This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 14 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 14 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Triplet codon refers to sequence of three bases on A) TRNA. B) RRNA. C) MRNA. D) All of these. Show Answer Correct Answer: C) MRNA. 2. The genome of humans contains only coding DNA. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 3. If a codon consists of 3 bases and there are 5 different kinds of bases in a nucleic acid altogether. How many codon will be there? A) 64. B) 61. C) 125. D) 27. Show Answer Correct Answer: C) 125. 4. What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized? A) Helicases and single-strand binding proteins work at the 5' end. B) DNA ligase works only in the 3' $\rightarrow$ 5' direction. C) The origins of replication occur only at the 5' end. D) DNA polymerase can join new nucleotides only to the 3' end of a pre-existing strand, and the strands are antiparallel. Show Answer Correct Answer: D) DNA polymerase can join new nucleotides only to the 3' end of a pre-existing strand, and the strands are antiparallel. 5. The regulator gene of a bacterial operon A) Is a binding site for RNA polymerase. B) Codes for inducer substances. C) Acts as an on-off switch for the structural genes. D) Codes for repressor proteins. Show Answer Correct Answer: D) Codes for repressor proteins. 6. Which of the following region(s) does not code for any proteins?(i) Introns(ii) Exons(iii) VNTRs A) Only i and iii. B) Only ii and iii. C) Only i. D) All i, ii and iii. Show Answer Correct Answer: A) Only i and iii. 7. What non-radioactive isotope was used by Meselson and Stahl to label DNA in their experiment? A) 35S. B) N15. C) P21. D) None. Show Answer Correct Answer: B) N15. 8. After the first replication was observed in their experiments testing the nature of DNA replication, Meselson and Stahl could be confident of which of the following conclusions? A) Replication is neither dispersive nor conservative. B) Replication is not conservative. C) Replication is semi-conservative. D) Replication is not dispersive. Show Answer Correct Answer: B) Replication is not conservative. 9. Direction that DNA is READ? A) 3' to 5'. B) 5' to 3'. C) All the above. D) None of the above. Show Answer Correct Answer: A) 3' to 5'. 10. During Griffith's experiments with Streptococcus pneumoniae in mice, material from ..... bacteria transformed ..... bacteria. A) Living pathogenic heat-killed nonpathogenic. B) Living nonpathogenic living pathogenic. C) Heat-killed nonpathogenic living pathogenic. D) Heat-killed pathogenic living nonpathogenic. Show Answer Correct Answer: D) Heat-killed pathogenic living nonpathogenic. 11. Minisatellite are A) Short non-coding repetitive sequences present throughout the chromosomes. B) 10-40bp sized short sequences within the genes. C) Short coding repetitive regions on the eukaryotic genome. D) Regions of chromosomes at centromere. Show Answer Correct Answer: A) Short non-coding repetitive sequences present throughout the chromosomes. 12. Which enzyme proofreads and removes RNA Primase A) Polymerase 1. B) HelicaseTagsDNA replication enzymes. C) Ligase. D) Polymerase 3. Show Answer Correct Answer: A) Polymerase 1. 13. Elect the two correct statements out of the four (l-IV) given below about Lac operon. I. Glucose or galactose may bind with the repressor and inactivate it. II. in the absence of lactose the repressor binds with the operator region III. The z-gene codes for regionIV. This was elucidated by Francois Jacob and Jacques Monad The correct statement are: A) I and II. B) II and IV. C) I and III. D) II and III. Show Answer Correct Answer: B) II and IV. 14. The following is not a character of RNA: A) RNA is unstable and degradable. B) RNA mutates at faster rate than DNA. C) RNA evolves slowly. D) RNA is catalytic /reactive. Show Answer Correct Answer: C) RNA evolves slowly. 