This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 5 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 5 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Sickle cell anemia results from a single base substitution in a gene, thus it is an example of A) Point mutation. B) Frame-shift muttion. C) Silent mutation. D) Both (a) and (b). Show Answer Correct Answer: A) Point mutation. 2. Who proposed central dogma? A) Crick. B) Beadle and Tatum. C) Klug. D) Watson and Crick. Show Answer Correct Answer: A) Crick. 3. In prokaryotes, the first amino acid in the polypeptide chain is A) Methionine. B) N-methyl methionine. C) N-formyl methionine. D) All of these. Show Answer Correct Answer: C) N-formyl methionine. 4. What were the main criteria taken under consideration for the experiment by Hershey and Chase? A) DNA contains phosphorus, protein contains sulfur. B) Protein contains phosphorus, DNA contains sulfur. C) Both DNA and protein contains phosphorus and not sulphur. D) Both DNA and protein contains sulfur and not phosphorus. Show Answer Correct Answer: A) DNA contains phosphorus, protein contains sulfur. 5. What is the major difference between bacterial chromosomes and eukaryotic chromosomes? A) Bacteria usually have a single circular chromosome whereas eukaryotes have several linear chromosomes. B) There is no difference between bacterial and eukaryotic chromosomes. C) Eukaryotes have a single circular chromosome whereas bacteria have several linear chromosomes. D) Bacterial chromosomes have much more protein associated with the DNA than eukaryotes. Show Answer Correct Answer: A) Bacteria usually have a single circular chromosome whereas eukaryotes have several linear chromosomes. 6. What sugar is in DNA? A) Oxyribose. B) DeoxyoseTagsDNA Structure. C) Ribose. D) Deoxyribose. Show Answer Correct Answer: D) Deoxyribose. 7. While analysing the DNA of an organism a total number of 5386 nucleotides were found out of which the proportion of different bases were Adenine = 29%, Guanine = 17%, Cytosine = 32%, Thymine = 17%. Considering the Chargaffs rule it can be concluded that A) No conclusion can be drawn. B) It is a double-stranded linear DNA. C) It is single-stranded DNA. D) T is a double-stranded circular DNA. Show Answer Correct Answer: C) It is single-stranded DNA. 8. The bacterial strains change from one form to another, from R strain into S strain. This is known as A) Transcription. B) Transformation. C) Transduction. D) Translation. Show Answer Correct Answer: B) Transformation. 9. According to chargaff's rule, in a DNA molecule A) The amount of adenine and thymine= the amount of guanine and cytosine. B) The amount of adenine and cytosine= the amount of guanine and cytosine. C) The amount of adenine and guanine= the amount of thymine and cytosine. D) All of these. Show Answer Correct Answer: C) The amount of adenine and guanine= the amount of thymine and cytosine. 10. What enzyme breaks the hydrogen bonds? A) Helicase. B) Topoisomerase. C) Polymerase. D) Ligase. Show Answer Correct Answer: A) Helicase. 11. Find out the wrongly matched pair with respect to lac operon. A) Presence of glucose-Switches off the lac operon. B) Inducer-Lactose. C) Lac z-codes for repressor protein. D) Repressor protein-Negative control of lac operon. Show Answer Correct Answer: C) Lac z-codes for repressor protein. 12. Telomerase is a protein-only enzyme. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 13. In DNA, the two purines are ..... , and the two pyrimidines are ..... A) Adenine and thymine cytosine and guanine. B) Adenine and guanine cytosine and thymine. C) Cytosine and thymine adenine and guanine. D) Adenine and cytosine guanine and thymine. Show Answer Correct Answer: B) Adenine and guanine cytosine and thymine. 14. Which of the following base pair sequences could be produced in DNA replication? A) 5' AGTCAT 3' 3' TCAGTA 5'. B) 5' AGTCUT 3' 3' TCUGTA 5'. C) 5' AGTCAT 3' 3' UCAGUA 5'. D) 5' AGTCAT 3' 3' CTGACG 5'. Show Answer Correct Answer: A) 5' AGTCAT 3' 3' TCAGTA 5'. 15. Who observed the constant ratio between Adenine and Thymine? A) James Watson. B) Gregory Mendel. C) Erwin Chargaff. D) Charles Darwin. Show Answer Correct Answer: C) Erwin Chargaff. 16. The promoter site and the terminator site for transcription are located at: A) 3' (downstream) end and 5' (upstream) end, respectively of the transcription unit. B) 5' (upstream) end and 3' (downstream) end, respectively of the transcription unit. C) The 5' (upstream) end. D) The 3' (downstream) end. Show Answer Correct Answer: B) 5' (upstream) end and 3' (downstream) end, respectively of the transcription unit. 17. The enzyme that unzips the DNA to prepare for replication A) Helicase. B) Polymerase. C) Synthase. D) Replicase. Show Answer Correct Answer: A) Helicase. 