Jennifer Brown

There were three main technologies that Rosalind Franklin was a detrimental part of. The technique of  X-ray diffraction (i.e. crystallography) was the first,  the studies of carbon and graphite micro-structures was the second, and her work on the Tobacco Mosaic Virus was the third.  All of these were important findings and have been instrumental in sciences and technology of this day and age.

Crystallography

X-Ray diffraction is the technique in which Rosalind Franklin was able to solve the DNA problem.  This method is used to determine the inner positions of atoms of a molecule.  This technique involves exposing a pure crystal to x-rays to produce a diffraction pattern.  Then it is likely to be able to place the atoms in the molecules. Scientists were becoming frustrated because their pictures were not coming out clear.  They didn’t know hot to separate the two different forms.  She was able to separate the two forms by using two different types of fibers.  One set of the fibers had been re-hydrated with water (Foundation, 2011).  Rosalind was able to provide “the first DNA crystals pure enough to yield interpretable diffraction patterns”.  With this she was able to  produce an x-ray of the DNA form B.   She was then able to discover that DNA had two strand and not three like other scientists had predicted.  Franklin also was able to prove other scientists mistaken as she found that the sugar-phosphate backbone lies on the outside of the molecule and not the inside.  The size and shape of the DNA double helix then also came apparent.  This is what was needed in order to realize how heredity in the cells work.  (Ardell,2006)

Studies of Carbon and Graphite

Coal has a huge economic importance.  Franklin’s research was able to shed the light on some of the many mysteries that the natural resource has to offer.  One of them being that coal is a molecular sieve and that, among other things,  it is used to filter Nitrogen from Oxygen in the air (Harris, 2001).   This process was demonstrated by measuring the density of coal.  Seeing as how coal is a porous substance, she set out trying to find the two densities, the lump density and the the true density, of coal.  The lump density is the density of the whole structure pores and all.  The second density involves trying to separate the pores and finding the density of the object without the pores.

The first density she found was relatively uncomplicated.  She was able to use the  Archimedes liquid displacement method, always ensuring that one employs a liquid which does not penetrate fine pores, such as mercury.  The second density form was a little more problematic.  Franklin had to use a substance that didn’t chemically alter the original substance and yet fill the coals pores.  This method was more or less trial and error.  Some of the gaseous substances that were used, she found interacted with the coal making the density heavier than the initial piece of coal that she used.  Then some of the liquids that she had used she found that some of the smaller particles were filling the small pores of the coal but the bigger ones were being kept out.  This was one of the first demonstrations of the molecular sieve. (Harris, 2001)

 

 

Tobacco Mosaic Virus

Her work with Tobacco Mosaic Virus (TMV), was nothing short of astounding.  With her knowledge of x-ray diffraction she was able to produce pictures  and models of the virus.  Her understanding of the virus led her to determine that the protein coat of the virus possessed helical features but that it was also more complex than previously thought.  She was asked to build models of the TMV virus for the 1958 World’s Fair in Brussels.  Her team constructed a 6 foot model of the virus and to this day it stands in the Cambridge University Medical Research Council’s Laboratory of Molecular Biology.(Stillwell, 2000)