1. The Importance of cell division
Reproduction
Growth
Repair & Replacement

2. More then 100 Trillion Cells
How do we
get from this
To this
2 Cells
1 Cell - Zygote
More then 100 Trillion Cells
To this
To this

3. We will get to that soon but first…
Who Cares???? Why do we need to have cell division? What did it ever do for you?
There are 3 main reasons for cell division
Reproduction
Growth
Repair/Replacement

4. 1) Cell Division for Reproduction
It is an important characteristic for life
All living things must reproduce
Each time a cell divides it produces two new cells which can be:
Identical  Asexual reproduction (Mitosis)
Different  Sexual reproduction (Meiosis)

5. 2) Cell Division for Growth
All living things must grow
When a multicellular organism grows it increases its number of cells
A unicellular (one cell) organism will enlarge its size slightly
How large will the cell get? Why aren’t we made of one or a few big cells?

6. ????????????

7. Cell Division for Growth
All cells need Oxygen, Water and Sugar which needs to be transferred to and through the cell
Cells also need to transfer CO2 and other waste products out of the cell

8. Cell Division and Growth
The movement of substances through the cell occurs by diffusion from an area of high concentration (more) to an area of low concentration
Why does this impact cell size???????

9. Cell Size
When a cell gets too large, chemicals and water cannot move fast enough to get where they need to go
This would cause the cell to either die from lack of nourishment (no O2 or sugar) or from poisoning (no waste removal)

10. 3) Cell Division for Repair & Replacement
Every day, your body sheds millions of dead skin cells and then replaces them.
Your body replaces red blood cells about every 120 days
Cuts and broken bones
need to be healed