According to the endosymbiotic theory, early eukaryotic cells became the mitochondria and chloroplasts found in prokaryotic cells.

Endosymbiotic Theory

Explanation of the evolution of eukaryotic organelles by phagocytosis of prokaryotes.

Eukaryotic Cells

Cells with a true nucleus enclosed in a membrane, along with other membrane-bound organelles, characterizing plants, animals, fungi, and protists.

Prokaryotic Cells

Cells without a defined nucleus or other membrane-bound organelles, commonly found in bacteria and archaea.