BIOL10003 Lecture 3: Prokaryotes
21 Jul 2018
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Document Summary
Lack a membrane bound nucleus, organelles, and cytoskeleton. Autotroph: can live exclusively on inorganic matter + an energy source. Earliest thought to be chemoautotrophic (obtain energy by the oxidation of electron donors in their environments) Photosynthetic but anoxygenic (phototrophic process where light energy is captured and converted to atp, without the production of oxygen. Water is therefore not used as an electron donor. ) Oxygenic bacteria (cyanobacteria) appeared about 3. 5 billion years ago. Nitrogen fixers convert n2 to ammonia, with nitrifiers convert ammonia to nitrate. Consequence: many species of archaea have bacterium in their name. Unusual lipids are used as a biomarker for the presence of archaea in the environment. Unique: sequence - linkage in terms of making membranes. Different type of linkage of the ball and stick. Lives in hypersaline water (very salty - requires salt for their growth) An organism that captures light energy without some form of chlorophyll.
