Bacteria are ______ celled organisms that live everywhere. They are the oldest life forms on Earth. ______________ is the most studied bacterium. All bacteria are __________________ meaning they have no true nucleus (they do still have genetic material). Bacteria do contain ____________ _____________ containing acids & sugars that provide support as well as a cell membrane inside of this cell wall. Some antibiotics work by attacking this structure.
KINGDOM EUBACTERIA – no membrane-bound organelles, nutrition by absorption (some are photosynthetic or chemosynthetic), reproduce by __________ or ______________. Eight groups:
1. __________________ - photosynthetic – have a gooey, deeply pigmented covering – common on land & in the ocean – probably ancestors of chloroplasts in some kinds of protists – ex. =
2. __________________ - ancient – grow without sunlight or other organisms – derive energy from reduced gases (ammonia, methane, hydrogen sulfide) – play critical roles in the nitrogen cycle – ex.=
3. __________________ - rigid, rod-shaped, heterotrophic bacteria – aerobic- have flagella – responsible for many diseases – ex. =
4. __________________ - straight or curved rods w/ flagella at 1 end – very common in soil – many are plant pathogens – ex. =
5. __________________ - long, spiral cells – flagella at each end – responsible for many diseases – ex. =
6. __________________ - filamentous bacteria – often mistaken for fungi – spore-producing – sources of antibiotics – ex. =
7. __________________ - obligate parasites – ex. =
8. __________________ - long-rod-shaped bacteria – secrete slimy polysaccharides – live mainly in soil – ex. =
KINGDOM ARCHAEBACTERIA – anaerobic & aerobic bacteria adapted to environments with extreme temps, acidity, or salt content; differ from eubacteria in structure of cell wall & cell membrane – RNA polymerase & ribosomal protein very similar to eukaryotes (believed to be more closely related to eukaryotes than eubacteria) – asexual reproduction only – Three groups:
1. _______________________ - anaerobic methane producers – use CO2 as carbon source – found in soil, swamps, & digestive tracts (especially cattle) – produce nearly 2 billion tons of methane gas annually
2. _______________________ - inhabit very hot environments that are often very acidic – require sulfur – nearly all are anaerobes – ex. =
3. _______________________ - live in high salt content environments – nearly all are aerobic – all are gram-negative
Bacteria come in 3 primary shapes
1. _________________ - sphere-shaped
2. _________________ - rod-shaped
3. _________________ - corkscrew-shaped
Bacteria may also be classified based on their shapes in a group. These include
1. ___________________ - found in pairs
2. ___________________ - found in clusters
3. ___________________ - found in chains