This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 8 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 8 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Transcription unit consists of A) Enhancer, operator. B) Origin, promoter. C) Promoter, structural gene, terminator. D) Codon only. Show Answer Correct Answer: C) Promoter, structural gene, terminator. 2. Which isotopes were used by Meselson and Stahl in their experiment to prove semiconservative DNA replication? A) Carbon-14 and Nitrogen-15. B) Hydrogen-1 and Oxygen-18. C) Oxygen-16 and Nitrogen-14. D) Nitrogen-15 and Nitrogen-14. Show Answer Correct Answer: D) Nitrogen-15 and Nitrogen-14. 3. RNA required for splicing ..... A) Sn rna. B) M rna. C) Hn rna. D) T rna. Show Answer Correct Answer: A) Sn rna. 4. The major approaches used in HGP for identifying were A) Sequence annotation. B) Expressed Sequence Tags. C) Both of the above. D) None of the above. Show Answer Correct Answer: C) Both of the above. 5. Which codon is not an indicator of completion of protein synthesis? A) UGA. B) UAG. C) AUG. D) UAA. Show Answer Correct Answer: C) AUG. 6. Which is the last human chromosome to be completely sequenced? A) Chromosome 21. B) Chromosome X. C) Chromosome 1. D) Chromosome Y. Show Answer Correct Answer: C) Chromosome 1. 7. If the sequence of bases in one strand of DNA is ATGCATGCA, what would be the sequence of bases on the complementary strand? A) AUGCAUGCA. B) TACTACGT. C) UACGUACGU. D) ATGCATGCA. Show Answer Correct Answer: B) TACTACGT. 8. What is base complementarity A) A=T, . G=C. B) Purine = pyrimidine. C) Purine = pyrimidine. D) A=G T=C. Show Answer Correct Answer: A) A=T, . G=C. 9. Chargaff's rules of base pairing states that A) The ratio of purine to pyrimidines is roughly equal in all tested organism. B) The ratio of A to T is roughly equal in all tested organisms. C) The ratio of A + T and G+ C is roughly equal in all tested organisms. D) Both1 and 2. Show Answer Correct Answer: D) Both1 and 2. 10. In *E. coli*, which enzyme catalyzes the elongation of a new DNA strand in the 5' $\rightarrow$ 3' direction? A) DNA polymerase III. B) Helicase. C) Primase. D) DNA ligase. Show Answer Correct Answer: A) DNA polymerase III. 11. All the living organism on earth has DNA as their genetic material A) True. B) Flase. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 12. The role of DNA polymerases in DNA replication is to ..... A) Synthesize an RNA primer to initiate DNA strand synthesis. B) Attach free nucleotides to the new DNA strand. C) Separate the two strands of DNA. D) Link together short strands of DNA. Show Answer Correct Answer: B) Attach free nucleotides to the new DNA strand. 13. RNA stores genetics information in A) Eukaryotes. B) Virus. C) Protozoa. D) Prokaryotes. Show Answer Correct Answer: B) Virus. 14. Synthesis of DNA from RNA is explained by: A) Central dogma reverse. B) Reverse transcription. C) Feminism. D) All of these. Show Answer Correct Answer: B) Reverse transcription. 15. Nucleotide base present in DNA and not in RNA is A) Thymine. B) Cytosine. C) Guanine. D) Uracil. Show Answer Correct Answer: A) Thymine. 16. Which site of the tRNA pairs through hydrogen bonding with the triplet codon on mRNA? A) 5' end of tRNA. B) Anticodon. C) Codon. D) 3' end of tRNA. Show Answer Correct Answer: B) Anticodon. 17. Which enzyme unwinds the DNA double helix at the replication fork to create single-stranded templates? A) Primase. B) Helicase. C) Topoisomerase. D) Ligase. Show Answer Correct Answer: B) Helicase. 18. The DNA dependent DNA polymerase catalysepolymerisation in A) 3' 5' direction. B) 5' 3' direction. C) Depend on the nature of template strand. D) Both (1) & (2. Show Answer Correct Answer: B) 5' 3' direction. 19. What is the LAST step of the completion of DNA replication? A) Topoisomerase relieves supercoilingTagsDNA replication process. B) DNA polymerase proofreads. C) Telomeres are added to ends of DNA. D) Ligase glues Okazaki fragments. Show Answer Correct Answer: C) Telomeres are added to ends of DNA. 20. Assertion:Transcription is the mode in which DNA passes its genetic information to RNA. Reason:Transcription takes place in the cytoplasm of eukaryotic cells. 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: C) Assertion is true but reason is false. 21. DNA replication in E.coli is A) Conservative and unidirectional. B) Semi conservative and unidirectional. C) Conservative and bidirectional. D) Semi-conservative and bidirectional. Show Answer Correct Answer: D) Semi-conservative and bidirectional. 