**Bacteria (singular bacterium) - any of a group of microscopic single-celled organisms that live in enormous numbers in almost every environment on Earth, from deep-sea vents to deep below Earth’s surface to the digestive tracts of humans.
We have about 100,000 bacteria per square centimeter of skin.
**Bacteria are simple organisms that come in 3 different shapes:
**1. Cocci - sphere shaped
**2. Bacilli - rod-shaped
**3. Spirillum - spiral shaped.
They are prokaryotic because they do not contain a membrane bound nucleus or other membrane-bound organelles.
**Bacteria reproduce by FISSION = process that produces two new cells with genetic material identical to each other & that of the original cell.
**Conjugation - process where genetic material is exchanged between 2 bacteria
**Aerobe - uses oxygen when breaking down food
**Anaerobe - is adapted to live without oxygen
**Kingdom Eubacteria -
- Grouped by
- Cell shape & structure
- How they obtain food
- Type of food they consume
- The wastes they produce
Example: Cyanobacteria = group of producers that make their own food using carbon dioxide, water & sun energy. Produce oxygen as a waste. Can pollute waterbodies with "blooms"
Consumer Eubacteria - gram-positive = thick walled, gram-negative= thin walled - affects antibiotic effectiveness
**Kingdom Archaebacteria - found in extreme conditions
- Grouped by where they live or how they get energy
- Salt, heat & acid lovers
- Methane producers
How we use bacteria
**Antibiotics - chemicals that limit the growth of other bacteria
**Pathogen - any organism that causes disease
**Toxin - poisonous substance produced by a bacterial pathogen
**Endospore - thick-walled structure produced by a bacteria
**Vaccine - Substance made from damaged particles taken from bacterial cell walls or killed bacteria that can preven some bacterial diseases.
**Saprophytes - consumer bacteria that use dead organism as food and energy sources. Help recycle nutrients.
**Nitrogen-fixing bacteria - change nitrogen from the air into forms that plants and animals can use. Peanuts, peas, legumes