Title 6. Molecular Basis of Inheritance.pdf ✅

6.1 The DNA 1. Which of the following statements is correct? (a) Adenine pairs with thymine through two H-bonds. (b) Adenine pairswith thymine through oneH-bond. (c) Adenine pairswith thymine through threeH-bonds. (d) Adenine does not pair with thymine. (NEET 2020) 2. Purines found both in DNA and RNA are (a) cytosine and thymine (b) adenine and thymine (c) adenine and guanine (d) guanine and cytosine. (NEET 2019) 3. The association of histone H1 with a nucleosome indicates that (a) DNA replication is occurring (b) the DNA is condensed into a chromatin fibre (c) the DNA double helix is exposed (d) transcription is occurring. (NEET 2017) 4. 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%. (2015 Cancelled) 5. The diagram shows an important concept in the genetic implication of DNA. Fill in the blanks A to C. DNA mRNA Proposed by Protein C A B (a) A - Transcription, B -Translation, C - Francis Crick (b) A- Translation, B - Extension,C- Rosalind Franklin (c) A- Transcription, B - Replication, C -James Watson (d) A - Translation, B - Transcription, C - Ervin Chargaff (NEET 2013) 6. DNA mRNA C Proposed by Protein A B The figure gives an important concept in the genetic implication of DNA. Fill the blanks A, B and C. (a) A-Maurice Wilkins, B-Transcription, C-Translation (b) A-James Watson, B-Replication, C-Extension (c) A-Erwin Chargaff, B-Translation, C-Replication (d) A-Francis Crick, B-Translation, C-Transcription (Karnataka NEET 2013) 7. What are the structures called that give an appearance as‘beads-on-string’ in the chromosomes when viewed under electron microscope? (a) Genes (b) Nucleotides (c) Nucleosomes (d) Base pairs (2011) 8. Which one of the following does not follow the central dogma of molecular biology? (a) Pea (b) Mucor (c) Chlamydomonas (d) HIV (2010) 9. The 3′ - 5′ phosphodiester linkages inside a polynucleotide chain serve to join (a) one DNA strand with the other DNA strand (b) one nucleoside with another nucleoside (c) one nucleotide with another nucleotide (d) one nitrogenous base with pentose sugar. (Main 2010) 10. Which one of the following statements about the particular entity is true ? (a) Centromere is found in animal cells, which produces aster during cell division. (b) The gene for producing insulin is present in every body cell. (c) Nucleosome is formed of nucleotides. (d) DNA consists of core of eight histones. (Main 2010) Molecular Basis of Inheritance 6 CHAPTER EduHulk.COM
68 11. In the DNA molecule, (a) the proportion of adenine in relation to thymine varies with the organism (b) there are two strands which run anti- parallel-one in 5′ → 3′ direction and other in 3′ → 5′ (c) the total amount of purine nucleotides and pyrimidine nucleotides is not always equal (d) there are two strands which run parallel in the 5′ → 3′ direction. (2008) 12. Which one of the following pairs of nitrogenous bases of nucleic acids, is wrongly matched with the category mentioned against it? (a) Guanine, Adenine - Purines (b) Adenine, Thymine - Purines (c) Thymine, Uracil - Pyrimidines (d) Uracil, Cytosine - Pyrimidines (2008) 13. One turn of the helix in a B-form DNAis approximately (a) 2 nm (b) 20 nm (c) 0.34 nm (d) 3.4 nm. (2006) 14. Antiparallel strands of a DNA molecule means that (a) one strand turns clockwise (b) one strand turns anti-clockwise (c) the phosphate groups of two DNA strands, at their ends, share the same position (d) the phosphate groups at the start of two DNA strands are in opposite position (pole). (2006) 15. Which one of the following makes use of RNA template to synthesise DNA? (a) DNA polymerase (b) RNA polymerase (c) Reverse transcriptase (d) DNA dependant RNA polymerase (2005) 16. Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain? (a) Lipase (b) Protease (c) Endonuclease (d) Exonuclease (2005) 17. The following ratio is generally constant for a given species: (a) A + G / C + T (b) T + C / G + A (c) G + C / A + T (d) A + C / T + G. (2004) 18. In a DNA percentage of thymine is 20% then what will be percentage of guanine? (a) 20% (b) 40% (c) 30% (d) 60% (2002) 19. Length of one loop of B-DNA (a) 3.4 nm (b) 0.34 nm (c) 20 nm (d) 10 nm. (2000) 20. DNA is mainly found in (a) nucleolus (b) nucleus only (c) cytoplasm only (d) none of these. (1999) 21. In prokaryotes, the genetic material is (a) linear DNA without histones (b) circular DNA without histones (c) linear DNA with histones (d) circular DNA with histones. (1999) 22. In DNA, when AGCT occurs, their association is as per which of the following pair? (a) AT-GC (b) AG-CT (c) AC-GT (d) All of these (1999) 23. The eukaryotic genome differs from the prokaryotic genome because (a) theDNAis complexedwith histone in prokaryotes (b) the DNA is circular and single stranded in prokaryotes (c) repetitive sequences are present in eukaryotes (d) genes in the former case are organised into operons. (1999) 24. Genes are packaged into a bacterial chromosome by (a) acidic protein (b) actin (c) histones (d) basic protein. (1997) 25. Radiotracer technique shows that DNA is in (a) multi-helix stage (b) single-helix stage (c) double-helix stage (d) none of these. (1996) 26. Nucleosome core is made of (a) H0, H2A, H2B and H3 (b) H1, H2A, H2B, H4 (c) H1, H2A, H2B, H3 and H4 (d) H2A, H2B, H3 and H4. (1993) 27. A DNA with unequal nitrogen bases would most probably be (a) single stranded (b) double stranded (c) triple stranded (d) four stranded. (1993) 28. Nucleotide arrangement in DNA can be seen by (a) X-ray crystallography (b) electron microscope (c) ultracentrifuge (d) light microscope. (1993) 29. An octamer of 4 histones complexedwith DNAforms (a) endosome (b) nucleosome (c) mesosome (d) centromere. (1990) 6.2 The Search for Genetic Material 30. The experimental proof for semi-conservative replication of DNA was first shown in a (a) fungus (b) bacterium (c) plant (d) virus. (NEET 2018) EduHulk.COM
Molecular Basis of Inheritance 69 31. Select the correct match. (a) Ribozyme - Nucleic acid (b) F2 × Recessive parent- Dihybrid cross (c) T.H. Morgan - Transduction (d) G. Mendel - Transformation (NEET 2018) 32. The final proof for DNA as the genetic material came from the experiments of (a) Hershey and Chase (b) Avery, MacLeod and McCarty (c) Hargobind Khorana (d) Griffith. (NEET 2017) 33. Taylor conducted the experiments to prove semi- conservative mode of chromosome replication on (a) Vinca rosea (b) Vicia faba (c) Drosophila melanogaster (d) E. coli. (NEET-II 2016) 34. A molecule that can act as a genetic material must fulfill the traits given below, except (a) it should be able to express itself in the form of ‘Mendelian characters’ (b) it should be able to generate its replica (c) itshould be unstable structurally and chemically (d) it should provide the scope for slow changes that are required for evolution. (NEET-II 2016) 35. Transformation was discovered by (a) Meselson and Stahl (b) Hershey and Chase (c) Griffith (d) Watson and Crick. (2014) 36. The unequivocal proof of DNAasthe genetic material came from the studies on a (a) bacterium (b) fungus (c) viroid (d) bacterial virus. (Main 2011) 37. Semi-conservative replication of DNA was first demonstrated in (a) Escherichia coli (b) Streptococcus pneumoniae (c) Salmonella typhimurium (d) Drosophila melanogaster. (2009) 38. Transformation experiment was first performed on which bacteria? (a) E. coli (b) Diplococcus pneumoniae (c) Salmonella (d) Pasteurella pestis (2002) 39. The Pneumococcus experiment proves that (a) bacteria do not reproduce sexually (b) RNA sometime controls the production of DNA and proteins (c) DNA is the genetic material (d) bacteria undergo binary fission. (1999) 40. DNA synthesis can be specifically measured by estimating the incorporation of radio-labelled (a) thymidine (b) deoxyribose sugar (c) uracil (d) adenine. (1997) 41. The transforming principle of Pneumococcus as found out by Avery, MacLeod and McCarty was (a) mRNA (b) DNA (c) protein (d) polysaccharide. (1993) 42. Who proved that DNA is basic genetic material? (a) Griffith (b) Watson (c) Boveri and Sutton (d) Hershey and Chase (1993) 43. Escherichia coli fully labelled with 15N is allowed to grow in 14N medium. The two strands of