Chapter 22protists

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Unformatted text preview: Chapter 22 Chapter 22 “Protists” – The Simplest Eukaryotes Protistans are Unlike Protistans are Unlike Prokaryotes • Eukaryotic: Have a nucleus and • • • • • • organelles Usually unicellular Have proteins associated with DNA The DNA is linear in chromosomes, not circular like prokaryotes Use microtubules in a cytoskeleton, spindle apparatus,cilia and flagella May contain chloroplasts May divide by mitosis and meiosis Difficult to Classify Difficult to Classify • Historically a catch­all kingdom • Differ enormously from one another in morphology and life­styles • Molecular and biochemical comparisons are clarifying the evolutionary picture • Protistans do not all stem from a common ancestor Impacts, Issues: Tiny Critters, Impacts, Issues: Big Impacts • • • • Protists – structurally the simplest of all eukaryotes Foraminiferans and coccolithophores have shells or plates hardened with calcium carbonate Dover, England’s white chalk...
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This note was uploaded on 12/02/2009 for the course SCI 013 taught by Professor Xxx during the Fall '09 term at Purdue University Calumet.

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