What does CaCl₂ do in bacterial transformation?

Calcium chloride (CaCl₂) is used in bacterial transformation to chemically prepare cells for DNA uptake. It helps destabilize the bacterial cell membrane by neutralizing its negative charge and increasing membrane permeability. This process creates a conducive environment for DNA to bind to the cell surface and enter the cells during heat shock. CaCl₂ treatment is a critical step in making cells competent for transformation.