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Putting the Pieces Together

The Discovery of DNA Structure and Replication

By Kevin M. Bonney

Putting the Pieces Together



This case study provides an overview of the seminal experimental work that led to the discovery of DNA structure and the confirmation of the semi-conservative model of DNA replication. By guiding students through a chronological series of historic experiments and discussing some of the collaborations and controversies involved in the original research, students learn about the history and nature of science in addition to several important biological concepts. A number of recommended videos, including one created by the author, enable instructors to use the "flipped-classroom" mode of instruction according to which students read primary literature and watch videos on their own before group discussions and activities. The case study was developed for use in an introductory undergraduate biology course, and would also be appropriate for use in a high school biology course. Some prior knowledge or instruction may be required, depending on the level and learning objectives of the course.


Date Posted




  • Describe the structure of DNA.
  • Summarize the specific contributions of Watson and Crick, Franklin, Wilkins, and Meselson and Stahl to discovering the structure of DNA and how DNA is replicated.
  • Justify, argue, and evaluate the ethical implications of the controversy surrounding the role of Rosalind Franklin in the discovery of DNA structure.
  • Compare and contrast the conservative, dispersive, and semi-conservative models of DNA replication.
  • Identify the model of DNA replication supported by the Meselson and Stahl experiment.
  • Describe how Meselson and Stahl experimentally demonstrated how DNA is replicated.
  • Describe the connection between DNA structure and function.


DNA structure; DNA replication; double helix; deoxyribose nucleic acid; dispersive; conservative; semi-conservative; Photo 51; Watson and Crick; Rosalind Franklin; Meselson and Stahl


Subject Headings

Biology (General)
Genetics / Heredity


High school, Undergraduate lower division






Ethics, History of science, Women in science






N/A, Debate, Demonstration, Discussion, Flipped



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