15. The capping of nucleotide prevents the rapid cleavage of mRNA and catalyzed by guanylyltransferase. Identify the nucleotide cap that is attached at the 5'end of mRNA. A) 5-methyl guanosine. B) 5-acetyl guanosine. C) 7-methyl guanosine. D) 7-acetyl guanosine. Show Answer Correct Answer: C) 7-methyl guanosine. 16. The genetic code of proline are: A) GUU GUC GUG. B) CCC CCG CCU. C) GGU GUC GGA. D) CUU UCA CUG. Show Answer Correct Answer: B) CCC CCG CCU. 17. Assertion:Adenine cannot pair with cytosine.Reason:Adenine and Cytosine do not have a perfect match between hydrogen donor and hydrogen acceptor sites. Hence they cannot pair.A-If both A and R are true and R is the correct explanation of A.B-If both A and R are true but R is not the correct explanation of A. C-If A is true but R is false. D-If both A and R are false. A) B. B) D. C) A. D) C. Show Answer Correct Answer: C) A. 18. Which of the following will form a palindromic sequence? A) GTTGGAAC. B) GTTCCAAG. C) ATTGCAAT. D) AGTCCTGA. Show Answer Correct Answer: C) ATTGCAAT. 19. The most abundant RNA is A) TRNA. B) RRNA. C) SnRNA. D) MRNA. Show Answer Correct Answer: B) RRNA. 20. In DNA replication each newly made strand is A) Identified in DNA sequence to the strand from which it was copied. B) Complementary in sequence to the strand from which it was copied. C) Oriented in the same 3' to 5' direction as the strand from which it was copied. D) An incomplete copy of one of the parental strands. Show Answer Correct Answer: B) Complementary in sequence to the strand from which it was copied. 21. To show that DNA in cell extracts was responsible for genetic transformation in Pneumococcus, important corroborating evidence was that A) Enzymes that destroyed polysaccharides also destroyed transforming activity. B) Enzymes that destroyed DNA also destroyed transforming activity. C) Boiling destroyed transforming activity. D) Enzymes that destroyed proteins also destroyed transforming activity. Show Answer Correct Answer: B) Enzymes that destroyed DNA also destroyed transforming activity. 22. In E. coli, 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. 23. If there are 999 bases in an RNA that codes for a protein with 333 amino acids, and the base at position 901 is deleted such that the length of the RNA becomes 998 bases, how many codons will be altered? A) 33. B) 1. C) 333. D) 11. Show Answer Correct Answer: A) 33. 24. Transcription occurs along a ..... template forming an mRNA in the ..... direction A) 3' to 5'; 3' to 5'. B) 5' to 3'; 3' to 5'. C) 3' to 5'; 5' to 3'. D) 5' to 3'; 5' to 3'. Show Answer Correct Answer: C) 3' to 5'; 5' to 3'. 25. Which of the following is not a part of a nucleoside? A) Base. B) Glycosidic linkage. C) Phosphate. D) Deoxyribose sugar. Show Answer Correct Answer: C) Phosphate. 26. The length of DNA molecule greatly exceeds the dimensions of the nucleus in eukaryotic cells. How is this DNA accommodated? A) Deletion of non-essential genes. B) Super-coiling in nucleosomes. C) Through elimination of repetitive DNA. D) DNAse digestion. Show Answer Correct Answer: B) Super-coiling in nucleosomes. 27. The total number of genes in human genome is approximately: A) 20, 000-25, 000. B) 5, 000. C) 1, 00, 000. D) 50, 000. Show Answer Correct Answer: A) 20, 000-25, 000. 28. At each end of a DNA replication bubble is ..... A) A ribosome. B) A gene. C) A replication fork. D) An origin of replication. Show Answer Correct Answer: C) A replication fork. 29. Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following? A) The evolution of telomerase enzyme. B) DNA polymerase that cannot replicate the leading strand template to its 5' end. C) Gaps left at the 5' end of the lagging strand because of the need for a 3' onto which nucleotides can attach. D) Gaps left at the 3' end of the lagging strand because of the need for a primer. Show Answer Correct Answer: C) Gaps left at the 5' end of the lagging strand because of the need for a 3' onto which nucleotides can attach. 