Modular design: New insights into protein factories in human mitochondria

The "power plants" of living cells, the mitochondria, probably evolved through endosymbiosis: A bacterium migrated into a primordial cell and eventually developed into an organelle that provides the cell with energy, among other things. Mitochondria produce some of the proteins they need themselves—with the help of special protein factories called mitoribosomes, which consist of RNA and proteins.