What characteristic is shared by both Bacteria and Archaea?

Bacteria and Archaea share the characteristic of being prokaryotic organisms. Prokaryotes are defined by their lack of a membrane-bound nucleus and other membrane-bound organelles, which distinguishes them from eukaryotic cells that do possess these structures. This fundamental difference in cellular organization is one of the key features that categorize these two domains of life.

Even though Bacteria and Archaea are both prokaryotes, they exhibit significant biochemical and genetic differences, leading to their classification into separate domains. This shared prokaryotic characteristic lays the foundation for understanding their simple cellular structure compared to more complex eukaryotic organisms, which have a defined nucleus and organelles affiliated with various cellular functions.