How does heat shock work in bacterial transformation?

Heat shock works by creating temporary pores in the bacterial cell membrane through a rapid increase in temperature. Chemically treated competent cells, typically chilled on ice, are exposed to heat for a short duration (e.g., 42°C for 30–60 seconds). This sudden thermal change disrupts the cell membrane’s fluidity and facilitates the uptake of plasmid DNA. Cooling the cells afterward stabilizes the membrane, trapping the introduced DNA inside. This technique is widely used due to its simplicity and efficiency.