DNA molecule of the first generation bacteria have (a) different density and do not resemble parent DNA (b) different density but resemble parent DNA (c) same density and resemble parent DNA (d) same density but do not resemble parent DNA. (1992) 6.3 RNA World 44. Which one of the following is not applicable to RNA? (a) Heterocyclic nitrogenous bases (b) Chargaff’s rule (c) Complementary base pairing (d) 5’ phosphoryl and 3’ hydroxyl ends (2015) 45. Similarity in DNA and RNA is that (a) both are polymer of nucleotides (b) both have similar pyrimidine (c) both have similar sugar (d) both are genetic material. (2000) 6.4 Replication 46. During DNA replication, Okazaki fragments are used to elongate (a) the lagging strand towards replication fork (b) the leading strand away from replication fork (c) the lagging strand away from the replication fork (d) the leading strand towards replication fork. (NEET 2017) EduHulk.COM EduHulk.COM
70 47. During replication of a bacterial chromosome DNA synthesis starts from a replication origin site and (a) RNA primers are involved (b) is facilitated by telomerase (c) moves in one direction of the site (d) moves in bidirectional way. (2004) 48. Method of DNA replication in which two strands of DNA separate and synthesise new strands is called (a) dispersive (b) conservative (c) semi-conservative (d) non conservative. (2000) 49. There are special proteins that help to open up DNA double helix in front of the replication fork. These proteins are (a) DNA ligase (b) DNA topoisomerase I (c) DNA gyrase (d) DNA polymerase I. (1994) 50. During DNA replication, the strands separate by (a) DNA polymerase (b) topoisomerase (c) unwindase/helicase (d) gyrase. (1993) 51. Experimental material in the study ofDNAreplication has been (a) Escherichia coli (b) Neurospora crassa (c) Pneumococcus (d) Drosophila melanogaster. (1992) 52. DNA replication is (a) conservative and discontinuous (b) semi-conservative and semi-discontinuous (c) semi-conservative and discontinuous (d) conservative. (1989) 6.5 Transcription 53. Name the enzyme that facilitates opening of DNA helix during transcription. (a) DNA ligase (b) DNA helicase (c) DNA polymerase (d) RNA polymerase (NEET 2020) 54. What will be the sequence of mRNA produced by the following stretch of DNA? 3′ATGCATGCATGCATG5′TEMPLATE STRAND 5′ TACGTACGTACGTAC3′ CODING STRAND (a) 3′AUGCAUGCAUGCAUG5′ (b) 5′UACGUACGUACGUAC 3′ (c) 3′ UACGUACGUACGUAC 5′ (d) 5′ AUGCAUGCAUGCAUG 3′ (Odisha NEET 2019) 55. Match the following RNA polymerase with their transcribed products : 1. RNA polymerase I (i) tRNA 2. RNA polymerase II (ii) rRNA 3. RNA polymerase III (iii) hnRNA Select the correct option from the following : (a) 1-i, 2-iii, 3-ii (b) 1-i, 2-ii, 3-iii (c) 1-ii, 2-iii, 3-i (d) 1-iii, 2-ii, 3-i (Odisha NEET 2019) 56. Select the correct statement. (a) Franklin Stahl coined the term ‘‘linkage’’. (b) Punnett square was developed by a British scientist. (c) Spliceosomes take part in translation. (d) Transduction was discovered by S. Altman. (NEET 2018) 57. AGGTATCGCAT is a sequence from the coding strand of a gene. What will be the corresponding sequence of the transcribed mRNA? (a) AGGUAUCGCAU (b) UGGTUTCGCAT (c) ACCUAUGCGAU (d) UCCAUAGCGUA (NEET 2018) 58. Whichofthe followingRNAsshouldbemost abundant in animal cell? (a) tRNA (b) mRNA (c) miRNA (d) rRNA (NEET 2017) 59. Spliceosomes are not found in cells of (a) fungi (b) animals (c) bacteria (d) plants. (NEET 2017) 60. The equivalent of a structural gene is (a) muton (b) cistron (c) operon (d) recon. (NEET-II 2016) 61. Which of the following rRNAs acts as structural RNA as well as ribozyme in bacteria? (a) 5S rRNA (b) 18S rRNA (c) 23S rRNA (d) 5.8S rRNA (NEET-II 2016) 62. DNA-dependent RNA polymerase catalyses transcription on one strand of the DNA which is called the (a) template strand (b) coding strand (c) alpha strand (d) antistrand. (NEET-II 2016) 63. Select the correct option. Direction of Direction of reading of RNA synthesis the template DNA strand (a) 5′ – 3′ 3′ – 5′ (b) 3′ – 5′ 5′ – 3′ (c) 5′ – 3′ 5′ – 3′ (d) 3′ – 5′ 3′ – 5′ (2014) EduHulk.COM