Bacteria Domain Bacteria and Archaea Kingdom Eubacteria and

Bacteria Domain: Bacteria and Archaea Kingdom Eubacteria and Archaebacteria (previously Monera) Crash Course: Bacteria Video 1

Characteristics Lack nucleus and organelles (prokaryotic) l Usually smaller than eukaryotic cells l Single cells but can form strands or clumps l Single circular piece of DNA l Reproduce by binary fission l l Can divide every 20 minutes l Limited food source reduces actual rate of division 2

Characteristics l Flagella that spins for movement l Some have pili l Shorter and thicker than flagella l Used for attachment www. ou. edu/class/pheidole/bacteria. html l Aerobic or anaerobic metabolism 3

Classification of Bacteria l Ways Bacteria are classified l Shape – most common way to classify l Arrangement (Number/ size) l Food requirements l Oxygen requirements l How they move/number of flagella l Cell wall composition (gram staining) l Method of reproduction – rarely used 4

Bacterial Shapes l Bacillus = rod l Coccus = round l Spirillum = spiral 5

Bacterial Arrangement l Diplococcus = 2 round bacteria cells l Streptococcus = chains of round bacteria l Staphylococcus = cluster of round bacteria l Tetrad = 4 round bacteria in a square 6

Bacterial Arrangement l Diplobacillus = pairs of rod shaped bacteria l Streptobacillus = chains of rod shaped bacteria 7

Bacteria Facts Bacteria is everywhere l The number of bacteria in the human mouth is greater than the number of people who ever lived on the earth. l Bacteriologist is a scientist who studies bacteria. l Bacteria is grown in a lab as a culture with nutrient agar (food source). l 8

Gram Staining Used to identify the type of bacteria present l Used to determine the best antibiotic needed to kill the bacteria l Antibiotic = interferes with the life processes of bacteria l l Alexander Fleming – penicillin inventor 9

Why are bacteria so resistant? l Endospores = thick walls around bacteria during harsh conditions l Ex- low nutrients, drought, high temperatures, low temperature, etc. l Endospores will open up when conditions become more favorable. 10

Bacteria Structure l Draw a bacterial cell. Label cytoplasm, DNA, ribosomes, flagella, pili, capsule, cell wall, cell membrane Capsule = purple outer layer 11

Obtaining Energy (nutrition) 1. 2. Photosynthetic = makes own food Heterotrophs = obtain food from another source a. b. Saprophytes = Eat dead organisms Symbiotic relationships = live in close association with another organism l Mutualism = both organisms are helped l l Example= sheep & cows have bacteria in stomach to aid in grass digestion Parasitism = one is helped; other is harmed l Host = organism that is harmed 12

Obtaining energy (nutrition) 3. Chemoautotrophs l l Use inorganic compounds such as ammonia and hydrogen sulfide to make food Use organic compounds such as methane to make food 13

Respiration Obligate aerobes - require oxygen l Obligate anaerobes – require no oxygen; oxygen will poison the bacteria and kill it l l Botulism – produces toxins in improperly canned foods l Facultative anaerobes – can function with or without oxygen but will not be poisoned by the presence of oxygen 14

Economic Importance l Pathogenic – disease causing l Examples: tuberculosis, anthrax, bubonic plague, cholera, dental cavities, lyme disease, typhus, strep throat, acne, tetanus, stomach ulcers l Food Poisoning l Botulism l E. l coli (ground beef) Food spoilage 15

Economic Importance Biowarfare l Food Production l l Pickles, buttermilk, cheese, sauerkraut, olives, vinegar, sourdough bread, sausage l Make chemicals l Acetone, l Mining l Extracts l butane, medicines minerals from impure sources Clean up petroleum and chemical spills 16

Preventing Food Spoilage Refrigeration l Freezing l Drying l Salting l Canning l Heating thoroughly l 17