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How the form and function of DNA relate. Before knowledge of DNA, how did we explain how traits are passed on from parent to offspring?. a lesson in progress…. Frederick Griffith (British, 1928): Wanted to find out how/why certain bacteria make you sick. What was Griffith’s grand conclusion?.
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Before knowledge of DNA, how did we explain how traits are passed on from parent to offspring?
a lesson in progress… • Frederick Griffith (British, 1928): • Wanted to find out how/why certain bacteria make you sick
What was Griffith’s grand conclusion? • Griffith performed what he called transformation, a term still used today
Step 2… • Oswald Avery(1944, Canadian) used enzymes to break down the primary components (lipids, nucleic acids, proteins, carbohydrates) of the bacteria cells in Griffith’s experiment to determine which component was exchanging information. • Results: Griffith’s process did not work when Avery used enzymes to breakdown the nucleic acid of the deadly bacteria
Hershey–Chase experiment: a verification of Avery Alfred Hershey and Martha Chase (American, 1952) • Conclusion?
Rosalind Franklin (50’s British) and the first image of DNA • Used x-ray diffraction to get this image • What hints about the structure can be gained from this?
Chargaff’s Rules and the first insight into how DNA works • American biochemist Erwin Chargaff isolated molecules from DNA in the following proportions: • Conclusion? • http://www.dnalc.org/resources/3d/21-chargaff-ratios.html
The grand conclusion • James Watson (British physicist) and Francis Crick (American biologist) 1953: • DNA is a….DOUBLE HELIX
DNA’s specifications • Width: 2 nanometer (nm), or 2 billionths of a meter • Length (per cell): 1 m • How does it all fit in one cell? • How much total length of DNA in one human? • How far is that?
Where does DNA live? • Click on the following link for a “journey into DNA.” • http://www.pbs.org/wgbh/nova/genome/dna.html#
List the ways form and function fulfilled. • Watch the replication of DNA: • http://www.hhmi.org/biointeractive/dna/animations.html(technical) • http://www.teachersdomain.org/asset/tdc02_vid_dnaanimation/ • http://www.pbs.org/wgbh/aso/tryit/dna/shockwave.html(replication workshop, Shockwave activity) • http://www.youtube.com/watch?v=OnuspQG0Jd0&safe=active(technical, but good)