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Bacteria

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  1. Bacteria Blue book-Chapter 23 (460-477) Your book- Chapter 20(572-596) Chapter 23 Bacteria

  2. Questions? Review • Differences bet. Prok and euk cells a. no nucleus, or membrane bound organelles, no cell well, smaller • What are two metabolic pathways by which cells obtain energy a. aerobic respiration, fermentation Chapter 23 Bacteria

  3. Objectives 23.1 • Explain the phylogenetic relationship between the domains Archaea, Bacteria, Eukarya • Identify three habitats of Archaea • Describe the common methods used to id bacteria • Identify five phyla of bacteria • Explain importance of nitrogen fixing bacteria for many of earths ecosystems Chapter 23 Bacteria

  4. Prokaryotes Prokaryotes are the most numerous organisms on Earth. They are found almost everywhere, from the skin of a fingertip to the waters of a thermal geyser to the freezing landscape of the Antarctic. The earliest fossils of prokaryotes, which are about 2.5 billion years old, indicate that prokaryotes lived long before other forms of life evolved. Chapter 23 Bacteria

  5. Prokaryotes- 1. Domain Bacteria Kingdom Eubacteria 2. Domain Archaea Kingdom Archaebacteria Eukaryotes 1. Domain Eukarya a. K. Protista b. K. Fungi C. K. Plantae d. K. Animalia Classification review Chapter 23 Bacteria


  6. Archaea- ancient (extreme environments) Bacteria- Prokaryotes- no nucleus, single-celled, live in all environments Two major Domains Chapter 23 Bacteria

  7. Domain Archaea Different from bacteria- • cell walls (NO peptidoglycan) • Membrane lipids • Genetics and metabolism • Found in extreme harsh environments 3 major groups: • Methanogens- convert Hgas and CO2 to methane gas • Halophiles- loves salt- live in high concentrations • Thermoacidophiles-acidic environment, high salt, high temps Chapter 23 Bacteria

  8. Domain Bacteria • Most known prokaryotes are bacteria 3 basic shapes: 1. bacilli- rod-shaped 2. spirilla- spiral shaped 3. cocci- sphere-shaped 2 major goups 1. strepto- chains 2. staphlo- clusters Chapter 23 Bacteria

  9. Chapter 23 Bacteria

  10. Gram stain • Used to put bacteria into categories based on cell walls • Gram-negative- have less peptidoglycan, absorb red dye, look pink/red in micro • Gram-positive- have more peptidoglycan in cells wall and look purple Chapter 23 Bacteria

  11. Chapter 23 Bacteria

  12. Important bacterial groups • Proteobacteria- nitrogen-fixing bac, convert nitrogen into usable ammonia • Gram-positive- • Cyanobacteria- use photosynthesis • Spirochetes- gram-neg, STDs • Chlamydia- gram-neg, no peptidoglycan Chapter 23 Bacteria

  13. Objectives 23.2 • Describe the internal and external structure of prokaryotic cells • Identify the need for endospores • Compare four ways in which prok get energy and carbon • Identify the different types of environments • List three types of genetic recombination that prok use Chapter 23 Bacteria

  14. Biology of Prokaryotes • A look at prok cells under a light microscope show that they are very small. Such a view, however, leaves unexplained the complexity of the cells’ internal workings. Here, we will study the structure of prok cells and the many ways that they gather nutrients and energy and reproduce. Chapter 23 Bacteria

  15. Structure and Function • Cell wall- shape, protection, peptidoglycan • Cell membrane/cytoplasm- selective barrier • DNA- single closed loop of double stranded DNA , Plasmids are small and self-replicating double stranded • Capsules- outer covering of polysaccharides, protection, made of glycocalyx (fuzzy coat of sticky sugars) • Pili- are short hairlike projections, help to connect to other surfaces, pass DNA • Endospores- gram +, thick coat for protection till conditions are good • Flagellum- whip like motion, movement CD 16B. Chapter 23 Bacteria

