Thursday, November 11, 2010

TOK: Theory of Knowledge (IB)

TOK: The structure of DNA

"The story of the discovery of DNA illustrates how communication between scientists is critical in the growth of knowledge. The discovery of the structure of DNA was one of the most significant biological milestones of the twentieth century, but it was not without controversy.

Chemist Rosalind Franklin began work on the structure of DNA in the early 1950's. Her area of expertise was making x-ray diffraction images that revealed the arrangement of atoms in molecules. Soon Franklin discovered key features of the structure of DNA such as the fact that there were two strands in DNA and that the bases were on the inside of the molecule. One x-ray diffraction image (photo 51) was shown by Franklin's colleague, Maurice Wilkins, to James Watson without her knowledge. Wilkins also shared Franklin's insights gained from the x-ray diffraction images with Watson. This information was critical to Watson and Francis Crick developing their model for the structure of DNA.

In acknowledgement of the discovery, Watson, Crick and Wilkins were all awarded the Nobel Prize for Medicine and Physiology in 1962. Franklin was not. She died from ovarian cancer at an age of 37 in 1956. Nobel prizes are not awarded posthumously, and no more than three people can be awarded a Nobel Prize for a discovery. Whether Franklin would have received the prize had she been alive has been the cause of much debate. The cause of the cancer was most likely the radiation she used to produce her images"


TOK is one of the foundations of the IB program. It attempts to answer the question, "How do we know what we know?". Please join us in our class blog as we look at the issue in terms of whether Ms Franklin was appropriately acknowledged for her contribution to the understanding of DNA. The blog can be accessed here. Thanks, Doug


1 comment:

Dave Tarwater said...

Behind all men is a good woman. I think Watson, Crick, and Wilkins never would have made their discoveries without the prior work of Rosalind Franklin. I understand from reading that Franklin was not terrible upset with the men. "After everything was said and done, Franklin was surprisingly not bitter. She and Crick became good friends professionally and personally [Judson, 1986]. She was offered the chance to be a senior member of the Cambridge unit's scientific staff, but she had recently learned that she had cancer and was too ill to accept"