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Friedrich Mischer
Friedrich Miester attempted to isolate cells from the pus of the bandage of a surgical activity. In this attempt, In this attempt, he managed to isolate leucocytes, which removed cotton fibers through a sheet. Next he did the impossible. He separated the nuclei from the cytoplasm. He realized that the new substance was not a protein and he termed the substance nuclein, which is still used for DNA. Meischer had made a breakthrough that would help advance in the discovery of DNA. -
Erwin Chargaff
Edwin Chargaff discovered Chargaff's rule which says that the percentage of adenine and thymine bases are almost equal and that guanine and cytosine are also equal. He analyzed the case composition of DNA to discover that the purines and pyrimidines are equal. His discovery helped other scientist to have proof of their models of DNA and why adenine equaled thymine and guanine equaled cytosine. -
Rosalind Franklin
Rosalind Franklin discovered the structure of DNA with the help of a technique call X-ray diffraction. In this technique, she purified the DNA, then elongated the DNA fibers in a thin glass tube. This would be so the strands would be parallel. She also used a powerful x-ray beam on the DNA and recorded the scattering patter of the x-ray film. In these patterns carried important clues that DNA is in a form of a helix. Franklin later gave Watson and Crick to publish their models of DNA. -
Alfred Hershey and Martha Chase
Hershey and Chase wanted to show that all the genetic information you have is from proteins. For their first experiment, they used the T2 bacteriophage to dispatch genetic material but the experiment was a fail. They wanted to demonstrate that at least a portion of the phage's proteins mass was transferred to the interior bacterium and as a result, the experiment was a fail. They had many other attempts but their last one showed that genetic information came from genes which makes up everything. -
James Watson and Francis Crick
Both James Watson and Francis Crick wanted to understand the structure of DNa. They used wire and cardboard to assemble a 3-D model of DNA to help them discover the double helix. The double helix model also explains Chargaff's rule of base pairing and how the two strands of DNA are held together. Their model of can tell us how DNA can function as a carrier of genetic material. -
Meselson and Stahl
They discovered that DNA replication is semiconservative meaning that the chromosome are half old and half new. Watson and Crick perviously suggested that their DNA model would be how replication occurs, but the proof of the model actually came from the experiments done by Meselson and Stahl. They grew E.coli and after many generations of growing it, the saw that it was heavier. As a result the concluded that the cells split and we almost identical. They found when the cells split. -
Bibliography
"The Francis Crick Papers: The Discovery of the Double Helix, 1951-1953." U.S. National Library of Medicine. National Institutes of Health, n.d. Web. 18 Jan. 2017. Concept 15 DNA and Proteins Are Key Molecules of the Cell Nucleus." Friedrich Miescher :: DNA from the Beginning. N.p., n.d. Web. 23 Jan. 2017. Erwin Chargaff." Biography - Famous Biologists. N.p., n.d. Web. 23 Jan. 2017. -
Bibliography
"Rosalind Elsie Franklin: Pioneer Molecular Biologist." Rosalind Elsie Franklin: Pioneer Molecular Biologist. N.p., n.d. Web. 23 Jan. 2017.
Copy & paste citation "Rosalind Franklin." Biography.com. A&E Networks Television, 07 July 2016. Web. 23 Jan. 2017. "The Hershey-Chase Blender Experiments." PaulingBlog. N.p., 29 Oct. 2015. Web. 23 Jan. 2017. Nature.com. Macmillan Publishers, n.d. Web. 23 Jan. 2017.
