This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 1 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 1 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. In a DNA strand the nucleotides are linked together by A) Phosphodiester bonds. B) Glycosidic bonds. C) Peptide bonds. D) Hydorgen bonds. Show Answer Correct Answer: A) Phosphodiester bonds. 2. Gene thatt are involved in turning on or off the transcription of a set of structural genes are called A) Polymorphic genes. B) Regulator genes. C) Operator gene. D) Redundant genes. Show Answer Correct Answer: C) Operator gene. 3. Which of the following help(s) to hold the DNA strands apart while they are being replicated? A) Single-strand DNA binding proteins. B) Topoisomerase. C) Primase. D) DNA ligase. Show Answer Correct Answer: A) Single-strand DNA binding proteins. 4. The Human Genome Project revealed that approximately what percentage of the human genome codes for proteins? A) 50%. B) 25%. C) 10%. D) Less than 2%. Show Answer Correct Answer: D) Less than 2%. 5. Hershey and Chase experiment used A) Virus and plants. B) Bacteriophage and bacteria. C) Fungi and algae. D) Human cells. Show Answer Correct Answer: B) Bacteriophage and bacteria. 6. 5-methyl uracil is a component of A) DNA. B) RNA. C) Amino acid. D) Both a and b. Show Answer Correct Answer: A) DNA. 7. A human gene is cloned in E. coli and then allowed to undergo gene expression. Upon performing downstreaming processes and testing for functionality of that gene product, it was found to be inactive. Which of the following can be a promisable reason for same? A) Coupled Transcription and Translation. B) Single type of RNA polymerase. C) Lack of Post-trancriptional machinery. D) Presence of extrachromosomal DNA along with genomic DNA. Show Answer Correct Answer: C) Lack of Post-trancriptional machinery. 8. The replication begins at a specific region called A) Replication initiation. B) Site of binding. C) Origin of replication. D) Replication termination. Show Answer Correct Answer: C) Origin of replication. 9. The process of creating mRNA based on a DNA sequence is called A) Replication. B) Reverse transcription. C) Transcription. D) Translation. Show Answer Correct Answer: C) Transcription. 10. What is the work of the sigma factor in transcription? A) Transcription initiation. B) Transcription elongation. C) Helicase action. D) Transcription termination. Show Answer Correct Answer: A) Transcription initiation. 11. Avery and his colleagues' 1944 experiment showed that DNA ..... A) Contains adenine, guanine, thymine, and cytosine. B) Consists of sugars, phosphate groups, and bases. C) Has two strands held together with hydrogen bonds. D) Was the substance that transformed the bacteria in Griffith's experiment. Show Answer Correct Answer: D) Was the substance that transformed the bacteria in Griffith's experiment. 12. The transforming principle in Griffith's experiment was later identified by Avery, MacLeod and McCarty as: A) Protein. B) Lipopolysaccharide. C) RNA. D) DNA. Show Answer Correct Answer: D) DNA. 13. The process of transofrmation is not affected by which of the following enzymes?A. DNaseB. RNaseC. PeptidaseD. Lipase A) A, B, C. B) A, B, C, D. C) B, C, D. D) A, B. Show Answer Correct Answer: C) B, C, D. 14. What does DNA have that RNA doesn't A) Presence of thymine. B) Presence of deoxyribose. C) Presence of ribose. D) Both a and b. Show Answer Correct Answer: D) Both a and b. 15. The scientists involved in the experiment that demonstrated DNA as the genetic material were: A) Watson and Crick. B) Hershey and Chase. C) All the above. D) None of the above. Show Answer Correct Answer: B) Hershey and Chase. 16. Suppose you are provided with an actively dividing culture of *E. coli* bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base? A) DNA in both daughter cells would be radioactive. B) All four bases of the DNA would be radioactive. C) Neither of the two daughter cells would be radioactive. D) One of the daughter cells, but not the other, would have radioactive DNA. Show Answer Correct Answer: A) DNA in both daughter cells would be radioactive. 17. All of the following statements characterize DNA replication except- A) Second DNA strand is in the form of Okazaki fragments. B) DNA is synthesized in 3' to 5' direction in one strand and 5' to 3' in another. C) Follows semiconservative mode of replication. D) Overall growth of DNA chain is bi directional. Show Answer Correct Answer: B) DNA is synthesized in 3' to 5' direction in one strand and 5' to 3' in another. 18. Which of the following describes the function of the tRNA? A) TRNA has the codon required for translation. B) TRNA allows for the translocation step. C) TRNA has the RNA transcript for protein synthesis. D) TRNA brings the amino acid to the ribosome. Show Answer Correct Answer: D) TRNA brings the amino acid to the ribosome. 