Biology 1201A Lecture Notes - Lecture 7: Spindle Apparatus, Motor Protein, Nuclear Membrane
9 Apr 2016
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Motor proteins walk" along microtubule (or microfilament) highways. A motor protein (e. g. kinesin, dynein, myosin) attaches to the cell structure and to a microtubule. Motor protein feet" alternatively attach and detach from microtubule, propelling motor (consumes energy, atp) Chromosome movement achieved by motor proteins and deletion of tubulin subunits. Pole separation is achieved by addition of tubulin subunits to polar microtubules. Motor proteins are walking the chromosomes down microtubules by connecting to the kinetochores and microtubules break apart as the motor protein moves the chromosomes towards centrosomes. Polar microtubules stretch from one pole and overlap from microtubules from other pole. Motor proteins in between two different microtubules walk them further and further apart, which in turn makes the poles get further and further apart. New nuclear envelope forms around daughter chromosomes at each pole. A ring of parallel microfilaments, mixed with myosin is present below the cell membrane. Sliding of microfilaments constricts the cell, creating a furrow.
