This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 11 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 11 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. RNA polymerase I in eukaryotes mainly synthesizes which RNA? A) TRNA. B) SnRNA. C) RRNA (large rRNAs). D) MRNA. Show Answer Correct Answer: C) RRNA (large rRNAs). 2. A nucleoside differs from a nucleotide. It lacks the: A) Base. B) Sugar. C) Hydroxyl group. D) Phosphate group. Show Answer Correct Answer: D) Phosphate group. 3. In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer? A) The 5' phosphate. B) C6. C) The 3' OH. D) A nitrogen from the nitrogen-containing base. Show Answer Correct Answer: C) The 3' OH. 4. The first phase of translation is A) Binding of mRNA to ribosome. B) Recognition of an anti-codon. C) Recognition of DNA molecule. D) Aminoacylation of tRNA. Show Answer Correct Answer: D) Aminoacylation of tRNA. 5. The function of DNA polymerase I is to ..... A) Add nucleotide complements to the growing strand. B) Remove the RNA primer. C) Bond the Okazaki fragments together on the lagging strand. D) Keep the DNA strands from reforming after DNA helicase "unzips" them. Show Answer Correct Answer: B) Remove the RNA primer. 6. During replication, what enzyme adds complimentary bases? A) Helicase. B) Synthesase. C) PolymeraseTagsDNA replication enzymes. D) Ligase. Show Answer Correct Answer: C) PolymeraseTagsDNA replication enzymes. 7. Adenylyl cyclase is an enzyme that is active in the absence of A) Allolactose. B) Glucose. C) Lactose. D) CAMP. Show Answer Correct Answer: B) Glucose. 8. Polycistronic messenger RNA (mRNA) usually occurs in A) Bacteria. B) Prokaryotes. C) Eukaryotes. D) Both (a) and (b). Show Answer Correct Answer: D) Both (a) and (b). 9. A gene is a unit of inheritance. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 10. Hershey and Chase set out to determine what molecule served as the unit of inheritance. They completed a series of experiments in which *E. coli* was infected by a T2 virus. Which molecular component of the T2 virus actually ended up inside the cell? A) Protein. B) DNA. C) RNA. D) Ribosome. Show Answer Correct Answer: B) DNA. 11. Method of DNA replication in which two strandsof DNA separates and synthesize new strands:-(4) A) Semiconservative. B) Dispersive. C) Non conservative. D) Conservative. Show Answer Correct Answer: A) Semiconservative. 12. With respect to lac operon, product of which of the following structural gene(s) converts lactose into galactose and glucose? A) Lac A gene. B) Lac i gene. C) Lac Y gene. D) Lac Z gene. Show Answer Correct Answer: D) Lac Z gene. 13. Regions of transcriptional unit are-I) Exon II) intron III) promoter IV) structural gene V) terminator VI) cistron A) I, II, III, IV, V. B) III, IV V. C) II, III & IV. D) I, II & III. Show Answer Correct Answer: B) III, IV V. 14. During the replication of DNA, the synthesis of DNA as lagging strand takes place in segment, these segments are called A) Kornberg segments. B) Double helix segments. C) Okazaki segments. D) Satellite segments. Show Answer Correct Answer: C) Okazaki segments. 15. In the process of replication deoxyribonucleosidetriphosphate A) Acting as substrate. B) Providing energy for polymerisation reaction. C) Acting as an enzyme. D) Both (1) & (2). Show Answer Correct Answer: D) Both (1) & (2). 16. ..... found that DNA was the reason that Griffith's bacterial strains transformed and killed the mice A) Watson and Crick. B) Hershey and Chase. C) Meselson and Stahl. D) Rosalind Franklin. Show Answer Correct Answer: B) Hershey and Chase. 17. Which of the following types of molecules help to hold the DNA strands apart while they are being replicated? A) Primase. B) Ligase. C) Single-stranded binding proteins. D) DNA polymerase. Show Answer Correct Answer: C) Single-stranded binding proteins. 