What are prokaryotic and eukaryotic cells? What is endosymbiosis? Why is it significant?

Endosymbiosis is important because it is a theory that explains the origin of chloroplast and mitochondria. It is also a theory that explains how eukaryotic cells came to be. Prokaryotes are organisms that consist of a single prokaryotic cell. Eukaryotic cells are found in plants, animals, fungi, and protists.