FIGURE A.4 - Electroporation. The lid to the chamber safe is closed and locked, and the power-out plug is inserted into the appropriate holes in the lid of the chamber safe. The cuvette dial on the lid of the chamber safe is turned to "1". A voltage is generated in the power unit. Once a desired voltage is obtained, the "TRIGGER" button is pushed, and the voltage is released into the wires of the power cord, through the power-out plug, into the pins in the lid of cuvette "1", and through the opposed metal liners along the sides of the cuvette. The voltage is eliminated by the passage of current through the path of least resistance (in this case, the transformation mixture). The current applied to the competent bacteria temporarily permeablilizes their cell membranes allowing BACs to enter the cells.