1. The Importance of Cell Division

2. What is the purpose of cell division?

3. 1. Healing & Tissue Repair
You don’t go through life with the same cells you had at birth
Every second, millions of your cells are injured or die
New cells replace dead cells
What are some daily activities that remove cells?

4. Interesting Fact!
If you were to examine the filter in your furnace about 50% of the dust would actually be dead human cells!

5. 2. Growth Increasing the number of cells
Human growth begins with the division of a single fertilized egg cell
Instead of dividing, why don’t cells just get bigger?
The distance from the nucleus to the organelles must be kept short so they can communicate

6. 3. Reproduction Cell division creates new organisms
Ex. Bacteria that divide in two

7. How long do cells live?? Red blood cells = 120 days
White blood cells = 13 days (blood)
Top layer Skin cells= 30 days
Brain cells rarely divide to make new cells, so be nice to the ones you have!

8. Interesting Fact ! Elizabeth Bathory 1560-1614 Countess Dracula
Used to kill all the young maidens around Hungary to bath and drink their blood.
young people’s blood = keep her youthful.
She killed 612 people
Why would she be wrong in her thoughts of using young peoples blood to stay youthful?

9. Review 1) Why is cell division important?
2) Give examples that show how cells in your body divide at different rates.
3) At one time, doctors transfused blood from younger people to the elderly. They believed that the younger blood would provide the elderly with more energy. Do older people actually have older blood? Think about what we talked about in class to support your answer.

10. How do cells divide ? Mitosis Meiosis Everywhere in your body
Except in your reproductive organs
Makes two daughter cells that are exact copies of original
Meiosis
Only happens in your reproductive organs
Makes 4 daughter cells that are all unique and different from original
Why?

11. Mitosis Foldable
Create your own notes using the textbook pages provided and the diagram from the board. Cut out each side and glue them into your note book or back to back. Be neat! You are expected to know all the stages of mitosis and identify them. Use mine as a template if you feel like you are stuck.