BIOL3090 Lecture Notes - Lecture 1: Dna Ligase, Photographic Emulsion, Alpha Particle
7 Aug 2018
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Used two different isotopes 15n and 14n. Could physically separate based on weight due to 15n heaviness. Dna helix was made of 15n if conservative should replicate to form heavy and light band. Semi-discontinuous thought could be continuous, semi discontinuous or discontinuous. Used radioactive thymine measures just dna synthesis as its only present in dna and a temp sensitive mutant of dna ligase (joins bits of dna together). Pulse labelling where you add radioactive isotope for defined periods of time. Found that with short pulses there was peaks of radioactivity corresponding to short pieces of dna. After 2 minutes there was a peak corresponding to a large piece of dna (stitched u by dna ligase). If done in temp sensitive mutant there was a peak that got bigger as the pulse went on no second peak. Looking at chromosomes replicating used radioactive isotope of hydrogen (tritium) but at two different concentrations, low and high.
