Biology 1002B Lecture 12: Bio Lecture 12 - Evolution of Eukaryotes.docx
27 Feb 2012
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Document Summary
The formation of the endomembrane system: ancestral prokaryotic cell, through infolding of the cytoplasmic membrane, created golgi body, er, nuclear envelope, defines the eukaryote with the presence of nucleus. Mitochondria: energy transducing organelles, gave rise from endosymbiosis, aerobic prokaryote incorporated into another prokaryotes. Intake of cyanobacterium: giving rise to heterotrophs. No strong evidence in the order of events. Morphology: looks very similar to bacteria. Formation/ division: unlike protein, no instruction in making it, simple divide to make more, can only make from pre-existing bacteria. Electron transport chains: similar to aerobic cell, cyanobacteria, they would have been able to live by themselves and collect energy. Transcription/ translation machinery: no other organelles have their own. Earliest prokaryotes were anaerobic, no oxygen in the reducing atmosphere. 2. 2 bya get cyanobacteria oxygenic photosynthesis (oxygen accumulates) Prokaryotes that undergo aerobic respiration: much higher atp yield. Through endosymbiosis cells overcame an energy barrier: lots of energy now available. dna replication 2% (very cheap to maintain)
