11:115:301 Lecture Notes - Lecture 23: Deinococcus Radiodurans, Thermus Aquaticus, Klenow Fragment
22 Sep 2019
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Document Summary
Dna is the only molecule that is repaired. Each daughter cells gets on strand of parental dna + one new strand. Extreme example of dna repair: deinococcus radiodurans. Carbohydrates, lipid, proteins get damaged disposed of. X-ray/gamma ray double stranded dna cuts. Related to thermus aquaticus heat resistant bacterium. Can sustain heavy radiation damage + put genome back together. Puts dna back together using other copies as template. 0 = irradiated genome: fragmented smear. 3 = spontaneously reassembled genome: distinct bands. Dna polymerases (1) require a primer and (2) synthesize dna in the 5" 3" direction. Dnapol needs a primer = different from rna polymerase. Synthesize 5 3" = similar to rna polymerase. No dna polymerase enzyme can start a new strand of dna on its own. To start synthesizing dna another enzyme must make a primer of rna. Rnapol that makes the primer dna primase.
