Archaea Bacteria

Key Features Extremophiles that can live in harsh conditions such as hot springs, salt water, and even inside the human stomach Single celled organisms that lack nuclei and peptidoglycan in their cell walls Most are cocci (spherical), bacilli (rod-shaped), or spiral shaped, but unusual forms exist also

Life Cycle Archaea reproduce asexually and divide by binary fission, fragmentation, or budding; in contrast to bacteria and eukaryotes, no species of archaea are known that form spores.

Interesting Facts Methanogenic archaea live in the stomachs of humans and ruminants and aid in digestion Some are used to make biogas or as part of sewage treatment Enzymes from archaebacteria are used in biotechnology because they can withstand high temperatures