BIO130H1 Lecture Notes - Lecture 24: Centromere, Spindle Apparatus, Chromosome
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BIO130H1 Full Course Notes
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The stage where the chromosomes are aligned on the metaphase plate: in order for this to happen, the microtubules have to be attached to the kinetochores of the sister chromatids. Kinetochores are located at the centromere of the chromosomes. The cell can proceed from anaphase to metaphase there is an exposed plus end in the kinetochore microtubule which will allow for polymerization and depolymerization. If you provide a pulse of labelled tubulin dimers, they will incorporate at the plus ends which are the metaphase plate. Over time there will be a flux of the labelled dimers into the spindle apparatus because there is addition of tubulins at the plus ends and loss of tubulins at the minus end. The lack of tubulin flux will prevent cells from dividing and arrest the cell cycle. Everything waits until all chromosomes are properly aligned on the metaphase plate: disruption of the check point segregation defects.
