Is self-enclosure life’s greatest trick? According to the lipid-first theory of the origin of life, a cell membrane gave primordial chemistry a place to gather.

Introduction

This explainer is part of Quanta Magazine ’s Origins of Life Week . Check back throughout the week for more stories about one of science’s biggest unknowns.

A t its core, every cell is just a bubble of chemistry sealed inside a membrane. In modern cells, that chemistry is extraordinarily complex, orchestrating some 1 billion reactions per second. Likewise, its container, the lipid membrane, is built and maintained by elaborate biochemical mechanisms. But even the much simpler first cells would have needed a bubble too.

Without a physical boundary corralling molecules into a small space, whatever it was that turned into early life would have been too dispersed to assemble the complex systems that life requires, said Bruce Damer , an astrobiologist at the University of California, Santa Cruz.…