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

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

3 Characteristics Flagella that spins for movement Flagella that spins for movement Some have pili Some have pili Shorter and thicker than flagella Shorter and thicker than flagella Used for attachment Used for attachment Aerobic or anaerobic metabolism Aerobic or anaerobic metabolism

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

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

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

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

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

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

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

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

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

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

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

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

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

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