BIO 121 Lecture Notes - Lecture 20: Tunxis Community College, Spindle Apparatus, Nucleolin
23 Nov 2020
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Document Summary
Entry triggered by activation of m-cdk by cdc25. Duplicated chromosomes condense, outside of nuc, the mitotic spindle assembles on either centrosome and start to move to the cell"s poles. H1, condensin chromosome condensation (sister chromes held by cohesins) Mt-associated proteins mitotic spindles form (starts in pro, continues to prometaphase) Selective stabilization of 2 interacting mts (interpolar mt) Kinetochores assemble on condensed chromosome (making the x) Starts with breakdown of nuclear envelope (into small vesicles) chromosomes attach to spindle mt via kinetochores for movement. Breakdown caused by nuclear lamina disassembling, triggered by phosphorylation of nuclear lamins by m-cdk. Chromosomes align at the equator of the spindle. 3 classes of mt make up the mitotic spindle. Fluorecently tagged tubulin added to cell in mitosis moves towards pole even though length of kinetochore-mt length does not change. Mt can polymerize and depolymerize while attached to kinetochore. Kinetochore has protein collar at mt (+) end allowing addition or removal of tubulin.
