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DNA Scientists, and their research
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Fredrick Griffith
In 1928 Fredrick Griffith studied a pair of bacteria called Streptococcus Pneumoniae. He discovered that one of the two strains could be changed into one or the other. One strain of the bacteria was smoth with a sugar coating,(S) strain, while the other was rough lacking a sugar coating, (R) strain. He injected the bacteria into mice he found that live(S) strain, kills the mouse and live(R) strain doesn't. However, dead(S) strain doesn't kill the mouse, dead(S) and live(R) strain do. -
P.A. Levene
P.A. Levene created developed the basic structure of nucleotides. Nucleotides, are the baby brothers of nucleic acids. These nucleotides are mad up of sugar deoxyribose, a phosphate, and one of four possible nitrogenous bases. The bases are either adenine, guanine, cytosine, or thymine. Guarine and Adenine are bases that are double ringed. Where as Thymine, Cytosine, and Uracil are only singular bases. -
Oswald Avery
Avery found out how to transform the (R) Strain into an (S) strain. He broke the the (S)strain into it's macromolecules. When(R)strain were exposed to isolated DNA from the (S)strain, the (R)strain turned into (S)cells. He finally decided that when the S cells from Griftith's experiments died, that DNA was released. -
Erwin Chargaff
Chargaff discovered the different amounts of Adenine, Guanine, Thymine, and Cytosine contained within DNA. He discovered that the amount of Guanine was about equal to the amount of Cytosine, and that the amount of Thymine was pretty close to the amount of Adenine. Chargaff's law. C=G and T=A. -
Rosalind Franklin
Rosalind was mainly known for her work done on X-ray diffraction on DNA, this later led to the discover of the double helix of DNA. This discovery confirmed the fact that the structure of DNA is helicular. The interpretations of the photos given of the diffraction of the X-rays gave very helpful information into DNA structure. -
Hershey and Chase
Alfred Hershey and Martha Chase came up with evidence that clearly showed that DNA is the transforming factor. Hershey and Chase used radioactive labeling to follow the DNA and the protein while the bacteriophages infected bacteria and while they reproduced. Their evidence showed that the infected DNA is the genetic information necisary to create new viruses and that DNA was the genetic material that traveled from Generation to Generation. -
Maurice Wilkins
Maurice Wilkins, working with Rosalind Franklin, worked with X-Ray diffraction. He concluded that it was possible to create thin threads from high concentrated DNA. He decided that these Arrays of DNA would work perfectly in X-ray diffraction patterns. His photo 51 showed that DNA is a double Helix which is a twisted latter shape, which is created by a pair of nucleotide strands that are twisted around one another. -
Linus Pauling
Linus Pauling was interested in the connection between cyrstals and molecules. He applied physical tecniques, such as x-rays, and used quantum physics to develop more information. Molecular interests led to interests in biological chemistry. He discovered the structure of proteins, and also made very vital conclusions about some diseases. -
James Watson and Francis Crick
James Watson and Francis Crick provided a very specific structure for the double helix DNA. They used data from Franklin and Chargaff to find the width of the helix. The two men made a model of the DNA with the double helix. The model showed a pair of strands that contained alternation between deoxyribos and phosphate. It showed that the bonds of Cytosine and Guarnine are paired by 3 H+ bonds. Lastly, it showed that Thymine and Adenine bases are held together by 2 H+ bonds.
