This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 6 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 6 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Process used for amplication or multiplication of DNA for finger printing is A) Northern blotting. B) Polymerase chain reaction. C) Southern blotting. D) Nesslerisation. Show Answer Correct Answer: B) Polymerase chain reaction. 2. Codons are read in A) 2' $\rightarrow$ 3' direction. B) 3' $\rightarrow$ 5' direction. C) 5' $\rightarrow$ 3' direction. D) Random. Show Answer Correct Answer: C) 5' $\rightarrow$ 3' direction. 3. If a double stranded DNA has 20% of cytosine, what will be the percentage of adenine in it? A) 20%. B) 60%. C) 30%. D) 40%. Show Answer Correct Answer: C) 30%. 4. What breaks the hydrogen bonds A) Helicase. B) Ligase. C) Topoisomerase. D) Polymerase. Show Answer Correct Answer: A) Helicase. 5. What is the function of missence strand of DNA? A) Coding strand. B) Template strand. C) All the above. D) None of the above. Show Answer Correct Answer: B) Template strand. 6. Which of the following statements is true regarding introns? A) Introns have no function. B) In general, human genes have fewer introns than genes of other organisms. C) Introns are the parts of mRNA that are translated. D) Introns may be involved in exon shuffling. Show Answer Correct Answer: D) Introns may be involved in exon shuffling. 7. To initiate translation, the tRNA first binds to: A) The whole ribosome. B) The smaller ribosomal sub-unit. C) No such specificity exists. D) The larger ribosomal sub-unit. Show Answer Correct Answer: B) The smaller ribosomal sub-unit. 8. The length of the DNA is usually defined as the number of ..... A) Nucleosides. B) Nucleotides. C) All the above. D) None of the above. Show Answer Correct Answer: B) Nucleotides. 9. Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? A) 16%. B) 8%. C) 58%. D) 42%. Show Answer Correct Answer: B) 8%. 10. Prokaryotes exhibit A) Polycistronic. B) Monocistronic. C) Polymorphic. D) Monosomic. Show Answer Correct Answer: A) Polycistronic. 11. DNA ligase adds nucleotides to growing DNA chain. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 12. During the replication of DNA, ..... A) The reaction is catalyzed by RNA polymerase. B) The cell undergoes mitosis. C) Both strands of a molecule act as templates. D) Errors never occur. Show Answer Correct Answer: C) Both strands of a molecule act as templates. 13. During expression of an operon, RNA polymerase binds to A) Regulator gene. B) Operator. C) Promoter. D) Structural gene. Show Answer Correct Answer: C) Promoter. 14. Name the RNA involved in structural and catalytic function during translation A) RRNA. B) MRNA. C) RNAi. D) TRNA. Show Answer Correct Answer: A) RRNA. 15. Hershey and Chase used a DNA-based virus for their work. How might the results have been different if they had used an RNA virus? A) With an RNA virus, neither sample would have had a radioactive pellet. B) With an RNA virus, radioactive protein would have been in the final pellet. C) With an RNA virus, radioactive RNA would have been in the final pellet. D) With an RNA virus, the protein shell would have been radioactive in both samples. Show Answer Correct Answer: C) With an RNA virus, radioactive RNA would have been in the final pellet. 16. Which of the following criteria must be fulfilled by a genetic material. A) Replication and Mutation. B) Stability. C) Express itself in the form of 'Mendelian Characters'. D) All of the above. Show Answer Correct Answer: D) All of the above. 17. On the lagging strand of DNA, the polymerase cannot just follow the DNA as it is separated. Because of this, it makes small segments called A) Restriction fragments. B) Ligase. C) Okazaki fragments. D) SSB proteins. Show Answer Correct Answer: C) Okazaki fragments. 18. During replication, the new DNA strand is synthesized A) In the 3' to 5' direction. B) From one end to the other, in the 3' to 5' or the 5' to 3' directions. C) In both the 3' to 5' and 5' to 3' directions from the replication fork. D) In the 5' to 3' direction. Show Answer Correct Answer: D) In the 5' to 3' direction. 19. RNA primase is used show where DNA polymerase III is to attach to add nucleotides on the exposed lagging strand. What is the name of the promoter strand on the DNA lagging strand called? A) Topoisomerase. B) Primer. C) Telomere. D) TATA box. Show Answer Correct Answer: D) TATA box. 20. True replication of DNA is possible due to A) Complementary base pairing rule. B) Hydrogen bonding. C) Phosphate backbone. D) None of the above. Show Answer Correct Answer: A) Complementary base pairing rule. 21. The base pairs of DNA double helix is given below. Select the suitable mRNA strand that derived from transcription is 3 '-ATTTCC-5'5'-TAAAGG-3' A) GAAAGG. B) CCUUUC. C) CUUUCC. D) UAAAGG. Show Answer Correct Answer: D) UAAAGG. 