GENE 540 Study Guide - Midterm Guide: Actomyosin Ring, Sister Chromatids, Telophase
Document Summary
The microtubule shortening occurs from the + end; the depolymerization occurs mostly from the plus end; microtubule shortening occurs during anaphase a as chromosomes separate. Experiment showing that kinetochore microtubules shorten by depolymerization mostly from the plus (kinetochore) end. Anaphase b poles moving apart are mediated by astral tubules and dyneins. Dyneins: the molecular motor proteins attached to the cell periphery (membrane) they pull on the astral microtubule to pull on the centrosome apart (dyneins walk in the minus direction) Microtubule-associated motor proteins contribute to pushing the poles apart. Kinesins: (+) end - directed pushing on adjacent polar mt. Dyneins anchored at the plasma membrane carry out (-) end - directed pulling on astral. Telophase chromosomes are being decondensed; cells are being pinched apart (cytokinesis) and nuclear envelope starts to form. Cytokinesis is mediated by the contractile ring. The contractile ring has actin and myosin ii. Contraction of muscle is myosin walking along actin using atp.
