November 19 Notes

I. Transformation- DNA donor is dead, and may not be a close relative of recipient
A) Artificial Transformation
example: Insulin for diabetes; insulin is processed from E. Coli, containing a gene for ampicillin resistance and plasmid with the
human insulin gene
*plasmid= circle of DNA with genes with promoter sequences and oriC site
1. Plasmid from bacteria is cut with restriction enzymes and treated with restriction enzymes with DNA swatches containing
genes we want and then treated with DNA ligase
2. Plasmid is put into bacteria by electric or heat shock (most of the bacteria die from this)
*Bacteria that grow on ampicillin-containing media after the shock with plasmids must have amp-R AND insulin gene
B) Natural Transformation
*"Naked DNA"= linear swatch of DNA
*must be "competent" (able to take up DNA or gene from environment)
*how natural transformation works:
1. Bacteria in envirnment with lots of naked DNA; the DNA binds to sites on bacterial cell wall
2. One strand of "naked DNA" swatch is destroyed and the other is brought into the bacterial cell
3. The strand of DNA brought into the cell is covered in SINGLE-STAND BINDING PROTEIN so its not destroyed
4. HOMOGOLOUS=same/similar DNA sequence
*if any of swatch is homologous with the bacteria's chromosomes, the homologous parts base pair with bacterial
5. Next time the bacteria divides, one cell gets a copy of the new swatch and one gets the original DNA

Danya Hangman

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