Biology 2581B Lecture 4: Smith Lecture 4-Organelles and their genomes
20 Feb 2017
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Document Summary
Chloroplasts from all three lineages (red algae, land plants and green algae) descend directly from the 2nd endosymbiotic event (eukaryote engulfs cyanobacterium). Horizontal transfer of chloroplasts and photosynthesis across the eukaryotic tree through secondary endosymbiosis. Go through steps of genetic merger until photosynthetic eukaryote integrates into non- photosynthetic eukaryote: feeding, endosymbiosis, sharing, entrapment, transfer of control, genetic. Integration: the symbiont, instead of being a bacterium, is a eukaryote with different compartments. Over time, the photosynthetic eukaryote can get whittled down and turned into a chloroplast: extra membrane b/c it used to be an eukaryote, spread of photosynthesis. Secondary 2 chloroplast chloroplast from photosynthetic eukaryote endosymbiont. Primary 1 chloroplast chloroplast from cyanobacterium endosymbiont. 2 chloroplast: contains a genome, no longer photosynthetic, came from a red alga, could be used as a drug target. Do not worry about targeting human chloroplast we b/c we don"t have one. Toxoplasma which causes toxoplasmosis also has 2 chloroplast.
