Heterotrophs get organic molecules from other organisms. Aerobes need O2 for cellular respiration Facultative anaerobes use O2 if available, otherwise have anaerobic metabolism Obligate anaerobes metabolize only anaerobically, with sulfate, nitrate or irone as electron acceptors instead of O2. No peptidoglycan in cell wall Plasma membrane lipids differ from Eubacteria Have similarities to Eukaryptes, especially in RNA polymerase and translational mechanisms. Methanogens produce methane from simple carbon compunds. Live in O2-less sewage, swamps, digestive tracts of humans and animals.
Extreme halophiles live in high salt ponds.
Purple pigment rhodopsin uses sun energy, but different from photosynthesis. Fix nitrogen from atmosphereic N2 to nitrates, which plants use for proteins and nucleic acids. Bacterial photosynthesis is half the primary productivity in aquatic habitats. Cyanobacteria use water as electron source, others use H2S and don t produce O2. Prevents harmful bacteria from growing, make vitamins, etc Opportunistic pathogens are normally present and harmless in body, but can cause problems if immune system isn t working right.