Title: Archaea | Microbiology
Headings: Archaea
Archaea
Learning Objectives
Crenarchaeota
Think about It
Euryarchaeota
Think about It
Finding a Link Between Archaea and Disease
Key Concepts and Summary
Multiple Choice
Fill in the Blank
Think about It

Content: One remarkable feature of these organisms is that they perform photosynthesis using the protein bacteriorhodopsin, which gives them, and the bodies of water they inhabit, a beautiful purple color (Figure 2). Figure 2. Halobacteria growing in these salt ponds gives them a distinct purple color. ( credit: modification of work by Tony Hisgett)
Notable species of Halobacteria include Halobacterium salinarum, which may be the oldest living organism on earth; scientists have isolated its DNA from fossils that are 250 million years old. [ 5] Another species, Haloferax volcanii, shows a very sophisticated system of ion exchange, which enables it to balance the concentration of salts at high temperatures. Think about It
Where do Halobacteria live? Finding a Link Between Archaea and Disease
Archaea are not known to cause any disease in humans, animals, plants, bacteria, or in other archaea. Although this makes sense for the extremophiles, not all archaea live in extreme environments.