The main objective of this experiment was that Boyer and Cohen wanted to isolate the recombinant plasmid, but in order to do so they had to first get their ligated plasmids into E.coli. They learned that Pneumococcus bacteria are "transformed" to virulence when they take up DNA from virulent strains. Their experiment continued by them performing a "heat shock" by rapidly raising and lowering the temperature. Because they did this the bacteria was able to take in the plasmic DNA. The bacteria is then placed in a petri dish and the bacteria with resistance to antibiotics )tetracyline and kanamycin) will be able to grow and continue to spread. This foreign DNA is otherwise known as transformation.
-The cell membrane is made up of lipid molecules that have negatively charged phosphates. The negatively charged phosphates on the DNA helix are repelled by the ones on the lipids. Heat shock creates a temperature imbalance on either side of the bacterial membrane. This is how the DNA is able to get through the adhesion zone.
SOURCES: http://www.dnalc.org/view/15916-DNA-transformation.html, bacteriakingdoms.com
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