1. Marconi 2007

2. Bacteria consist of only a single cell, but don't let their small size and seeming simplicity fool you. They're an amazingly complex and fascinating group of creatures.

3. Marconi 2007 Builders of Modern Life Bacteria are among the earliest forms of life that appeared on Earth billions of years ago. Bacteria helped shape and change the young planet's environment, eventually creating atmospheric oxygen that enabled other, more complex life forms to develop.

4. Marconi 2007 What are bacteria? Bacteria are unicellular, living things. Prokaryotic cells (without a nucleus). Obtain nutrients is different ways:  Photosynthetic autotrophs- convert inorganic molecules into sugar using sunlight  Heterotrophs- consume food by growing on it  Saprophytes- obtain food by decomposing dead material  Chemotrophs- manufacture organic compounds from inorganic compounds such as hydrogen sulfides

5. Marconi 2007 Cyanobacteria in a lake Bacteria feeding on saguaro Chemotrophs at hydrothermal Vent Bacteria used in wastewater treatment

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8. Classification of Prokaryotes All prokaryotes belong to the kingdoms:  Archaea  Eubacteria

9. Marconi 2007 Archaea First discovered in 1970’s Discovery made the term “Moneran” obsolete Biochemically different from eubacteria May have evolved in the harsh conditions of early Earth They are abundant in, but not restricted to, extreme environments because of their ability to withstand the harshest of environments May be the early ancestors of eubacteria

10. Marconi 2007 Characteristics of Archaea Archaea (Formerly Archaebacteria)  Lack an important carbohydrate (peptidoglycan) found in the cell wall of nearly all Eubacteria.  Live in harsh environments Oxygen-free environments  Methanogens (ex. Thick mud & digestive tracts)  Produce methane gas Salty environments  Extreme Halophiles  Great Salt Lake/Dead Sea Hot Springs  Thermoacidophiles

11. Marconi 2007 Characteristics of Eubacteria Eubacteria = Modern Bacteria  Unicellular  Cell walls contain peptidoglycan  Genes lack introns  Reproduce asexually by binary fission  Either autotrophic or heterotrophic  Extremely diversified groups  Certain types may be ancestors of mitochondria

12. Marconi 2007 Identifying Prokaryotes Bacterial Shapes  Bacillus = Rod  Coccus = Round  Sprillium = Spiral Colony growth  Cells arranged in particular ways Form long chains Grow in clusters Bacterial movement  Flagella  Some do not move  Some glide

13. Marconi 2007 Shape #1 is rod shape, also known as bacillus.

14. Marconi 2007 Shape #2 is sphere shaped, also known as coccus.

15. Marconi 2007 Shape #3 is spiral shape, also known as sprillum

16. Marconi 2007 Micrococcus luteus tetradBacillus cereus VibrioRhodospirillum

17. Marconi 2007 Bacterial Structures Cell Wall- support and protection No nucleus- Bacterial DNA is usually coil- shaped and not enclosed in a nuclear membrane.  Most bacteria also have small ring-shaped pieces of DNA called plasmids Capsule- protective layer that surrounds the cell Some have flagellum to aide with movement Pilus aides in adhesion to other cells

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19. Bacterial growth and reproduction Grow and reproduce at an incredible rate when conditions are favorable Bacterial growth stays under control due to limiting factors such as nutrient availability and production of waste products. Reproduction methods  Binary fission  Conjugation

20. Marconi 2007 Binary fission Asexual reproduction When a bacterium is almost double in size, it replicates it’s DNA and divides in half.  Example: E. coli

21. Marconi 2007 Conjugation Sexual reproduction Long bridge of protein in between 2 bacterial cells connecting them. Genetic material from donor cell is transferred to the other cell. Recipient cell ends up with different combo of genes.  Leads to genetic variation, evolution, antibiotic resistance Example

22. Marconi 2007 Spore formation Spores form when conditions become unfavorable. Endospore is a type of spore that forms a thick internal wall that protects the DNA and cytoplasm. Endospores can remain dormant for months to years while waiting for favorable conditions to arise.

23. Marconi 2007 Food production  Yogurt, cheese, buttermilk, sour cream, pickles Used in industry  Digest petroleum; clean up oil spills  Used in mining  Used in sewage treatment plants Symbiosis  Digestion  Nitrogen-fixation and plants

24. Marconi 2007 Pathogens  Disease causing agents  Small number of bacteria are pathogens Examples of pathogenic bacterial infections:  Syphilis, cholera, tuberculosis, bubonic plague, botulism, tetanus, gingivitis, strep throat Pathogens cause disease by:  Damaging cells and tissues for use of nutrients  Release toxins

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26. Antibiotics destroy bacteria by disrupting the structure of the cell wall Over prescribing of antibiotics is causing antibiotic resistance because bacteria mutate readily

27. Marconi 2007 Bacterial respiration Energy is supplied by respiration and fermentation  Respiration involves oxygen and breaks down food molecules to release energy  Fermentation is energy production without oxygen Obligate aerobes  Bacteria that require a constant supply of oxygen Obligate anaerobes  Must live in the absence of oxygen  Example: Clostridium botulinum If subjected to air and allowed to grow on food, it will produce toxins that cause severe food poisoning. Facultative anaerobes  Can survive with or without oxygen  Allow facultative anaerobes to live almost anywhere.

28. Marconi 2007 The End