18. If in a scenario, the tRNA molecules present in the cell are mutated such that the DHU loop is not functional then which of the following step will be directly affected? A) Translation. B) Charging of tRNA. C) Binding of Larger subunit of ribosome to initiation complex. D) Polypeptide synthesis. Show Answer Correct Answer: B) Charging of tRNA. 19. What is the first step in the transcription process? A) Initiation. B) Elongation. C) Termination. D) Splicing. Show Answer Correct Answer: A) Initiation. 20. Experimental evidence supporting concept of triplet genetic code was first provided by A) Watson. B) Crick. C) Michaelis and Menten. D) Beadle and Tatum. Show Answer Correct Answer: B) Crick. 21. What methionine code for A) UGA. B) AUG. C) UAA. D) CGA. Show Answer Correct Answer: B) AUG. 22. Replication fork is the junction between the two ..... A) Newly separated DNA strands and the unreplicated DNA. B) Newly separated DNA strands and newly synthesized DNA strands 1. C) Newly synthesized DNA. D) Unreplicated DNA. Show Answer Correct Answer: A) Newly separated DNA strands and the unreplicated DNA. 23. Nonsense codon is responsible for A) Elongation of polypeptide chain. B) Putting a wrong amino acid. C) Termination of protein synthesis. D) Hydrolysis of GTP. Show Answer Correct Answer: C) Termination of protein synthesis. 24. What is the process of removing introns from RNA called? A) Capping. B) Splicing. C) Tailing. D) Transcription. Show Answer Correct Answer: B) Splicing. 25. RNA polymerase I, transcribes all the given types of RNA, except A) 28 s rRNA. B) 5 s rRNA. C) 5.8 s rRNA. D) 18 s rRNA. Show Answer Correct Answer: B) 5 s rRNA. 26. The switching 'on' and 'off ' of the lac operon in prokaryotes is regulated by A) Lactose. B) Galactose. C) Glucose. D) Fructose. Show Answer Correct Answer: A) Lactose. 27. Which of the following describes the direction the template strand is read? A) C terminus to N terminus. B) N terminus to C terminus. C) 3' to 5'. D) 5' to 3'. Show Answer Correct Answer: C) 3' to 5'. 28. Name the chemical used by Taylor and co workers to show semi-conservative method of replication A) Iron. B) Titanium. C) Copper. D) Thymidine. Show Answer Correct Answer: D) Thymidine. 29. How many types of DNA dependent RNA polymerase catalysis transcription of all RNA in prokaryotes? A) Multiple. B) Six. C) Two. D) One. Show Answer Correct Answer: D) One. 30. Adenine & guanine A) Are pyrimidine nitrogenous bases. B) Are heterocyclic compounds. C) Have 9-membered single ring structure. D) Does not contain pyrimidine ring. Show Answer Correct Answer: B) Are heterocyclic compounds. 31. DNA duplication occurs at A) Meiosis-II. B) Mitotic interphase. C) Mitosis only. D) Meiosis and mitosis both. Show Answer Correct Answer: D) Meiosis and mitosis both. 32. What gives DNA its stability A) Hydrogen bond. B) Double stranded str. C) Thymine, deoxyribose. D) All of these. Show Answer Correct Answer: D) All of these. 33. The hypothesis that RNA was the first genetic material is supported by RNA's ability to: A) Form hydrogen bonds. B) Act as both genetic material and enzyme. C) Pair with DNA. D) Undergo transcription. Show Answer Correct Answer: B) Act as both genetic material and enzyme. 34. The nitrogenous bases (and the two strands of the DNA double helix) are held together by A) Weak van der Waals forces. B) Covalent bonds. C) Hydrogen bonds. D) A and b. Show Answer Correct Answer: C) Hydrogen bonds. 35. What is the function of lactose in lac operon A) To bind with repressor protein. B) To initiate the transcription. C) To synthesize structural genes. D) All of the above. Show Answer Correct Answer: A) To bind with repressor protein. 36. The structure of DNA is characterized by a A) Right-or-left-handed double helix and antiparallel strands. B) Right-handed double helix and antiparallel strands. C) Right-handed single helix. D) Right-handed single helix and parallel strands. Show Answer Correct Answer: B) Right-handed double helix and antiparallel strands. 37. Which mRNA codon will match with the DNA strand ATG? A) TAC. B) ATG. C) CGT. D) UAC. Show Answer Correct Answer: D) UAC. 38. Which experiment provided unequivocal proof that DNA is the genetic material? A) Griffith's transformation experiment. B) Avery, MacLeod and McCarty's experiment. C) Hershey-Chase experiment. D) Meselson-Stahl experiment. Show Answer Correct Answer: C) Hershey-Chase experiment. 39. Muscle cells differ from nerve cells mainly because they A) Use different genetic codes. B) Have unique ribosomes. C) Express different genes. D) Contain different genes. Show Answer Correct Answer: C) Express different genes. 