VPB 321: Animal Biotechnology (2+1)

COMPETENT CELLS

• As the DNA is a very hydrophilic molecule, it won't normally pass through a bacterial cell's membrane. In order to make bacteria take in the plasmid, they must first be made "competent" to take up DNA.
• This is done by creating small holes in the bacterial cells by suspending them in a solution with a high concentration of calcium.
• DNA can then be forced into the cells by incubating the cells and the DNA together on ice, placing them briefly at 42^oC (heat shock), and then putting them back on ice.
• This causes the bacteria to take up the DNA.
• The cells are then plated out on antibiotic containing media.