1. I. MITOSIS A. Cell Division:
1. Needed for normal growth, repair, & development
2. Occurs in somatic cells (body cells)
3. Daughter cells have an exact copy of DNA of parent cell
4. Each parent cell produces 2 daughter cells

2. B. Why Do Cells Divide?
1. Volume Limit: a) food intake b) waste removal
2. Volume to Surface Area Ratio
-Volume increases much more rapidly than surface area as the cell grows in size
Will do lab on Volume to Surface Area ratio. Cells can only take in food/get rid of waste at the surface of cells. If the volume to surface area ratio is too big, cells cannot take in enough food or get rid of all the waste.
Pause to do examples with cube dimensions, SA, vol, ratio

3. II. Cell Cycle

4. A. Interphase 1. Not part of Mitosis 2. 90 % time here
3. Carries out metabolic processes:
Making new molecules & organelles
Normal growth/development
Cell prepare for division
4. DNA replication
5. Chromosomes are not distinguishable (chromatin)
6. Prepares for cell division
Chromosomes contain the DNA/genetic material. Called chromatin when not consolidated

5. 1. G1 phase (normal growth) 2. S phase (synthesis)
7. Cell Cycle:
1. G1 phase (normal growth)
2. S phase (synthesis)
3. G2: prepares to divide
4. Mitosis/Cytokineses
G1 and G2 the cell grows and functions normally
DNA replicates in S phase

6. Mitosis Begins
Cell Cycle Continues

7. B. Prophase 1. First stage of mitosis
2. Chromosomes appear (shorten & thicken = sister chromatids)
3. Centrioles, spindle fibers appear
4. Nuclear membrane dissolves
Sister chromatids contain two copies of identical DNA (replicated during S phase)

8. C. Metaphase 1. Chromosomes line up at the equator
Spindle fibers attach to each chromosome at the centromere, the center portion holding the sister chromatids together

9. D. Anaphase
1. Chromosomes separate and migrate to the opposite ends of the cell
1 copy of DNA to each end of the cell

10. E. Telophase
1. Reorganization a) spindle fibers disappear b) nuclear membrane forms
2. Chromosomes lengthen & disappear
3. Cytoplasm splits (cytokinesis) into two daughter cells
Cell Plate forms for plant cells
Chromosomes turn back into chromatin

11. Mitosis in Animal Cells
Prophase – can see chromosomes
Prometaphase – in between the two phases, students do not need to know
Metaphase – can see spindle fibers and the chromosomes lined up
Anaphase – Chromosomes are separating
Telophase – spindle fibers are starting to disappear, cell is starting to split

12. Mitosis in Whitefish Blastula

14. Cytokinesis in Plant Cells
Thick line down the middle is the cell plate (unique to mitosis in plants)

15. Mitosis in Plant Cells

16. Mitosis in Onion Root Tip
Each cell goes through mitosis at different times, this picture shows several different stages of mitosis

17. F. Significance 1. TWO Daughter cells 2. Identical DNA to parent cell
3. Healing
Growth
Mitosis Animation
Mitosis Animation has music but no narration, lasts about 1 minute

18. G. Cell Cycle From Individual Daughter cell  complete cell division
Two Parts:
a. Interphase: G1, S, G2
b. Mitosis/Cytokinesis
Reminder: Cell Cycle is Interphase + Mitosis. Mitosis does not include interphase, it is just the process of cell division

19. H. Role of the Cell Cycle A. Nearing the end of G1, two options:
1. Continue cell cycle; committed to initiating DNA replication OR
2. GO (resting phase): cell remains viable and metabolically active but are nonproliferative (don’t reproduce)
3. Cancer cells avoid entering GO or go through very quickly

20. B. Tumors and Cancer
1. Tumor: mass of cells formed from out of control cell reproduction
2. Benign tumors: abnormal mass of normal cells
-remain at original site
3. Malignant tumor: abnormal rapidly dividing cells
4. Metastasis: spread of cancer cells
Cancer Cell Explanation
Metastasis Video
Cancer Cell Explanation – 20 seconds
Metastasis video – 2:12

21. C. Protein p53 (Tumor Suppressor Gene)
1. Protein to control cells w/damaged DNA: a. code to stop cell cycle
b. repair DNA
c. program cell death
2. Mutation of p53 gene
a. found in many cancers
b. does not stop mitosis
P53 is a gene that recognizes damaged cells and stops the cell division (mitosis). It initiates either cell repair or cell death

22. Can ignore bottom row of pictures