1. The Cell Cycle and Mitosis:
“You Complete Me”
A process where one parent cell gives rise to two daughter cells- exact replicas of the original cell.

2. The Cell Cycle
Every cell goes through a process of growth, this is called the cell cycle.
Interphase is where DNA is synthesized (copied) in preparation of Mitosis.

3. The Cell Cycle Purpose: to replace dead or dying cells (repair)
division of zygote into an embryo
to allow an organism to grow and develop
asexual reproduction

4. zygote
Zygote

5. Interphase
It may not look like much is going on here, but there is a lot of activity because the cell must prepare for mitosis
Onion root tip (on left side), whitefish (on right side)

6. Interphase protein synthesis DNA synthesis/chromosomes are replicated
replication of other cellular structures

7. Mitosis 4 phases: Prophase Metaphase Anaphase Telophase
Cytokinesis (division of the cytoplasm)
one cell becomes two!

8. Mitosis: Prophase Chromosomes condense and become visible
Nuclear envelope breaks down
Spindle begins to form
In animal cells centrioles move to poles
Onion root tip (top photo), whitefish (bottom photo)

9. Mitosis: Metaphase Spindle fibers attach to the centromeres
Line up in the middle (the equator) of the cell
Onion root tip (top photo), whitefish (bottom photo)

10. Mitosis: Anaphase
The sister chromatids separate and are pulled to opposite sides of the cell by the spindle
Onion root tip (top photo), whitefish (bottom photo)

11. Mitosis: Telophase Chromosomes now uncoil
Nuclear envelope reappears and surrounds the chromosomes
Onion root tip (top photo), whitefish (bottom photo)

12. Mitosis: Telophase Cytokinesis
The cytoplasm and all its contents are divided between the 2 daughter cells (cytoplasmic division)

13. Daughter Cells
The 2 daughter cells are exact replicas of the original parent cell
they are clones
have the exact same genetic make-up as the parent cell.
mitosis = cell division

14. Can you identify these stages?B D C
A. Telophase B. Prophase C. Cytokinesis D. Metaphase
Answers:

15. Summary
One parent cell begins the journey through the cell cycle and 2 new identical daughter cells emerge from one cycle.

16. Mitosis occurs regularly in tissues that require new cells continuously such as skin cells, hair follicles, the lining of the digestive tract and in a newly fertilized egg (zygote).

17. This process is important as it allows for an organism to grow and develop over its lifespan and replenishes dead or dying cells in certain tissues.

18. The cells that result are identical to the original cell
The cells that result are identical to the original cell. There are no genetic differences. So skin cells make skin cells. But if you reproduce this way (paramecium, ameba) what kills one of you will kill all of you.