This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 15 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 15 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Which one of the following is not applicable to RNA? A) Heterocyclic nitrogenous bases. B) Chargaff's rule. C) Complementary base pairing. D) 5' phosphoryl and 3' hydroxyl ends. Show Answer Correct Answer: B) Chargaff's rule. 2. A deoxyribose nucleoside is a A) Deoxyribose plus a nitrogenous base. B) Sugar and a phosphate. C) Deoxyribose plus a nitrogenous base and a phosphate. D) Ribose plus a nitrogenous base. Show Answer Correct Answer: A) Deoxyribose plus a nitrogenous base. 3. If the percentage of DNA is made of 30% Thymine, what is the correct percentage of Guanine? A) 15. B) 30. C) 60. D) 20. Show Answer Correct Answer: D) 20. 4. Which process separates DNA fragments by size? A) DNA sequencing. B) Polymerase chain reaction. C) Recombinant DNA technology. D) Gel electrophoresis. Show Answer Correct Answer: D) Gel electrophoresis. 5. Which of the following best describes the key function of helicases during transcription? A) Cleaving methyl groups from an unwound DNA strand. B) Catalyzing the interaction between transcription factors and the DNA strand. C) Separation of two strands of DNA; "unwinding" gives polymerases access to the strand. D) Relief of tension in the DNA strands to prevent breakage. Show Answer Correct Answer: C) Separation of two strands of DNA; "unwinding" gives polymerases access to the strand. 6. The process of going from DNA to mRNA is called A) Transportation. B) Transcription. C) Translation. D) Transient. Show Answer Correct Answer: B) Transcription. 7. Which component of a nucleosome forms the core? A) Only H2. B) Only H1. C) H3-H4 tetramer + H2A-H2B dimer. D) H2A-H2B tetramer. Show Answer Correct Answer: C) H3-H4 tetramer + H2A-H2B dimer. 8. Taylor conducted the experiment to prove semiconservative mode of chromosome replication on: A) Vicia faba. B) Vinca rosea. C) E. coli. D) Drosophila melanogaster. Show Answer Correct Answer: A) Vicia faba. 9. Mention the anticodon sequence of bases for AUG A) TAC. B) UAC. C) All the above. D) None of the above. Show Answer Correct Answer: B) UAC. 10. Which one of the following group of codons is called as degenerate codons? A) UAA, UAG and UGA. B) GUA, GUG, GCA, GCG and GAA. C) UUC, UUG, CCU, CAA and CUG. D) UUA, UUG, CUU, CUC and CUG. Show Answer Correct Answer: A) UAA, UAG and UGA. 11. Which was the last human chromosome to be completely sequenced: A) Chromosome 11. B) Chromosome 21. C) Chromosome 1. D) Chromosome x. Show Answer Correct Answer: C) Chromosome 1. 12. According to HGP, human genome consists of approximately A) 1 lac genes. B) 50 thousand genes. C) 30 thousand genes. D) 20 thousand genes. Show Answer Correct Answer: C) 30 thousand genes. 13. If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is:5'-ATGAATG-3', the sequence of bases in its RNA transcript would be: A) 5'-AUG A AUG-3'. B) 5'-UACUU AC-3'. C) 5'-CAUUCAU-3'. D) 5'-GUAAGUA-3'. Show Answer Correct Answer: D) 5'-GUAAGUA-3'. 14. What is central dogma A) Formation of RNA from DNA and formation of proteins from RNA. B) Formation of protein from DNA and formation of RNA from protein. C) Formation of DNA from RNA and formation of protein from DNA. D) None of the above. Show Answer Correct Answer: A) Formation of RNA from DNA and formation of proteins from RNA. 15. The proof for semiconservative nature of DNA replication was given by A) Watson and Crick. B) Hershey and Chase. C) Meselson and Stahl. D) Avery, MacLeod and McCarty. Show Answer Correct Answer: C) Meselson and Stahl. 16. Which of the following statements about replication origins is/are correct? A) The two strands of DNA at the origin of replication are separated, creating a replication bubble. B) The DNA sequence at the origin of replication is recognized by specific proteins that bind to the origin. C) Replication proceeds in both directions from each origin. D) All of the listed responses are correct. Show Answer Correct Answer: D) All of the listed responses are correct. 17. Semi-conservative method of DNA replication was first demonstrated in A) D.melanogaster. B) S. pneumonae. C) E.coli. D) Bacteriophage. Show Answer Correct Answer: C) E.coli. 18. The supporting evidence for the semi conservative replication of DNA are A) E. Coli culturing in $^{15}$N medium. B) Radioactive thymidine usage in Vicia faba plant's DNA replication. C) Both (a) and (b). D) Protein syntehsis. Show Answer Correct Answer: C) Both (a) and (b). 19. During transcription, the DNA site at which RNA polymerase binds is called A) Receptor. B) Enhancer. C) Promoter. D) Regulator. Show Answer Correct Answer: C) Promoter. 20. What are the coding sequences in eukaryotes known as? A) Terminals. B) Exons. C) Introns. D) Promoters. Show Answer Correct Answer: B) Exons. 