a type of organism that has only one cell and does not have a nucleus (= central part), for example a bacterium

The eukaryotic cell is much larger and more efficient than the procaryote, carrying more genetic material. 真核细胞比原核细胞大得多，效率更高，携带更多遗传物质。

All the contents of the cells of prokaryote organisms (which lack a cell nucleus) are contained within the cytoplasm. 原核生物（无细胞核的）细胞内所含物质都在细胞质中。