1. Cell Division

2. Are you two twins? Asexual Reproduction:
Used by many unicellular organisms, plants, and lower animals.
Involves only mitotic cell division = each offspring has exactly the same heredity as its parent.
Usually rapid compared to sexual reproduction.

3. Phases of the Cell Cycle
The cell cycle consists of
Interphase (cell growth and copying of chromosomes in preparation for cell division)
Mitotic (M) phase (mitosis and cytokinesis)
Interphase (about 90% of the cell cycle) can be divided into subphases:
G1 phase (“first gap”) – cell growth & normal functions
S phase (“synthesis”) – DNA copies
G2 phase (“second gap”) – mitosis

5. Animated Cycle

6. Mitosis Cells divide to form 2 identical “daughter cells”
Occurs in stages
I PMAT C

7. Interphase The cell prepares for division
DNA replicated
Organelles replicated
Cell increases in size

8. Interphase Plant Cell Animal Cell
Photographs from:

9. Mitosis Stage 1 - Prophase
DNA coils into chromosomes
Centrioles move to opposite sides of cell
Nuclear membrane dissolves
Spindle fibers form between the centrioles as they move apart

10. Prophase Plant Cell Animal Cell
Photographs from:

11. Mitosis Stage 2 - Metaphase
Chromosomes attach to spindle fibers and line up in the middle

12. Metaphase Plant Cell Animal Cell
Photographs from:

13. Mitosis Stage 3 - Anaphase
Chromosomes separate
Spindle fibers retract, pulling the chromosome pairs apart

14. Anaphase Plant Cell Animal Cell
Photographs from:

15. Mitosis Stage 4 - Telophase
New nuclear membrane forms around chromosomes
Cell membrane pinches in to form the 2 new daughter cells

16. Telophase Plant Cell Animal Cell
Photographs from:

17. Mitosis Stage 5 - Cytokinesis
Division of cytoplasm & organelles
Begins in anaphase
“Pinches off” between new nuclei to form 2 individual cells

18. Mitosis
Cell division regulated by cell type (depends on gene activation)
Uncontrolled cell division = cancer

19. Mitosis Animation