Phospholipids can spontaneously form vesicles in water, creating protocell-like structures.

Experiments show that amphiphilic molecules, such as phospholipids, when present in water, naturally self-assemble into spherical membranes (vesicles or liposomes). These structures can encapsulate internal contents, mimicking the basic compartmentalization necessary for the first protocells and supporting the idea of a self-assembly pathway for cellularization.