22. Operon unit consists of A) Regulator, operator and repressive genes. B) Regulator, structural & operator gene. C) Regulator, structural, operator & promoter gene. D) Regulator, structural & promotor. Show Answer Correct Answer: C) Regulator, structural, operator & promoter gene. 23. Which of the following forms a base pair with thymine? A) Deoxyribose. B) CytosineTagsDNA Structure. C) Adenine. D) Guanine. Show Answer Correct Answer: C) Adenine. 24. The result of which of the following experiments carried out by Avery et al on Streptococcus pnuemoniae has proved conclusively that DNA is the genetic material? A) Live R strain+ DNA from S strain+ RNAse. B) Heat killed R strain + DNA from S strain + RNase. C) Live R strain + DNA from S strain + protease. D) Live R strain+ DNA from S strain+ DNase. Show Answer Correct Answer: D) Live R strain+ DNA from S strain+ DNase. 25. Nitrogenous bases are joined by which type of bond? A) Polar bonds. B) Hydrogen bonds. C) Covalent bonds. D) Ionic bonds. Show Answer Correct Answer: B) Hydrogen bonds. 26. Site where replication begins A) In the front. B) Replication Origin. C) Polymerase action site. D) Replication fork. Show Answer Correct Answer: B) Replication Origin. 27. The human genome consists of over ..... base pairs. A) 3.6 million. B) 46 billion. C) 1 million. D) 3 billion. Show Answer Correct Answer: D) 3 billion. 28. Which of the following structural characteristics is most critical for the association between histones and DNA? A) Histones are positively charged. B) Histones are small proteins. C) There are at least five different histone proteins in every eukaryote. D) Histones are highly conserved (that is, histones are very similar in every eukaryote). Show Answer Correct Answer: A) Histones are positively charged. 29. Name the enzyme which can stop the bacterial transformation A) DNase. B) DNAs. C) Lipases. D) RNases. Show Answer Correct Answer: A) DNase. 30. Which one of the following pairs of nitrogenous bases of nucleic acids, is wrongly matched with the category mentioned against it? A) Guanine, Adenine-Purines. B) Adenine, Thymine-Purines. C) Uracil, Cytosine-Pyrimidines. D) Thymine, Uracil-Pyrimidines. Show Answer Correct Answer: B) Adenine, Thymine-Purines. 31. Why might a point mutation in DNA make a difference in the level of a protein's activity? A) It might result in a chromosomal translocation. B) It might substitute a different amino acid in the active site. C) It might exchange one serine codon for a different serine codon. D) It might exchange one stop codon for another stop codon. Show Answer Correct Answer: B) It might substitute a different amino acid in the active site. 32. Which enzyme seals okazaki fragments together on the lagging strand? A) Topoisomerase. B) Ligase. C) Polymerase. D) Helicase. Show Answer Correct Answer: B) Ligase. 33. 'DNA is more stable than RNA', which of these options support this statement. A) Due to chemical modifications. B) Double stranded structure with complementary strand. C) Evolved a process of repair. D) All of the above. Show Answer Correct Answer: D) All of the above. 34. Which of the following steps in transcription is catalysed by RNA polymerse? A) Initiation. B) Elongation. C) Termination. D) All of these. Show Answer Correct Answer: B) Elongation. 35. Control of gene expression takes place at the level of: A) Translation. B) Transcription. C) None of the above. D) DNA-replication. Show Answer Correct Answer: B) Transcription. 36. RNA can act as an enzyme in some organisms. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 37. Largest gene in human is A) Tumour suppressing gene. B) Oncogene. C) Dystrophin. D) Insulin. Show Answer Correct Answer: C) Dystrophin. 38. Each mRNA codon codes for ..... A) An enzyme. B) A carbohydrate. C) An amino acid. D) A protein. Show Answer Correct Answer: C) An amino acid. 39. A mature mRNA consists of 900 bases without any stop codon in between. Calculate the number of amino acids coded by the mRNA during translation. A) 299. B) 9000. C) 300. D) 450. Show Answer Correct Answer: C) 300. 40. The transcription unit doesnot consist of A) Terminator. B) Promoter. C) Origin of replication. D) Structural gene. Show Answer Correct Answer: C) Origin of replication. 41. In lac operon, structural gene 'Z' synthesises A) Beta galactosidase. B) Galactosidase permase. C) Galactosidase transacetylase. D) None of these. Show Answer Correct Answer: A) Beta galactosidase. 