Precells

Precells are theoretical primitive cellular-like entities that predate modern cellular membranes and sophisticated genetic systems. In origin-of-life research, the term is used to describe early compartments or aggregates that could concentrate reactants, harness simple metabolic-like processes, and replicate or propagate to some extent, but do not yet meet the criteria of a true cell.

In many discussions, precells are contrasted with protocells and protobionts. Precells are often envisioned as non-membrane-bound systems—such as coacervates, mineral surfaces, or other crowded compartments—that supplied a localized environment for chemistry. Protocells, by contrast, typically incorporate a primitive boundary, such as a lipid or other membrane, enabling more discrete, semi-autonomous metabolism and growth.

Laboratory models often use coacervates, micelles, or simple lipid vesicles to illustrate how precells might have concentrated reactants and catalyzed basic reactions. These systems can exhibit growth and division-like behavior under environmental cycles, yet lack a stable, self-replicating genetic system.

In contemporary origins-of-life theory, precell-like stages are part of a continuum from chemistry to biology, bridging nonliving chemistry to cellular life. Some researchers reserve "precell" for directly preceding protocells, while others employ "precell" as a broader term for early non-membrane compartments.

See also protocell, protobiont, origin of life, coacervate, liposome, vesicle.