Biology 2382B Lecture Notes - Lecture 9: Endocytosis, Basal Body, Neuron
13 Feb 2017
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Document Summary
The cytoskeleton is an intricate network of protein filaments that extend throughout the cytoplasm. Biological molecules are 3-dimensional with specific shape and take up space. Every molecule in a cell takes up space; no empty space inside cell. 2 tubulin monomers (55kda each) a and b, form ab dimer. After translation of separate monomers, dimer forms instantly, so cell only uses dimer. Rarely depolarize (typically not by cell) microtubules: hollow tube structure make up structures like cilia and flagella, polarity just means one side different from other. 13 protofilament chains are formed into the microtubule. The microtubule has polarity (one end is alpha subunits, other is beta) Protofilament ab dimer polymerizes and forms a long alpha beta chain. Polarity one end is always alpha (-) and the other beta (+) not charges. The ends of the 13-protofilament sheets don"t form nicely, so the edges. As protofilament grows beta"s gtp gets hydrolyzed because dimers are.