19. The direction of D.N.A. replication is: A) Amino terminus to carboxy terminus. B) Carboxy terminus to amino terminus. C) From 3' end towards 5' end. D) From 5' end towards 3' end. Show Answer Correct Answer: D) From 5' end towards 3' end. 20. What are those structures that appear as 'beads-on-string' in the chromosomes when viewed under electron microscope? A) Genes. B) Nucleosomes. C) Base pairs. D) Nucleotides. Show Answer Correct Answer: B) Nucleosomes. 21. The RNA involved in transporting aminoacids and reads genetic code are A) RRNA. B) TRNA. C) MRNA. D) RNAi. Show Answer Correct Answer: A) RRNA. 22. In eukaryotes, the process of processing of primary transcript involves A) Removal of introns. B) Capping at 5'end. C) Tailing (polyadenlation) at 3' end. D) All of these. Show Answer Correct Answer: B) Capping at 5'end. 23. The DNA segments in eukaryotes that do NOT code for proteins are A) Exons. B) Codons. C) Cistrons. D) Introns. Show Answer Correct Answer: D) Introns. 24. What do Bacteriophages infect A) Humans. B) Fungus. C) Viruses. D) Mice. E) Bacteria. Show Answer Correct Answer: E) Bacteria. 25. Five types of histone proteins are- A) H1, H2A, H2B, H3 & H4. B) H1, H2, H3, H4 A & H4B. C) H1, H2A, H2C, H2D & H3A. D) H1, H2A, H2, H3A & H4. Show Answer Correct Answer: A) H1, H2A, H2B, H3 & H4. 26. ASSERTION-The nitrogenous base of two chains of DNA are held together by hydrogen bondsReason-Both chains of DNA are antiparallel A) If both Assertion and Reason are true and reason is correct explanation of Assertion. B) If both Assertion and Reason are true but reason is not correct explanation of Assertion. C) Assertion is true reason is false. D) Both Assertion and Reason are false. Show Answer Correct Answer: B) If both Assertion and Reason are true but reason is not correct explanation of Assertion. 27. The association of histone H1 with a nucleosome indicates: A) The DNA double helix is exposed. B) DNA replication is occurring. C) The DNA is condensed into a Chromatin Fibre. D) Transcription is occurring. Show Answer Correct Answer: C) The DNA is condensed into a Chromatin Fibre. 28. One of two scientists who determined the double helix structure of DNA A) Francis Crick. B) P.A. Levene. C) Oswald Avery. D) Erwin Chargaff. Show Answer Correct Answer: A) Francis Crick. 29. What is the function of the enzyme topoisomerase in DNA replication? A) Elongating new DNA at a replication fork by adding nucleotides to the existing chain. B) Building RNA primers using the parental DNA strand as a template. C) Reattaching the hydrogen bonds between the base pairs in the double helix. D) Relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix. Show Answer Correct Answer: D) Relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix. 30. Which of these is correct fullform of BAC? A) Bacterial artificial chromosome. B) Bacterial artificial centre. C) Biotechnolofical articicial chromosome. D) Biotechnological application on chromososme. Show Answer Correct Answer: A) Bacterial artificial chromosome. 31. The effort to decipher the genetic code was led by ..... who was awarded Nobel Prize for his work A) Watson. B) Lederberg. C) Crick. D) Nirenberg. Show Answer Correct Answer: D) Nirenberg. 32. Which of the following is the function of RNA A) Adapter. B) Structural. C) Catalytic. D) All of the above. Show Answer Correct Answer: D) All of the above. 33. Select the correct match of enzyme with its related function. A) DNA polymerase-Synthesis of DNA strands. B) Helicase-Unwinding of DNA helix. C) Ligase-Joins together short DNA segments. D) All of these. Show Answer Correct Answer: D) All of these. 34. The model organism used by Meselson and Stahl to prove semi conservative DNA replication was A) Streptococcus pneumoniae. B) Drosophila melanogaster. C) Escherichia coli. D) Bacteriophage lambda. Show Answer Correct Answer: C) Escherichia coli. 35. The isotopes used by Hershey and Chase to prove that DNA is the genetic material R A) P32 and S35. B) P35 and S32. C) N15 and N15. D) N14 and N15. Show Answer Correct Answer: A) P32 and S35. 36. Nucleosome core is intimately associated with: A) 100 bp of DNA. B) 250 bp of DNA. C) 160 bp of DNA. D) 210 bp of DNA. Show Answer Correct Answer: C) 160 bp of DNA. 37. Which scientist(s) said that adenine and guanine equals thymine and cytosine? A) Griffith. B) Hershey & Chase. C) Franklin & Watkins. D) Chargaff. Show Answer Correct Answer: D) Chargaff. 38. The site of tRNA that binds to mRNA is A) 5' end. B) Anticodon. C) Codon. D) 3' end. Show Answer Correct Answer: B) Anticodon. 39. The enzyme peptidyl transferase of prokaryotes resides in A) 30S ribosome. B) 40S ribosome. C) 50S ribosome. D) 60S ribosome. Show Answer Correct Answer: C) 50S ribosome. 