22. Which of the following is true of DNA but not of RNA? A) It is made up of a single strand of nucleotides. B) It contains the sugar deoxyribose. C) It leaves the nucleus to translate protein. D) It contains the nitrogen base uracil. Show Answer Correct Answer: B) It contains the sugar deoxyribose. 23. The experiments of Meselson and Stahl showed that DNA ..... A) Replicates in a semiconservative fashion. B) Contains complementary base pairing. C) Is the genetic material. D) Is composed of nucleotides. Show Answer Correct Answer: A) Replicates in a semiconservative fashion. 24. In DNA promoter is the site for the initiation of A) Replication. B) Translation. C) Transcription. D) Both (2) & (3). Show Answer Correct Answer: C) Transcription. 25. Enzyme DNA polymerases catalyze polymerization in A) Deoxyribonucleosides. B) 5'-3' direction. C) Ribonucleotides. D) 3'-5' direction. Show Answer Correct Answer: B) 5'-3' direction. 26. Okazaki Fragments are A) Short DNA fragments on the lagging strand. B) Short DNA fragments on the leading strand. C) The RNA primer required for the initiation of DNA synthesis. D) The DNA fragment produced due to radiation action. Show Answer Correct Answer: A) Short DNA fragments on the lagging strand. 27. The three codons which result in the termination of polypeptide chain synthesis are: A) UAA, UGA, UUA. B) UGU, UAG, UGA. C) UAA, UAG, UGA. D) UAA, UAG, GUA. Show Answer Correct Answer: C) UAA, UAG, UGA. 28. What does the base 'G' pair with? A) T. B) C. C) A. D) G. Show Answer Correct Answer: B) C. 29. Where translation takeplace A) Nucleus. B) Mitochondria. C) Cytoplasm. D) Ribosome. Show Answer Correct Answer: C) Cytoplasm. 30. Identify the type of RNA which is not involved in gene expression A) HnRNA. B) RRNA. C) MRNA. D) TRNA. Show Answer Correct Answer: A) HnRNA. 31. Which of these is not the step involved transcription A) Termination. B) Elongation. C) Initiation. D) Insertion. Show Answer Correct Answer: D) Insertion. 32. Which of the following techniques was most helpful to Watson and Crick in developing their model for the structure of DNA? A) Radioactive labeling. B) Electrophoresis. C) Cloned DNA. D) X-ray crystallography. Show Answer Correct Answer: D) X-ray crystallography. 33. What would happen if in a genre encoding a polypeptide of 50 amino acids, 25th codon (UAU) Is mutated to UAA? A) A polypeptide of 25 amino acids will be formed. B) A polypeptide of 24 amino acids will be formed. C) Two polypeptide of 24 and 25 amino acids will be formed. D) A polypeptide of 49 amino acids will be formed. Show Answer Correct Answer: B) A polypeptide of 24 amino acids will be formed. 34. What is meant by the term 'transformation' in the context of DNA as the genetic material? A) The process by which DNA is transferred from one organism to another. B) The change in the structure of DNA within a cell. C) All the above. D) None of the above. Show Answer Correct Answer: A) The process by which DNA is transferred from one organism to another. 35. TRNA is present corresponding to each of the following specified codons, except the codon A) UGA. B) UUU. C) AUG. D) UGG. Show Answer Correct Answer: A) UGA. 36. The leading strand and lagging strand in DNA replication differ in that only on the lagging strand A) Okazaki fragments are not needed. B) DNA is replicated as short fragments. C) Replication proceeds in the 5' to 3' direction. D) RNA primer is present. Show Answer Correct Answer: B) DNA is replicated as short fragments. 37. Chargaff contributed to the understanding of DNA by figuring out that the percentages of adenine and cytosine were almost equal in any sample of DNA. A) True. B) FalseTagsDNA replication experimentschargaff. C) All the above. D) None of the above. Show Answer Correct Answer: B) FalseTagsDNA replication experimentschargaff. 38. Who gave the experimental proof for semiconservative mode of replication A) Hershey & Chase. B) Watson & Crick. C) Griffith. D) Messolson & Stahl. Show Answer Correct Answer: D) Messolson & Stahl. 39. Why is DNA polar A) It has two charges. B) It has two open ends. C) It has 3rd carbon free at one end and 5th carbon free at other end in sugar. D) It has 3rd carbon free at one end and 5th carbon free at other end in nitrogen base pair. Show Answer Correct Answer: C) It has 3rd carbon free at one end and 5th carbon free at other end in sugar. 40. A segment of DNA has 120 adenine and 120 cytosine bases.The total number of nucleotides present in the segment is ..... A) 120. B) 240. C) 480. D) 60. Show Answer Correct Answer: C) 480. 41. The electric charge on DNA and histones is A) Both positive. B) Both negative. C) Zero. D) Negative and positive respectively. Show Answer Correct Answer: D) Negative and positive respectively. 