Supernatant pellet supernatant pellet blender

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Supernatant Pellet Supernatant Pellet Blender Centrifuge tube Hershey & Chase radioactively labeled viral protein with 35 S and let the viruses infect bacteria. (The amino acid methionine has S in its side chain) viruses bacteria viruses bacteria
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Further evidence... DNA content doubles just before cells divide, suggesting that an equal portion will be passed to the daughter (offspring) cells. Also, body cells—called somatic cells – are diploid . That means they have twice as much DNA as egg and sperm (haploid ) cells. That suggests they contain DNA from both parents.
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Also, by 1950, the components of DNA were known DNA was known to have a sugar & phosphate backbone, and nitrogenous bases as side groups DNA was known to be a polymer constructed of nucleotide monomers
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The backbone Deoxyribose sugars are joined together by a phosphodiester bond (i.e., a bond centered around a phosphate group) Notice the Carbon position numbers: 1-5. This is important for understanding the structure of DNA. This is OH in RNA 1’ 2’ 3’ 4’ 5’
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The nitrogenous base Attached to the 1-position of the deoxyribose sugar is a “nitrogenous base” that makes the nucleotide either a purine or pyrimidine Adenine base A Guanine base G Cytosine base C Thymine base T Purine bases (two circles) Pyrimidine bases (single circle)
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Finally, a bit more of info was known before the actual structure of DNA was discovered Erwin Chargaff’s Rules : G content = C content A content = T content AT:GC content (or ratio) varies among species E.g., in humans: A&T ~60%, G&C ~ 40% Now, the trick was to figure out the 3-D structure of DNA and how it caused DNA to operate as the genetic material: - How the polymers fit together - How this structure coded genetic information -And How the DNA replicated itself to assure genetic continuity among generations
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Now the trick was to figure out the 3-D structure, i.e.: -How the polymers fit together -How this structure coded genetic information -How DNA was replicated to assure genetic continuity among generations Back to figuring out the exact structure of DNA and how it worked as the genetic material
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Watson & Crick: Super nerds James Watson -- a Yank; Francis Crick -- a Brit.
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  • Fall '19
  • DNA, Frederick Griffith

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