Guiding Questions
DNA as the Genetic Material
- Explain why researchers originally thought protein was the genetic material.
- Summarize the experiments performed by the following scientists that provided evidence that DNA is the genetic material:
- Frederick Griffith
- Oswald Avery, Maclyn McCarty, and Colin MacLeod
- Alfred Hershey and Martha Chase
- Erwin Chargaff
- Explain how Watson and Crick deduced the structure of DNA and describe the evidence they used.
- Explain the significance of the research of Rosalind Franklin.
- Describe the structure of DNA. Explain the base-pairing rule and describe its significance.
DNA Replication and Repair
- Describe the semiconservative model of replication and the significance of the experiments of Matthew Meselson and Franklin Stahl.
- Describe the process of DNA replication, including the role of the origins of replication and replication forks.
- Explain the role of DNA polymerases in replication.
- Explain what energy source drives the polymerization of DNA.
- Define antiparallel and explain why continuous synthesis of both DNA strands is not possible.
- Distinguish between the leading strand and the lagging strand.
- Explain how the lagging strand is synthesized even though DNA polymerase can add nucleotides only to the 39 end. Describe the significance of Okazaki fragments.
- Explain the roles of DNA ligase, primer, primase, helicase, topoisomerase, and single-strand binding proteins.
- Explain why an analogy can be made comparing DNA replication to a locomotive made of DNA polymerase moving along a railroad track of DNA.
- Explain the roles of DNA polymerase, mismatch repair enzymes, and nuclease in DNA proofreading and repair.
- Describe the structure and function of telomeres.
- Explain the possible significance of telomerase in germ cells and cancerous cell.





