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Bacteria

Bacteria. Kingdom Archaebacteria. Prokaryotes Single celled Cell Wall (does not have peptidoglycan) Live in harsh environments 3 major groups 1) methanogens – swamps, digestive tracts 2) halophiles – salty areas 3) thermoacidophiles – hot & acidic areas. Kingdom Eubacteria.

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Bacteria

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  1. Bacteria

  2. Kingdom Archaebacteria Prokaryotes Single celled Cell Wall (does not have peptidoglycan) Live in harsh environments 3 major groups 1) methanogens – swamps, digestive tracts 2) halophiles – salty areas 3) thermoacidophiles – hot & acidic areas

  3. Kingdom Eubacteria Prokaryotes Single celled Cell wall with peptidoglycan Can live almost anywhere

  4. 3 major bacterial shapes • Cocci – round • Bacilli – rod • Spirilli – spiral Other terms about bacterial arrangements • Strep = chains • Staphylo = clusters

  5. Bacteria are classified according to • Cell wall composition (gram staining) • Evolutionary relationship (phylogeny) • Shape • Motility (how they move) • Genetics/DNA • Metabolism (autotroph or heterotroph)

  6. Gram Staining Uses 2 colored stains to determine the amount of peptidoglycan in the bacterial cell walls Gram + = purple, peptidoglycan, penicillin Gram - = red/pink, low peptidoglycan

  7. Helpful bacteria • Most (about 90%) of all bacteria are harmless or helpful to us. Can be used for: 1) foods (cheese, buttermilk, yogurt, etc…) 2) decomposers 3) used in industry

  8. Harmful bacteria • Some bacteria can be pathogens (disease causing) Bacterial infections & diseases strep throat food poisoning (botulism) gonorrhea tuberculosis salmonella lyme disease tetanus

  9. What makes some bacteria harmful? 1) toxins (Exotoxins- are released by living bacteria Endotoxins- are released when the bacteria die) 2) the bacteria destroy tissues

  10. How do we treat bacterial infections? ANTIBIOTICS – drugs that inhibit or kill bacteria There are several types of antibiotics. Some are made from fungi or other bacteria.

  11. Problems caused by antibiotics • Antibiotic resistance • Some people have reactions to antibiotics

  12. Special structures Capsules – some bacteria form a hard outer covering to protect them from drying out or your bodies immune system Pili – short, ahir-like structures on the bacterial surface, used to help bacteria “stick”.

  13. 3) Endospores – another covering that protects the bacteria from a harsh environment, allows the bacteria to go dormant. 4) Flagella – whip-like tail to help with movement

  14. Bacteria & reproduction Reproduce asexually by binary fission Reproduce sexually by conjugation (exchange genetic information between 2 bacteria)

  15. How bacteria get their energy • Heterotrophs saprophytes – decomposers 2) Autotrophs photoautotrophs – photosynthesis (no chloroplasts!!)

  16. Some bacteria need oxygen – obligate aerobes Some bacteria die around oxygen – obligate anaerobes Some bacteria can live with or without oxygen – facultative anaerobes

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