18. We cannot predict the correct sequence of m-RNA from sequence of amino acid. It is due to which property of genetic code. A) Non overlapping nature. B) Unambiguoty. C) Universality. D) Degeneracy. Show Answer Correct Answer: D) Degeneracy. 19. The tRNA is coded by A) DNA sequence or gene. B) RNA sequence. C) Introns in the mature RNA. D) None of the above. Show Answer Correct Answer: A) DNA sequence or gene. 20. The anticodon of tRNA is complementary to: A) The template strand of DNA. B) The coding strand of DNA. C) The codon on mRNA. D) Another tRNA molecule. Show Answer Correct Answer: C) The codon on mRNA. 21. Which statement best describes the antiparallel nature of the DNA double helix proposed by Watson and Crick? A) Both strands run 5'$\rightarrow$3'. B) One strand runs 5'$\rightarrow$3' and the other 3'$\rightarrow$5'. C) Both strands run 3'$\rightarrow$5'. D) Strands have no directionality. Show Answer Correct Answer: B) One strand runs 5'$\rightarrow$3' and the other 3'$\rightarrow$5'. 22. What was most remarkable about the Griffith's experiment? A) Griffith obtained his results despite the fact that he failed his medical board exam. B) DNA, not protein, was found to be the genetic molecule. C) Viruses, which were nonliving, could change living cells. D) Something from a dead organism could change living cells. Show Answer Correct Answer: D) Something from a dead organism could change living cells. 23. In Meselson and Stahl experiment, 20 min after shifting E. coli from N15 to N14 medium, the bacterial cells will have A) Heavy DNA. B) Hybrid DNA. C) Light DNA. D) Hybrid and light DNA in 1:1. Show Answer Correct Answer: B) Hybrid DNA. 24. During transcription, if the nucleotide sequence ofthe DNA strand that is being coded is ATACG, thenthe nucleotide sequence in the mRNA would be A) TATGC. B) UAUGC. C) UATGC. D) TCTGG. Show Answer Correct Answer: B) UAUGC. 25. W.r.t the organization of eukaryotic chromosome choose the correct sequence of steps A) Chromatin $\rightarrow$ Solenoid $\rightarrow$ Nucleosome. B) Solenoid $\rightarrow$ Nucleosome $\rightarrow$ Chromatid. C) DNA $\rightarrow$ Solenoid$\rightarrow$ Nucleosome. D) Nucleosome $\rightarrow$ Solenoid $\rightarrow$ Nuclear scaffold proteins. Show Answer Correct Answer: D) Nucleosome $\rightarrow$ Solenoid $\rightarrow$ Nuclear scaffold proteins. 26. As the number of base pairs in prokaryotes is 4.6 x 10$^{6}$bp and if it takes 38min to replication then what is the polymerisation rate A) 3000bp/s. B) 2000 bp/s. C) 1000bp/s. D) 4000 bp/s. Show Answer Correct Answer: B) 2000 bp/s. 27. Which one of the following triplet codes, is correctly matched with its specificity for an aminoacid in protein synthesis or as 'starts or ' stops codon? A) UCG Start. B) UUU Stop. C) UGU Leucine. D) UAC Tyrocine. Show Answer Correct Answer: D) UAC Tyrocine. 28. The pathogenic nature is provided by the following part of pneumococcus A) Nucleoprotein. B) Protein coat. C) Cell wall. D) Carbohydrate capsule. Show Answer Correct Answer: D) Carbohydrate capsule. 29. Select the correct box to complete:The promoter region in prokaryotes contains the ..... box. A) -10 (Pribnow). B) Kozak. C) -35. D) TATA. Show Answer Correct Answer: A) -10 (Pribnow). 30. Which enzyme is responsible for the transcribing the precursor of mRNA in eukaryotes? A) RNA polymerase I. B) RNA polymerase III. C) DNA polymerase. D) RNA polymerase II. Show Answer Correct Answer: D) RNA polymerase II. 31. Discontinuous synthesis of DNA occurs in one strand, because: A) DNA ligase has to have a role. B) DNA molecule being synthesised is very long. C) DNA dependent DNA polymearse catalyses polymerisation only in one direction (5' $\rightarrow$ 3'). D) It is a more efficient process. Show Answer Correct Answer: C) DNA dependent DNA polymearse catalyses polymerisation only in one direction (5' $\rightarrow$ 3'). 