This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 4 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 4 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following? A) The same codons in different organisms translate into the different amino acids. B) A gene from an organism can theoretically be expressed by any other organism. C) All organisms have experienced convergent evolution. D) DNA was the first genetic material. Show Answer Correct Answer: B) A gene from an organism can theoretically be expressed by any other organism. 2. In eukaryotic transcription, RNA polymerase II is responsible for transcribing: A) RRNA genes. B) TRNA genes. C) MRNA precursor (hnRNA). D) All types of RNA. Show Answer Correct Answer: C) MRNA precursor (hnRNA). 3. In the "beads on a string" structure of unfolded chromatin, the "beads" are ..... A) Nucleosomes. B) Heterochromatin. C) Nucleoids. D) Genes. Show Answer Correct Answer: A) Nucleosomes. 4. Transcription occurs in the ..... A) Ribosomes. B) Nucleus. C) Cytoplasm. D) Kitchen. Show Answer Correct Answer: B) Nucleus. 5. Assertion (A):The anticodon loop of the tRNA contains bases that are complementary to the codes. Reason(R):The stop codons are UAA, UAG and UGA 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: B) Both assertion and reason are true but the reason is not the correct explanation of assertion. 6. Length of DNA will be ..... , if it consists of 10, 000 base pairs. A) 34000 nm. B) 0.034 nm. C) 340 nm. D) 3400 nm. Show Answer Correct Answer: D) 3400 nm. 7. Who discovered presence of DNA in the nucleus for the first time? What name was given to it by him? A) Friedrich Meisher; nucleic acid. B) Francis Crick, nucleic acid. C) Francis Crick, nuclein. D) Friedrich Meisher; nuclein. Show Answer Correct Answer: D) Friedrich Meisher; nuclein. 8. The sequence of structural gene in lac operon is A) Lac A, Lac Y, Lac Z. B) Lac A, Lac Z, Lac Y. C) Lac Y, Lac Z, Lac A. D) Lac Z, Lac Y, Lac A. Show Answer Correct Answer: D) Lac Z, Lac Y, Lac A. 9. Name the polarity of the strand which is used as a template for transcription A) 5'-3'. B) 3'-5'. C) Both. D) None. Show Answer Correct Answer: B) 3'-5'. 10. During transcription of a eukaryotic cell, what determines the template strand? A) The location of the AUG start codon. B) The base sequence of the operator. C) The base sequence of the enhancer. D) The base sequence of the promoter. Show Answer Correct Answer: D) The base sequence of the promoter. 11. To prove that DNA is the genetic material, which radioactive isotopes were used by Hershey and Chase (1952) in experiments? A) 33S and 15N. B) 32P and 35S. C) 32P and 15N. D) 14N and 15N. Show Answer Correct Answer: D) 14N and 15N. 12. The genetic code is A) Triplet. B) Quartet. C) Singlet. D) Doublet. Show Answer Correct Answer: A) Triplet. 13. Origins of Replication A) Specific sequences in the DNA where the replication process begins. B) Types of mutations caused by replication errors. C) Locations where DNA replication ends. D) Proteins involved in DNA replication. Show Answer Correct Answer: A) Specific sequences in the DNA where the replication process begins. 14. Which of the following is called adaptor molecule- A) DNA. B) M-RNA. C) T-RNA. D) RNA. Show Answer Correct Answer: C) T-RNA. 15. In bacteria, the structural genes can be turned on when- A) The end product of a reaction combines with the repressor protein and activates it. B) The substrate combines with a repressor protein and inactivates it. C) The substrate combines with the promoter. D) The substrate combines with its enzyme and produces a repressor molecule. Show Answer Correct Answer: B) The substrate combines with a repressor protein and inactivates it. 16. Who conducted bacteriophage experiment? A) Frederich Griffth. B) Averoy & bMacleod. C) Hershy and Chase. D) Watson and Crick. Show Answer Correct Answer: C) Hershy and Chase. 17. Bacterial DNA is A) Linear. B) Circular and double-stranded. C) Circular and single-stranded. D) Linear and single-stranded. Show Answer Correct Answer: B) Circular and double-stranded. 18. If DNA Polymerase is responsible for synthesizing DNA on the Leading Strand, what enzyme synthesizes DNA on the Lagging Strand? A) Primase. B) RNA Polymerase. C) DNA Polymerase. D) Helicase. Show Answer Correct Answer: C) DNA Polymerase. 