The stages of meiosis

Prophase ll Nuclear envelope breaks down Microtubules (from centrosomes) Prophase II The nuclear envelope breaks down, and centro- somes duplicate and begin migrating to opposite poles of the cell. Microtubules emanate from the centro- somes, producing kineto- chore, nonkinetochore, and astral microtubules. Chro- mosome recondensation takes place. MEIOSIS ll: Separates sister chromatids Metaphase plate Metaphase ll Sister chromatids are attached to kinetochore microtubules from opposite poles of the cell. The force of microtubule pull and the resistance created by cohe— sin leads to chromosome alignment along the meta- phase plate. Nonkinetochore microtubule Kinetochore microtubule Anaphase ll Sister chromatid separation begins with the breakdown of cohesin by separase and the depolymerization of kinetochore microtubules. As the sister chromatids move toward opposite poles, polymerization of nonkinetochore microtu- bules elongates the cell. Nuclear envelope re-forms Telophase II and Cytokinesis Chromosome migration is completed, and the chro- mosomes begin to decon— dense. The nuclear enve- lope re—forms around chromosomes. Cytokinesis separates the newly formed nuclei and divides the cytoplasmic material, perhaps unevenly.