MBIO 3280 Lecture Notes - Lecture 11: Myxobacteria, Lithosphere, Valles Marineris
13 Oct 2017
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Document Summary
Inorganic: nutrients for biosynthesis (co2, nitrate, phosphate, sulfate, iron ect, for energy (electron donors, acceptors, even nutrients can be inhibitory and sometimes toxic all depends on concentration. Organic: critical for heterotrophs (most organisms) for biosynthesis and energy, usable organic compounds often limited in natural environments, chemical structures and physical properties affect use. Diffusion: aqueous and terrestrial environments, depends on porosity of soil and whether filler with water or gases. Absorption: restricts movement of chemicals, may accumulate limiting nutrients on a surface. Solid organic substrates: most organic substrates are polymers, plants: 50% cellulose, 10-25% lignin, 10-20% hemicelluloses and pectin, 5- 10% protein, 2-5% lipids, less than 2% nucleic acids, and less than 5% are dissolved compounds. Organisms that prefer to be at low concentrations of organic nutrients. Most microbes isolated today are mesotrophs or eutrophs yet most microbes in nature are oligotrophs ( starvation is normal) Some gram negative bacteria reduce the size by x30 in poor conditions.
