BIMM 120 Lecture Notes - Lecture 11: Great Oxygenation Event, Lebron James, Hydrogen Sulfide
26 Dec 2018
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Document Summary
Metabolism of microbes: consists of anabolic (synthesis of organic compounds) and catabolic (breaking down of organic compounds) reactions. Acorns get most biomass from air (photosynthesize and create more biomass from co2 in air); lebron james gets majority of dry biomass from diet. Metabolism of primitive cells was exclusively anaerobic and likely chemolithotrophic: obtained carbon from carbon dioxide, obtained energy from h2, use hydrogen as alternate source, producing hydrogen sulfide. Early life on earth: ~2. 7 bya, cyanobacteria changed metabolic system and developed photosystem that could use water instead of h2s, generating oxygen as product. Oxygen started to accumulate in planet: ~2. 4 bya, the great oxidation event (great pollution event) occurred and oxygen level continued to rise, many organisms evolved ability to live in presence of oxygen. Free oxygen is toxic free-oxygen is toxic: strong oxidizer, forming very reactive species. Oxygen has highest reduction potential, so releases lots of energy when reduced, so can create large amount of atp.