32. Which of the following is not true of RNA processing? A) Ribozymes(enzymes that work only on RNA) may function in RNA splicing. B) Exons are cut out before mRNA leaves the nucleus. C) RNA splicing can be catalyzed by spliceosomes. D) Nucleotides may be added at both ends of the RNA. Show Answer Correct Answer: B) Exons are cut out before mRNA leaves the nucleus. 33. Which of the following combination is a correct observation for the transformation experiment performed by Griffith? A) Type IIIS (heat killed) + mouse = dead. B) Type IIIS (heat killed) + type IIR (living) + mouse = living. C) Type IIR (living) + mouse = dead. D) Type IIIS (living) + mouse = dead. Show Answer Correct Answer: D) Type IIIS (living) + mouse = dead. 34. What is the nature of the strands of the DNA duplex? A) Anti parallel and complementary. B) Identical and complementary. C) Anti-parallel and non-complementary. D) Dissimilar and non-complementary. Show Answer Correct Answer: A) Anti parallel and complementary. 35. What is the fully processed hnRNA which moves out of the nucleus is called A) TRNA. B) SnRNA. C) RRNA. D) MRNA. Show Answer Correct Answer: D) MRNA. 36. The sugar lactose induces synthesis of the enzyme lactase. What happens when an E.coli (bacterial) cell runs out of lactose? A) RNA polymerase attaches to the promoter. B) RNA polymerase attaches to the repressor. C) Repressor protein binds to the promoter. D) Repressor protein binds to the operator. Show Answer Correct Answer: D) Repressor protein binds to the operator. 37. Correct order of molecular weight is:- A) T-RNA < m-RNA < DNA. B) DNA < r-RNA < t-RNA. C) DNA < m-RNA < r-RNA. D) T-RNA < DNA < m-RNA. Show Answer Correct Answer: A) T-RNA < m-RNA < DNA. 38. What enzyme joins Okazaki fragments? A) DNA ligase. B) Helicase. C) Primase. D) Topoisomerase. Show Answer Correct Answer: A) DNA ligase. 39. In Hershey and chase experiments, radioactive 32P was used to culture bacteriophages which resulted in radioactive A) Viral DNA. B) Viral proteins capsule of bacteriophage. C) Viral Head and Tail part. D) None of these. Show Answer Correct Answer: A) Viral DNA. 40. Which of the following is not the characteristic feature of genetic code A) Degeneracy. B) Ambiguous. C) Triplet nature. D) Mostly universal. Show Answer Correct Answer: B) Ambiguous. 41. Regulation of gene expression occurs at the level of A) Transcription. B) Processing/splicing. C) Translation. D) All of these. Show Answer Correct Answer: D) All of these. 42. Which of the following describes the conversion factor between nucleic acids and proteins? A) 3 nucleotides = 3 amino acids. B) 3 amino acids = 3 nucleotides. C) 3 amino acids = 1 nucleotide. D) 3 nucleotides = 1 amino acid. Show Answer Correct Answer: D) 3 nucleotides = 1 amino acid. 43. Replication Fork A) A protein used during DNA replication. B) A Y-shaped region where DNA replication ends. C) A Y-shaped region where the parental strands of DNA are being unwound. D) Y-shaped enzymes used to separate DNA. Show Answer Correct Answer: C) A Y-shaped region where the parental strands of DNA are being unwound. 44. In transcription in eukaryotes, heterogeneous nuclear RNA (hnRNA) is transcribed by: A) RNA polymerase II. B) RNA polymerase I. C) RNA polymerase III. D) All of these. Show Answer Correct Answer: A) RNA polymerase II. 45. A DNA molecule has 240bp and 30% guanosine, how many adenine present in this molecule of DNA? A) 40 nucleotide. B) 120 nucleotide. C) 160 nucleotide. D) 80 nucleotide. Show Answer Correct Answer: A) 40 nucleotide. 