Biology 2382B Lecture Notes - Lecture 9: Tubulin, Cell Adhesion, Microtubule
13 Feb 2018
School
Department
Course
Professor
Document Summary
The cytoskeleton is an intricate network of protein filaments that extend through the cytoplasm. Cells, organelles, dna and membranes can be moved by being driven (road), pulled (ropes) or pushed (rods) The cytoskeleton"s roles include organelle/protein trafficking, cilia/flagella, karokinesis/cytokinesis, muscle contraction, cell adhesion, cell migration and extravasation. Unlike what is often shown in videos, biological molecules are three-dimensional and take up space, so there is no empty space in the cell. Microtubules are protein polymers of alpha and beta tubulin dimers. These structures protrude outside of the cell, as seen in cilia and flagella. When dimers polymerize they have a polarity an alpha-beta dimer is always added, never beta-alpha. When multiple dimers polymerize end-to-end they form a long chain called a protofilament. 13 protofilaments polymerize side by side-to-form a micro tubulin. An alpha-beta dimer is called a basic subunit. Therefore, the old end of the microtubule is the alpha end and the new end is the beta end.
