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Unformatted text preview: , tetranucleotide the structure of thymonucleic acid was ATCGATCGATCG... The tetranucleotide The hypothesis, introduced in 1921 dominated the thinking of scientists for more than twenty years. The technique of X-ray diffraction was proposed by The Max von Laue (1915) and developed by Lawrence and William Bragg (1922,1924) to determine the arrangement of atoms in molecules. William T. arrangement Astbury (1938) first used X-ray diffraction to Xdetermine the structure of DNA. structure X-ray Diffraction of DNA
The X-ray data obtained by XAstbury and Bell (1938) indicated regular repeats regular every 0.33-0.34 nm which 0.33they believed were due to the nucleotides, and a 2.7 nm repeat which they believed indicated that the DNA molecule was composed of a repeating repeating sequence of 8 or 16 nucleotides. Perfection of X-ray image Suggests that Perfection XDNA is Too Simple to be the Genetic Material
Astbury (1947) concluded: "It Astbury "It seems improbable, too, to judge by the degree of perfection of the X-ray fibre Xdiagram that these fou...
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