In animal cells

1. Separating sister chromatids Astral microtubules Centriole Metaphase plate Kinetochore Microtubules Centrosome Kinetochore microtubules Re-forming nuclear envelope Centromere Chromosome Polar microtubules Sister chromatids Nucleoli reappear Chromatin Nuclear envelope In animal cells (a) Prophase: (1) Chromosomes condense and become visible; (2) centrosomes move apart toward opposite poles and generate new microtubules; (3) nucleoli begin to disappear. (b) Prometaphase: (1) Nuclear envelope breaks down; (2) microtubules from the centrosomes invade the nucleus; (3) sister chromatids attach to microtubules from opposite centrosomes. (d) Anaphase: (1) Centromeres divide; (2) the now separated sister chromatids move to opposite poles. (c) Metaphase: Chromosomes align on the metaphase plate with sister chromatids facing opposite poles. (f) Cytokinesis: The cytoplasm divides, splitting the elongated parent cell into two daughter cells with identical nuclei. (e) Telophase: (1) Nuclear membranes and nucleoli re-form; (2) spindle fibers disappear; (3) chromosomes uncoil and become a tangle of chromatin.

2. Centriole Centromere Chromosome Sister chromatids Nuclear envelope In animal cells (a) Prophase: (1) Chromosomes condense and become visible;

3. Centriole Microtubules Centrosome Centromere Chromosome Sister chromatids Nuclear envelope In animal cells (a) Prophase: (1) Chromosomes condense and become visible; (2) centrosomes move apart toward opposite poles and generate new microtubules;

4. Centriole Microtubules Centrosome Centromere Chromosome Sister chromatids Nuclear envelope In animal cells (a) Prophase: (1) Chromosomes condense and become visible; (2) centrosomes move apart toward opposite poles and generate new microtubules; (3) nucleoli begin to disappear.

5. (b) Prometaphase: (1) Nuclear envelope breaks down;

6. Astral microtubules Kinetochore Kinetochore microtubules Polar microtubules (b) Prometaphase: (1) Nuclear envelope breaks down; (2) microtubules from the centrosomes invade the nucleus;

7. Astral microtubules Kinetochore Kinetochore microtubules Polar microtubules (b) Prometaphase: (1) Nuclear envelope breaks down; (2) microtubules from the centrosomes invade the nucleus; (3) sister chromatids attach to microtubules from opposite centrosomes.

8. Metaphase plate (c) Metaphase: Chromosomes align on the metaphase plate with sister chromatids facing opposite poles.

9. (d) Anaphase: (1) Centromeres divide;

10. Separating sister chromatids (d) Anaphase: (1) Centromeres divide; (2) the now separated sister chromatids move to opposite poles.

11. Re-forming nuclear envelope Nucleoli reappear (e) Telophase: (1) Nuclear membranes and nucleoli re-form;

12. Re-forming nuclear envelope Nucleoli reappear (e) Telophase: (1) Nuclear membranes and nucleoli re-form; (2) spindle fibers disappear;

13. Re-forming nuclear envelope Nucleoli reappear Chromatin (e) Telophase: (1) Nuclear membranes and nucleoli re-form; (2) spindle fibers disappear; (3) chromosomes uncoil and become a tangle of chromatin.

14. (f) Cytokinesis: The cytoplasm divides, splitting the elongated parent cell into two daughter cells with identical nuclei.