MICR-4010 Lecture Notes - Lecture 1: Hadean, Extreme Environment, Deep Sea
3 Sep 2018
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Document Summary
Earth = ~4. 5 to 4. 8 bil years old. First evidence of life = ~4. 1 bil years ago. Theory #1: rna catalytic activity catalyzed its own synthesis. Theory #2: early viruses evolved from rna genome cell like structures. Evolution of organisms assisted by earth becoming oxic. Deep sea conditions beneficial to help escape these conditions. Photoautotrophs: use water to synthesize molecules from carbon dioxide and use solar energy to oxidize h2s to s. Cyanobacteria: able to use water to generate oxygen. Cause rise in oxygen to allow energy exploitation. Tree of life: based on 16s small subunit rrna gene. 60+ genes shared by nearly all cells must have been present in luca. Membrane lipids = bacteria (ester link) and archaea (ether link) Endosymbiotic hypothesis: chemoorganotrophic bacteria and cyanobacteria stably incorporated into another cell type to create mitochondria and chloroplast. Euk genes reassembling bact genes acquire through gene transfer i. Doesn"t account for structurally similar membrane in bacteria and euk.
