This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 2 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 2 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Which of the following composes the ribosomes? A) DNA. B) MRNA. C) RRNA. D) TRNA. Show Answer Correct Answer: C) RRNA. 2. Which of the following set of options is used in translation? A) MRNA, tRNA, hnRNA. B) HnRNA, tRNA, rRNA. C) MRNA, tRNA, rRNA. D) HnRNA, rRNA, tRNA. Show Answer Correct Answer: C) MRNA, tRNA, rRNA. 3. The codon AUG is A) Termination codon. B) Ochre. C) Initiation codon. D) Amber. Show Answer Correct Answer: C) Initiation codon. 4. Which is catalytically active- A) DNA. B) RNA. C) Protein. D) Both B and C. Show Answer Correct Answer: D) Both B and C. 5. Under which conditions B-DNA is converted into A and C A) High temperature. B) Low temperature. C) Low humidity. D) High humidity. Show Answer Correct Answer: C) Low humidity. 6. Removal of introns and joining of exons in a defined order during transcription is called: A) Slicing. B) Looping. C) Splicing. D) Inducing. Show Answer Correct Answer: C) Splicing. 7. The lactose operon is likely to be transcribed when ..... ? ..... A) There is glucose but no lactose in the cell. B) The cyclic AMP levels are low. C) The cyclic AMP and lactose levels are both high within the cell. D) There is more glucose in the cell than lactose. Show Answer Correct Answer: C) The cyclic AMP and lactose levels are both high within the cell. 8. ..... helps in the removal of RNA primer A) DNA polymerase I. B) DNA polymerase III. C) RNA polymerase. D) DNA polymerase II. Show Answer Correct Answer: A) DNA polymerase I. 9. TRNA has a cloverleaf structure. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 10. Attach the codons with their respective amino acids and choose the correct answer. A UUU 1. Serine B GGG 2. Methionine C UCU 3 Phenylalanine D CCG 4 Glycine E AUG 5 Proline A) 3 1 4 5 2. B) 2 4 1 3 5. C) 3 4 1 5 2. D) 2 4 1 5 2. Show Answer Correct Answer: C) 3 4 1 5 2. 11. DNA is present in A) Mitochondria. B) Nucleus. C) Chloroplast. D) All of these. Show Answer Correct Answer: D) All of these. 12. What determines the nucleotide sequence of the newly synthesized strand during DNA replication? A) The particular DNA polymerase catalyzing the reaction. B) The relative amounts of the four nucleoside triphosphates in the cell. C) The nucleotide sequence of the template strand. D) The primase used in the reaction e. the arrangement of histones in the sugar phosphate backbone. Show Answer Correct Answer: C) The nucleotide sequence of the template strand. 13. The basis of DNA fingerprinting is A) Polymorphism in sequence. B) Double helix. C) Errorrs in base sequence. D) DNA replication. Show Answer Correct Answer: A) Polymorphism in sequence. 14. If the sequence of bases in the coding strand of DNA is ATTCGATG, then the sequence of bases in mRNA will be: A) ATTCGATG. B) TAAGCTAC. C) AUUCGAUG. D) UAAGCUAC. Show Answer Correct Answer: C) AUUCGAUG. 15. 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 modifications would you choose? A) Replace purine with pyrimindines. B) Remove/Replace 3' OH group in deoxy ribose. C) Remove/Replace 2' OH group with some other group in deoxy ribose. D) Both (b) and (c). Show Answer Correct Answer: B) Remove/Replace 3' OH group in deoxy ribose. 16. The deflection of pitch angle between two successive steps (rungs) of DNA is A) 18$^{o}$. B) 54$^{o}$. C) 36$^{o}$. D) 72$^{o}$. Show Answer Correct Answer: C) 36$^{o}$. 17. RNA is the genetic material in A) Eukaryotes. B) Tabacco Mosaic Virus (TMV). C) E.coli. D) Prokaryotes. Show Answer Correct Answer: B) Tabacco Mosaic Virus (TMV). 18. Which of the following are Chargaff rules A) Purine = pyrimidine. B) Sugar = phosphate. C) A+T/G+C=Constant. D) All of these. Show Answer Correct Answer: D) All of these. 19. The length of DNA has 45000 base pairs. How many complete turns will the DNA molecule take? A) 4500. B) 450. C) 45000. D) 45. Show Answer Correct Answer: A) 4500. 20. In the base sequence of one strand of DNA isGAT, TAG, CAT, GAC what shall be thesequence of its complementary strand- A) CAT, CTG, ATC, GTA. B) GTA, ATC, CTG, GTA. C) ATC, GTA, CTG, GTA. D) CTA, ATC, GTA, CTG. Show Answer Correct Answer: D) CTA, ATC, GTA, CTG. 21. Why is only one strand of DNA copied during transcription? A) To form double-stranded RNA. B) To prevent mutations. C) To increase protein diversity. D) To simplify genetic information transfer. Show Answer Correct Answer: D) To simplify genetic information transfer. 22. Which of the following effects might be caused by reduced or very little active telomerase activity? A) Cells age and begin to lose function. B) Cells maintain normal functioning. C) Telomere lengthens in germ cells. D) Cells may become cancerous. Show Answer Correct Answer: A) Cells age and begin to lose function. 