30. If the DNA of this virus was labelled with $^{32}$P and the protein of the virus was labelled with $^{35}$S, which molecule(s) would be present inside the cells? A) $^{35}$S and $^{32}$P. B) $^{35}$S only. C) $^{32}$P only. D) Neither molecule would be present inside the cell. Show Answer Correct Answer: C) $^{32}$P only. 31. Which is the primary purpose of using restriction enzymes in gel electrophoresis? A) It allows the strands of DNA to be cut into various lengths for testing. B) It restricts the number of base pairs that can be tested in a sample. C) It makes the testing simpler by moving the strands into the gel faster. D) It charges the DNA strands. Show Answer Correct Answer: A) It allows the strands of DNA to be cut into various lengths for testing. 32. If the sequence of bases in DNA is ATTCGATG, then the sequence of bases in its transcript will be A) CAUCGAAU. B) GUAGCUUA. C) UAAGCUAC. D) AUUCGAUG. Show Answer Correct Answer: C) UAAGCUAC. 33. What is the approximate number of base pairs present in a DNA molecule with length 34 nm? A) 34. B) 68. C) 100. D) 340. Show Answer Correct Answer: C) 100. 34. A bacterium with completely radioactive DNAwas allowed to replicate in a non-radioactivemedium for two generation what % of the bacteriashould contain radioactive DNA:- A) 100 %. B) 25 %. C) 12.5 %. D) 50 %. Show Answer Correct Answer: D) 50 %. 35. In 125 amino acid sequence if the codon for 25th amino acid is mutated to UAA, then A) A polypeptide of 25 amino acids is formed. B) No polypeptides are formed. C) A polypeptide of 24 amino acids is formed. D) A polypeptide of 124 amino acids is formed. Show Answer Correct Answer: C) A polypeptide of 24 amino acids is formed. 36. Template strand is decided based on A) Promoter. B) Coding seqeuence of DNA. C) Centromere. D) Telomere. Show Answer Correct Answer: A) Promoter. 37. Name the chemical substance used as the source of nitrogen by Meselson and Stahl A) NH4Cl. B) NH4OH. C) NH3. D) None of the above. Show Answer Correct Answer: A) NH4Cl. 38. Which of the following components is required for DNA replication? A) Ribosomes. B) Sucrases. C) RNA primer. D) Messenger RNA. Show Answer Correct Answer: C) RNA primer. 39. In prokaryotes, which of the following statement is incorrect with relation to transcription? A) MRNA does not require processing to become active. B) Transcription and translation in same compartment. C) MRNA requires processing to become active. D) Translation may begin much before mRNA is fully transcribed. Show Answer Correct Answer: C) MRNA requires processing to become active. 40. When synthesizing a new DNA strand, DNA polymerase writes ..... A) 5' to 3'. B) 3' to 5'. C) 3' to 5' or 5' to 3'. D) None of the above. Show Answer Correct Answer: A) 5' to 3'. 41. Semiconservative replication involves a template. What is the template? A) An RNA molecule. B) One strand of the DNA molecule. C) Single-stranded binding proteins. D) DNA polymerase. Show Answer Correct Answer: B) One strand of the DNA molecule. 42. The building blocks for a new DNA molecule are A) Deoxyribose nucleoside tetraphosphates. B) Deoxyribose nucleoside monophosphates. C) Deoxyribose nucleoside triphosphates. D) Deoxyribose nucleoside diphosphates. Show Answer Correct Answer: C) Deoxyribose nucleoside triphosphates. 43. DNA replication in bacteria occurs in A) S Phase. B) M Phase. C) G2 Phase. D) G1 Phase. Show Answer Correct Answer: D) G1 Phase. 