42. Which of the following RNAs is not transcribed by RNA polymerase III? A) 5sRNA. B) TRNA. C) MRNA. D) SnRNA. Show Answer Correct Answer: C) MRNA. 43. The incorporation of an incorrect base into the DNA during replication ..... A) Will almost certainly lead to the death of the cell. B) Cannot be repaired, and a new mutation will invariably result. C) Can be repaired by the mismatch repair system. D) Is virtually impossible, as the accuracy of DNA polymerase is such that errors almost never occur. Show Answer Correct Answer: C) Can be repaired by the mismatch repair system. 44. The steps (rungs) of the DNA ladder are made up of ..... A) Amino acids. B) Nitrogen bases. C) Sugars. D) Phosphate groups. Show Answer Correct Answer: B) Nitrogen bases. 45. A stretch of which nucleotide in the DNA acts as the termination signal? A) Poly C. B) Poly A. C) Poly T. D) Poly G. Show Answer Correct Answer: B) Poly A. 46. Which of the following lists represents the order of increasingly higher levels of organization of chromatin? A) Looped domain, 30-nm chromatin fiber, nucleosome. B) Nucleosome, 30-nm chromatin fiber, looped domain. C) Nucleosome, looped domain, 30-nm chromatin fiber. D) 30-nm chromatin fiber, nucleosome, looped domain. Show Answer Correct Answer: B) Nucleosome, 30-nm chromatin fiber, looped domain. 47. The two strands in a DNA double helix are joined by A) Phosphodiester bonds between bases. B) Phosphodiester bonds between sugars. C) Hydrogen bond between bases. D) Hydrogen bonds between sugars. Show Answer Correct Answer: C) Hydrogen bond between bases. 48. The Hershey-Chase experiment A) Proved semiconservative replication is the mode for DNA replication. B) Used $^{32}$P to label protein. C) Helped to prove DNA was the genetic molecule. D) Used $^{35}$S to label DNA. Show Answer Correct Answer: C) Helped to prove DNA was the genetic molecule. 49. Which of these statement gives the correct chargaff's rule? A) A=T and G=C. B) G/C=A/T. C) A+G=T+C. D) ALL OF THE ABOVE. Show Answer Correct Answer: D) ALL OF THE ABOVE. 50. Okazaki is known for his contribution to the understanding of A) Transcription. B) Translation. C) DNA replication. D) Mutation. Show Answer Correct Answer: C) DNA replication. 51. What is meant by the description "antiparallel" regarding the strands that make up DNA? A) The twisting nature of DNA creates nonparallel strands. B) One strand is positively charged and the other is negatively charged. C) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. D) Base pairings create unequal spacing between the two DNA strands. Show Answer Correct Answer: C) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. 52. Which of these enzymes is responsible for breaking the hydrogen bonds which "unzips" the DNA molecule? A) Helicase. B) Topoisomerase. C) Zippase. D) Primase. Show Answer Correct Answer: A) Helicase. 53. The unwinding of DNA at the replication fork causes twisting and strain in the DNA ahead of the fork, which is relieved by an enzyme called ..... A) Primase. B) Helicase. C) Topoisomerase. D) Ligase. Show Answer Correct Answer: C) Topoisomerase. 54. DNA replication in eukaryotes differs from replication in bacteria because A) Synthesis of the new DNA strand is from 3' to 5' in eukaryotes and from 5' to 3' in bacteria. B) Synthesis of the new DNA strand is from 5' to 3' in eukaryotes and from 3' to 5' in bacteria. C) There are many replication forks in each eukaryotic chromosome and only one in bacterial DNA. D) Synthesis of the new DNA strand is from 5' to 3' in eukaryotes and is random in prokaryotes. Show Answer Correct Answer: C) There are many replication forks in each eukaryotic chromosome and only one in bacterial DNA. 55. Histones proteins are rich in amino acid residues A) Lysine and Histamine. B) Histamine and arginine. C) Lysine and arginine. D) None of these. Show Answer Correct Answer: C) Lysine and arginine. 56. Which nitrogen base does RNA have that DNA does not? A) Cytosine. B) Adenine. C) Thymine. D) Uracil. Show Answer Correct Answer: D) Uracil. 57. The first genetic material could be A) RNA. B) DNA. C) Cabohydrates. D) Protein. Show Answer Correct Answer: A) RNA. 58. DNA replication is A) Semi-conservative, continuous, unidirectional. B) Conservative, continuous. C) Semi-continuous, conservative. D) Semi-conservative, semi-discontinuous. Show Answer Correct Answer: D) Semi-conservative, semi-discontinuous. 59. Other than DNA polymerase, which are the enzymes involved in DNA synthesis? A) Topoisomerase. B) Helicase. C) RNA primase. D) All of these. Show Answer Correct Answer: D) All of these. 60. Which set of enzymes is involved in nucleotide excision repair? A) Ligase, nuclease, and primase. B) Nuclease, DNA polymerase, and ligase. C) DNA polymerase, helicase, primase. D) Nuclease, DNA polymerase, primase. Show Answer Correct Answer: B) Nuclease, DNA polymerase, and ligase. ← 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 7Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 8Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 9 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books