BACTERIA Unit 6

Classified by: Respiration: anaerobes - cannot survive in the presence of atmospheric oxygen. aerobes - cannot survive without atmospheric oxygen. O2O2 O2O2

Classified by: Shape: Cocci - round bacterial cells. Bacilli - rod- shaped bacterial cells. Spirilli - spiral- shaped bacterial cells.

Classified by: Clustering: diplo - a prefix used with the shape name to indicate pairing of cells. strepto - a prefix used with the shape name to indicate filaments/strip staphylo - a prefix used with the shape name to indicate clusters.

For Review…. A. Bacilli B. Cocci C. Spirilli

For Review…. A. Streptobacillus B. Streptococcus C. Diplobacillus D. Diplococcus E. Staphylococcus

Parts of a Bacterial Cell Cell wall - some rigid and others flexible. Cell membrane - same as other cells. Cytoplasm - same as other cells. DNA - a single, circular chromosome located in the cytoplasm.. Capsule - a thick, gel-like, protective coating on some bacteria cells. Pilli - short, hair like protein structures on the surface of some bacteria that help them stick to host cells. Flagella - long protein structures that turn to propel some bacteria cells.

Nutrition Most are heterotrophic – use food produced by other organisms. Bacteria that feed on dead or decaying organic matter are heterotrophic bacteria called saprophytes. Some are autotrophic - able to produce their own food. Photoautotrophs - use sunlight as a source of energy like plants. Chemoautotrophs - use energy from chemical reactions to make their food.

Archaebacteria A. Methanogens: oxygen is a poison to these bacteria, live in anaerobic conditions. they produce energy by converting H 2 and CO 2 into methane gas

B. Halophiles: these "salt-loving" bacteria live in environments with a very high salt concentration that would kill most other bacteria. Halophiles use salt to generate ATP for energy. Archaebacteria

C. Thermoacidophiles: live in extremely acidic environments (pH less than 2) extremely high temperatures (up to 110o C). live in environments like the geothermal springs at Yellowstone National Park. Archaebacteria

Eubacteria contains the bacteria commonly referred to as germs contains most of the world's bacteria, 12 different phyla live in environments ranging from temperatures near the boiling point of water to well below the freezing point of water

Reproduction Binary fission – (asexual) the DNA replicates and then the cell pinches inward and splits in two. Conjugation – (simple sexual reproduction) two cells exchange a portion of their DNA across a bridge formed between the cells.

Toxins Poisons produced by bacterial pathogens PATHOGEN = organism that produces disease Endospores – during adverse conditions, the DNA is encased in a protective envelope. This endospore can lie dormant for years or until favorable conditions return.

Antibiotics Antibiotics are chemicals that inhibit the growth of some bacteria. Penicillin - interferes with cell wall synthesis. Tetracycline - interferes with bacterial protein synthesis. Many antibiotics are derived from chemicals that bacteria and fungi produce

Study antibiotic resistance (handout) and answer the following questions: What is antibiotic resistance? Why should antibiotics not be used for most sore throats? Infer how a bacterium becomes antibiotic resistant?

Pasteurization Heat food to a temperature that kills a harmful bacteria Milk, fruit juices Louis Pasteur developed this process for wine in 19 th century

Good Bacteria Escherichia coli is a bacteria that lives in the human intestine and aids digestion. Lactobacillus lactis Milk to Yogurt Streptococcus diacetilactis Milk to Sour cream Streptococcus faecalis Milk to Cheese Leuconostoc mesenteroides Cabbage to sauerkraut Streptococcus diacetilactis Cucumbers to Pickle

Good Bacteria Soil bacteria that makes streptomycin (antibiotic) Cleans waste from sewage water at water treatment plants

Good Bacteria Natural pest-killer in gardens and on crops Helps crops take up nutrients from the soil

Good Bacteria Bacteria eat methane gas to clean up hazardous waste dumps and landfills Used to clean up oil spills in ocean They turn oil into CO 2 and other harmless byproducts Used to make wine, infant formula, chewing gum, paper, stonewashed jeans