Prokaryotes: Bacteria and Archaea
22.1 Prokaryotic Diversity
Prokaryotic organisms were the first living things on earth and still inhabit every environment, no matter how extreme.
Prokaryotes, the First Inhabitants of Earth
Archaea are believed to have evolved from gram-positive bacteria and can occupy more extreme environments.
Microbes Are Adaptable: Life in Moderate and Extreme Envi...
Prokaryotes are well adapted to living in all types of conditions, including extreme ones, and prefer to live in colonies called biofilms.
22.2 Structure of Prokaryotes
The Prokaryotic Cell
Prokaryotes, found in both Domain Archaea and Bacteria, are unicellular organisms that lack membrane-bound organelles and a defined nucleus.
Prokaryotes reproduce asexually by binary fission; they can also exchange genetic material by transformation, transduction, and conjugation.
22.3 Prokaryotic Metabolism
Needs of Prokaryotes
Prokaryotes need a source of energy, a source of carbon, macronutrients, and micronutrients to survive.
Role of Prokaryotes in Ecosystems
Prokaryotes play vital roles in the movement of carbon dioxide and nitrogen in the carbon and nitrogen cycles.
22.4 Bacterial Diseases in Humans
History of Bacterial Diseases
Infectious diseases, spread from person to person by bacteria, are among the leading causes of death despite advances in medical research.
Biofilms and Disease
Biofilms, complex colonies of bacteria acting as a unit in their release of toxins, are highly resistant to antibiotics and host defense.
Antibiotics: Are We Facing a Crisis?
Excessive use of antibiotics in animals or as imprudent medical treatments has resulted in the propagation of antibiotic-resistant bacteria.
Foodborne diseases can be associated with bacteria-caused illnesses in both animal and plant-based food sources.
22.5 Beneficial Prokaryotes
Cooperation between Bacteria and Eukaryotes: Nitrogen Fix...
Prokaryotes fix nitrogen into a form that can be used by eukaryotes.
Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt
Some of the earliest biotechnology used prokaryotes for the production of food products such as cheese, bread, wine, beer, and yogurt.
Using Prokaryotes to Clean up Our Planet: Bioremediation
Bioremediation occurs when prokaryotes clean up a polluted environment through the natural breakdown of pollutants.