46. In *E. coli*, to repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act? A) DNA ligase, nuclease, helicase. B) Nuclease, DNA polymerase, RNA primase. C) Nuclease, DNA polymerase, DNA ligase. D) Helicase, DNA polymerase, DNA ligase. Show Answer Correct Answer: C) Nuclease, DNA polymerase, DNA ligase. 47. Amino acid acceptor end of tRNA lies at: A) TVC loop. B) 5' end. C) DHU loop. D) 3' end. Show Answer Correct Answer: D) 3' end. 48. Which of the following characteristics of eukaryotic telomeres cause them to replicate differently than the rest of the chromosome? A) They are gaps left at the 5' end of the lagging strand template. B) The activity of telomerase enzyme. C) DNA polymerase that cannot replicate the leading strand template to its 5' end. D) Gaps left at the 3' end of the lagging strand because of the need for a primer. Show Answer Correct Answer: A) They are gaps left at the 5' end of the lagging strand template. 49. DNA polymerase requires ..... to initiate replication. A) RNA primer. B) RNA polymerase. C) DNA polymerase I. D) Ligase. Show Answer Correct Answer: A) RNA primer. 50. The difference between DNA and RNA is that A) DNA has thymine and RNA has uracil. B) DNA has no oxygen bonded to the 2' carbon; RNA does. C) DNA is the genetic material; RNA is not. D) DNA is double stranded and RNA can't have hydrogen bond. Show Answer Correct Answer: B) DNA has no oxygen bonded to the 2' carbon; RNA does. 51. Which of the following statement is NOT true regarding transcription/RNA synthesis? A) RNA synthesis occurs in the nucleus. B) Unlike DNA synthesis, the only selective sequence of DNA is transcribed to RNA. C) RNA synthesis requires a short stretch of RNA primers. D) DNA sequences, specific proteins, and small RNAs regulate RNA synthesis. Show Answer Correct Answer: C) RNA synthesis requires a short stretch of RNA primers. 52. Introns code for proteins. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 53. Which of the following is true regarding the replication of prokaryotes and eukaryotes? A) Prokaryotic DNA is linear. B) Eukaryotic DNA can initiate replication at multiple origins. C) Eukaryotic DNA has a single replication bubble. D) Eukaryotic DNA elongates faster than prokaryotes. Show Answer Correct Answer: B) Eukaryotic DNA can initiate replication at multiple origins. 54. Which scientist first identified DNA as the genetic material? A) Frederick Griffith. B) Gregor Mendel. C) Alfred Hershey. D) Friedrich Meischer. Show Answer Correct Answer: D) Friedrich Meischer. 55. Which of the following acts as substrate as well as provide energy for DNA polymerisation? A) Ribonucleoside. B) Ribonucleotide. C) Deoxyribonucleoside. D) Deoxyribonucleoside triphosphate. Show Answer Correct Answer: D) Deoxyribonucleoside triphosphate. 56. Which enzyme is responsible for adding nucleotides? A) PrimaseTagsDNA replication enzymes. B) Topoisomerase. C) Ligase. D) DNA Polymerase. Show Answer Correct Answer: D) DNA Polymerase. 57. A DNA molecule in which both strands haveradioactive thymidine is allowed to duplicate inan environment containing non-radioactivethymidine. What will be the exact number of DNAmolecules that contains the radio active thymidineafter 3 duplications- A) 4. B) 2. C) 8. D) 1. Show Answer Correct Answer: B) 2. 58. Polymerase that synthesizes tRNA in eukaryotes A) RNA Pol I. B) DNA Pol I. C) RNA Pol II. D) RNA Pol III. Show Answer Correct Answer: D) RNA Pol III. 59. Which of the following is not a component of an operon? A) Structural gene. B) Operator. C) Ribosome. D) Promoter. Show Answer Correct Answer: C) Ribosome. 60. Select the correct term to complete:The tails of histones help in DNA ..... A) Replication. B) Transcription. C) Translation. D) Packaging. Show Answer Correct Answer: D) Packaging. ← 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