Summary

3.1 Prokaryote Habitats, Relationships, and Microbiomes

• Prokaryotes are unicellular microorganisms whose cells have no nucleus.
• Prokaryotes can be found everywhere on our planet, even in the most extreme environments.
• Prokaryotes are very flexible metabolically, so they are able to adjust their feeding to the available natural resources.
• Prokaryotes live in communities that interact among themselves and with large organisms that they use as hosts (including humans).
• The totality of forms of prokaryotes (particularly bacteria) living on the human body is called the human microbiome, which varies between regions of the body and individuals, and changes over time.
• The totality of forms of prokaryotes (particularly bacteria) living in a certain region of the human body (e.g., mouth, throat, gut, eye, vagina) is called the microbiota of this region.
• Prokaryotes are classified into domains Archaea and Bacteria.