19. Which of the following type of rRNA is not present in prokaryotic cell? A) 5.8 S. B) 5 S. C) 16 S. D) 23 S. Show Answer Correct Answer: A) 5.8 S. 20. Transcription unit is a part of A) Structural gene. B) Terminator. C) Promoter. D) Regulator. Show Answer Correct Answer: A) Structural gene. 21. Commonly used vectors for human genome sequencing are A) T/A cloning vectors. B) Expression vectors. C) T-DNA. D) BAC and YAC. Show Answer Correct Answer: D) BAC and YAC. 22. What is the function of a promoter in a transcription unit? A) Binds RNA polymerase. B) Terminates transcription. C) Initiates translation. D) Repairs DNA. Show Answer Correct Answer: A) Binds RNA polymerase. 23. The human genome project was initiated by A) NIH and DOE. B) NIH and FDA. C) NIH and CDC. D) DOE and CDC. Show Answer Correct Answer: A) NIH and DOE. 24. Which of the following statements is the most appropriate for sickle cell anaemia? A) All of the above. B) It confers resistance to acquiring malaria. C) It is a molecular disease. D) It cannot be treated with iron supplements. Show Answer Correct Answer: A) All of the above. 25. Direction that DNA is replicated A) 3' to 5'. B) 5' to 3'. C) All the above. D) None of the above. Show Answer Correct Answer: B) 5' to 3'. 26. The number of stop codons which do not code for any amino acid is A) 3. B) 2. C) 1. D) 4. Show Answer Correct Answer: A) 3. 27. A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in A) Irreversible binding of the repressor to the operator. B) Inactivation of RNA polymerase by alteration of its active site. C) Complete inhibition of transcription of the structural gene controlled by that regulator. D) Continuous transcription of the structural gene controlled by that regulator. Show Answer Correct Answer: D) Continuous transcription of the structural gene controlled by that regulator. 28. In sea urchin DNA, which is double stranded, 17% of the bases were shown to be cytosine. The percentages of the other three bases expected to be present in this DNA are A) G 17%, A 16.5%, T 32.5%. B) G 17%, A 33%, T 33%. C) G 34%, A 24.5%, T 24.5%. D) G 8.5%, A 50%, T 24.5%. Show Answer Correct Answer: B) G 17%, A 33%, T 33%. 29. Which of the following phenomena was experimentally proved by Meselson and Stahl? A) Transduction. B) Semi conversative DNA replication. C) Transformation. D) Central dogma. Show Answer Correct Answer: B) Semi conversative DNA replication. 30. According to the Jacob-Monod (lac operon) model of gene regulation, inducer substances in bacterial cells probably A) Combine with promoter regions, activating RNA polymerase. B) Combine with structural genes, stimulating them to synthesize messenger RNA. C) Combine with repressor proteins, inactivating them. D) Combine with operator regions, activating the associated operons. Show Answer Correct Answer: C) Combine with repressor proteins, inactivating them. 31. If the mechanism of DNA replication in this bacterium were dispersive, what results would be found when the double-stranded DNA was analyzed in a CsCl gradient after two generations in 15N-medium? a) . b) . c) . d) A) One band would be observed containing all the DNA. B) Two bands would be observed containing equal amounts of DNA. C) Two bands would be observed containing unequal amounts of DNA. D) The DNA cannot form any bands if replication is dispersive. Show Answer Correct Answer: C) Two bands would be observed containing unequal amounts of DNA. 32. The codon UUU codes for A) Lysine. B) Methionine. C) Phenylalanine. D) Valine. Show Answer Correct Answer: C) Phenylalanine. 33. In a nucleosome, the DNA is wrapped around A) A thymine dimer. B) Histones. C) Polymerase molecules. D) Ribosomes. Show Answer Correct Answer: B) Histones. 34. SNP which is pronounced as "snips" stands for A) Small nuclear protein. B) Single nucleotide particle. C) Single nucleotide polymorphism. D) Small nicking ponts. Show Answer Correct Answer: C) Single nucleotide polymorphism. 35. An enzyme that joins the strands of nucleic acid is A) Synthetase. B) Helicase. C) Ligase. D) Polymerase. Show Answer Correct Answer: C) Ligase. 36. Mode of DNA replication in E. coli is:- A) Conservative and unidirectional. B) Semi conservative and unidirectional. C) Conservative and bidirectional. D) Semi conservative and bidrectional. Show Answer Correct Answer: D) Semi conservative and bidrectional. 37. Polymerase is able to replicate the new DNA ..... along the leading strand. A) Continuously. B) Only in short fragments. C) Very slowly. D) Prokaryotically. Show Answer Correct Answer: A) Continuously. 38. DNA replication begins at A) Promoter. B) Ori-site. C) Ribosomes. D) Terminal regions. Show Answer Correct Answer: B) Ori-site. 39. Which enzyme is responsible for maintaining telomeres? A) Hexokinase. B) Helicase. C) Topoisomerase. D) Telomerase. Show Answer Correct Answer: D) Telomerase. 