21. In bacteriophage experiment, performed by Hershey and Chase, radioactivity in supernatant was due to A) S35 in capsid of T2 bacteriophage. B) P32 in capsid of T2 bacteriophage. C) P32 in DNA of T2 bacteriophage. D) S35 in DNA of T2 bacteriophage. Show Answer Correct Answer: A) S35 in capsid of T2 bacteriophage. 22. The DNA of telomeres has been found to be highly conserved throughout the evolution of eukaryotes. What does this most probably reflect? A) That the critical function of telomeres must be maintained. B) The low frequency of mutations occurring in this DNA. C) That mutations in telomeres are relatively advantageous. D) That new evolution of telomeres continues. Show Answer Correct Answer: A) That the critical function of telomeres must be maintained. 23. If the sequence of bases in DNA is GCTTAGGCAA then the sequence of bases in its transcript will be A) GCTTAGGCAA. B) CGAAUCCGUU. C) CGAATCCGTT. D) AACGGAUUCG. Show Answer Correct Answer: B) CGAAUCCGUU. 24. With regard to mature mRNA in eukaryotes: A) Exons and introns do not appear in the mature RNA. B) Exons appear but introns do not appear in the mature RNA. C) Introns appear but exons do not appear in the mature RNA. D) Both exons and introns appear in the mature RNA. Show Answer Correct Answer: B) Exons appear but introns do not appear in the mature RNA. 25. Name the enzyme that facilitates opening of DNA helix during transcription. A) DNA ligase. B) DNA helicase. C) DNA polymerase. D) RNA polymerase. Show Answer Correct Answer: D) RNA polymerase. 26. Portion of gene which is transcribed but nottranslated is:- A) Cistron. B) Exon. C) Intron. D) Codon. Show Answer Correct Answer: C) Intron. 27. Single-strand binding protein A) Breaks apart the DNA molecules. B) Bind to the unpaired DNA strands, keeping them from repairing. C) Untwist the DNA molecule. D) Bind to the paired DNA strands, keeping them from repairing. Show Answer Correct Answer: B) Bind to the unpaired DNA strands, keeping them from repairing. 28. The two antiparallel strands of nucleotides that form the DNA double helix are held together by ..... A) Covalent bonds between carbon atoms in deoxyribose molecules. B) Hydrogen bonds between nucleotide bases. C) 5' deoxyribose and phosphate bonds. D) Ionic bonds between guanine and cytosine. Show Answer Correct Answer: B) Hydrogen bonds between nucleotide bases. 29. Choose the correct option w.r.t. RNA. A) Absence of free 2' OH in sugar. B) Presence of thymine in place of uracil. C) Is non-catalytic. D) Mutates at faster rate. Show Answer Correct Answer: D) Mutates at faster rate. 30. In the nuclein obtaining experiment, if scientist used RBC instead of WBC, whether he would discovered it? A) Yes. B) No. C) All the above. D) None of the above. Show Answer Correct Answer: B) No. 31. What are the gaps between the newly synthesized DNA on the lagging strand called? A) Helicase fragments. B) Acidic gapsTagsDNA replication terms. C) Okazaki fragments. D) Polymer gaps. Show Answer Correct Answer: C) Okazaki fragments. 32. ABCDEFGH. If it is changed to ACGH, this is acase of A) Inversions. B) Duplication. C) Deletions. D) Frame-shift mutations. Show Answer Correct Answer: C) Deletions. 33. The important enzyme required for the process of transcrption from DNA to mRNA is ..... A) DNA polymerase. B) DNA helicase. C) DNA ligase. D) RNA polymerase. Show Answer Correct Answer: D) RNA polymerase. 34. Why are DNA dependent DNA polymerase enzymes very efficient? A) They catalyze polymerization very fast. B) They can catalyse with high degree of accuracy. C) The catalyse the reactions only in 5'-3' direction. D) All of the above. Show Answer Correct Answer: D) All of the above. 35. What is the main enzyme involved in DNA replication? A) DNA ligase. B) DNA-dependent DNA polymerase. C) RNA polymerase. D) Helicase. Show Answer Correct Answer: B) DNA-dependent DNA polymerase. 36. When adding the next monomer to a growing DNA strand, the monomer is added to the A) 2' carbon of the deoxyribose. B) 1' carbon of the deoxyribose. C) 3' carbon of the deoxyribose. D) 4' carbon of the deoxyribose. Show Answer Correct Answer: C) 3' carbon of the deoxyribose. 37. Column I Column II A) Watson and Crick P) DNA fingerprinting B) R. W. Holley Q) Decipher genetic code C) Marshal Nirenberg R) Double helix of DNA D) Jacob and Monod S) Clover model of tRNA E) Alec Jeffrey T) Lac operon concept A) R Q P T S. B) R S Q T P. C) R S P T Q. D) R T S P Q. Show Answer Correct Answer: B) R S Q T P. 38. If a completely radioactively labelled DNA molecule undergoes 2 rounds of replicationona anon radioactive medium, then what will be the radioactive status of the four resulting molecules? A) Half of the members contain no radioactivity. B) All four contain radioactivity. C) Three out of 4 contain radioactivity. D) None will be radioactive. Show Answer Correct Answer: A) Half of the members contain no radioactivity. 