01:119:115 Lecture 14: DNA
17 Jan 2019
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Early research hypothesis => genes made of protein (wrong!) Conclude that dna is the one killing the mouse. Viruses that infect bacteria and inserts dna, controlling bacteria and exploded. Conclusion: injected dna of phage is the genetic information. James watson and francis crick determined structure of dna in 1953. X-ray diffraction to determine 3d structure of molecules. Her images of dna enabled watson to deduce. Made up of two strands, forming a double helix. Double helix composed of 2 strands of dna. 3" end => free 3" hydroxyl (oh) group. Purine (big, 2 rings) always pair with pyrimidine. Dna replication = each strand is a template. Dna helicases = helix enzyme made of polypeptide, spins and breaks hydrogen bond. Single-strand binding proteins ssbp"s prevent closing, small proteins that bind. Topoisomerase corrects "over winding" => prevents formation of knots by dna helicase c. Primase helps by starting a place for dna to attach and put pieces of rna.
