This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Biology > Class 12 Biology Chapter 6 Molecular Basis Of Inheritance – Quiz 3 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Biology Chapter 6 Molecular Basis Of Inheritance Quiz 3 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Which of the following sugars is found in RNA? A) Hexose. B) Glucose. C) Ribose. D) Fructose. Show Answer Correct Answer: C) Ribose. 2. The human chromosome with the highest and least number of genes in them are respectively: A) Chromosome 21 and Y. B) Chromosome 1 and X. C) Chromosome 1 and Y. D) Chromosome X and Y. Show Answer Correct Answer: C) Chromosome 1 and Y. 3. The prime objective of HGP was A) To sequence the entire base pairs that makes up the 24 chromosomes. B) To sequence the entire base pairs that makes up the 23 chromosomes. C) To find out the exact functions of proteins in humans. D) To find out the active genes in human genome. Show Answer Correct Answer: A) To sequence the entire base pairs that makes up the 24 chromosomes. 4. The ..... contains ..... A) Leading Strand / Okazaki Fragments. B) Lagging Strand / Okazaki Fragments. C) Leading Strand / Topoisomerase. D) Lagging Strand / dispersive replication. Show Answer Correct Answer: B) Lagging Strand / Okazaki Fragments. 5. Which scientist confirmed the DNA is genetic material? A) Chargraff. B) Crick. C) Levene. D) Hershey. Show Answer Correct Answer: D) Hershey. 6. Which is not found in RNA A) Uracil. B) Guanine. C) Cytosine. D) Thymine. Show Answer Correct Answer: D) Thymine. 7. During translation, activated amino acids get linked to tRNA. This process is commonly called as A) Charging of tRNA. B) Discharging of tRNA. C) Aminoacylation of tRNA. D) Both (a) and (c). Show Answer Correct Answer: B) Discharging of tRNA. 8. If the distance between two consecutive base pairs is 0.34nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is $6.6\times10^9$ A) 2.7 meters. B) 2.5 meters. C) 2.0 meters. D) 2.2 meters. Show Answer Correct Answer: D) 2.2 meters. 9. The chain-terminating codon is A) CCC. B) AUG. C) GGG. D) UAG. Show Answer Correct Answer: D) UAG. 10. RRNA is the least abundant RNA. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 11. Which scientists used X-ray crystallography to determine the helical structure of DNA? A) Meselson & Stahl. B) Watson & Crick. C) Franklin & Watkins. D) Hershey & Chase. Show Answer Correct Answer: C) Franklin & Watkins. 12. The strand of DNA, which does not code for anythingis referred to as:- A) Template strand. B) Antisense strand. C) Coding strand. D) Noncoding strand. Show Answer Correct Answer: D) Noncoding strand. 13. Which of the following is Circular DNA-(D) All A) Mitochondrial DNA. B) Chloroplast DNA. C) Plasmid DNA. D) All. Show Answer Correct Answer: D) All. 14. 3'-ATGCATGCATGCATGCATGCATGC-5' Template Strand find the coding strand? A) 5'-TACGTACGTACGTACGTACGTACG-3' Coding Strand. B) 5'-TACGTACGTACGTACGTACGTAGC-3' Coding Strand. C) 5'-TACGTACGTACGTACGTACGATCG-3' Coding Strand. D) 5'-TACGTACGTACGTACGTACGTCAG-3' Coding Strand. Show Answer Correct Answer: A) 5'-TACGTACGTACGTACGTACGTACG-3' Coding Strand. 15. Which of the following statements accurately describes the structure of a eukaryotic chromosome? A) It is a single linear molecule of double-stranded DNA plus proteins. B) It has different numbers of genes in different cell types of an organism. C) It is composed of a single strand of DNA. D) It is constructed as a series of nucleosomes wrapped around two DNA molecules. Show Answer Correct Answer: A) It is a single linear molecule of double-stranded DNA plus proteins. 16. In 1868 DNA was discovered by the Swedish biochemist A) Luria. B) Mirsky. C) Feulgen. D) Friedrich Miescher. Show Answer Correct Answer: D) Friedrich Miescher. 17. The satellite DNA used in DNA fingerprinting consists of: A) Highly conserved sequences. B) Variable Number of Tandem Repeats (VNTR). C) Protein coding sequences. D) Ribosomal RNA genes. Show Answer Correct Answer: B) Variable Number of Tandem Repeats (VNTR). 18. The first genetic material could have been A) Cabohydrates. B) RNA. C) DNA. D) Protein. Show Answer Correct Answer: B) RNA. 19. What are dimensions of DNA molecule A) 3.4 A, 0.34 A, 20 A. B) 3.4 nm, 0.34nm, 20nm. C) 3.4 m, 0.34 m, 20m. D) All of these. Show Answer Correct Answer: B) 3.4 nm, 0.34nm, 20nm. 20. Out of 64 codons, the number of codons with GGG is A) 4. B) 2. C) 1. D) 6. Show Answer Correct Answer: C) 1. 