1. 7th Grade Science
Cell Cycle

2. How do little elephants grow up to be BIG elephants?

3. Why do animals shed their skin?

4. Three reasons why cells reproduce exact copies of each other by mitosis are: Growth Repair Replacement
Cells that reproduce by mitosis reproduce constantly!

5. Animated Mitosis Cycle
Interphase
Prophase
Metaphase
Anaphase
Telophase & Cytokinesis

6. “Cell growth and development”
Interphase
“Cell growth and development”

7. Interphase (occurs before Mitosis begins)
A cell grows in size, performs its function, and creates organelles needed to perform functions
Chromatin are copied (# doubles) called sister chromatin
A cell creates specific organelles for the purpose of dividing (Centrioles, Spindle Fibers)
A cell spends most of its life in this phase!
CELL MEMBRANE
Nucleus
Cytoplasm

8. Interphase Plant Cell Animal Cell
Photographs from:

9. “Division of the nucleus”
Mitosis
“Division of the nucleus”

10. Prophase 1st step in Mitosis
Chromitin condenses to form chromatids and begin to attach to sister chromatids (clones from interphase)
Centrioles appear and begin to move to opposite ends of the cell and spindle fibers form between the centrioles.
Nuclear Envelope begins to break down.
Centrioles
Sister chromatids
Spindle fibers

11. Prophase Plant Cell Animal Cell Spindle fibers Centrioles
Photographs from:

12. Metaphase 2nd step in Mitosis
Chromatids attach and move to the equator (middle) of the cell
Sister Chromatids (or pairs of chromosomes) attach to the spindle fibers at the centromere
Centromere
Centrioles
Spindle fibers

13. Metaphase Plant Cell Animal Cell
Photographs from:

14. Anaphase 3rd step in Mitosis
Centromeres split and sister chromatids (or pairs of chromosomes) separate
Sister chromatids begin to move to opposite ends of the cell
Opposite ends of the cell begin to push apart
Centrioles
Spindle fibers

15. Anaphase Plant Cell Animal Cell
Photographs from:

16. Telophase 4th step in Mitosis
Nuclear envelope begins to form and two new nuclei form.
Chromosomes appear as chromatin (threads rather than rods).
(Mitosis ends)
Nuclei
Nuclei
Chromatin

17. Telophase Plant Cell Animal Cell
Photographs from:

18. “Division of the cytoplasm”
Cytokinesis
“Division of the cytoplasm”

19. Cytokinesis occurs after mitosis
Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

20. Animal Mitosis -- Review
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

21. Plant Mitosis -- Review
Interphase                                                             
Prophase                                                             
Metaphase                                                             
Anaphase                                                             
Telophase                                                             

22. Mitosis Animation