Cell division occurs through mitosis and cytokinesis to produce two identical daughter cells. Mitosis involves nuclear division through the phases of prophase, metaphase, anaphase and telophase where the chromosomes align and separate. Cytokinesis then divides the cytoplasm, forming a contractile ring that pinches the cell in half to complete cell division. DNA replication occurs prior to nuclear division to duplicate all DNA molecules so each daughter nucleus receives an identical copy.

1. Lesson #5
CELL DIVISION: MITOSIS AND CYTOKINESIS

2. MITOSIS
CELL DIVISION

3. MITOTIC PHASE
Division of a cell into 2 identical cells, with the same amount of DNA.
1. Mitosis: division of the nucleus
2. Cytokinesis: division of the cytoplasm
2n
2n
2n
Parent cell
Daughter cells
Identical nuclei

4. DNA Replication
◦ All DNA molecules need to be doubled o replicated in order for the cell
to be able to make 2 nuclei out of one. Each nucleus must receive the
same DNA molecules.
◦ Takes place during Interphase (Phase S)

5. MITOSIS: Nuclear division
 Four main phases
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

6. MITOSIS
1. PROPHASE
◦ Chromatin condenses into structures called chromosomes
◦ Spindle forms and centrioles migrate to the poles
◦ Nuclear membrane disassembles.
◦ Nucleolus disassembles.

7. MITOSIS
2. METAPHASE
◦ Chromosomes align in the metaphase plate at the equator of the
cell.
◦ Centrosomes are at opposite poles.
◦ Mitotic spindle fibers connect with the kinetocore

8. MITOSIS
3. ANAPHASE
◦ Chromosomes align in the center.
◦ Centrosomes are at opposite poles
◦ Mitotic spindle fibers connect with the kinetocore

9. MITOSIS
4. TELOPHASE
◦ Chromatids reach the opposite poles of the cell.
◦ There is a copy of each DNA molecule in each side.
◦ Nuclear envelope and nucleolus begin to reappear.
◦ Chromosomes uncoil and become less condensed.
◦ Two new nuclei are formed. The is still just 1 cell, but with 2
nuclei.

10. Cytokinesis
Cytoplasm divides, cell membrane surrounds each or the two daughter
cells, leaving a nucleus in each side and hence allows for the
completion of cell division.
In animal cells:
◦ A contractile ring forms around the equator of the cell.
◦ The contractile ring shrinks at the equator of the cell, pinching the
plasma membrane inward, forming a cleavage furrow.
◦ Eventually, there are two separate cells each with its own nucleus
and surrounded by its own plasma membrane.
Source: Scitable. By Nature Education

11. http://www.argosymedical.com/Cellular/samples/animations/Mitosis/index.html

12. REVIEW
WORKSHEETS

13. Worksheet (printed)