DNA as genetic material, DNA and RNA structure, DNA packaging
- Match List I with List II :List-I: A. Alfred Hershey and Martha Chase; B. Euchromatin; C. Frederick Griffith; D. HeterochromatinList-II: I. Streptococcus pneumoniae; II. Densely packed and dark-stained; III. Loosely packed and light-stained; IV. DNA… Answer: 3. A-IV, B-III, C-I, D-II Hershey and Chase: confirmed DNA as genetic material (IV) Euchromatin: loosely packed, light-stained (III)... 1
- Histones are enriched with - Answer: 1. Lysine & Arginine Key idea: Histones are basic proteins that bind the acidic, negatively charged DNA. They are rich in the positi... 1
- Match List I with List IIList I: A. Frederick Griffith; B. Francois Jacob & Jacque Monod; C. Har Gobind Khorana; D. Meselson & StahlList II: I. Genetic code; II. Semi-conservative mode of DNA replication; III. Transformation; IV. Lac operonChoose the… Answer: 3. A-III, B-IV, C-I, D-II Key idea: match the scientist with the discovery. Griffith: transformation (III). Jacob and Monod: lac ope... 1
- Unequivocal proof that DNA is the genetic material was first proposed by Answer: 3. Alfred Hershey and Martha Chase Key idea: Hershey and Chase (1952) gave the unequivocal proof that DNA is the genetic material. T... 1
- If the length of a DNA molecule is 1.1 metres, what will be the approximate number of base pairs ? Answer: 2. 3.3×10⁹ bp Key idea: Distance between two base pairs is 0.34\ nm = 0.34×10⁻⁹ m. N = dfrac1.10.34×10⁻⁹ ≈ 3.2×10⁹ ≈ 3.3×10⁹ bp, whi... 1
- If Adenine makes 30% of the DNA molecule, what will be the percentage of Thymine, Guanine and Cytosine in it ? Answer: 3. T : 30 ; G : 20 ; C : 20 By Chargaff's rule A = T and G = C. A = 30% so T = 30%. A + T = 60%, leaving 40% for G + C, so G = C = 2... 1
- Which one of the following statements about Histones is wrong ? Answer: 2. The pH of histones is slightly acidic. Histones are rich in basic amino acids lysine and arginine, which carry positive charge, s... 1
- Which of the following statements is correct ? Answer: 1. Adenine pairs with thymine through two H-bonds. In DNA, adenine pairs with thymine by two hydrogen bonds, and guanine pairs with... 1
- If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6×10^9 bp, then the length of the DNA is approximately : Answer: 3. 2.2 meters Length = number of bp x distance per bp. L = 6.6×10⁹×0.34×10⁻⁹\ m = 2.244\ m≈ 2.2\ m So the answer is about 2.2 metres... 1
- Purines found both in DNA and RNA are : Answer: 2. Adenine and guanine The purines are adenine and guanine, and both are present in DNA and RNA. Thymine and cytosine are pyrimidine... 1
- Select the *correct* match : Answer: 4. Francois Jacob and Jacques Monod – *Lac* operon Jacob and Monod proposed the lac operon model of gene regulation in E. coli. Jeff... 1
- The final proof for DNA as the genetic material came from the experiments of : Answer: 1. Hershey and Chase Hershey and Chase used radioactive ³²P (labels DNA) and ³⁵S (labels protein) in bacteriophages. Only the DNA en... 1
- The association of histone H1 with a nucleosome indicates : Answer: 2. The DNA is condensed into a Chromatin Fibre. Key idea: Histone H1 is the linker histone that seals the nucleosome. H1 binds the l... 1
- A molecule that can act as a genetic material must fulfill the traits given below, except Answer: 2. it should be unstable structurally and chemically A genetic material must: replicate itself, express itself (as Mendelian charact... 1