the head is made, erm, the tail, all the bits are made and eventually they, they all stick together like a kind of lego, and the result is a new bacteria  is made and this goes on until eventually the cell, there are so many inside the cell, that erm the cell just ruptures, when there're about two hundred or so, the  cell is now bulging with t four bacteria , it ruptures and releases a whole blob of new ones to start the cycle all over again.