23. One complete turn of DNA contains A) 20 bp. B) 5 bp. C) 30 bp. D) 10 bp. Show Answer Correct Answer: D) 10 bp. 24. In E. coli, there is a mutation in a gene called dnaB that alters the DNA helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation? A) Replication will occur via RNA polymerase alone. B) The DNA will supercoil. C) No proofreading will occur. D) No replication fork will be formed. Show Answer Correct Answer: D) No replication fork will be formed. 25. Which of the following is a stop codon? A) AUG. B) AAA. C) UGC. D) UGA. Show Answer Correct Answer: D) UGA. 26. Statement I:The two strands of DNA are parallel to each other with both the strands running in 3' $\rightarrow$ 5' direction.Statement II:Complementary base pairing between Adenine with guanine and cytosine with thymine is present in DNA. A) Both the statements are correct. B) Statement I is correct, while statement II is incorrect. C) Statement I is incorrect, while statement II is correct. D) Both the statements are incorrect. Show Answer Correct Answer: D) Both the statements are incorrect. 27. The histone proteins present in a histone octamer are A) H2A, H2B, H2C, H3. B) H2A, H2B, H1, H3. C) H2A, H2B, H3, H4. D) None of the above. Show Answer Correct Answer: C) H2A, H2B, H3, H4. 28. DNA and RNA are macromolecules in the category of A) Proteins. B) Carbohydrates. C) Nucleic Acids. D) Lipids. Show Answer Correct Answer: C) Nucleic Acids. 29. In lac operon, RNA polymerase binds to A) Operator gene. B) Lac Z gene. C) Promoter gene. D) Regulator gene. Show Answer Correct Answer: C) Promoter gene. 30. Which of these is true about HGP? A) Its goal was to identify the non-coding parts. B) Its goal was to store information in libraries for easy access. C) Target to improve tools for analysis. D) BYpass ELSI and successfully apply the data. Show Answer Correct Answer: C) Target to improve tools for analysis. 31. Name the scientists who proved that DNA replication was semi conservative A) Kornberg. B) Chargaff. C) Meselson and Stahl. D) Watson and Crick. Show Answer Correct Answer: C) Meselson and Stahl. 32. Translation occurs in A) Cytoplasm. B) Lysosome. C) Nucleolus. D) Nucleus. Show Answer Correct Answer: A) Cytoplasm. 33. The mutations that involve addition, deletion or substitution of a single pair in a gene are referred to as A) Retrogressive mutations. B) Silent mutations. C) Lethal mutations. D) Point mutations. Show Answer Correct Answer: D) Point mutations. 34. Which process is unique to eukaryotic transcription but absent in bacterial transcription? A) Use of DNA as a template. B) Coupling of transcription and translation. C) MRNA capping and polyadenylation. D) Synthesis of RNA in the 5'$\rightarrow$3' direction. Show Answer Correct Answer: C) MRNA capping and polyadenylation. 35. Consider Griffith's experiments on transformation in Streptococcus pneumoniae. Now imagine that you are extending these experiments by injecting a mixture of heat killed strain R bacteria and live strain S bacteria into a mouse. The result will be that the mouse will ..... , and you will find live strain ..... bacteria in its blood. A) Die, R. B) Die, S. C) Live, R. D) Live, S. Show Answer Correct Answer: B) Die, S. 36. Out of 64 codons how many of them code for amino acids? A) 32. B) 20. C) 61. D) 64. Show Answer Correct Answer: C) 61. 37. The final proof for DNA as the genetic material come from experiments of A) Griffith. B) Hershey and Chase. C) Avery, Macleod and McCarty. D) Hargobind Khorana. Show Answer Correct Answer: B) Hershey and Chase. 38. The information in DNA is contained in ..... A) The types of sugars used in making the DNA molecule. B) The sequence of amino acids that makes up the DNA molecule. C) The sequence of nucleotides along the length of the two strands of the DNA molecule. D) The variation in the structure of nucleotides that make up the DNA molecule. Show Answer Correct Answer: C) The sequence of nucleotides along the length of the two strands of the DNA molecule. 39. Bacillus thuringiensis is used as biocontrol agent against A) Butterfly caterpillars. B) Pathogenic fungi. C) Mosquitoes. D) Aphids. Show Answer Correct Answer: A) Butterfly caterpillars. 40. Name the enzyme which is important for DNA template to catalyze the polymerization of deoxynucleotides? A) DNA dependent RNA polymerase. B) DNA dependent DNA polymerase. C) RNA dependent RNA polymerase. D) None of the above. Show Answer Correct Answer: B) DNA dependent DNA polymerase. 41. E.coli divides in every A) 20 mins. B) 30 mins. C) 60 mins. D) 40 mins. Show Answer Correct Answer: A) 20 mins. 42. Which of the following is the site for attachment of amino acid in tRNA molecule? A) 5' end. B) 3' end. C) Anti-codon loop. D) None of the above. Show Answer Correct Answer: C) Anti-codon loop. 43. What is the function of primer A) To help RNA polymerase for termination. B) To help RNA polymerase for initiation. C) To help DNA polymerase for initiation. D) To help DNA polymerase for termination. Show Answer Correct Answer: B) To help RNA polymerase for initiation. 