18.4 Bacteria and Archaea Kingdom Eubacteria Domain Bacteria 18.4 Bacteria and Archaea Description Bacteria are single-celled prokaryotes. 18.4 Bacteria and Archaea Where do they live? Prokaryotes are widespread on Earth. ( Est. over 1 billion types of bacteria, and over 1030 individual prokaryote cells on earth.) Found in all land and ocean environments, even inside other organisms! 18.4 Bacteria and Archaea Common Examples • E. Coli • Tetanus bacteria • Salmonella bacteria • Tuberculosis bacteria • Staphylococcus • Streptococcus 18.4 Bacteria and Archaea Modes Of Nutrition • Bacteria may be heterotrophs or autotrophs 18.4 Bacteria and Archaea Bacteria Reproduce How? • by binary fission. • exchange genes during conjugation= conjugation bridge increases diversity. • May survive by forming endospores = specialized cell with thick protective cell wall. TEM; magnification 6000x • Can survive for centuries until environment improves. Have been found in mummies! 18.4 Bacteria and Archaea • Bacteria Diagram – plasmid = small piece of genetic material, can replicate independently of the chromosome – flagellum = different than in eukaryotes, but for movement – pili = used to stick the bacteria to eachpili other or surfaces plasma 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 • Classified by: their need for oxygen, how they gram stain, and their shapes 18.4 Bacteria and Archaea Main Groups by Shapes – rod-shaped, called bacilli – spiral, called spirilla or spirochetes – spherical, called cocci Spirochaeta: spiral Lactobacilli: rod-shaped Enterococci: spherical 18.4 Bacteria and Archaea • Main Groups by their need for oxygen. • obligate anaerobes are poisoned by oxygen - Ex. Clostridium botulinum - Ex. Clostridium tetani – obligate aerobes need oxygen - Ex. Mycobacterium tuberculosis – facultative aerobes can live with or without oxygen - Ex. E. Coli 18.4 Bacteria and Archaea • Main Groups by Gram staining – stains polymer peptidoglycan – gram-positive stains purple, more peptidoglycan – gram-negative stains pink, less peptidoglycan Gram-negative bacteria have a thin layer of Gram-positive bacteria have a thicker peptidoglycan and stain red. peptidoglycan layer and stain purple. 18.4 Bacteria and Archaea – The amount of peptidoglycan within the cell wall can differ between members of kingdom (eu)bacteria. GRAM NEGATIVE GRAM POSITIVE 18.4 Bacteria and Archaea So, Why is Gram Staining Important? • Different types of infectious bacterial diseases respond differently to antibiotics when they are gram- positive or gram-negative! 18.4 Bacteria and Archaea KEY CONCEPT How Bacteria help man. 18.4 Bacteria and Archaea • Bacteria help ferment many foods. – yogurt, cheese – pickles, sauerkraut – soy sauce, vinegar 18.4 Bacteria and Archaea Bacteria provide nutrients to humans and other animals. • Live in digestive systems of animals – LIKE US!!!. – make vitamins (Ex. E. coli in our lg. intestine make B vitamins for us!) – break down food (Ex. Bacteria in cow stomach digest cellulose in grass, hay, etc. – fill niches Human intestinal bacteria 18.4 Bacteria and Archaea • Bioremediation uses bacteria to break down pollutants. – oil spills – biodegradable materials 18.4 Bacteria and Archaea How Bacteria Hurt Man! 18.4 Bacteria and Archaea Some bacteria cause disease. • Bacteria cause disease by invading tissues or making toxins. • A toxin is a poison released by an organism. Clostridium botulinum bacteria cause botulism food poisoning. 18.4 Bacteria and Archaea • Example: Flesh Eating Bacteria – may colonize new tissues Flesh eating Streptococcus bacteria, normally do not harm us. Only become dangerous when come in contact with other tissues like fat or muscle. 18.4 Bacteria and Archaea 18.4 Bacteria and Archaea Antibiotics are used to fight bacterial disease. • Antibiotics may stop bacterial cell wall formation. • Antibiotics do not work on viruses. • Prevention is best method to fight bacterial disease. 18.4 Bacteria and Archaea Bacteria can evolve resistance to antibiotics. • Bacteria are gaining resistance to antibiotics, due to:. – overuse A bacterium carries (Handsanitizers?) genes for antibiotic – underuse resistance on a plasmid. (Take your RX as directed) A copy of the plasmid is – misuse transferred through conjugation. (For livestock raising?) – Read p. 565! Resistance is quickly • Antibiotics must be spread through many used properly. bacteria. 18.4 Bacteria and Archaea Bacteria play important roles in ecosystems. • Prokaryotes have many functions in ecosystems. – photosynthesize – recycle carbon, nitrogen, hydrogen, sulfur – fix nitrogen = Nitrogen fixation Root nodules of white clover contain Nitrogen fixing bacteria, which convert atmospheric nitrogen into a form the clover can use. The bacteria get sugars from the clovers’ photosynthesis. This is an example of mutualistic symbiosis. 18.4 Bacteria and Archaea Turn your pink sheet over, to put the Archaea on the other side!!!! 18.4 Bacteria and Archaea Kingdom Archaeabacteria, Domain Archaea 18.4 Bacteria and Archaea Description Archaeabacteria are single-celled prokaryotes that live in extreme environments. They do NOT have peptidoglycan in their cell walls. 18.4 Bacteria and Archaea Where do they live? • Hot springs • Deep sea vents • Bottoms of Swamps • Mouths of volcanoes • Extra Salty lakes and seas 18.4 Bacteria and Archaea Common Examples • Methanogens = methane gas lovers • Thermophiles = heat lovers • Halophiles = salt lovers 18.4 Bacteria and Archaea Modes of nutrition • Heterotrophs and Chemoautotrophs • Chemoautotrophs use chemicals in their environment to create their own food (Unlike photosynthesizers, that rely on energy from the sun.) 18.4 Bacteria and Archaea Reproduce how? • Same as Eubacteria 18.4 Bacteria and Archaea Diagrams (omit) pili plasma 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 Classified by: • Shapes (See Eubacteria notes)- cocci, spirilli, bacilli • Where they live 18.4 Bacteria and Archaea Main Groups – see common examples 18.4 Bacteria and Archaea Special roles in ecosystems – fill niches in extreme environments • Fill niches in extreme environments • Many of them are chemosynthesizers .