Why we use calcium chloride(CaCl2) in transformation of bacteria?
To get the DNA into the bacteria, we have to poke holes in them with the chemical calcium chloride (CaCl2). CaCl2 will dissociate into Ca2+ and 2 Cl-, and the positive charge of the Ca2+ cancels the negative charge of the DNA, allowing it to cross the cell wall and cell membrane. The holes poked to allow the DNA in leaves the bacteria leaky. If we don’t keep them on ice, they’ll ‘bleed’ to death.