1. (a) Prophase: (1) Chromosomes condense and become visible;
In animal cells
Centriole
Astral microtubules
Microtubules
Centrosome
Kinetochore
Centromere
Kinetochore
microtubules
Chromosome
Sister chromatids
Nuclear envelope
Polar
microtubules
(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.
Metaphase
plate
Separating sister
chromatids
(c) Metaphase: Chromosomes align on the metaphase plate with
sister chromatids facing opposite poles.
(d) Anaphase: (1) Centromeres divide; (2) the now separated
sister chromatids move to opposite poles.
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.
(f) Cytokinesis: The cytoplasm divides, splitting the elongated
parent cell into two daughter cells with identical nuclei.

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

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

4. (a) Prophase: (1) Chromosomes condense and become visible;
In animal cells
Centriole
Microtubules
Centrosome
Centromere
Chromosome
Sister chromatids
Nuclear envelope
(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. (b) Prometaphase: (1) Nuclear envelope breaks down;
Astral microtubules
Kinetochore
Kinetochore
microtubules
Polar
microtubules
(b) Prometaphase: (1) Nuclear envelope breaks down;
(2) microtubules from the centrosomes invade the nucleus;

7. (b) Prometaphase: (1) Nuclear envelope breaks down;
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. (c) Metaphase: Chromosomes align on the metaphase plate with
sister chromatids facing opposite poles.

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

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

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

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

13. (e) Telophase: (1) Nuclear membranes and nucleoli re-form;
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.