Introduction
On April 25th 1953, there appeared three papers in the journal, Nature, which changed our view of the world. The structure of DNA was published based upon the pioneerin work of Rosalind Franklin. Without her X-Ray diffraction work on DNA, as well as Erwin Chargaff's base pairing data (A-T, G-C), the structure of DNA would not have been determined.
In this directed webquest, you will research and report on the structure of DNA and how research was the foundation for this discovery.
Task
Go to the following website:
http://courses.umass.edu/physics890b-parsegia/pdf_files/klug-DNA.pdf
Answer the directed questions that follow.
1. What is the transforming principle?
2. Summarize the main structure characteristics of the DNA molecule.
3. What is the "crucial feature" of the structure of DNA?
4. Why did most biochemists not believe that DNA was the hereditary molecule? What biological molecule did they think was probably the blueprint for life?
5. What is X-Ray diffraction? Why was it critical in determining the structure of DNA?
6. Summarize Wilkins and Gosling's work in respect to the DNA molecule.
7. Who was Rosalind Frankline and what did she do to further the work of X-Ray crystallography?
8. What are the "A and B forms" of DNA?
9. Summarize Rosalind Franklin's report in November of 1951 at King's College.
10. Why did Franklin believe that DNA might be non-helical? What research pointed her, wrongly, in this direction?
11. Linus Pauling was incorrect in his DNA model postulate. Why was this the case?
12. When did the the first proof of the Watson and Crick model arrive? What was it based upon?
13. What is the semi-conservative model of DNA replication?
14. After the DNA model postulate was presented, there were a number of fundamental questions that had to be answered in respect to the DNA molecule. Summarize each from the questions below:
a. The problem of DNA replication
b. The transfer of information from DNA to protein creation
15. What are the future challenges of DNA that are presented in the twenty first century?
16. Summarize the function of the 30S and 50S components of the ribosome.
Go to the following website:
http://learn.genetics.utah.edu/content/molecules/builddna/
Explore and complete this interactive as you build a DNA molecule virtually.
Evaluation
Please utilize the posted assessment rubric for webquests from the classroom website.
Conclusion
The focus of this unit will the Central Dogma of Biology.
DNA-----------------------> RNA-------------------------------->Protein
Transcription Translation
The structure of DNA was the start point for this exploration. Enjoy the unit!