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18.4 Bacteria and Archaea KEY CONCEPT Eubacteria and Archaea are both single-celled prokaryotes. 18.4 Bacteria and Archaea Characteristics of Kingdoms Kingdom Archaea bacteria Eubacteria Protista Fungi Plantae Animalia Uni cellular Multi cellular Auto trophic Hetero trophic Cell wall No cell wall Eu karyotic Pro karyotic Interesting Fact 18.4 Bacteria and Archaea Prokaryotes are widespread on Earth. Eubacteria and Archaea The most widespread and abundant organisms on Earth Only a small number of bacteria are pathogens • Prokaryotes can be grouped by their need for oxygen. – obligate anaerobes are poisoned by oxygen – obligate aerobes need oxygen – facultative aerobes can live with or without oxygen 18.4 Bacteria and Archaea Eubacteria and archaea are structurally similar but have different molecular characteristics. • Bacteria commonly come in three forms. – rod-shaped, called bacilli – spiral, called spirilla or spirochetes – spherical, called cocci Lactobacilli: rod-shaped Enterococci: spherical • Archaea have many shapes. Spirochaeta: spiral 18.4 Bacteria and Archaea • Eubacteria and archaea have similar structures. – plasmid – flagellum pili plasma – pili membrance flagellum chromosome cell wall plasmid This diagram shows the typical structure of a prokaryote. Archaea and bacteria look very similar, although they have important molecular differences. 18.4 Bacteria and Archaea Archaea • The “Chuck Norris” of prokaryotes. • Tough! • Found in extreme conditions. Eubacteria • More diverse. • More widespread. 18.4 Bacteria and Archaea Examples of Archaea • Methanogens-produce methane gas as a waste product of making energy. • Psychrophiles-usually live at low temperatures. • Halophiles-live in salty environments. • Thermophiles-live at extremely high temperatures 18.4 Bacteria and Archaea Kingdom Eubacteria • Needed for growth: – Nutrients – Water – Warmth – Darkness • Question---What would inhibit growth? 18.4 Bacteria and Archaea Benefits of Bacteria for Humans • Used to make common foods. 18.4 Bacteria and Archaea Prokaryotes provide nutrients to humans and other animals. • Prokaryotes live in digestive systems of animals. – make vitamins – break down food – fill niches 18.4 Bacteria and Archaea Prokaryotes play important roles in ecosystems. • Prokaryotes have many functions in ecosystems. – photosynthesize – recycle carbon, nitrogen, hydrogen, sulfur – fix nitrogen 18.4 Bacteria and Archaea • Bioremediation uses prokaryotes to break down pollutants. – oil spills – biodegradable materials 18.4 Bacteria and Archaea Bacterial Diseases • • • • • • • Strep Anthrax Food Poisoning Lyme Disease Tetanus Tooth Decay Tuberculosis 18.4 Bacteria and Archaea Reproduction • Eukaryotic cells reproduce by Mitosis • Prokaryotic cells reproduce by Binary Fission 18.4 Bacteria and Archaea • Gram staining identifies bacteria. – stains polymer peptidoglycan – gram-positive stains purple, more peptidoglycan – gram-negative stains pink, less peptidoglycan Gram-negative bacteria have a thin layer of peptidoglycan and stain red. Gram-positive bacteria have a thicker peptidoglycan layer and stain purple. 18.4 Bacteria and Archaea
