This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 9 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 9 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Origins of Replication A) Locations where DNA replication ends. B) Proteins involved in DNA replication. C) Types of mutations caused by replication errors. D) Specific sequences in the DNA where the replication process begins. Show Answer Correct Answer: D) Specific sequences in the DNA where the replication process begins. 2. 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. 3. 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. 4. 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. 5. Helicase A) Enzymes that break down protein. B) Enzymes that keep DNA from repairing. C) Enzymes that untwist the double-helix at the replication forks. D) Enzymes that bind DNA together. Show Answer Correct Answer: C) Enzymes that untwist the double-helix at the replication forks. 6. 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. 7. 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. 8. Which of the following type of rRNA is not present in prokaryotic cell? A) 5 S. B) 5.8 S. C) 16 S. D) 23 S. Show Answer Correct Answer: B) 5.8 S. 9. Transcription unit is a part of A) Structural gene. B) Promoter. C) Regulator. D) Terminator. Show Answer Correct Answer: A) Structural gene. 10. 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. 11. What is the function of a promoter in a transcription unit? A) Repairs DNA. B) Terminates transcription. C) Binds RNA polymerase. D) Initiates translation. Show Answer Correct Answer: C) Binds RNA polymerase. 12. 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. 13. 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. 14. 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'. 15. The association of histone H 1 with a nucleosome indicates that A) DNA replication is occurring. B) The DNA is condensed into a chromatin fibre. C) DNA double helix is exposed. D) Transcription is occurring. Show Answer Correct Answer: B) The DNA is condensed into a chromatin fibre. 16. The number of stop codons which do not code for any amino acid is A) 1. B) 2. C) 3. D) 4. Show Answer Correct Answer: C) 3. 17. 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) Complete inhibition of transcription of the structural gene controlled by that regulator. C) Inactivation of RNA polymerase by alteration of its active site. 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. 18. 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 33%, T 33%. B) G 8.5%, A 50%, T 24.5%. C) G 34%, A 24.5%, T 24.5%. D) G 17%, A 16.5%, T 32.5%. Show Answer Correct Answer: A) G 17%, A 33%, T 33%. 19. Which of the following phenomena was experimentally proved by Meselson and Stahl? A) Transformation. B) Transduction. C) Semi conversative DNA replication. D) Central dogma. Show Answer Correct Answer: C) Semi conversative DNA replication. 20. According to the Jacob-Monod (lac operon) model of gene regulation, inducer substances in bacterial cells probably A) Combine with operator regions, activating the associated operons. B) Combine with structural genes, stimulating them to synthesize messenger RNA. C) Combine with repressor proteins, inactivating them. D) Combine with promoter regions, activating RNA polymerase. Show Answer Correct Answer: C) Combine with repressor proteins, inactivating them. 21. 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. 22. The codon UUU codes for A) Valine. B) Methionine. C) Phenylalanine. D) Lysine. Show Answer Correct Answer: C) Phenylalanine. 23. In a nucleosome, the DNA is wrapped around A) Histones. B) Polymerase molecules. C) A thymine dimer. D) Ribosomes. Show Answer Correct Answer: A) Histones. 24. 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. 25. An enzyme that joins the strands of nucleic acid is A) Synthetase. B) Polymerase. C) Helicase. D) Ligase. Show Answer Correct Answer: D) Ligase. ← PreviousNext →Related 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 8Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 10Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 11 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books