40. In prokaryotes, the region where DNA is organized is called: A) Nucleoid. B) Chromatin. C) Nucleosome. D) Nucleus. Show Answer Correct Answer: A) Nucleoid. 41. Which out of the following statements is incorrect? A) Genetic code is ambiguous. B) Genetic code is degenerate. C) Genetic code is universal. D) Genetic code is non-overlapping. Show Answer Correct Answer: A) Genetic code is ambiguous. 42. RNA that acts as ribozyme is A) MRNA. B) RRNA. C) SnRNA. D) TRNA. Show Answer Correct Answer: B) RRNA. 43. DNA is acidic due to A) Pyrimidine. B) Sugar. C) Purine. D) Phosphoric acid. Show Answer Correct Answer: D) Phosphoric acid. 44. Which non radioactive isotope was used by Meselson and Stahl in their experiments? A) $^{32 }$P. B) $^{35}$ S. C) $^{15}$ N. D) None. Show Answer Correct Answer: C) $^{15}$ N. 45. How did Meselson and Stahl distinguish the heavy DNA from the light DNA molecule? A) CsCl density gradient centrifugation. B) Buffer centrifugation. C) Spectroscopy. D) None of the above. Show Answer Correct Answer: A) CsCl density gradient centrifugation. 46. In prokaryotes, control of gene expression takes place at the level of A) Transcription. B) Translation. C) DNA replication. D) All of the above. Show Answer Correct Answer: A) Transcription. 47. Nucleotide excision repair A) Cell division. B) Protein synthesis. C) DNA repair mechanism that removes bulky DNA lesions. D) Photosynthesis. Show Answer Correct Answer: C) DNA repair mechanism that removes bulky DNA lesions. 48. What is the role of RNA polymerase in transcription? A) To repair DNA. B) To replicate DNA. C) To unwind DNA. D) To synthesize RNA. Show Answer Correct Answer: D) To synthesize RNA. 49. The enzyme that relieves the tension created ahead of the replication fork by unwinding DNA is: A) DNA ligase. B) DNA primase. C) DNA helicase. D) DNA topoisomerase. Show Answer Correct Answer: D) DNA topoisomerase. 50. Which of the following statements is correct regarding ribosomes? A) DNA replication takes place there. B) Most of a cell's DNA molecule are stored there. C) MRNAs are produced there. D) Complete polypeptide is released from there. Show Answer Correct Answer: D) Complete polypeptide is released from there. 51. What is the primary function of a terminator in a transcription unit? A) Ends transcription. B) Binds RNA polymerase. C) Terminates translation. D) Initiates transcription. Show Answer Correct Answer: A) Ends transcription. 52. Isotopes used in proving semiconservative replication of DNA were A) $^{14}$N $^{15}$N. B) $^{14}$N $^{14}$C. C) $^{14}$C $^{31}$P. D) $^{14}$N $^{31}$P. Show Answer Correct Answer: A) $^{14}$N $^{15}$N. 53. Assertion (A):tRNA is called an 'adapter' Reason(R):tRNA on one hand bind to a specific amino acid and on the other hand reads the codon of the amino acid bound to it through its anticodon A) Both assertion and reason are true and the reason is the correct explanation of assertion. B) Both assertion and reason are true but the reason is not the correct explanation of assertion. C) Assertion is true but reason is false. D) Both assertion and reason are false. Show Answer Correct Answer: A) Both assertion and reason are true and the reason is the correct explanation of assertion. 54. Recognition sequence for transcription in prokaryotes is A) TATAAT. B) TATATAT. C) TATAAAT. D) CAAT. Show Answer Correct Answer: A) TATAAT. 55. Which of the following does not affect DNA replication? A) Antiparallel nature of DNA. B) End specificity of polymerase. C) SSB protein. D) Helicase. Show Answer Correct Answer: C) SSB protein. 56. Termination of polypeptide chain is brought about by A) UUG, UAG and UCG. B) UCG, GCG and ACC. C) UAA, UAG and UGA. D) UUG, UGC and UCA. Show Answer Correct Answer: C) UAA, UAG and UGA. 57. How many percent of genome code for proteins? A) < 5%. B) < 3%. C) < 2 %. D) < 1%. Show Answer Correct Answer: C) < 2 %. 58. The Human Genome Project as megaproject was a 13 year project coordinated by the A) U.S. Department of Energy. B) National Institute of Health. C) U.S. Department of Molecular Biology. D) Both (a) and (b). Show Answer Correct Answer: D) Both (a) and (b). 59. DNA-dependent RNA polymerase catalyzes transcription on one strand of the DNA which is called the A) Template strand. B) Coding strand. C) Alpha strand. D) Anti strand. Show Answer Correct Answer: A) Template strand. 60. DNA has genetic properties was revealed for the first time by A) Chargaff. B) Griffith. C) Avery. D) Wilkins. Show Answer Correct Answer: C) Avery. Next →Related QuizzesScience QuizzesClass 12 QuizzesClass 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 8Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 9 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books