21. One strand of a DNA molecule has the base sequence 5'-ATAGGT-3'. The complementary base sequence on the other strand of DNA will be 3' ..... 5'. A) TGGATA. B) ATAGGT. C) TGGAUA. D) TATCCA. Show Answer Correct Answer: D) TATCCA. 22. The purine binds with pyrimidine which result in A) Uniform distance between two strands. B) Zig-zag arrangement between two strands. C) Irregular distance between two strands. D) None of the above. Show Answer Correct Answer: A) Uniform distance between two strands. 23. What is nucleosome? A) A vesicle containing positively charged histones within nucleolus. B) They are similar to endosomes. C) They are the transforming principles discovered by Griffith. D) A structure formed by wrapping of negatively charged DNA around positively charged histone octamer. Show Answer Correct Answer: D) A structure formed by wrapping of negatively charged DNA around positively charged histone octamer. 24. If the base sequence of a codon in mRNA is 5'-AUG-3', the sequence of tRNA pairing with it must be: A) 5'-CAU-3'. B) 5'-GUA-3'. C) 5'-UAC-3'. D) 5'-AUG-3'. Show Answer Correct Answer: A) 5'-CAU-3'. 25. Replication is continuous in A) The leading strand. B) The lagging strand. C) The strand where okazaki fragments are present. D) Both the strands. Show Answer Correct Answer: A) The leading strand. 26. Why does the DNA double helix have a uniform diameter? A) Purines pair with pyrimidines. B) C nucleotides pair with A nucleotides. C) Deoxyribose sugars bind with ribose sugars. D) Nucleotides bind with nucleoside triphosphates. Show Answer Correct Answer: A) Purines pair with pyrimidines. 27. In lac operon the i gene codes for A) Permease. B) Inducer of lac operon. C) Repressor of lac operon. D) Hydrolysis of Disaccharide. Show Answer Correct Answer: C) Repressor of lac operon. 28. A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? A) Okazaki fragments. B) DNA polymerase. C) DNA ligase. D) Primase. Show Answer Correct Answer: C) DNA ligase. 29. Which of the following codons acts as both start codon and codes for methionine? A) UAA. B) UUG. C) AUG. D) GUG. Show Answer Correct Answer: C) AUG. 30. Removal of introns and joining of exons is called A) Capping. B) Tailing. C) Splicing. D) All. Show Answer Correct Answer: C) Splicing. 31. The structure in chromatin seen as 'beads-on string' when viewed under electron microscope are called A) Nucleotides. B) Chromosomes. C) Nucleosomes. D) Histone octamer. Show Answer Correct Answer: C) Nucleosomes. 32. What element(s) do all eukaryotic promoter regions share? A) Transcription factors. B) Enhancers that accept binding agents. C) A basal promoter (TATA box). D) All of these. Show Answer Correct Answer: D) All of these. 33. Which of the following types of cells are affected most by telomere shortening? A) Only eukaryotic cells. B) Only animal cells. C) Cells in prokaryotes and eukaryotes. D) Only prokaryotic cells. Show Answer Correct Answer: A) Only eukaryotic cells. 34. The anti-parallel nature of DNA is due to A) Its charged phosphate groups. B) The formation of hydrogen bonds between bases from opposite strands. C) The opposite direction of the two strands. D) The pairing of bases on one strand with bases on the other strand. Show Answer Correct Answer: C) The opposite direction of the two strands. 35. The process of transformation is not affected by which of the following enzymes? A) Peptidase. B) Lipase. C) DNase. D) RNase. Show Answer Correct Answer: A) Peptidase. 36. Which of the following RNAs should be most abundant in animal cell? A) T RNA. B) Mi RNA. C) R RNA. D) M RNA. Show Answer Correct Answer: C) R RNA. 37. Which of the following is a salient feature of the DNA double-helix structure? A) Ribose sugar forms the backbone. B) Uracil pairs with adenine. C) Complementary base pairing stabilizes the strands. D) Peptide bonds hold bases together. Show Answer Correct Answer: C) Complementary base pairing stabilizes the strands. 38. The process of transformation is not affected by which of the following enzymes?a) DNaseb) RNasec) Peptidased) Lipase A) A, B, C. B) B, C, D. C) A, B, C, D. D) A, B. Show Answer Correct Answer: B) B, C, D. 39. The process of removal of introns by endonuclease enzyme and joining of exon by ligase enzyme. A) Capping. B) Tailing. C) Spicing. D) Splicing. Show Answer Correct Answer: D) Splicing. 40. The amino acid attaches to the mRNA at its A) 3' end. B) Anticodon site. C) DHU LOop. D) 5' end. Show Answer Correct Answer: A) 3' end. 41. The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage? A) DNA ligase, replication fork proteins, adenylyl cyclase. B) Telomerase, helicase, single-strand binding protein. C) Telomerase, primase, DNA polymerase. D) Nuclease, DNA polymerase, DNA ligase. Show Answer Correct Answer: D) Nuclease, DNA polymerase, DNA ligase. 