40. Okazaki fragments appear on which strand of DNA during DNA replication? A) Lagging. B) LeadingTagsreplication fork. C) All the above. D) None of the above. Show Answer Correct Answer: A) Lagging. 41. If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is A) Sex-linked recessive. B) Autosomal dominant. C) Autosomal recessive. D) Sex-linked dominant. Show Answer Correct Answer: A) Sex-linked recessive. 42. DNA replication needs A) RNA primer. B) DNA template. C) DNTPs. D) All are correct. Show Answer Correct Answer: D) All are correct. 43. The net electric charge on DNA and histones is A) Both positive. B) Both negative. C) Negative and positive, respectively. D) Zero. Show Answer Correct Answer: C) Negative and positive, respectively. 44. Which of the following is NOT a component of the lac operon structural genes? A) Permease gene (y). B) Repressor gene (i). C) Transacetylase gene (a). D) $\beta$-galactosidase gene (z). Show Answer Correct Answer: B) Repressor gene (i). 45. Which of the following is not the positive regulator of Lac operon A) Allolactose. B) Glucose. C) Lactose. D) CAMP. Show Answer Correct Answer: B) Glucose. 46. The process of copying genetic information from one strand of DNA to RNA is termed as ..... A) Reverse transcription. B) Translation. C) Transcription. D) Replication. Show Answer Correct Answer: C) Transcription. 47. Assertion:The two strands of DNA are antiparallel Reason:Only antiparallel polynucleotides form a stable double helix. 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. 48. Griffith performed an experiment to prove the chemical nature of genetic material. In Griffith's experiment: A) The protein coat from pathogenic cells was able to transform non-pathogenic cells. B) Heat killed pathogenic cells caused pneumonia. C) Some substance from pathogenic cells was transferred to non-pathogenic cells and causes transformation. D) The polysaccharide coat of bacteria caused Pneumonia. Show Answer Correct Answer: C) Some substance from pathogenic cells was transferred to non-pathogenic cells and causes transformation. 49. Who is credited with explaining the structure of the DNA double helix? A) Watson and Crick. B) Avery, McCarty, and MacLeod. C) Rosalind Franklin. D) Hershey and Chase. Show Answer Correct Answer: A) Watson and Crick. 50. Which of the following is true about histones? A) Histones are basic proteins. B) Histones are acidic proteins. C) Histones are-vely charged. D) None of the above. Show Answer Correct Answer: A) Histones are basic proteins. 51. How many strands of nucleotides does a molecule of RNA contain? A) One. B) Two. C) Three. D) Four. Show Answer Correct Answer: A) One. 52. DNA polymerase has no proofreading activity. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 53. Lactose from the external medium is transported inside the bacterial cell with the help of A) Beta-galactosidase. B) Permease. C) Transferases. D) Transacetylase. Show Answer Correct Answer: B) Permease. 54. What event is indicative of transcription initiation? A) RNA polymerase is removed from the DNA. B) RNA polymerase binds to the promoter. C) The RNA strand begins to be synthesized. D) Telomerase lengthens the telomeres of the DNA. Show Answer Correct Answer: B) RNA polymerase binds to the promoter. 55. The process of converting mRNA to protein is A) Transcription. B) Replication. C) Splicing. D) Translation. Show Answer Correct Answer: D) Translation. 56. Which of the following is a complete assembled prokaryotic Ribosome? A) 23S rRNA. B) 16S rRNA. C) 50S rRNA. D) 70S RNA. Show Answer Correct Answer: D) 70S RNA. 57. Hydrogen bonds occur between which of the following constituents of DNA? A) Sugar and base. B) Phosphate and base. C) Complementary bases. D) Phosphate and sugar. Show Answer Correct Answer: C) Complementary bases. 58. Amino acids which are specified by single codons are A) Phenylalanine and arginine. B) Tryptophan and methionine. C) Valine and proline. D) Methionine and arginine. Show Answer Correct Answer: B) Tryptophan and methionine. 59. The RNA polymerase holoenzyme transcribes: A) The structural gene only. B) The structural gene and the terminator region. C) The promoter and the terminator region. D) The promoter, structural gene and the terminator region. Show Answer Correct Answer: C) The promoter and the terminator region. 60. Which of the following RNA molecules serves as an adaptor molecule during proteins synthesis A) RRNA. B) MRNA. C) TRNA. D) TRNA and mRNA. Show Answer Correct Answer: C) TRNA. ← 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 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