Biology 1001A Chapter Notes - Chapter 12: Autopsy, Polysaccharide, Cell Nucleus
25 May 2016
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Living cells successfully prevent or repair most of this dna damage, but post mortem degradation can be extensive. Sustained cold temperatures preserve dna well creating opportunity to extract dna from samples (such as mammoths preserved in permafrost): dna contamination modern or ancient sources of contamination is another issue, causing a need for ultraclean laboratories. Suspicions of contamination have clouded some of the most dramatic reports of adna. Miescher studied composition of the cell nucleus, extracted nuclein (dna) from puss on bandages. Before this people did not know what substance in cells carried information for reproducing parental traits in children. Watson and crick made first model of structure of dna. This model enabled scientists to understand key processed in cells in terms of structure and molecule interaction. Previously people thought proteins were the most likely candidates for heredity molecules. Griffith experiments with bacterium that cause pneumonia. He used two different strains, smooth (s) and rough (r).
