BIOA01H3 Chapter Notes -Proteobacteria, Zooplankton, Human Parasite
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BIOA01H3 Full Course Notes
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23. 1 evolution of protists involved endosymbiosis (pg 498) Evolved 1. 5 to 2 billion years ago. Endosymbiosis played an important role: contain mitochondria and some contain chloroplasts, earliest eukaryotes acquired mitochondria by engulfing proteobacteria becoming heterotrophic eukaryotes. Chroloplast endosymbiosis: cyanobacteria ingested by eukaryote that already had mitochondria, formed symbiotic relationship, over evolutionary time, lost genes no longer required for independent existence and transferred most of its genes to the host"s nuclear genome. Gave the host cell better control of overall cell function: prokaryote became an organelle of an eukaryote, some evolved this way, other: eukaryote engulfed a photosynthetic eukaryote that eventually became a chloroplast. Microtubules and microfilaments. cytoplasmic organelles: mitochondria and chloroplast (in some species: provide motility and cytoskeletal support characteristics of transcription and translation like eukaryotes. Phylogenetic relationship btw protists and eukaryotes is more complex: over evolutionary time, the eukaryotic family tree branched out in many directions, plants, animals and fungi diverged from protest ancestors, some features similar, other distinctive.
