Pili make first contact. Only one endospore formed per bacterial cell. 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.