The Kingdoms Bacteria

Diversity of Prokaryotes Recall that prokaryotes are single celled organisms without a nucleus or membrane bound organelles They are classified into two kingdoms Archaebacteria and Eubacteria

Archaebacteria-The extremists 1. There are three types of archaebacteria that live mainly in extreme environments that contain little or no free oxygen available Methanogens Halophytes Sulfur bacteria

Methanogens Methanogens live in oxygen free environments and produces methane They live in marshes, lake sediments, and the digestive tracts of some mammals (like cows) They are also found at sewage treatment plants where they are important in the break down of wastes

Halophytes 3. A second type of archaebacterium that lives only in water with high concentrations of salt Dead Sea

4. Sulfur bacteria A third type lives in the hot, acidic waters of sulfur springs (like in Yellowstone) Some also live in deep cracks in the ocean floor…there they are autotrophic producers (chemoautotrophs)

5. Eubacteria – the heterotrophs Eubacteria are the other type of prokaryotes…they live in more hospitable environments Heterotrophic eubacteria live almost everywhere and use organic molecules as their food source

6. Eubacteria – the heterotrophs Some bacterial heterotrophs are parasitic Others are saprophytes-organisms that feed on dead organisms or organic wastes

7. Eubacteria – photosynthetic autotrophs A second type of eubacterium is the photosynthetic autotroph These eubacteria live in places with sunlight because they need light to make the organic molecules that are their food Cyanobacteria

8. Eubacteria – chemosynthetic autotrophs A third type of eubacterium is the chemosynthetic autotroph They make their own food without sunlight They break down and release energy from inorganic nitrogen and sulfur compounds (biogeochemical cycling)

9. What is a bacterium? A bacterium consists of a very small prokaryotic cell Although small they have all of the structures that they need to survive

The structure of bacteria Capsule Cell Wall Chromosome Flagellum Plasmid Pilus Plasma membrane Cytoplasm Ribosome Chromosome Flagellum Cell Membrane Cell Wall Gelatinlike capsule

10. Antibiotics In 1928, Alexander Fleming accidentally discovered penicillin – the first antibiotic that is used to kill bacteria Penicillin interferes with the bacteria’s ability to produce its cell wall The holes in the cell wall then allow water to enter the cell and it will rupture penicillin

11. Identifying bacteria There are three ways that you can use to identify bacteria without chemical/biological tests Gram stain Shape Arrangement

12. Gram staining After staining, Gram positive bacteria are purple and Gram negative bacteria are pink Gram-positive bacteria Gram-negative bacteria

13. Shape The three most common shapes are spheres, called coccus; rods, called bacillus; and spirals, called spirillum

14. Arrangement Diplo–is a prefix that refers to a paired arrangement of cell growth. The prefix staphylo–describes an arrangement of cells that resemble grapes or clusters Strepto–is a prefix that refers to an arrangement of chains of cells.

15. Bacterial reproduction Bacteria reproduce asexually through a process known as binary fission Under ideal conditions, some bacteria could reproduce every 20 minutes…why don’t they?

16. More bacterial reproduction Sometimes bacteria undergo a form of “sexual” reproduction called conjugation During conjugation one bacteria transfers all or part of its chromosome to another using the pilus The spread of antibiotic resistance is a result of conjugation

17.The importance of bacteria Compared to beneficial bacteria, there are relatively few bacteria that cause disease In contrast, many bacteria allow us to survive…here are some of the things that they do…

18. Bacterial Jobs Nitrogen fixation Recycling nutrients Production of foods (pickles, cheese, yogurt, Sauerkraut, cured meats) Help produce vitamins and enzymes to digest food Produce antibiotics that kill bacteria that cause disease (streptomycin, erythromycin, bacitracin, and neomycin )

19. Some bacterial diseases Bacteria can harm you in two ways: by interfering with normal body function or by producing toxins that poison the body Diseases Caused by Bacteria Disease Transmission Symptoms Treatment Strep throat (Streptococcus) Inhale or ingest through mouth Fever, sore throat, swollen neck glands Antibiotic Tuberculosis Inhale Fatigue, fever, night sweats, cough, weight loss, chest pain Tetanus Puncture wound Stiff jaw, muscle spasms, paralysis Open and clean wound, antibiotic; give antitoxin Lyme disease Bite of infected tick Rash at site of bite, chills, body aches, joint swelling Dental cavities (caries) Bacteria in mouth Destruction of tooth enamel, toothache Remove and fill the destroyed area of tooth Diptheria close contact Sore throat, fever, heart or breathing failure Vaccination to prevent, antibiotics