A eukaryote is any cell or organism that possesses a clearly defined nucleus. Eukaryotic cells form the foundation of complex, multicellular life, including apple trees, mushrooms, fish and humans.

In addition to the nucleus, eukaryotic cells may contain several other types of organelles, which may include mitochondria, chloroplasts, the endoplasmic reticulum, the Golgi apparatus ...

Both organelles have made substantial contributions to the complement of genes that are found in eukaryotic nuclei today. The figure shows a schematic diagram of the evolution of eukaryotes ...

Bacteria are amongst the simplest of organisms – they are made of single cells. Their cell structure is simpler than the cells of animals, plants and fungi.