Chapter 22
Prokaryotes: Bacteria and Archaea
By Boundless
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Prokaryotic organisms were the first living things on earth and still inhabit every environment, no matter how extreme.
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Archaea are believed to have evolved from gram-positive bacteria and can occupy more extreme environments.
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Prokaryotes are well adapted to living in all types of conditions, including extreme ones, and prefer to live in colonies called biofilms.
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Prokaryotes, found in both Domain Archaea and Bacteria, are unicellular organisms that lack membrane-bound organelles and a defined nucleus.
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Prokaryotes reproduce asexually by binary fission; they can also exchange genetic material by transformation, transduction, and conjugation.
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Prokaryotes need a source of energy, a source of carbon, macronutrients, and micronutrients to survive.
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Prokaryotes play vital roles in the movement of carbon dioxide and nitrogen in the carbon and nitrogen cycles.
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Infectious diseases, spread from person to person by bacteria, are among the leading causes of death despite advances in medical research.
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Biofilms, complex colonies of bacteria acting as a unit in their release of toxins, are highly resistant to antibiotics and host defense.
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Excessive use of antibiotics in animals or as imprudent medical treatments has resulted in the propagation of antibiotic-resistant bacteria.
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Foodborne diseases can be associated with bacteria-caused illnesses in both animal and plant-based food sources.
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Prokaryotes fix nitrogen into a form that can be used by eukaryotes.
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Some of the earliest biotechnology used prokaryotes for the production of food products such as cheese, bread, wine, beer, and yogurt.
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Bioremediation occurs when prokaryotes clean up a polluted environment through the natural breakdown of pollutants.