Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 18 Bacteria Concept Map Section 191 Bacteria are classified into the kingdoms of Eubacteria Archaebacteria include a variety of lifestyles such as Living in soil Go to Section: Infecting large organisms live in harsh environments such as Thick mud Animal digestive tracts Salty lakes Hot springs Bacteria are part of two kingdoms: Archaebacteria Eubacteria Eubacteria The larger of the two kingdoms prokaryotes Cell walls contain peptidoglycan Archaebacteria Prokaryotes, although the DNA are more like those of eukaryotes than eubacteria Cell walls lack peptidoglycan Membrane lipids are different than those of eubacteria Many scientists think that archaebacteria may be the ancestors of eukaryotes Archaebacteria (cont.) Many archaebacteria live in harsh environments Methanogens – produce methane gas Extreme halophiles – salt-loving archaebacteria Thermoacidophiles – live in extremely acidic environments that have extremely high temperatures, like hot springs Identifying Prokaryotes Shape Bacilli – rod-shaped Cocci- spherical Spirilla – spiral and corkscrew shaped Identifying Prokaryotes (cont.) Cell walls Two different types of cell walls in eubacteria The Gram stain is used to tell them apart Gram-positive – stain purple Gram-negative – stain red/pink Identifying Prokaryotes (cont.) Movement flagella- whip-like structures used for movement Other prokaryotes lash, snake, or spiral forward Some other prokaryotes glide slowly along slime they produce Many prokaryotes do not move at all Obtaining Energy Autotrophs – produce their own food Photoautotrophs – use light for the energy source Example: cyanobacteria Chemoautotrophs – obtain energy from inorganic molecules (such as ammonia) Heterotrophs – obtain energy by the food it consumes Photoheterotrophs – obtain energy from light and also from inorganic molecules Releasing Energy Cellular respiration – requires oxygen Called obligate aerobes Fermentation – does not require oxygen Called obligate anaerobes Some bacteria can survive with or without oxygen Called facultative anaerobes Growth and Reproduction Replicates DNA and simply divides in half (asexual reproduction) Binary fission Some bacteria can transfer genetic material from one cell to another Conjugation When growth conditions become unfavorable, some bacteria form endospores to protect their genetic material Bacteria in Nature Decomposers – bacteria act as “recyclers Nitrogen fixation Convert nitrogen from N2 into a form that plants can use Bacteria and Disease – disease causing bacteria are called pathogens Bacteria cause disease in one of two ways Damage tissues by breaking them down for food Release toxins (poisons) that harm the body Antibiotics can be used to kill bacteria Common Diseases Caused by Bacteria Section 19-2 Go to Section: Disease Pathogen Prevention Tooth decay Streptococcus mutans Regular dental hygiene Lyme disease Borrelia burgdorferi Protection from tick bites Tetanus Clostridium tetani Current tetanus vaccination Tuberculosis Mycobacterium tuberculosis Vaccination Salmonella food poisoning Salmonella enteritidis Proper food-handling practices Pneumonia Streptococcus pneumoniae Maintaining good health Cholera Vibrio cholerae Clean water supplies Any Questions ?