01:119:116 Lecture Notes - Lecture 3: Symbiogenesis, Red Algae, Proteobacteria
6 Feb 2018
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Lecture three: eukaryotes: introduction to eukaryotes, eukaryotic cell structures. The root of eukarya is not known. And the eukaryotic tree is a polytomy (we are not sure who is the ancestor of whom) Size typically 10 - 100 um (micrometer) All eukaryotes have endosymbiotic relationships (mitochondria and some chloroplasts) Serial endosymbiosis: is when this happens in series. Primary phagocytosis of an aerobic bacterium led to today"s mitochondria. Primary phagocytosis of cyanobacterium led to the ancestor of red and green algae. Primary endosymbiosis = eukaryote engulfs a bacteria. Secondary endosymbiosis = eukaryote engulfs a eukaryote. Engulfed an alpha proteobacterium (ancestor of the endosymbiont) Endosymbiosis of chloroplast - also primary endosymbiosis. All plants and their relatives share a common ancestor that engulfed a chloroplast. Secondary phagocytosis of red and green algae occured frequently. 2 endosymbiosi s of red & green algae. All come from the same eukaryotic ancestor. But rest are land plants, fungi, and animals.
