Human: Can you explain the difference between a bacterium and an eukaryote? Assistant: 
A bacterium is a single-celled organism that lacks a nucleus, while an eukaryote is any organism with a nucleus. Bacteria are prokaryotes, meaning they have no membrane-bound organelles such as mitochondria or chloroplasts. Eukaryotic cells contain membrane-bound organelles such as mitochondria and chloroplasts. The differences in structure and function of these two types of cell make them distinct from each other.