ONE:

Who am I? Rosalind Rosy Franklin

Where did I work? Franklin worked as an assistant to Marice Wilkins at the King's College London. (She also had a student known as R.G. Gosling) (pg. 12)

What was my contribution to the discovery of the structure of DNA in The Double Helix?

Although her colleagues gave her an incredibly hard time, Rosalind had the evidence for a new three-dimensional form of DNA. Her discovery shocked her collaborators because it was much simpler and than what they had previously hypothesized. Franklin took pictures of DNA and discovered that there were two forms: a dry form of DNA known as the A form and a wet B form. An X-ray diffraction picture of the "B" form of DNA, (known as Photograph 51 in the video watched in class, but not mentioned in the passage) became famous as critical evidence in identifying the structure of DNA. This photo was made possible by 100 hours of X-ray exposure by a machine of Franklins invention. (pg. 58) Watson took her work after she died and made it seem like it was his own findings.

TWO:

Who am I?Linus Pauling

Where do I work?He was a chemist at Cal Tech. (pg 9)

What was my contribution to the discovery of the structure of DNA in The Double Helix? Linus Pauling discovered something known as the alpha helix. It is a simple single strand coiled like a spring. Pauling had built paper and wire models of the amino acid chains in proteins and twisted them into different possible shapes. He then compared it to the x-ray patterns, and tried to match it up against the data already had. Watson followed Pauling's example of model-building in his argument of the double helix. (pg. 14 & 26)

THREE:

Who am I?Francis Crick

Where do I work?Francis Crick worked at the Strangeways Research Laboratory before moving on to Cavendish Laboratory in Cambridge. (pg. 8 & 22)

What was my contribution to the discovery of the structure of DNA in The Double Helix?

Using X-ray diffraction studies of DNA Crick (along with Watson) constructed a molecular model representing the known physical and chemical properties of DNA (which they based off of Paulings work). The model consisted of two intertwined spiral strands that looked like a twisted ladder ("double helix"). Crick and Watson then hypothesized that if the two sides of the DNA split from each other then each side would become the basis for a pattern for the formation of new strands identical to their former partners. (pg. 64)

FOUR:

Who am I?James Watson

Where do I work?The Cavendish, a chemical lab at Cambridge University.

What was my contribution to the discovery of the structure of DNA in The Double Helix? (Same as Above)Using X-ray diffraction studies of DNA Crick (along with Crick) constructed a molecular model representing the known physical and chemical properties of DNA (which they based off of Paulings work). The model consisted of two intertwined spiral strands that looked like a twisted ladder ("double helix"). Crick and Watson then hypothesized that if the two sides of the DNA split from each other then each side would become the basis for a pattern for the formation of new strands identical to their former partners. (pg. 64)

FIVE:

Who am I?Maurice Wilkins

Where do I work?Kings College, London

What was my contribution to the discovery of the structure of DNA in The Double Helix? Wilkins studied DNA. He used X-rays to produce diffraction images of DNA molecules. The X-ray diffraction images produced by him and his assistant Rosalind Franklin led to the 3-dimensional DNA idea. Wilkins ended up sharing the 1962 Nobel Prize in with Watson and Crick for this discovery.

SIX:Who am I?Erwin Chargaff

Where do I work?Columbia (pg. 45)

What was my contribution to the discovery of the structure of DNA in The Double Helix? He discovered two rules on the basis of which we were able to figure out that the DNA had a double helical structure. The first was that DNA had an equal percentage of Adenine and Thymine, and an equal percentage of Guanine and Cytosine. The second rule was that the pairs were always paired with each other (A&T, G&T). (Pg. 46)

SEVEN:Who am I?Jerry Donohue

Where do I work?He was an American Crystallographer. (Didnt say where)

What was my contribution to the discovery of the structure of DNA in The Double Helix?

Donohue pointed out that Crick and Watson were using the wrong structures for the nitrogen bases in their research, and that the correct structures would form hydrogen bonds with one another. That was a valuable contribution because it showed an error in the research that had to be corrected in order to be valid. (pg. 67-88)

EIGHT:Who am I?Sir Lawrence Bragg

Where do I work?The Director of the Cavendish (pg. 6)

What was my contribution to the discovery of the structure of DNA in The Double Helix? Although he played no direct part in the discovery of DNA structure, Watson writes that the X-ray method which he developed 40 years prior was significant in his research. (pg. 6)