  16. Chapter 23 Bacteria

  17. Chapter 23 Bacteria

  18. Heterotrophs photoheterotrophs- use light energy and get carbon from other organisms Chemohetertrophs- obtain energy and carbon from other organisms Autotrophs- 1. photoautrophs- use light energy, CO2 2. chemoautrophs- use inorganic molecules, and CO2 Nutrition and metabolism Chapter 23 Bacteria

  19. Chapter 23 Bacteria

  20. Prokaryotic Habitats • Live in certain habitats based on their biochemical abilities • Obligate anaerobes- no O2 present • Faculatative anaerobes- can live w/wo • Obligate aerobes- must have O2 Chapter 23 Bacteria

  21. Chapter 23 Bacteria

  22. Reproduction and Recombination • Most reproduce by Binary fission • Prok can exchange pieces of DNA that can be added to the cell’s DNA w/o reproduction recombination To get DNA in 3 ways: • Transformation- take DNA from outside • Conjugation- 2 prok bind and pass DNA • Transduction- virus changes DNA Chapter 23 Bacteria

  23. Transformation Binary Fission Chapter 23 Bacteria

  24. Transduction with a virus conjugation Chapter 23 Bacteria

  25. Objectives 23.3 • Describe the ways in which bacteria can cause disease in humans • Explain how a bacterial population can develop resistance to antibiotics • Identify reason for recent increased in the numbers of certain bacterial infections • Identify ways of preventing a food born illness at home • List four industrial uses of bacteria Chapter 23 Bacteria

  26. Bacteria and humans Bacteria are probably best know for the disease that they cause in humans. However, most bacteria that live on human skin are harmless, and other bacteria are used biotechnologically, as in the production of yogurt. Still, other bacteria that live in soil change atmospheric nitrogen into ammonia and nitrites, which plants use for growth Chapter 23 Bacteria

  27. Bacteria and Health • Pathology- study of diseases (pathogen) Bacteria can cause diseases by: • Exotoxins- toxic substances that bacteria secret into environment • Endotoxins- not released until the cell dies, causes fevers, body aches, diarrhea, (made of lipids and carbs) Chapter 23 Bacteria

  28. Antibiotics and resistance • Antibiotics affect bacteria by interfering with certain cellular activities • Resistances- evolution of populations of bacteria that antibiotics can no longer kill • Zoonosis- pass diseased from animals to humans- (http://aboundlessethic.com/?cat=46) Foodborne- • Industrial uses today Chapter 23 Bacteria

  29. Chapter 23 Bacteria http://www.cdc.gov/

  30. Review Questions • List 4 diseases caused by bacteria (see last slide) • Explain Antibiotic Resistance- • How is bacteria used in industry (discovery video)- • What is the difference between bacterial cell walls and plant cell walls? • Diff bet photoautroph and chemoautotroph? Chapter 23 Bacteria

  31. 6. Bacteria reproduce- 7. Name 3 groups of archaea- 8. Name some characteristics of spirochetes 9. How are bacteria classified (web quest/notes) Chapter 23 Bacteria

  32. Review Answers • List 4 diseases caused by bacteria (see last slide) • Explain Antibiotic Resistance- evolution of populations of pathogenic bacteria that antibiotics are unable to kill • How is bacteria used in industry (discovery video)- bacteria are used to make and process food and chemicals. Help break down sewage and recycle carbon and nitrogen, used in mining, used to clean up oil spills, make pesticides Chapter 23 Bacteria

  33. 4. What is the difference between bacterial cell walls and plant cell walls? BC are made of peptidoglycan and pc have cellulose 5. Diff bet photoautroph and chemoautotroph? makes carbon cpds by light energy, makes carbon by breaking down inorganic sub 6. Bacteria reproduce- binary fission 7. Name 3 groups of archaea- methanogens, halophiles, theromophiles Chapter 23 Bacteria

  34. 8. Name some characteristics of spirochetes • Gram -, sprial-shaped, aerobic and anaerobic 9. How are bacteria classified (web quest/notes) Shape, gram stain, biochemical prop, evolutionary relationships Chapter 23 Bacteria

  35. Chapter 23 Bacteria