Biology 1001A Lecture Notes - Lecture 4: Deuterostome, Global Catastrophic Risk, Protostome
8 Nov 2012
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Document Summary
The two-kingdom, five-kingdom and three-kingdom (three domain) sys- tems for classifying living things. Assignment to one kingdom or the other was based on structure and function, type of metabolism (plants use photosynthesis), movement (animals can move from place to place) Two domain - prokaryotes (single celled) and eukaryotes (multicellular) Prokaryotes do not contain nuclear membranes, organelles or cytoskeletons. Prokaryotes reproduce by binary fission and eukaryotes by mitotic cell division. Prokaryotes lack: endoplasmic reticulum associated with ribosomes in protein synthesis, golgi apparatus, and a mitochondria for energy production. Membrane closed compartments allow eukaryotic cells to isolate enzymes for specific reactions(translation of dna into rna to cytoplasm) The evolution of compartmentalization was a major series of steps in the origin and di- versification of eukaryotes. Two became five - prokaryotes, eukaryotes => (protists, fungi, plants, and animals) Prokaryotic and eukaryotic domains reflect the two types of cellular organizations but they are not monophyletic, they are polyphyletic.
