DNA Structure, Chargaff's Rules & Replication

20 questions β€’ 1 test β€’ tap a section to begin

Welcome! 8.1 DNA Structure, Chargaff's Rules & Replication β€” Test 1 — 20 questions, CSIR-NET style.

What this test covers

  • DNA double helix & A/B/Z forms
  • Chargaff's rules & base composition
  • Semiconservative replication (Meselson-Stahl)
  • Replication enzymes & Okazaki fragments

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8.1 DNA Structure, Chargaff's Rules & Replication β€” Test 1
Q1. In the Watson-Crick model of B-DNA, the distance (rise) between adjacent base pairs is:βœ“ 0.34 nm
Q2. In DNA, complementary hydrogen bonds form between:βœ“ A and T (and G and C)
Q3. The B-form of DNA has how many base pairs per helical turn?βœ“ 10.5
Q4. The classic (rounded) number of base pairs in one turn of the DNA double helix is:βœ“ 10
Q5. Which form of DNA is left-handed?βœ“ Z-DNA
Q6. The Z-DNA form is most readily adopted by:βœ“ Methylated alternating C-G repeats under high salt
Q7. Regarding glycosidic-bond orientation and sugar pucker, which is correct for B-DNA?βœ“ Anti orientation, 2'-endo pucker
Q8. In a double-stranded DNA molecule with a guanine content of 19%, the expected percentage of adenine is:βœ“ 31%
Q9. A virus genome has 20% G, 30% A, 26% C and 40% T. The genome is most likely:βœ“ Single-stranded DNA
Q10. In double-stranded DNA, which ratio always equals 1?βœ“ (A+G)/(T+C)
Q11. The semiconservative nature of DNA replication was proven (Meselson-Stahl) using the isotopes:βœ“ ¹⁴N and ¹⁡N
Q12. Okazaki fragments are formed during:βœ“ Synthesis of the lagging strand of DNA
Q13. Okazaki fragments are processed and joined into a continuous strand by:βœ“ DNA polymerase I and DNA ligase
Q14. Which of the following is NOT required for DNA replication?βœ“ Ribozyme
Q15. In bacteria, chromosomal DNA replication begins at:βœ“ One specific locus (a single origin)
Q16. Which statement about DNA replication is TRUE?βœ“ Eukaryotes use multiple origins; one strand is continuous and one discontinuous; replication is bidirectional
Q17. A template-independent DNA polymerase is:βœ“ Terminal deoxynucleotidyl transferase (TdT)
Q18. The enzyme that adds a phosphate to the free 5' terminus of DNA is:βœ“ Polynucleotide kinase
Q19. Which properties of bacterial DNA polymerase III are correct?βœ“ 5'β†’3' polymerisation with 3'β†’5' (proofreading) exonuclease
Q20. Match each replication component with its role and select the correct option.βœ“ A-ii, B-iv, C-iii, D-i