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Gregor Mendel
Introduced the concept of individual inherited 'particles' - genes. Chromosomes duplicated and moved during cell division -
DNA
The basic structure of DNA was know and that there was only 4 variations of bases. Scientist felt this wasn't enough for the 20 amino acids found in human protein -
Transformation
Late 40's/early 50's Oswald Avery, Colin Macleod and Maclyn McCarty destroyed different types of molecules to see inherited change in Bacteria -
Evidence of DNA
Erwin Chargaff discovered that in every case the proportions of cytosine and guanine was the same, the same between adenine and thymine -
Evidence- double helix
Linus Pauling, showed that polypeptide chains are held in an alpha-helix shape by hydrogen bonds. -
X-ray diffraction of DNA
Rosalind Franklin used X-rays and took a complex picture of a DNA and created a two stranded model- 3D model -
Deducing the structure
James Watson and Francis Crick created the first accepted 3D model of DNA using others research (Rosalind Franklin). They used the idea of complimentary base pairing etc. They won a Nobel prize for their work