40. 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 modification would you choose A) Replace purine with pyrimidine. B) Remove 3' OH group in deoxyribose. C) Remove 2'OH group with some other group in deoxyribose. D) Both B and C. Show Answer Correct Answer: B) Remove 3' OH group in deoxyribose. 41. What are the roles of replication and replication forks in DNA replication? A) Replication is the process of copying DNA, and replication forks are the areas where the DNA double helix is unwound to allow replication. B) Replication forks are the enzymes that synthesize new DNA strands, and replication is the process of unwinding the DNA. C) All the above. D) None of the above. Show Answer Correct Answer: A) Replication is the process of copying DNA, and replication forks are the areas where the DNA double helix is unwound to allow replication. 42. In eukaryotes, in order to initiate transcription A) RNA strand must be present. B) RNA polymerase must be present. C) Core promoter sequence must be present. D) None of these. Show Answer Correct Answer: C) Core promoter sequence must be present. 43. AGGTATCGCAT is a sequence from the coding strand of a gene. What will be the corresponding sequence of the transcribed mRNA? A) ACCUAUGCGAU. B) UGGTUTCGCAT. C) AGGUAUCGCAU. D) UCCAUAGCGUA. Show Answer Correct Answer: C) AGGUAUCGCAU. 44. Which eukaryotic RNA polymerase primarily transcribes mRNA-coding genes? A) RNA polymerase III. B) RNA polymerase I. C) RNA polymerase II. D) Mitochondrial RNA polymerase. Show Answer Correct Answer: C) RNA polymerase II. 45. In a DNA molecule, if adenine comprises 15% of the bases, what percentage will be guanine? A) 35%. B) 15%. C) 30%. D) 70%. Show Answer Correct Answer: A) 35%. 46. In the lactose operon system in E. coli, the repressor is- A) Lactose. B) A protein. C) Bound to the promoter sequence. D) A product of a structural gene locus. Show Answer Correct Answer: B) A protein. 47. The lac operon consists of? A) 3 regulatory genes and 3 structural genes. B) 2 regulatory genes and 2 structural genes. C) One regulatory gene and 3 structural genes. D) 4 regulatory genes only. Show Answer Correct Answer: C) One regulatory gene and 3 structural genes. 48. Sickle-cell anemia is due to A) Addition. B) Inversion. C) Substitution. D) Deletion. Show Answer Correct Answer: C) Substitution. 49. Anti-codons are found on which molecule? A) TRNA. B) DNA. C) MRNA. D) RRNA. Show Answer Correct Answer: A) TRNA. 50. UTRs are the untranslated regions present on A) HnRNA. B) /RNA. C) MRNA. D) RRNA. Show Answer Correct Answer: C) MRNA. 51. Which was the first catalytic molecule during evolution of life? A) DNA. B) RRNA. C) TRNA. D) MRNA. Show Answer Correct Answer: B) RRNA. 52. A mutation always results in harmful effects. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 53. Okazaki fragments are synthesised on:- A) Leading strands of DNA only. B) Lagging strands of DNA only. C) Both leading and lagging strands of DNA. D) Complementary DNA. Show Answer Correct Answer: B) Lagging strands of DNA only. 54. More than one initiation codon and termination codons are found in which RNA A) Prokaryotic m-RNA. B) Eukaryotic m-RNA. C) Ribosomal RNA. D) Hetero nuclear RNA. Show Answer Correct Answer: A) Prokaryotic m-RNA. 55. Removal of introns and joining of exons in a defined order in a transcription unit is called A) Splicing. B) Transformation. C) Capping. D) Tailing. Show Answer Correct Answer: A) Splicing. 56. Transcription and translation of a gene composed of 30 nucleotides would form a protein containing no more than ..... amino acids. A) 15. B) 60. C) 90. D) 10. Show Answer Correct Answer: D) 10. 57. Select the correct term to complete:A segment of DNA used to make rRNA is called ..... A) SsDNA. B) RDNA. C) CDNA. D) MtDNA. Show Answer Correct Answer: B) RDNA. 58. Transformation experiment were done by A) Lederberg. B) Tautum. C) Zinder. D) Griffith. Show Answer Correct Answer: D) Griffith. 59. Boiling DNA causes it to become A) Single stranded. B) Monomers. C) Destroyed. D) Smaller the longer it is boiled. Show Answer Correct Answer: A) Single stranded. 60. What 3 models were suggested to show how the double helix separates during replication? A) Conservative, semi-conservative, and non-conservative. B) Conservative, semi-dispersive, and dispersive. C) Conservative, semi-conservative, and dispersive. D) Conversive, semi-conservative, and displaced. Show Answer Correct Answer: C) Conservative, semi-conservative, and dispersive. ← 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 6Class 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