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Concept of individual "paticles", later known as genes
This was showen by the scientists seeing how chromosomes duplicated and moved around during cell devision, chromosomes where quickly accepted as the means of transferring inherited infomation. -
Basic structure of DNA known
including that there where only 4 variations of bases, however some scientists disagreed and thought that wasn't enogh to produce 20 amino acids. -
The devlopment of X-ray crystallography
1920-1950, DNA is hard to obtain pure cyrstals from, however Franklin managed to obatin the high quality images resulted in obtainign accurate measurements, the distance between DNA molecules was worked out by their relative distances. This resulted in her building up a two standed helical model. -
DNA was proved as a material of inheritance
Oswald Avery, Colin MacLoed and Maclyn McCarty destroyed molecules to see is this affected the inherited change (therefore the DNA) in bacteria. If DNA was destroyed, no transformation took place. No other molecules had an effect on the transformation, showing that DNA was inherited, therefore not created but passed on. -
The proportions of partnering bases where found
Arwin Chargaff anaysled DNA from a large variety of species and found the proportions of cytosine and guanine where the same in every animal, and also that the propotions of adenine where not always the same as thymine. Also he found that there was not other relationships between the bases. -
Deducing the structure
The known facts found by other scientists where combined together to form the strucutre, by James Watson and Francis Crick to form the double helix. The patterns from the X-ray cystallography showed a 3.4nm for every complete turn, with every cytosine combined with guanine, and thymine with adenine, with hydrgogen bonds holding them together. These chains could also open up along the line of hydrogen bonds -
was found that alpha helix holds the polypeptide chains together
Linus Pauling found that polypeptide chains are held together in an alpha helix held together by hydrogen bonds, which can be broken by moderate heating, and he also suggested a similiar helical structure explaining the changes on DNA by heating