42. Which of the following statements accurately describes one characteristic of histones? A) Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together. B) Each nucleosome consists of two molecules of histone H1. C) The carboxyl end of each histone extends outward from the nucleosome and is called a "histone tail.". D) Histones are found in mammals, but not in other animals or in plants or fungi. Show Answer Correct Answer: A) Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together. 43. In the base sequence of one strand of DNA isCAT, TAG, CAT, CAT, GAC what would be thebase sequence of its complementary m-RNA- A) GUA, AUC, GUA, GUA, CUG. B) GUA, GUA, CUG, AUC, CUG. C) GUC, CUG, CUG, CUA, CUU. D) AUG, CUG, CUC, GUA, CUG. Show Answer Correct Answer: A) GUA, AUC, GUA, GUA, CUG. 44. What is the consequence of a failure in cell division after DNA replication? A) Aneuploidy. B) Mutations. C) Apoptosis. D) Polyploidy. Show Answer Correct Answer: D) Polyploidy. 45. DNA replication in eukaryotes starts from a single origin. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 46. In a healthy eukaryotic cell, the rate of DNA repair is typically equal to the rate of DNA mutation. When the rate of repair lags behind the rate of mutation, what is a possible fate of the cell? A) RNA may be used instead of DNA as inheritance material. B) DNA replication will continue by a new mechanism. C) DNA replication will proceed more quickly. D) The cell can be transformed into a cancerous cell. Show Answer Correct Answer: D) The cell can be transformed into a cancerous cell. 47. A DNA with unequal nitrogen bases would most probably be A) Single stranded. B) Double stranded. C) Four stranded. D) None of the above. Show Answer Correct Answer: A) Single stranded. 48. Which of the following steps in transcription is catalyzed by RNA polymerase? A) Initiation. B) All of the above. C) Elongation. D) Termination. Show Answer Correct Answer: B) All of the above. 49. In RNA, uracil pairs with A) A. B) C. C) G. D) T. Show Answer Correct Answer: A) A. 50. Nucleosome core contains A) 100 bp DNA. B) 146 bp DNA. C) 50 bp DNA. D) 300 bp DNA. Show Answer Correct Answer: B) 146 bp DNA. 51. Double-stranded DNA looks a little like a ladder that has been twisted into a helix or spiral. The side supports of the ladder are A) Individual nitrogenous bases. B) Alternating bases and sugars. C) Alternating bases and phosphate groups. D) Alternating sugars and phosphates. Show Answer Correct Answer: B) Alternating bases and sugars. 52. In some viruses, DNA is synthesised by using RNA as template. Such a DNA is called A) RDNA. B) A-DNA. C) CDNA. D) B-DNA. Show Answer Correct Answer: C) CDNA. 53. In eukaryotes, RNA polymerase III catalyses the synthesis of A) 5 S rRNA, tRNA & SnRNA. B) MRNA, HnRNA & SnRNA. C) 28 S rRNA, 18 S rRNA & 5 S rRNA. D) All types of rRNA & tRNA. Show Answer Correct Answer: A) 5 S rRNA, tRNA & SnRNA. 54. DNA is made up of A) Ribonucleotide. B) Nucleoside. C) Nucleotide. D) Deoxyribonucleotide. Show Answer Correct Answer: D) Deoxyribonucleotide. 55. Which of the following hydrolyses internalphosphodiester bonds in a polynucleotidechain A) Lipase. B) Endonuclease. C) Protease. D) Exonuclease. Show Answer Correct Answer: B) Endonuclease. 56. The enzyme that joins Okazaki fragments during DNA replication is: A) DNA helicase. B) DNA polymerase. C) DNA primase. D) DNA ligase. Show Answer Correct Answer: D) DNA ligase. 57. During biochemical characterization of transforming principle, the digestion with ..... did inhibit transformation suggesting that DNA caused the transformation. A) Protease. B) RNAase. C) DNA polymerase. D) DNAase. Show Answer Correct Answer: D) DNAase. 58. Which of the following base pairs would never be found in the cell? A) Adenine $\rightarrow$ thymine. B) Thymine$\rightarrow$ uracil. C) Cytosine $\rightarrow$ guanine. D) Adenine $\rightarrow$ uracil. Show Answer Correct Answer: B) Thymine$\rightarrow$ uracil. 59. Precursor of m-RNA is A) Sn rna. B) T rna. C) Hn rna. D) M rna. Show Answer Correct Answer: C) Hn rna. 60. In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules? A) A = C. B) A + T = G + C. C) A + G = C + T. D) A = G. Show Answer Correct Answer: C) A + G = C + T. ← 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 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