44. Which of the following statements about the structure of DNA is false? A) The width of the DNA molecule is variable since it can accommodate nucleotides containing varying number of nitrogen-based 'rings'. B) Hydrogen bonds determine which nitrogenous bases can pair together. C) A total of 10 pairs of nuecleotides are included in each complete 'turn' of the double helix. D) Minor and major grooves alternate along the length of the molecule. Show Answer Correct Answer: A) The width of the DNA molecule is variable since it can accommodate nucleotides containing varying number of nitrogen-based 'rings'. 45. Select the correct requirement to complete:DNA polymerase cannot initiate synthesis; it needs ..... A) RNA primer. B) Helicase. C) Topoisomerase. D) DNA ligase. Show Answer Correct Answer: A) RNA primer. 46. What are telomeres? A) The ends of linear chromosomes. B) The sites of origin of DNA replication. C) The structures that hold two sister chromatids together. D) Enzymes that elongate the DNA strand during replication. Show Answer Correct Answer: A) The ends of linear chromosomes. 47. Which enzyme catalyzes the elongation of a DNA strand in the 5' $\rightarrow$ 3' direction? A) Helicase. B) DNA polymerase III. C) Topoisomerase. D) DNA polymerase I. Show Answer Correct Answer: B) DNA polymerase III. 48. The chemical nature of a gene is A) Protein. B) Acid. C) Base. D) None of these. Show Answer Correct Answer: B) Acid. 49. The flow of information from DNA to mRNA and then to proteins is called A) Transcription. B) Genetic code. C) Translation. D) Central dogma. Show Answer Correct Answer: D) Central dogma. 50. To initiate translation, the wiRNA first bind to A) The smaller ribosomal sub-unit. B) The larger ribosomal sub-unit. C) The whole ribosome. D) No such specificity exists. Show Answer Correct Answer: A) The smaller ribosomal sub-unit. 51. The process of transfer of genetic information from DNA to RNA/ formation of RNA from DNA is A) Translation. B) Transcription. C) Transversion. D) Translocation. Show Answer Correct Answer: B) Transcription. 52. DNA contains the template needed to copy itself, but it has no catalytic activity in cells. What catalyzes the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed during DNA replication? A) RNA primers. B) Ribozymes. C) DNA polymerase. D) ATP. Show Answer Correct Answer: C) DNA polymerase. 53. Select the correct term to complete:DNA in eukaryotes is wrapped around ..... proteins. A) Kinesins. B) Actins. C) Histones. D) Tubulins. Show Answer Correct Answer: C) Histones. 54. UAA, UAG, UGA are known as nonsense codons. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 55. Regulatory proteins are the accessory proteins that interact with RNA polymerase and affect its role in transcription. Which of the following statements is correct about regulatory protein? A) They only increase expression. B) They only decrease expression. C) They interact with RNA polymerase but do not affect the expression. D) They can act both as activators and as repressors. Show Answer Correct Answer: D) They can act both as activators and as repressors. 56. The enzyme that restores the phosphodiester linkage between adjacent fragments in the lagging strand during DNA replication is A) Reverse transcriptase. B) Helicase. C) DNA ligase. D) Primase. Show Answer Correct Answer: C) DNA ligase. 57. In Hershey and Chase experiment, the protein of T2 phage was made radioactive by using A) P$^{31}$. B) P$^{32}$. C) S$^{35}$. D) S$^{32}$. Show Answer Correct Answer: C) S$^{35}$. 58. Initiation of DNA strand synthesis is performed by: A) DNA polymerase I. B) DNA Helicase. C) DNA Topoisomerase. D) DNA Primase. Show Answer Correct Answer: D) DNA Primase. 59. R strain of the bacteria was non virulent due to lack of lipopolysaccharide coat A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 60. Which of the following does not take part in stabilizing the cloverleaf model of the tRNA? A) Hydrogen bond. B) Ionic bond. C) Base and sugar-phosphate backbone interaction. D) Base stacking. Show Answer Correct Answer: B) Ionic bond. ← 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