Biochemistry 2280A Lecture Notes - Lecture 21: Formamide, Chromosome, Southern Blot
8 Aug 2016
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Document Summary
Biotechnology: mass production of rare proteins, ability to move genes between species, creation of novel proteins, modified organisms, and novel organisms. Has led to changes in : medicine. Enhanced crops that are more resistant to pests and rot: environment. Ex. oil-eating microbes for cleaning up oil spills: forensics and law. One method of visualizing dna in gel fluorescence: etbr (ethidium bromide) used to stain dna, fluoresces red under uv light, won"t work if amount of dna is low, use radioactive labeling then. Tm = temperature at which half of specific double stranded dna has become single stranded. More g-c pairs means higher tm: length of helix. Extrinsic factors: counter ions increase tm by neutralizing the negative charge of the phosphate backbone, reduce repulsion, solvents like urea and formamide decrease tm by weakening hydrogen bonds between complementary bases. Note: imperfect matches have a lower tm than perfectly matched strands. Northern blot has rna filter, southern blot has dna filter.
