TAILIEUCHUNG - Lecture Biology (6e): Chapter 27 - Campbell, Reece
Chapter 27 - Prokaryotes and the origins of metabolic diversity. This chapter distinguish between the cell walls of gram-positive and gram-negative bacteria; state the function of the following features: capsule, fimbriae, sex pilus, nucleoid, plasmid, and endospore; explain how R plasmids confer antibiotic resistance on bacteria; explain the importance of/uses for prokaryotes. | CHAPTER 27 Prokaryotes and the Origins of Metabolic Diversity Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section A: The World of Prokaryotes 1. They’re (almost) everywhere! An overview of prokaryotic life 2. Bacteria and archaea are the two main branches of prokaryote evolution Prokaryotes were the earliest organisms on Earth and evolved alone for billion years. Today, prokaryotes still dominate the biosphere. Their collective biomass outweighs all eukaryotes combined by at least tenfold. More prokaryotes inhabit a handful of fertile soil or the mouth or skin of a human than the total number of people who have ever lived. 1. They’re (almost) everywhere! An overview of prokaryotic life Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Prokarytes are wherever there is life and they thrive in habitats that are too cold, too hot, too salty, too acidic, or too alkaline for any eukaryote. The vivid reds, oranges, and yellows that paint these rocks are colonies of prokaryotes. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. We hear most about the minority of prokaryote species that cause serious illness. During the 14th century, a bacterial disease known as bubonic plague spread across Europe and killed about 25% of the human population. Other types of diseases caused by bacteria include tuberculosis, cholera, many sexually transmissible diseases, and certain types of food poisoning. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings However, more bacteria are benign or beneficial. Bacteria in our intestines produce important vitamins. Prokaryotes recycle carbon and other chemical elements between organic matter and the soil and atmosphere. Prokaryotes often live in close association among themselves and with eukaryotes in symbiotic relationships. Mitochondria and chloroplasts evolved from prokaryotes that became residents in larger host cells. Copyright
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