44. Who amongst the following scientist had no contribution in the development of the double helix model for the structure of DNA? A) Rosalind Franklin. B) Maurice Wilkins. C) Erwin Chargaff. D) Meselson and Stahl. Show Answer Correct Answer: B) Maurice Wilkins. 45. Wrapping of negatively charged DNA around positively charged histone octamer is called A) Nucleosome. B) Chromatin. C) Chromosome. D) Histone. Show Answer Correct Answer: A) Nucleosome. 46. One strand of DNA (non template) has base sequence CAG TCG GAT. What will be the sequence of bases in mRNA? A) GTC AGC CTC. B) GAC TAG CTA. C) CAG UCG GAU. D) AGC CTA CTA. Show Answer Correct Answer: C) CAG UCG GAU. 47. Who coined the term nuclein? A) Franklin. B) Watson. C) Crick. D) Friedrich Meischer. Show Answer Correct Answer: D) Friedrich Meischer. 48. During replication of DNA okazaki fragments are formed in the direction of ..... A) 3'$\rightarrow$3'. B) 3'$\rightarrow$5'. C) 5'$\rightarrow$3'. D) 5'$\rightarrow$5'. Show Answer Correct Answer: C) 5'$\rightarrow$3'. 49. Which base forms two hydrogen bonds with adenine? A) Cytosine. B) Adenine itself. C) Thymine. D) Guanine. Show Answer Correct Answer: C) Thymine. 50. In *E. coli*, what is the function of DNA polymerase III? A) To unwind the DNA helix during replication. B) To add nucleotides to the 3' end of a growing DNA strand. C) To degrade damaged DNA molecules. D) To seal together the broken ends of DNA strands. Show Answer Correct Answer: B) To add nucleotides to the 3' end of a growing DNA strand. 51. Semiconservative DNA replication was proved by Messelson and Stahl, in which DNA was made A) Heavy using $^{14}$NH$_{4}$Cl. B) Heavy using $^{15}$NH$_{4}$Cl. C) Radioactive using $^{14}$NH$_{4}$Cl. D) Radioactive using N$^{15}$. Show Answer Correct Answer: B) Heavy using $^{15}$NH$_{4}$Cl. 52. Which of the following statements is incorrect regarding the Hershey and Chase experiment? A) They worked with viruses that infect bacteria called bacteriophage. B) Viruses grown in the presence of radioactive 32P contain radioactive DNA. C) The viral coats were removed from the bacteria by agitating in a blender. D) Bacteria that were infected with bacteriophage that had radioactive proteins showed radioactive signals after centrifugation. Show Answer Correct Answer: D) Bacteria that were infected with bacteriophage that had radioactive proteins showed radioactive signals after centrifugation. 53. Which of the following ensures the stability of the helical structure of a DNA? A) Presence of aneuploidy. B) Presence of repetitive structures of a DNA code. C) Occurrence of chromosomal rearrangements. D) Stacking of one base pair over the other. Show Answer Correct Answer: D) Stacking of one base pair over the other. 54. Adenine pairs with guanine. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 55. If there was a mutation in the gene that coded for RNA primase, then what would most likely happen? A) RNA bases would start to be found in the DNA. B) DNA wouldn't unwind. C) The lagging strand would elongate, but the leading strand wouldn't. D) DNA polymerase would be unable to initiate replication. Show Answer Correct Answer: D) DNA polymerase would be unable to initiate replication. 56. Which of the following types of bacteria were used in Griffith's transformation experiment? A) Diplococcus, R-III and S-II type. B) Pneumococcus, T$_{2}$ phage. C) Streptococcus, R-II and S-III type. D) Diplococcus, E. coli. Show Answer Correct Answer: C) Streptococcus, R-II and S-III type. 57. HnRNA converts to mRNA by A) Translation. B) Crossing over. C) Splicing. D) Replication. Show Answer Correct Answer: C) Splicing. 58. Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways? A) Allowing young organisms to respond differently from more mature organisms. B) Organizing gene expression so that genes are expressed in a given order. C) Allowing the organism to adjust to changes in environmental conditions. D) Allowing each gene to be expressed an equal number of times. Show Answer Correct Answer: C) Allowing the organism to adjust to changes in environmental conditions. 59. Triplet UUU codes for A) Glycine. B) Phenylalanine. C) Methionine. D) Leucine. Show Answer Correct Answer: B) Phenylalanine. 60. Where does the DNA get energy for polymerization? A) Polymerase. B) Deoxynucleotide triphosphates. C) Hydrogen bond breaking. D) By breakdown of phosphodiester bonds. Show Answer Correct Answer: B) Deoxynucleotide triphosphates. ← 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 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