2. The Process of Cell Division

4. Tetrad Centromere Kinetocore Sister Chromatid Chromosome Homologous Chromosome

5. The cell grows to double its size (G 1 phase) to compensate for division. The centrioles divide as the DNA doubles.

6. The nuclear membrane and the nucleolus gradually dissipates over the phase. The centrioles move to the poles of the cell as the chromatin condenses into chromosomes.

7. The chromosomes line up at the equator of the cell. The centrioles now expel thin strands, called spindle fibers, which attach to the kinetocore of the chromosome. Once attached, the spindle fibers are called polar fibers.

8. The spindles retract, ripping the chromosomes apart.

9. The polar fibers dissipate.

10. The chromatids gather as the nuclear membrane and the nucleolus re-appear Now, the chromatids uncoil into chromatin again.

11. Slowly, the cell starts to split apart. Cleavage Furrow

12. The cell has now separated from one cell into two

13. The cycle begins again when the cells start to grow.