What does heat shock do in bacterial transformation?

Heat shock temporarily disrupts the integrity of a bacterial cell membrane, creating pores that allow plasmid DNA to enter the cell. During this process, the competent cells are exposed to a sudden increase in temperature, typically from ice-cold conditions to around 42°C for a brief period. This thermal shock destabilizes the cell membrane, facilitating the uptake of DNA. Subsequent cooling restores membrane stability, trapping the foreign DNA inside the bacterial cell.