39. What is the function of tRNA A) To carry amino acids to ribosome. B) To synthesize protein. C) To help in replication. D) A binding site for RNA polymerase. Show Answer Correct Answer: A) To carry amino acids to ribosome. 40. Which of the following life processes is evolved around RNA? A) Metabolism. B) Translation. C) Splicing. D) All of these. Show Answer Correct Answer: B) Translation. 41. Give the sequence of bases AUG is transcribed from A) TAC. B) UAC. C) All the above. D) None of the above. Show Answer Correct Answer: A) TAC. 42. Anticodons are found in:- A) M RNA. B) T RNA. C) R RNA. D) In all. Show Answer Correct Answer: B) T RNA. 43. Bacteriophage lambda has how many base pairs A) 56398. B) 48502. C) 46390. D) 36000. Show Answer Correct Answer: B) 48502. 44. In E. colt, the lac operon gets switched on when A) Lactose is present and it binds to the repressor. B) Repressor binds to operator. C) RNA polymerase binds to the operator. D) Lactose is present and it binds to RNA polymerase. Show Answer Correct Answer: A) Lactose is present and it binds to the repressor. 45. ..... occurs in RNA instead of the nitrogenous base thymine found in DNA A) Guanine. B) Adenine. C) Cytosine. D) Uracil. Show Answer Correct Answer: D) Uracil. 46. The unequivocal proof that DNA is the genetic material came from the experiment which utilised- A) E. coli, heavy nitrogen. B) P$^{32}$, S$^{35}$, R-type bacteria. C) T$_{2}$, E. coli. D) Streptococcus. Show Answer Correct Answer: C) T$_{2}$, E. coli. 47. In eukaryotic genes, coding sequences are called A) Repretitive DNA. B) Introns. C) Regulatory sequence. D) Exons. Show Answer Correct Answer: D) Exons. 48. Which experimental technique did Meselson and Stahl use to prove semiconservative DNA replication? A) X-ray crystallography. B) Electron microscopy. C) Density gradient centrifugation. D) Gel electrophoresis. Show Answer Correct Answer: C) Density gradient centrifugation. 49. The amino acid that is incorporated at the start of protein synthesis in prokaryotes is: A) Glycine. B) Methionine. C) Formyl methionine. D) Alanine. Show Answer Correct Answer: C) Formyl methionine. 50. Guanine is bonded with Cytosine with how many hydrogen bonds A) Three. B) One. C) Two. D) None of the above. Show Answer Correct Answer: A) Three. 51. Mutations that change one base pair are A) Chromosomal mutation. B) Point mutation. C) Frame-shift. D) Polyploidy. Show Answer Correct Answer: B) Point mutation. 52. Select the correct term to complete:A mutation that changes the reading frame is a ..... mutation. A) Silent. B) Nonsense. C) Point. D) Frame-shift. Show Answer Correct Answer: D) Frame-shift. 53. Choose the correct sequence in which the following enzyme are used in DNA replication-I) Helicase II) Primase III) SSBPs IV) DNA polymerase v) DNA ligase A) I IV III II I. B) I III II IV V. C) I V IV III II. D) I II III IV V. Show Answer Correct Answer: B) I III II IV V. 54. Discountinuous synthesis of DNA occurs in one strand, because A) DNA dependent DNA polymerase catalysed polymerisation only in one direction (5'-3' ). B) DNA molecule being synthesised is very long. C) DNA ligase joins the short stretches of DNA. D) It is a more efficient process. Show Answer Correct Answer: A) DNA dependent DNA polymerase catalysed polymerisation only in one direction (5'-3' ). 55. In eukaryotes t-RNa is made up of which enzyme A) RNA polymerase. B) RNA polymerase III. C) RNA polymerase I. D) RNA polymerase II. Show Answer Correct Answer: B) RNA polymerase III. 56. Select the correct enzyme to complete:The enzyme responsible for transcription is ..... A) Reverse transcriptase. B) DNA polymerase. C) Ligase. D) RNA polymerase. Show Answer Correct Answer: D) RNA polymerase. 57. Which of these enzymes is not a part of DNA Replication? A) Helicase. B) Topoisomerase. C) Ligase. D) Hexokinase. Show Answer Correct Answer: D) Hexokinase. 58. What type of bond forms between the two strands of DNA? A) Ionic. B) Hydrogen. C) Phosphodiester. D) Polar Covalent. Show Answer Correct Answer: B) Hydrogen. 59. Monomers for the synthesis of DNA are called ..... A) Amino acids. B) Nucleotides. C) Monosaccharides. D) Disaccharides. Show Answer Correct Answer: B) Nucleotides. 60. Chargaff's rule states that A) Viruses enter cells without their protein coat. B) Only protein from the infecting phage can also be detected in progeny phage. C) The amount of cytosine equals the amount of guanine. D) DNA must be replicated before a cell can divide. Show Answer Correct Answer: C) The amount of cytosine equals the amount of guanine. ← 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