The most prominent theory about chemical evolution suggests that the first cells arose from simple sacs of biological molecules called protocells.

Protocells are hypothetical structures that are thought to have been the precursors to modern cells. They are believed to have been formed by the self-assembly of organic molecules in a primordial soup, and they would have been able to enclose and concentrate these molecules, allowing for the development of the first metabolic processes.

While the exact details of protocell formation are still under debate, the concept of protocells is a key component of the theory of chemical evolution.