Welcome to Quantum Magazine's podcast.

Each episode we bring you stories about developments in science and mathematics.

I'm Susan Vallett.

Open a Basic Biology textbook published decades ago, or one published recently,

and both will define the two major categories of cells in the same

way. Eukaryotes have membrane-bound compartments called organelles, including a nucleus

where they store their genetic information. Well, prokaryotes don't. But it turns out that

these simple bacteria may be more complex than we originally thought.

As the evolutionary story is usually told, first came the prokaryotes. These are the archaea and

bacteria, which are simple bags of enzymes without an intricate structure.

Then, more than one and a half billion years ago, eukaryotes evolved. This marked the advent of

unprecedented cellular complexity. It permanently transformed life on Earth, allowing for the rise of

animals, plants, fungi, and protists.

The eukaryotes represented a substantial departure from their predecessors,

and the transition from an all-prokaryote world to one that contained eukaryotes

is often described as abrupt and explosive.

But this version of events ignores one key fact. For the past few decades, researchers have been quietly uncovering many complex structures within prokaryotes,

including membrane-bound organelles.

Eukaryotes have a suite of organelles in common, but different types of prokaryotes have their own specialized compartments.

One kind of bacterial organelle is essentially a little magnet wrapped in a lipid package.

Another hosts a series of reactions crucial for energy metabolism. Still, others serve as small storage

units for nutrients. And that list is only growing as scientists discover more and more compartments

...