42. During replication of a bacterial chromosome DNAsynthesis starts from a replication origin site and A) RNA primers are not involved. B) Is facilitated by telomerase. C) Moves in one direction of the site. D) Moves in bi-directional way. Show Answer Correct Answer: D) Moves in bi-directional way. 43. Identify the correct order of organisation of genetic material from largest to smallest A) Genome, chromosome, nucleotide, gene. B) Chromosome, gene, genome, nucleotide. C) Chromosome, genome, nucleotide, gene. D) Genome, chromosome, gene, nucleotide. Show Answer Correct Answer: D) Genome, chromosome, gene, nucleotide. 44. Why is only one DNA strand transcribed for a given gene? A) Transcribing both strands would produce identical RNAs and waste energy. B) RNA polymerase can bind only the lagging strand. C) Promoter orientation specifies a single template strand, preventing conflicting transcripts. D) Only one strand contains bases. Show Answer Correct Answer: C) Promoter orientation specifies a single template strand, preventing conflicting transcripts. 45. Shine Dalgarno sequence is located six to ten bases upstream of the initiation codon of mRNA. It consists of A) Purine-rich nucleotide sequence. B) Pyrimidine rich nucleotide sequence. C) Uracil-containing nucleotide sequence. D) None of the above. Show Answer Correct Answer: A) Purine-rich nucleotide sequence. 46. What will be the sequence of mRNA produced by the following stretch of DNA? 3' ATGCATGCATGCATG 5' TEMPLATE STRAND 5' TACGTACGTACGTAC 3' CODING STRAND A) 3' UACGUACGUACGUAC 5'. B) 3' AUGCAUGCAUGCAUG 5'. C) 3' AUGCAUGCAUGCAUG 3'. D) 5' UACGUACGUACGUAC 3'. Show Answer Correct Answer: D) 5' UACGUACGUACGUAC 3'. 47. Which RNA carries the amino acids from the amino acid pool to mRnA during protein synthesis? A) RRNA. B) /RNA. C) HnRNA. D) MRNA. Show Answer Correct Answer: B) /RNA. 48. This enzyme synthesizes short RNA sequences to guide DNA Polymerase A) DNA Primase. B) TopoisomeraseTagsDNA replication enzymes. C) Primers. D) DNA Polymerase. Show Answer Correct Answer: A) DNA Primase. 49. F. Griffith conducted the experiment with bacteriophages A) Yes. B) No. C) All the above. D) None of the above. Show Answer Correct Answer: B) No. 50. DNA synthesis takes place during A) M phase. B) S phase. C) G1 phase. D) G2 phase. Show Answer Correct Answer: B) S phase. 51. When scientists say that DNA transmits information, they mean that it passes information from one generation to the next. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 52. Molecules which play the key role in the transfer of genetic information during protein synthesis are ..... A) DNA. B) Lipids. C) RNA. D) Nucleic acid. Show Answer Correct Answer: C) RNA. 53. Histone H1 is associated with A) Ribosome. B) Core particle. C) MRNA. D) Linker DNA. Show Answer Correct Answer: D) Linker DNA. 54. Name the stage in the cell cycle where DNA replication occurs . A) S-phase. B) M-phase. C) G1-phase. D) G2-phase. Show Answer Correct Answer: A) S-phase. 55. The two strands of a DNA double helix are antiparallel. This means that ..... A) They both run in the 3' to 5' direction. B) The two strands are mirror images. C) One strand runs in the 5' to 3' direction, and the other runs in the 3' to 5' direction. D) One strand is actually composed of RNA. Show Answer Correct Answer: C) One strand runs in the 5' to 3' direction, and the other runs in the 3' to 5' direction. 56. Which of the following are the functions of RNA? A) It is a carrier of genetic information from DNA to ribosomes synthesizing polypeptides. B) It carries amino acids to ribosomes. C) It is a constituent component of ribosomes. D) All of the above. Show Answer Correct Answer: D) All of the above. 57. How introns are removed in eukaryotic cells A) Splicing. B) Silencing. C) Capping. D) Tailing. Show Answer Correct Answer: A) Splicing. 58. Select the correct component to complete:Spliceosome contains proteins and ..... A) TRNA. B) MRNA. C) SnRNA. D) RRNA. Show Answer Correct Answer: C) SnRNA. 59. Who proposed the double helical structure of DNA A) Meselson and Stahl. B) Taylor et.al. C) Watson and Crick. D) Hershey and Chase. Show Answer Correct Answer: C) Watson and Crick. 60. Find out the wrong statement about heterochromatin: A) It is late replicating. B) It is transcriptionally active. C) It stains dark. D) It is densely packed. Show Answer Correct Answer: B) It is transcriptionally active. ← 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 9 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books