1. How do little elephants grow up to be BIG elephants?
Objectives: 1. Review cell cycle 2. Describe the stages of mitosis 3. Explain why cells need to divide.

2. Why do animals shed their skin?

3. How do our bodies heal when
we are injured?

4. THE CELL CYCLE:
Throughout their lives, cells go through a continual process of controlled growth and division
3 main stages
Interphase
Mitosis
Cell division or
Cytokinesis

5. The process of mitosis begins after a sperm fertilizes an egg
The process of mitosis begins after a sperm fertilizes an egg. This is how all of the somatic or body cells are formed - all cells, excluding the sex cells (sperm & eggs)

6. Mitosis allows cells or organisms to:
Grow
Repair damage to tissues and/or organs
Replace dead or dying cells
Cells that reproduce by
asexual reproduction
(mitosis) are able to
reproduce constantly.

7. Skin cancer is the abnormally fast growth of skin cells – most often develops on skin exposed to the sun.

8. THE CELL CYCLE
The greater portion of a cell’s life is spent in interphase
“Inter” means between
Growth and normal cell functioning occurs during interphase (i.e. heart cells work to pump blood during Interphase)

9. The cell cycle is a continuous process of: mitosis, cell division and interphase.

10. Animated Cell Cycle Interphase Prophase Metaphase Anaphase Telophase
Cytokinesis
Video Animation (Virtual Cell)

11. Interphase occurs before mitosis begins
Chromosomes are copied (# doubles)
Chromosomes appear as threadlike coils (chromatin) at the start.
Each chromosome and its copy = sister chromatids
CELL MEMBRANE
Nucleus
Cytoplasm

12. Interphase Plant Cell Animal Cell
Photographs from:

13. Prophase 1st step in Mitosis
Chromosomes are condensed and visible.
Nuclear membrane starts to disappear.
Centrioles appear and begin to move to opposite ends of the cell.
Spindle fibers form between the poles.
Centrioles
Sister chromatids
Spindle fibers

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

15. Metaphase 2nd step in Mitosis
Sister Chromatids attach to the spindle fibers and line up along the equator of the cell.
Centrioles
Spindle fibers

16. Metaphase Plant Cell Animal Cell
Photographs from:

17. Anaphase 3rd step in Mitosis
Sister Chromatids separate as the spindle fibres pull them. They begin to move to opposite ends of the cell.
Centrioles
Spindle fibers

18. Anaphase Plant Cell Animal Cell
Photographs from:

19. Telophase 4th step in Mitosis
Two new nuclei form.
Spindle fibres disappear.
Chromosomes reappear as chromatin (threads rather than rods).
Mitosis ends.
Nuclei
Nuclei
Chromatin

20. Telophase Plant Cell Animal Cell
Photographs from:

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

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

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

24. IPMATC REMEMBER! Interphase Prophase Metaphase Anaphase Telophase
Cytokinesis
IPMATC
A mnemonic to help remember the stages of mitosis.
Can you create an mnemonic to remember the stages of mitosis? 24

25. Cell Cycle 25

26. Music Time!
Time for Mr. W!!!