BIOL 103 Lecture Notes - Lecture 5: Santa Barbara City College, Spindle Apparatus, Sister Chromatids
Document Summary
Metaphase plate consequence of the chromosomes being pulled simultaneously towards both spindle poles by the kinetochore microtubules, as well as being pushed around by the motor proteins. Tension on the microtubules and the kinetochores provides the most stability for the overall structure. The state of spindle microtubules is still very dynamic due to both ends of the microtubule being held in the mitotic spindle- tubulin units are continually being added and removed at both ends. New tubulin units are assembled onto the plus end of the microtubules at the kinetochore and the microtubule is being disassembled at the minus end of the spindle pole. Errors at this stage could result in improper separation of chromosomes at anaphase, which would be disastrous for the daughter cells- explains slow-like division because one final checkpoint. Cohesins that hold sister chromatids together are dissolved and the chromatids separate.
