became the first woman to win a Nobel Prize and the only woman to win the award in two different fields (physics and chemistry).
Was the first person to work on DNA. He isolated a new substance from the nuclei of white blood cells. After the discovery that cells were the basic unit of life, Meischer was interested in their chemical components.Adding alkali to white blood cells he made them burst open and from it he extracted DNA, which at the time he called ‘nuclein’
He published a series of papers in which he showed that the second law of thermodynamics, which concerns energy exchange. Could be explained by applying the laws of mechanics and the theory of probability to the motions of atoms. He made clear that the second law is essentially statistical and that as system approaches a state of thermodynamics equilibrium. Because equilibrium is overwhelming the most probable state of a material system.
Working in the Institution of Plant Physiology, discovered a strange phenomenon. He was conducting experiments on a cholesterol based substance trying to figure out the correct formula and molecular weight of cholesterol. When he was trying to find the melting point he was struck by the fact that this substance seemed to have 2 melting points.
On his return to America, he received the most brilliant work of his life - an original study of cathode rays culminating in the discovery of the electron,
He was the first to discover the order of the three major components of a single nucleotide; the first to discover the carbohydrate component of RNA; the first to discover the carbohydrate component of DNA; and the first to correctly identify the way RNA and DNA molecules are put together.
Levene proposed that nucleic acids were composed of a series of nucleotide, and that each nucleotide was constructed of one of four nitrogen-containing bases, a sugar molecule, and a phosphate group.
Two major facts were already known about DNA. The first was that it is contained in the nucleus of every living cell. The second was that, in addition to sugar and phosphate, DNA was composed of two bases: pyrimidines, of which there are two types (cytosine and thymine), and purines, of which there are also two types(adenine and guanine).
He discovered that adenine and thymine existed in equal proportions in all organisms, aswell as cytosine and guanine, and that the proportions between the two pairs were different depending on the organism.
From his research Chargaff drew the conclusion that it was the DNA in the nucleus of the cell that that carried genetic information rather than the protein
Made a crucial contribution to the discovery of the double helix structure of DNA using X-ray crystallography.
Whithout her ‘photo 51’ Watson and Crick may have never completed their work.
Up until this time no progress in the study of DNA had been made since Chargaff’s idea of a double helic structure
Like Franklin, his partner at a time before they went their seperate ways, Wilkins was using X-Ray diffraction to study DNA and sperm heads. He like Franklin discovered the well defined helix patterns that led to the deriving of the molecular structure of DNA by Watson and Crick.
Alfred Hershey and Martha Chase suggest that only DNA is needed for viral replication. Using radioactive isotopes 35S to track protein and 32P to track DNA, they show that progeny T2 bacteriophage isolated from lysed bacterial cells have the labeled nucleic acid. Further, most of the labeled protein doesn’t enter the cells but remains attached to the bacterial cell membrane
Watson and Crick were not the discoverers of DNA, but they were the first scientists to construct a detailed three dimensional model of the molecules complex double-helical Structure