1. Mitosis
Section 9-2

2. What is it?
The stage of the cell cycle during which the cell’s nucleus and nuclear material divide.

3. Why does is it occur? For an organism to grow larger
To replace damaged cells
As a means of reproducing in asexual organisms

4. How does it occur? It has 4 stages Prophase Metaphase Anaphase
Telophase

5. Prophase Chromatin coils into visible chromosomes
Nuclear membrane & nucleolus disappear
Centrioles migrate to poles
Spindle fibers begin to form between poles
**Longest phase

6. Metaphase Chromosomes attach to spindle fibers at their centromeres
Chromosomes line up across the equator of the cell

7. Anaphase Microtubules of the spindle shorten
This separates the sister chromatids at their centromeres and moves them to opposite poles

8. Telophase Chromosomes arrive at the poles of the cell
Chromosomes relax (unwind)
Two new nuclear membranes form
Nucleoli reappear
Spindle breaks down

9. Cytokinesis What? When? Why? How? The division of the cytoplasm
Following mitosis
Why?
To finish dividing the cells, to form two new cells
How?
It differs in plants and animals

10. Cytokinesis In Animals In Plants
Microfilaments pinch in and form a cleavage furrow, which cut the cytoplasm into two
A rigid cell plate is laid down between the two new nuclei
Cell walls then form on either side of the cell plate

11. How does mitosis look?
Mitosis Animation