DNA Replication (AIG IRP)

Stage 2: Elaborate

If this is assigned as an individual out of class task- have the students answer the following questions using the above websites, other websites they find or an AP level text. If assigned to a group of 3-4 students, allow students to use a computer to answer the following questions.

Once students have answered the questions(either as individuals or as a group), use the questions as a guideline for a class discussion on the details of the process of DNA replication.

Part 1- Questions

  1. Explain the purpose of DNA replication.
  2. Summarize the general process of DNA replication
  3. Explain why DNA replication is called semi-conservative.
  4. Explain what a replication fork is and why they are critical to DNA replication.
  5. Write a brief outline of the steps involved in DNA replication.
  6. Describe the role of Okazaki fragments.
  7. Distinguish between:
    • SSBs, Helicase, RNA primase, sliding clamp, RNAse (exonuclease), ligase, DNA polymerase
    • 5’ end and 3’ end of DNA
    • Leading strand and lagging strand
  8. Hypothesize what would happen if: (Teacher note:  REALLY emphasize this step to ensure that students truly understand DNA replication and how exact yet fragile the process is. A further task you might add is for students to develop a story, a poster, a video to explain just how intricate the process of DAN replication is and how exact it is and how just one minor change ( a single bases substitution) can cause DNA replication to be done incorrectly and the results if that in terms of protein synthesis.
    • Helicase did not work correctly
    • The DNA polymerase added the incorrect nucleotide
    • Ligase appeared before the strand was completed
    • Only one replication fork opened
    • SSBs were malformed

Closure question/activity- Have students compare DNA replication to one of the following: ( or they could come up with their own example)

  • Knitting a scarf from a template
  • Sewing a dress from a template
  • Building a table from a template
  • Building a model car or airplane from a template

Part 2- Using a variety of craft items (different color yarn or pipe cleaners, buttons, beads, etc.) or types of candy (different color Twizzlers, licorice, mints, etc.), create a model of DNA replication. Include the proteins required, Okazaki fragments and label the 5’ & 3’ ends and the replication fork. Use the model to explain to classmates the steps of DNA replication.