1. Cell Division

2. Why do cells divide?
So that multicellular organisms can grow from one cell.
So that cells can reproduce for growth & repair.

3. How?
Asexual reproduction – reproduction involving one (or a) parent cell
Cell division – a type of asexual reproduction where one cell divides and becomes two identical copies of itself.
Mitosis – a special part of cell division where the nucleus of the cell makes a copy of itself and then divides into two new nuclei.

4. Cell Division Math
If a cell divides once a day, how many cells will there be in one week (7 days)? One month?
7 days: 64
1 month: 1,073,741,824

5. The Cell Cycle foldable
Directions are on the board.
Should be completed in the composition book.

6. Warm up
Biology is the only science in which multiplication means the same thing as division.
Copy this statement on your warm up sheet. We will answer it at the end of the lesson
Take out your Cell Cycle foldable (should be in your composition book).

7. Interphase Cell grows Chromosomes are copied
Chromatids – the two chromosome copies
Centromere – region where chromatids are held together

8. Chromosomes

9. Mitosis
Mitosis – process of cell division that forms two new nuclei, each of which has the same number of chromosomes.
4 phases:
Prophase
Metaphase
Anaphase
Telophase

10. Mitosis (Prophase) Prophase = chromosomes pair up with their “twin”.
Chromosomes twist, coil & condense into an “X” shape
Spindle fibers form
Nuclear membrane begins to break down

11. Mitosis (Metaphase) Nuclear membrane disappears
Chromatid pairs line up in the middle of the cell
metaphase = middle

12. Mitosis (Anaphase) Chromatids separate
Move apart to opposite sides of the cell
anaphase = apart
Cell becomes stretched

13. Mitosis (Telophase)
Two nuclear membranes form around each set of chromosomes
telophase = two new nuclear membranes
Mitosis is over

14. Cytokinesis Cells without a cell wall (ex: animal cells):
Cell pinches in two
Cells with a cell wall (ex: plants):
A cell plate forms between the two new cells

16. Demo of Mitosis See “Cells Alive” video/demo