Bacteria and Archaea All single-celled organisms in the Bacteria and Archaea domains are referred to as prokaryotes. Prokaryotes are organisms whose genetic material is not contained within a nuclear envelop. These cells are profoundly important to the environment, medicine, and industry. (Postlethwait & Hopson, 2010, p. 196) Bacteria and Archaea are similar in shape, size, and appearance. They are both found occurring as rods (bacilli), spheres (cocci), spirals (spirilla), or curved, comma-shaped rods (vibrios). (Postlethwait & Hopson, 2010, p. 198) Prokaryotic cells have an outer cell wall that surrounds the plasma membrane. (Postlethwait & Hopson, 2010, p. 197) In species within the domain Bacteria, the prokaryotic cell wall is a strong but flexible covering, made primarily of sugar-protein complexes called peptidoglycans. In contrast, species in the domain Archaea may have cell walls made of polysaccharide, protein, or glycoprotein, but they never contain true peptidoglycans. (Postlethwait & Hopson, 2010, p. 198) Both, Archaea and Bacteria use flagella to swim. But, Archaea flagella evolve from bacterial type IV pili while bacterial flagella evolve from type III secretion system. Bacterial flagellum is like a stalk which is hollow and is assembled by subunits that are free to move up the central pore adding on to tip of flagella while in archaea flagella subunits are added on to the base. Similarly, Archaea and Bacteria reproduce asexually by the process of binary fission, budding, and fragmentation, but bacteria have the unique ability to form spores to remain dormant over years, a trait that is not exhibited by Archaea. (Archaea vs. Bacteria, n.d., n.p.) The tiny prokaryotes are, the important they are. Many prokaryotic organisms can cause diseases, but far more prokaryotes benefit the environment and the human body. (Postlethwait & Hopson, 2010, p. 196)
References
Postlethwait, J., & Hopson, J. (2010).
References: Postlethwait, J., & Hopson, J. (2010). Single-Celled Life. In Life (Student ed., pp. 196-198). Belmont, CA: Cengage Learning. "Archaea vs. Bacteria." Diffen. N.p., n.d. Web. 07 Oct. 2014. <http://www.diffen.com/difference/Archaea_vs_Bacteria>.