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Transcript

How was DNA structure

discovered?

What did Franklin do?

  • Back in the day no person was sure of the structure of DNA, and a lot of people did not know what DNA even was.
  • Many people contributed to the finding of the structure of DNA. One of whom was Rosalind Franklin who tested many experiments in the search for answers about DNA.
  • Her contributions lead to very important findings in science history
  • Around 1950 Franklin started to focus on X-Ray diffraction analysis on DNA. During this time period nobody knew much about DNA, but it was suspected that it was genetic.
  • Franklin did an experiment after arriving at King’s. She identified two configurations in which DNA could exist.
  • She called it her A and B forms. Her work was eventually published and became essential to determine the structure of DNA.
  • Franklin’s experiment continued to her hydrating and dehydrating her DNA sample to have good pictures of the A form. Getting her samples of DNA was a little difficult but she managed to get some with the help of Wilkins. (Elkin, 2003)

Her A- form of DNA in a X- ray diffraction photo.

Her notebook entries are shown. (Hutchison Dictionary of Scientific Biography, 2005)

  • With the findings of her B-form data Franklin then was able to determine the DNA’s density, unit cell size, and water content.
  • With that data she was further able to purpose a double helix structure with precise measurements for the diameter, the separation between each of the coaxial fibers along the fiber axis direction, and the pitch of the helix. (Elkin, 2003)
  • Franklin’s discoveries continued, in 1952 she presented her best evidence of the helical backbone. Even though she did not realize some things about her research, her notebook entries that started January 1951 show that she was making great progress in solving the two aspects of DNA

Who is Rosalind Franklin?

  • Franklin was born July 25, 1920. During this time women were expected to prepare to become wives and mothers, but Franklin’s parents raised her in a different was by encouraging her interests.
  • Eventually they enrolled her in St. Paul's School for Girls, where she learned about chemistry and physics.
  • Franklin then decided she wanted to become a scientist.
  • In 1938 she was accepted in Newnham College, at the University of Cambridge. She eventually got her degree in 1941.
  • After receiving her degree Franklin was hired to research gas-phase chromatography, a technique to separate the components of mixtures, with chemist Ronald G.W. Norrish.
  • A year later In 1942 she learned the basics of molecular biology and crystallography. Then in 1945 she earned her Ph.D. from Cambridge.
  • In 1947 Franklin moved to Paris to join the Central Laboratory of Chemical Services. There she studied carbons using X-ray diffraction. (Farrell, 2003)
  • She eventually moved to London for a research fellowship from King’s college. There Franklin faced many difficulties because she was a woman.For example, Franklin and the other woman were restricted to scientific collaboration and the exchange of ideas. However, this did not stop Franklin. (Mielczarek, 2003)

Rosalind Franklin's Discovery of the DNA Structure!

Facing troubles positively

  • In a 1951 incident, Franklin was furious that one of her acquaintances planned on publishing an idea of hers without giving proper acknowledgment. She shocked him by the tone of her letter in which she demanded acknowledgment for it being her work/ discovery. (Litman )
  • Even though Franklin had a strong character she took other scientists suggestions and criticism in a positive way to help her improve her discoveries. For example, when Crick and Watson found the missing puzzle piece to Franklin’s work , Franklin was not aware that they had her photograph. However, she knew her findings had missing pieces but she always looked at everything she did as a race to find out of figure out the truth and was never disappointed in herself.

How did it end?

  • Eventually Franklin moved to Birkbeck College in London. She died of cancer five years later, in 1958, at the age of 37. (Eaglesham, 2011)
  • In 1962 , Crick and Wilkins were awarded the Noble Peace Prize for the discovery of the structure of DNA. (Eaglesham, 2011) If Rosalind Franklin would of have been alive she would of received that prize.
  • Watson feels that Rosalind Franklin would have received it instead of Wilkins. Many say that if Franklin and Wilkins had been on friendlier terms, maybe the discovery would have been made sooner, and she might have lived long enough to enjoy the success of her findings.

By: Alitzel Neri

Citations!

1) Elkin, L. (2003). Rosalind Franklin and the Double Helix. Physics Today, 56(3), 42.

2) Farrell, C. (2006). Rosalind Franklin. Rosalind E Franklin, 1.

3) Franklin, Rosalind Elsie (1920 - 1958). (2005). Hutchinson Dictionary of Scientific Biography, 1.

4) Litman, R. M. (1976). ROSALIND FRANKLIN AND DNA. Bioscience, 26(9), 572.

5) Mielczarek, E. V. (2003). Rosalind Franklin (Book). Physics Today, 56(2), 61.

6) Eaglesham, B. (2011). ROSALIND FRANKLIN. Odyssey, 20(6), 34.

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