1. Cell Division Mitosis

2. Overview of Mitosis
1 Cell (mother cell) divides into 2 Cells (daughter cells)
Each new cell is an exact copy of the mother cell

3. Importance of Mitosis Growth – adding new cells
Replacement – replacing dead cells
Repair – Replacing cells that are damaged or injured

4. Structures - Nucleus
The Nucleus is the control center of the cell
Chromatin is the threadlike structures in the nucleus
Chromatin is made of DNA and a few other things

5. Structures – Nuclear Membrane
The Nuclear Membrane separates the nucleus from the rest of the cell
The Nuclear Membrane disappears during cell division

6. Structures - Chromosomes
Chromosomes are visible when a cell is dividing
All species of plants and animals have a certain number of chromosomes in their body cells

7. Structures - Chromosomes
Chromosomes are made of two chromatids connected by a centromere

8. Structures - Genes
Genes are structures or locations on the chromosomes that carry information for the cell’s activity
Genes carry coded instructions that are similar to an architect’s blueprint

9. Structures - DNA
DNA is the chemical that makes up genes and chromosomes

10. Structures - Centrioles
Centrioles are organelles outside the nucleus that anchor the spindle fibers

11. Structures – Spindle Fibers
Spindle fibers form when a cell is dividing
They pull chromosomes to opposite ends of the mother cell

12. Chromosome Numbers Examples
Man – 46 (23 pair) Chromosomes
Midge – 4 (2 pair)
Crayfish – 208
Fern – 768
Pea – 14
Corn – 20
Monkey – 42
Rabbit – 44
Mouse – 4
Moth – 62
Potato – 48
Tomato – 24
Sunflower-34
Frog-26
Cow-60
Horse-64
All members of an animal or plant species have the same number of chromosomes

13. The Cell Cycle Prophase Anaphase Telophase Metaphase Interphase
The cellscycle includes a resting phase, the 4 phases of mitosis, and cell separation.
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis

14. Mitosis - Interphase
Interphase is a resting phase - a period of growth and development where the chromosomes are not visible.
Duplication of the chromosomes takes place (exact copies are made)

15. Mitosis - Prophase
In Prophase, the chromosomes become visible under a microscope
They become short, thick, and paired up
The nuclear membrane begins to disappear

16. Mitosis - Metaphase Nuclear Membrane completely gone
Pairs of Chromosomes line up in the middle of the cell
Spindle fibers attach to the chromosome pairs

17. Mitosis - Anaphase
The chromosomes are pulled apart and the chromatids are pulled and move to the opposite ends of the cell

18. Mitosis - Telophase Spindle fibers disappear
Chromosomes begin to stretch out and lose their rodlike appearance.
A new nuclear membrane forms around each region of chromosomes.

19. Cytokinesis Cell membrane pinches in around the middle of the cell.
The result is a new daughter cell that is identical to the parent cell. It should have the same number of identical chromosomes.