1. Cell Division
The Cell Cycle

2. Reviewing the Chromosome…
Each chromosome (coiled DNA) consists of two identical “sister” chromatids.
Each pair of chromatids are attached at an area called the centromere.
Sister chromatids
Centromere

3. Cell Cycle
The cell cycle is the series of events that cells go through as they grow and divide.

4. Cell Cycle
Interphase is the period of rest and growth that occurs between cell divisions.

5. Your Turn!
Based on the image, what does a cell spend most of its time doing?

6. The characteristics of Interphase…
G1 Phase:
The cell grows
S Phase:
The DNA of the cell is copied into 2 sets (DNA replication)
G2 Phase:
The cell finishes growing and gets ready for mitosis!

7. Cell Cycle Cell Division:
Mitosis – the division of the nucleus that results in two genetically identical cells
Cytokinesis – the division of the cytoplasm

8. Your Turn!
What is the purpose of mitosis?

9. Mitosis

10. PROPHASE Things to remember… it is the start of mitosis
Spindle fibers
Things to remember…
it is the start of mitosis
the nucleus breaks down
the chromosomes form
Centrioles
Nuclear membrane
Chromosomes
(paired chromatids)

11. METAPHASE Things to remember…
the chromosomes line up across the middle of the cell
the spindle fibers attach at the centromeres

12. ANAPHASE Things to remember…
the chromatids are pulled away from each other

13. TELOPHASE Things to remember… two nuclei start to reform
cytokinesis starts

14. Your Turn!
What do you think each cell would look like if this did occur? Why?

15. CELL DIVISION
AT THE CONCLUSION OF CELL DIVISION EACH OFFSPRING WILL RECEIVE IDENTICAL COPIES OF THE CELL’S CHROMOSOMES.

16. Your Turn!
How many chromosomes are in a human skin cell before mitosis? After?