Biology 1002B Lecture Notes - Lecture 12: Euglena, Phos, Archaea
12 Apr 2017
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What happened that differentiated eukaryotes and archaea. Eukaryotes are much bigger and complex (somewhat related) 2. 2 bya: cyanobacteria- oxygenic photosynthesis: led to rise of atmospheric oxygen. Bacteria that undergo aerobic respiration: o2= terminal e, selective advantage of this is much higher, a lot more atp is produced this way. Proton motive force (pmf: gradient of concentration & charge, concentration & charge difference across membrane. Volume must be supported by e generated by ox phos. As volume increases, sa to v ratio decreases: constrains bacterial cell size. Bacteria are small because ox phos has to be on the membrane, cannot support volumes that are too large because of sa to v ratio. Euglena: mitochondria has large sa which can do ox phos (doesn"t occur on the membrane, explains why they"re bigger than bacteria. Problem with sa/v hypothesis: bacteria can have internal membranes (derived from plasma membrane, but still small.
