Question

CHEM 161

"The Double Helix” Worksheet

Reading (file:///C:/Users/Kayla/Desktop/Watson_The_Double_Helix.pdf)

1. With whom was Francis Crick talking when he revealed he did not remember the structure of the four bases of DNA? What was that person's own contribution to understanding DNA structure?

2. Watson and Crick hypothesized an early DNA structure model that they showed to Wilkins and Franklin. What were they major structural features of that model, and what was the evidence that made that model less attractive?

3. The structure of DNA was essentially a side-project for Watson and Crick. What project was (or at least was supposed to be) the main focus for Watson. What was the main project for Crick?

4. From whom did Watson and Crick obtain a copy of Pauling's manuscript describing a DNA structure?

5. What were the major structural features of the Pauling model? What fundamental chemistry was incompatible with that model?

6. Who initially had the insight to suggest that the sugar-phosphate backbone was on the outside of the molecule and the bases on the inside?

7. Which form of DNA was originally crystallized and refracted (A, B or Z)?

8. At one point, Watson considered a "like-for-like" pairing of the bases in DNA. However, what chemical insight into the form of the bases (provided by crystallographer Jerry Donohue) suggest that those pairings would not work?

9. One of the key tenets of the scientific method is that hypotheses are tested using experimental data. What experiment did Watson and Crick perform to provide evidence for their model of DNA (see the original structure papers posted on the SacCT site)?

10. Watson, Crick and Wilkins all received the Nobel Prize for their work. Why didn't Franklin win a Nobel Prize?

Answer 1