosomes is known as ..... A) Polysome. B) Polyamine-ribosome complex. C) MRNA ribosome complex. D) Small subunit-mRNA-initiator tRNA complex. Show Answer Correct Answer: A) Polysome. 37. Select the correct number to complete:A codon consists of ..... nucleotides. A) Four. B) Five. C) Three. D) Two. Show Answer Correct Answer: C) Three. 38. The Hershey-Chase experiment determined that A) Protein and DNA are the hereditory materials of viruses. B) Protein, not DNA, is the hereditary material of viruses. C) Viruses do not contain hereditary material. D) DNA, not protein, is the hereditary material of viruses. Show Answer Correct Answer: D) DNA, not protein, is the hereditary material of viruses. 39. During transcription the DNA site at which the RNA polymerase binds is called as- A) Ori. B) Enhancer. C) Promoter. D) Shine Dalgarno Sequence. Show Answer Correct Answer: C) Promoter. 40. The process of splicing in eukaryotes involves: A) Removal of exons and joining of introns. B) Removal of introns and joining of exons. C) Addition of methyl cap to 5' end. D) Addition of poly-A tail to 3' end. Show Answer Correct Answer: B) Removal of introns and joining of exons. 41. Some amino acids are coded by more than one codon, hence the genetic code is: A) Wobbled. B) Degenerate. C) Overlapping. D) Unambiguous. Show Answer Correct Answer: B) Degenerate. 42. A + G = C + T is applicable to A) DsDNA. B) Rna. C) TRNA. D) All. Show Answer Correct Answer: A) DsDNA. 43. Unwinding of DNA is done by- A) Ligase. B) Helicase. C) Topoisomerase. D) Gyrase. Show Answer Correct Answer: B) Helicase. 44. Chargaff found that for DNA ..... A) The ratio of A to G is close to 1:1 and the ratio of T to C is close to 1:1. B) A + T = 50% of the total bases. C) A + T = G + C. D) The ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1. Show Answer Correct Answer: D) The ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1. 45. What is the main difference between monocistronic and polycistronic structural genes? A) Number of terminators. B) Number of promoters. C) Number of polypeptides encoded. D) Number of coding strands. Show Answer Correct Answer: C) Number of polypeptides encoded. 46. Select the correct term to complete:A sequence of three bases on tRNA is called ..... A) Anticodon. B) Codon. C) Promoter. D) Operator. Show Answer Correct Answer: A) Anticodon. 47. Which of the following provides some evidence that RNA probably evolved before DNA? A) RNA polymerase uses DNA as a template. B) DNA polymerase III does not require localized unwinding of the DNA. C) DNA polymerase III uses primer, usually made of RNA. D) RNA polymerase makes a single-stranded molecule. Show Answer Correct Answer: C) DNA polymerase III uses primer, usually made of RNA. 48. What is the backbone of DNA made of? A) Double H. B) Sugar & PhosphateTagsDNA Structure. C) Amino acids. D) Nitrogen bases. Show Answer Correct Answer: B) Sugar & PhosphateTagsDNA Structure. 49. The RNA copy that carries information from DNA in the nucleus into cytoplasm is ..... RNA. A) Anticodon. B) TRNA. C) Template. D) MRNA. Show Answer Correct Answer: D) MRNA. 50. State chargaff's rule A) Adenine=cytosine and guanine=thyamine. B) Adenine=thyamine and cytosine=guanine. C) Adenine=guanine and thyamine=cytosine. D) None of the above. Show Answer Correct Answer: B) Adenine=thyamine and cytosine=guanine. 51. One of the following is true with respect to AUG (a) b)(c)(d) A) It codes for methionine only (. B) It is also an initiation codon. C) It codes for methionine in both prokaryotes and eukaryotes. D) All of the above. Show Answer Correct Answer: D) All of the above. 52. Which of the following molecular characteristics cause histones to bind tightly to DNA? A) Histones are negatively charged, and DNA is positively charged. B) Histones are positively charged, and DNA is negatively charged. C) Both histones and DNA are strongly hydrophobic. D) Histones are covalently linked to the DNA. Show Answer Correct Answer: B) Histones are positively charged, and DNA is negatively charged. 53. Which one of the following makes use of RNA asa template to synthesize DNA- A) RNA polymerase. B) DNA polymerase. C) DNA dependant RNA polymerase. D) Reverse transcriptase. Show Answer Correct Answer: D) Reverse transcriptase. 54. In microbial genetics which one is referred to as 'Griffith effect'? A) Transduction. B) Transcription. C) Transformation. D) Conjugation. Show Answer Correct Answer: C) Transformation. 55. On the lagging strand in replication, the Okazaki fragments must be joined by which enzyme? A) Ligase. B) Primase. C) DNA polymerase. D) Helicase. Show Answer Correct Answer: A) Ligase. 56. Select the incorrect statement among the following. A) The plane of one base pair stacks over the other in a double helix of DNA. B) The pitch of the DNA double helix is 3.4 nm. C) H-bonds confer additional stability to the double stranded DNA structure. D) Two nucleotides are linked through H-bonds to form a dinucleotide. Show Answer Correct Answer: D) Two nucleotides are linked through H-bonds to form a dinucleotide. 57. Although there are a limited number of amino acids, many different types of proteins exist because the ..... A) Size of a given amino acid can vary. B) Chemical composition of a given amino acid can vary. C) Sequence and number of amino acids is different. D) Same amino acid can have many different properties. Show Answer Correct Answer: C) Sequence and number of amino acids is different. 58. The genetic material of $\Phi$ A) DsDNA. B) SsRNA. C) DsRNA. D) SsDNA. Show Answer Correct Answer: D) SsDNA. 59. The RNA polymerase holocnzyme transcribes A) The promoter, structural gene and the terminator region. B) The promoter and the terminator region. C) The structural gene and the terminator region. D) The structural gene only. Show Answer Correct Answer: B) The promoter and the terminator region. 60. Who amongst the following scientist had no contribution in the development of the double helix model for the structure of DN A? A) Rosalind Franklin. B) Maurice Wilkins. C) Erwin Chargaff. D) Meselson and Stahl. Show Answer Correct Answer: B) Maurice Wilkins. ← PreviousNext →Related QuizzesScience QuizzesClass 12 QuizzesClass 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 1Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 2Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 3Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 4Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 5Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 6Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 7Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 8 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books