BIOL 2004 Lecture Notes - Lecture 15: Cell Envelope, Actinobacteria, Nucleoid
Document Summary
Lithotrophy: needs a source of reduced inorganic compounds. Many metals/metal ions, sulfur compounds, nitrogen compounds, hydrogen gas: produced by geological processes, produced by other organisms. Sulfur cycling examples: end- prduct of anaerobic respiration used as food by lithotrophs. Hydrogen (h2: very negative reduction potential. Therefore an energy-rich food": sources: geological (hydrothermal vents) Hydrogenotrophy: oxidising (eating) h2 special type of lithotrophy. Biosynthesis: making new biomass: raw material for biosynthesis. A sulfur-oxidising lithotroph in 90 degrees c acidic hot spring. Autotrophy: fixation from inorganic carbon (usually co2) to form organic carbon: i. e. reduction of co2, most phototrophic and lithotrophic prokaryotes are capable of autotrophy, requires energy (generated via phototrophy or lithotrophy) including reducing power (e. g. nadh) Some unusual ecosystems are based on microbial lithoautotrophy: sulfur hot spring, hydrothermal vents. Nitrogen: for biosynthesis of amino acids, nucleotides, vitamins etc, most prokaryoted can assimilate ammonium (nh4+) Many also assimilate nitrate (no3-) (no3- nh4+) A very few require organic n (amino acids)
