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Question : (a) Explain Griffith’s series of exeeriments where he witnessed transformatio in bacteria he worked with. (b) Name the scientists responsible for determining the biochemical nature I “transforming principle” in Griffith’s experiments. What did they prove ? |
Answer» Solution :(a) Frederick Griffith, in a series of a EXPERIMENTS with streptococcus pneumonia witnessed a miraculous transformation in the bacteria. During the course of his experiment, living organism had changed in PHYSICAL form. n When streptococcus preumoniae bacteria are grown on a culture plate, some produce smoot ‘ shiny colonies (S) while other produce ROUGH colonies (R). This is because the S strain bacteri have a mucous(polysaccha1ide)coat, while R strain does not. S strairi mice die from pneumonia but R strain mice did not develop pneumonia. S (strain)--Inject into mice `to` Mice die. R (strain)-Inject into mice `to` Mice LIVE. S strain (heat-killed)-Inject into mice-Mice live. S strain (heatrkilledy-Inject into‘ mice-Mice die. + R strain (live) He concluded that the R strain bacteria have been TRANSFORMED by tho heat-killed S-strain bacteria. (b) momma work of Oswald Avery, Colin Macleod and Maclyn McCarty the genetic mater was through to be a protein, They worked to determine the Biochemical nature of 'transforming - Pmmple’ in Griffith’s experiment. They purified biochemicals (proteins, DNA, RNA etc. )from the heat-killid S cells to whichones could transform live R cells into S cells. They discovered that DNA alone from S bacteria caused R bacteria to become transformed. |
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