Bacteria The Prokaryotes 1 vacuole 2 3 Prokaryotes

Bacteria The Prokaryotes 1

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Prokaryotes • Most numerous organisms on Earth • Includes all bacteria • Earliest fossils date 2. 5 billion years old 4

Three Domains of Life • Archaea – prokaryotes living in extreme habitats • Bacteria- Cyanobacteria and eubacteria • Eukarya – Protozoans, fungi, plants, & animals 5

Bacteria Archaebacteria: ü Found in harsh environments ü Undersea volcanic vents, acidic hot springs, salty water 6

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Bacteria Eubacteria: ü Called the true bacteria ü Most bacteria are in this group ü Include photosynthetic Cyanobacteria 8

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Bacterial Structure • Microscopic prokaryotes • No nucleus or membrane-bound organelles • Contain ribosomes • Single, circular chromosome in nucleoid region 10

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Protection • Cell Wall made of Peptidoglycan • May have a sticky outer coating called the capsule for attachment to host or other bacteria 12

Bacterial Structure • Most grow best at p. H of 6. 5 to 7. 0 • Many act as decomposers recycling nutrients • Some cause disease or health problems or ZITS! 13

Staphylococcus Bacteria 14

Useful Bacteria • Some bacteria can degrade oil • Used to clean up oil spills 15

Useful Bacteria • Other uses for bacteria include making yogurt, cheese, and buttermilk. 16

Shapes of Bacteria • Bacillus: Rod shaped 17

Bacillus - E. coli 18

Shapes of Bacteria • Coccus: Spherical (round) 19

Streptococcus Causes Strep Throat 20

Shapes of Bacteria • Vibrio: Comma shaped with flagella • Spirillum: Spiral shape • Spirochete: wormlike spiral shape 21

Grouping of Bacteria • Diplo- groups of two • Strepto- chains • Staphylo. Grapelike clusters 22

Streptobacilli 23

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Bacillus - E. coli 25

Archaebacteria • Lack peptidoglycan in cell walls • Have different lipids in their cell membrane • Different types of ribosomes • Very different gene sequences 26

Archaebacteria • Archaebacteria can live in extremely harsh environments • They do not require oxygen and can live in extremely salty environments as well as extremely hot environments • Called the Ancient bacteria 27

Archaebacteria • Subdivided into 3 groups: Methanogens Thermoacidophiles Extreme Halophiles 28

Methanogens • Live in anaerobic environments (no oxygen) • Get energy by changing H 2 & CO 2 into methane gas • Found in swamps, sewage treatment plants, digestive tracts of animals 29

Methanogens • Break down cellulose in a cow’s stomach • Produce marsh (methane) gas 30

Extreme Halophiles • Live in very salty water • Use salt to generate ATP (energy) • Dead Sea, Great Salt Lake inhabitants 31

Thermoacidophiles or Thermophiles • Live in extremely hot environments • Found in volcanic vents, hot springs, cracks on ocean floor that leak acid 32

Eubacteria • 3 most common shapes – coccus, bacillus, spirilla • Most are heterotrophic (can’t make their own food) • May be aerobic or anaerobic • Identified by Gram staining 33

Gram Staining • Developed in 1884 by Hans Gram • Bacteria treated with purple Crystal Violet & red Safranin stains • Cell walls either stain purple or reddish pink 34

Gram Positive Bacteria • Have thick layer of peptidoglycan (proteinsugar complex) • Single lipid layer • Stain purple • Can be treated with antibiotics 35

List of Gram Positive Bacteria ü Lactobacilli (makes yogurt & buttermilk) ü Actinomycetes (make antibiotics) ü Clostridium (lockjaw bacteria) ü Streptococcus (strep throat) ü Staphylococcus (staph infections) 36

• • • Gram Negative Bacteria Thin layer of peptidoglycan in cell wall Extra thick layer of lipids Stain pink or reddish Hard to treat with antibiotics Some photosynthetic but make sulfur not oxygen • Some fix nitrogen for plants 37

Gram Negative • Rhizobacteria grow in root nodules of legumes (soybeans, peanuts) • Fix N 2 from air into usable ammonia 38

Gram Negative • Rickettsiae are parasitic bacteria carried by ticks • Cause Lyme disease & Rocky Mountain Spotted Fever 39

Cyanobacteria • Gram negative • Photosynthetic • Called blue-green bacteria • Contain phycocyanin (red-blue) pigments & chlorophyll 40

Cyanobacteria 41

Enteric Bacteria • • Gram negative Can live in aerobic & anaerobic habitats Includes E. coli in intestines Salmonella – causes food poisoning 42

Chemoautotrophs • Gram negative • Obtain energy from minerals like iron • Found in freshwater ponds 43

Reproduction • Bacteria reproduce asexually by binary fission • Single chromosome replicates & then cell divides • Rapid/fast • All new cells identical (clones) 44

Cellular organism copies it’s genetic information then splits into two identical daughter cells 45

Binary Fission E. coli 46

Reproduction • Bacteria reproduce sexually by Conjugation • Form a tube between 2 bacteria to exchange genetic material • Held together by pili • New cells NOT identical 47

Conjugation Tube 48

Spore Formation • Some bacteria can form a endospores when habitat conditions become harsh (little food) • They are able to survive for long periods of time as endospore • They are difficult to destroy (heat resistant) 49