BIOL 110 Lecture Notes - Lecture 10: Pathogenic Bacteria, Parasitism, Nitrogen Fixation
Document Summary
Biol 110 - lecture 10 - prokaryotic evolution and early metabolism. Symbionts - interacting organisms with varying relationships. Host - larger of the two species. Microsymbiont - smaller of the two species. Mutualism - symbiosis where both symbionts derive mutual benefit from the association. Parasitism - symbiosis where one symbiont derives benefit at the expense of the other. Endotoxins - surface protein components of the outer cell membrane in some gram-negative bacteria. Ex: pathogenic bacteria cause disease by producing exotonins. Commensalism - symbiosis where associations appear benign (are neither of benefit nor harm) to either or both species. Opportunistic infection - event where a normally commensalistic bacteria becomes pathogenic, or parasitic, in response to a change in environment. Nitrogen is found in all proteins and nucleic acids. Nitrogen in its elemental form, n2 (g), is unusable by most organisms, but it can be transformed by certain nitrogen-fixing bacteria.
