Study Guide 3-1

Lecture 3.1 Competencies and Study Guide

DNA Structure and Replication

Vocabulary

  • X-ray crystalography
  • Antiparallelism
  • Major groove
  • Minor groove
  • Genome
  • DNA sequencing
  • Polymerase chain reaction (PCR)
  • Single-stranded DNA
  • Double-stranded DNA
  • Leading strand
  • Lagging strand
  • Okazaki fragment
  • DNA primer
  • Nucleotide triphosphates
  • Replisome

Competencies

  1. Compare and contrast Linus Pauling’s triple helix hypothesis to the double helix hypothesis of Watson, Crick, Franklin and Wilkins.
  2. Explain how the method used by Franklin and Wilkins to visualize the DNA molecule.
  3. Explain how the x-ray crystalograph of DNA produced by Franklin supported the double-helix, and not the triple helix, hypothesis.
  4. Describe in outline (not detail) the purpose of the following biotechnologies derived from our knowledge of the structure of DNA:
    1. DNA sequencing;
    2. Polymerase chain reaction (PCR);
    3. Molecular surgery using CRISPR-Cas9.
  5. Explain Watson and Crick’s first oversimplified model of DNA replication.
  6. Describe the conceptual schematic of DNA replication, including the function of the following macromolecules:
    1. Helicase and topoisomerase;
    2. Single-strand DNA binding proteins (SSBPs);
    3. Primase;
    4. DNA polymerase III;
    5. DNA polymerase I;
    6. DNA ligase.
  7. Compare and contrast DNA replication on the leading and lagging strands.
  8. Explain in detail how DNA polymerase III attaches nucleotides to the growing DNA strand; include the energy source and pyrophosphate (=diphosphate) byproduct.
  9. Describe how the ends of chromosomes are replicated, and use that description to explain why chromosomes cannot be replicated indefinitely.
  10. Describe the actual geometry of the DNA replisome and compare and contrast this geometry to that described in the conceptual schematic presented in this lecture and the text.