- A cell is the basic unit of structure and function in living organisms.
- Eukaryotic cells have a membrane-bound nucleus and organelles, while prokaryotic cells like bacteria do not have a nucleus.
- Key organelles in eukaryotic cells include the nucleus, which contains DNA; the cell membrane, which encloses the cell; mitochondria, which generate energy; and ribosomes, which produce proteins. Plant cells also have a cell wall, chloroplasts, and a vacuole.