Did chemical analysis 9 finding the transforming

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Unformatted text preview: id chemical analysis 9 Finding the “transforming principle” 1944  Avery, MacLeod and McCarty Prepared various purified and semi-purified components from the mixture and tested to see if they could transform R form bacteria. The only one that could was determined to be DNA. Further tested this preparation by subjecting it to various chemicals………. They suggested genes were made up of DNA 10 Avery’s demonstration of in vitro transformation 11 More evidence that genes are made of DNA 1952 – Experiments of Chase and Hershey, infecting bacterial cells with bacteriophages (know these) looked at viruses instead of cells 12 Evidence that genes are made of DNA T2 bacteriophages are very small, and are composed of approximately equal weights of protein and DNA. They depend on the host cell machinery for their replication. What substance directs the production of new phage particles, DNA or protein ? 13 Evidence that genes are made of DNA 14 attachment / injection Electron microscope revealed that when phage infect bacteria, they leave the viral shell (ghost) on the surface of 15 the cell. It appeared that the substance for phage replication was injected into the cell. Hershey and Chase set about showing which substance was DNA and which was protein. 16 The chemical constituents of DNA The parts: 17 The chemical constituents of DNA Assembly into a nucleotide : 18 The chemical constituents of DNA Nucleotides linked in a directional chain through phosphodiester bonds: 5’ phosphate and 3’ hydrox...
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