1. Phases of Mitosis
Biology
Fall 2016

2. Mitosis is a continuous process.
The Phases of Mitosis
Mitosis is a continuous process.
Biologists have divided the mitotic phase into 4 main stages:
Prophase
Metaphase
Anaphase
Telophase

3. Prophase This is the first and longest phase.
The chromatin bundles up to form chromosomes in the nucleus.
Each chromosome consists of a pair of sister chromatids.
Sister chromatids are joined at the centromere.

5. Chromatin

6. Chromosomes

7. centromere

8. Prophase The chromosome duplicates during INTERPHASE.
The nucleolus disappears.
Cells stop making ribosomes and a football shaped structure called the mitotic spindle (aka spindle fibers) forms.
The spindle fibers start tugging chromosomes toward the center of the cell.

9. Metaphase This is a brief, second phase of mitosis.
The chromosomes are pulled toward the center of the cell.
Spindle fibers pull the centromere and align the chromosomes at the equator of the cell.

10. ANaphase The third stage of mitosis.
The spindle fibers begin to shorten.
The sister chromatids separate.
Each chromatid is now considered a “daughter”.
Spindle fibers begin to shorten, puling the split chromatids to opposite poles of the cell.

11. Telophase Final stage of mitosis
Chromatids move to opposite sides of the cell.
Two new nuclei are formed- one on each side of the cell.
Two daughter cells are formed when a new double membrane forms.
This allows the cytoplasm to divide by CYTOKINESIS.

12. Telophase The final stage of mitosis
A complete set of identical chromosomes is positioned at each pole of the cell.
The nuclear membranes start to reform.
The chromosomes begin to uncoil.
The spindle fibers fall apart.

13. Mitosis in Real Time

14. Mitosis in Real Time

15. mitosis in Real Time