Exploring Bacteria: From History to Structures and Functions

1. BACTERIAThe Prokaryotes:Eubacteria and Archaea SBI3U Biology Dr. Oz (4:37 min): http://www.youtube.com/watch?v=CljhLb1Ar9U Toilet germs (1:53 min): http://www.youtube.com/watch?v=v6nGgS6ADoI&feature=related Cell Phones! (3:01 min): http://www.youtube.com/watch?v=4lmwbBzClAc&feature=related

2. Bacteria Introduction Bacteria are important to many nutrient cycles and are important decomposers of organic material. Bacteria are found all over the human body, however the majority are harmless or even beneficial. Some bacteria are pathogenic and cause disease.

3. Bacteria History • Bacteria were first observed by Anton Van Leeuwenhoek in 1676. • The term ‘bacteria’, Greek for ‘small stuff’ was first used in 1838.

4. Bacterial History Robert Koch and Louis Pasteur were the first to discover that bacteria caused many diseases (mid 19th century) The first antibiotic used to treat bacterial disease was made by Paul Ehrlich in 1910. It was used to treat syphilis.

5. The Evolution of Bacteria Bacteria are thought (by some) to be the first forms of life, about 4 billion years ago. It is believed that both the Domain Archaea and the Domain Eukarya evolved from bacteria. Due to a poor fossil record, scientists are unable to determine from what bacteria evolved.

6. Bacteria Cell See Fig. 6 on page 48 in text.

7. Important Structures: • Capsule • Cell wall – made of peptidoglycan and outer membrane • Plasma membrane • Nucleoid region – condensed DNA molecule • Ribosomes in the cytoplasm • Pili • Flagellum

9. Characteristics of BacteriaProkaryotic Cells: unicellular (single-celled) no nuclear membrane or other membranes around organelles small—less than 2 µm only 1 circular chromosome

10. Identifying Prokaryotes Cell Shape Cell Wall Movement

11. Bacterium Shapes And Groupings SHAPES Coccus~ Sphere shaped bacteria Bacillus~ Rod shaped bacteria Spirillium ~ Spiral shaped bacteria GROUPINGS Mono - one Diplo - two Strepto - in a chain Staphylo - cluster Draw what you think the following look like: • Streptobacilli • Staphylococci

12. Bacterium Cell Walls: Gram + and Gram –

13. Cell Walls cont’d Chemical nature of a cell wall can be determined by Gram Staining. By finding out what colour the cell produces when it is gram stained you can figure out the type of carbohydrates in the cell wall. Why would this be helpful?

14. Gram + vs. Gram - walls

15. Describe the two populations of bacteria in this stain Why might gram staining be helpful?

16. Movement Flagellum ~ Tail like structure that whips around to propel the bacterium Cilia~ small hair-like projections surrounding the cell that help it to “swim”, moves back and forth in a synchronized movement Non motile ~ Sticky cilia like structures that keep the bacterium from moving

17. Flagella

18. Cilia

19. OTHER TERMS USED TO CLASSIFY BACTERIA

20. Bacterial Respiration Aerobic Anaerobic Obligate Aerobes Obligate Anaerobes Facultative Anaerobes Grows in the presence of oxygen Grows in the absence of oxygen Must have oxygen Must have NO oxygen Can grow with or without oxygen

21. Bacteria and Metabolism Autotrophs Heterotrophs Chemotrophs

22. Autotrophs make their own energy use solar energy (or other chemical compounds) to ‘fix’ carbon dioxide eg. Cyanobacteria uses photosynthesis to make glucose

23. Example: Cyanobacteria Photosynthetic bacterium Bluish-greenish color Contain membranes that carry out the process of photosynthesis Do not contain the same type of chloroplasts as plants do This bluish-greenish algae can be found nearly everywhere on earth. Can survive in extremely hot environments and even extremely cold environments

24. Why are Cyanobacteria not in the Plant Kingdom?? • Can exist unicellularly • Prokaryotic (no nucleus and membrane-bound organelles)

25. Heterotrophs Obtain energy from eating other organisms Eg. E. coli

26. Chemotrophs makes own energy from chemicals like sulfur or hydrogen sulfide Eg. Archaebacteria living in deep sea vents

27. Other Archaea Terms • Chemotrophs/Methanogens– convert chemical compounds into methane gas • Halophiles– like salt water (oceans) • Extreme Thermophiles– like warm environments (hot springs) • Psychrophiles– cold-loving organisms (Arctic soil)

28. Bacterial Reproduction Binary Fission Conjugation Spore Formation

29. 1) 2) 3) Cellular organism copies its genetic information then splits into two identical daughter cells.

30. Conjugation Bacteria sex! 1 bacterial cell passes a copy of a plasmid through a hollow pilus For example, that contains the information such as a resistance to penicillin 1) 2) 3)

31. Spore Formation: Endospore A type of dormant cell (sometimes for years) Exhibit no signs of life Highly resistant structure that forms around the chromosome when cell is under some sort of environmental stress such as: -High temperatures -Irradiation -Strong acids -Disinfectants

32. Bacterial Interactions Mutualism: an interaction where all parties benefit. Examples are nitrogen fixing bacteria in the soil as well as the naturally occurring bacteria in our gut.

33. Bacterial Interactions Parasitism: An interaction where one party benefits and the other is negatively affected. Bacteria cause disease in many organisms. These bacteria are said to be pathogenic.

34. Treatment of Bacterial Diseases Antibiotics are used to treat bacterial diseases. Antibiotics work by punching holes in the cell walls of bacteria to allow the body’s natural defenses to be more effective OR they prevent the bacteria from reproducing.

35. Antibiotic Resistance Many bacteria are resistant to antibiotics due to their overuse for treatment of things not caused by bacteria, patients not following their prescriptions properly or just by natural selection. This has created what is known as a ‘superbug’, which is a term for a bacterium that cannot be destroyed by antibiotics.

36. Bacteria and Technology Food Preparation: Lactobacillus is used in making pickles, soy sauce, cheese, wine, yoghurt, etc… Bioremediation: Cleaning up toxic chemicals in the environment by breaking them down into less toxic products Bioengineering: Used to reproduce specific genes quickly to mass produce their protein products (i.e. insulin).

37. Archaebacteria or Archaea(see handout for more information) Lack important carbohydrate found in cell walls (Gram -) Have different lipids in their cell membrane Different types of ribosomes Very different gene sequences Do not cause disease Archaebacteria can live in extremely harsh environments They do not require oxygen (anaerobic) and can live in extremely salty (halophiles) environments, as well as extremely hot (thermophiles)or cold (psychrophiles) environments.

38. Eubacteria (see handout for more information) Make up the larger of the two prokaryote kingdoms Generally are surrounded by a cell wall composed of complex carbohydrates Gram + and – Can cause disease Live nearly everywhere