Our cells are different to bacterial cells in that our cells contain membrane-bound compartments known as organelles, allowing proteins to be sorted to different areas. While bacteria are known as prokaryotes, what term is used to describe animals and plants, specifically reflecting the presence of a membrane-bound nucleus?

"Eukaryote" roughly translates as "truly nucleated" and refers to organisms with a membrane-bound nucleus.

Such membrane-bound organelles are thought to have arisen via the invagination of the cell's own plasma membrane.

Other organelles such as the mitochondria and the chloroplast are believed to have once existed as separate organisms, but which were engulfed by other cells, forming a symbiotic relationship.