Cell Biology
Prokaryote
Single-celled organisms lacking a membrane-bound nucleus and other membrane-bound organelles. Includes bacteria and archaea—the oldest and most numerous life forms.
Biological Context
Prokaryotes are smaller and simpler than eukaryotes but incredibly diverse metabolically. They dominate Earth by numbers, drive biogeochemical cycles, live in extreme environments, and form the base of many food webs. The distinction between prokaryotes and eukaryotes is fundamental to understanding life.