1. CHAPTER 10 CELL DIVISION
Mitosis - One cell dividing into 2 identical cells (somatic cells)
healing and growth
Meiosis - production of sex cells (gametes)

2. THE CELL CYCLE A “DAY” IN THE LIFE OF A CELL
Interphase
G1 - Period of growth for the new cell
S (synthesis) - Copying of DNA (replication)
G2 - Preparation for division, organelles needed for cell division are produced
M - Cell Division
Division of the nucleus - Mitosis
Division of the cytoplasm - Cytokinesis

3. Cell Geography Chromosomes are pulled towards the poles
Equator
Pole
Pole
Chromosomes line-up on the equator during cell division
Chromosomes are pulled towards the poles

4. Structures Necessary for Cell Division
Centrioles - organelles that help to separate
chromosomes in animal cells only
Spindle - formed by and between the centrioles,
made from microtubules, attaches to each chromosome

5. Replicated Chromosomes
1. Made up of DNA and proteins
2. Only visible prior to cell division during rest the DNA takes the form of chromatin
3. Replicated chromosomes are made up of 2 sister chromatids held together by a centromere (separate but joined)
4. Sister chromatids are identical (duplicated chromosome)
Text
Replicated Chromosomes
Human somatic cells have 46 chromosomes
Sister chromatids
Spindle

6. Interphase Period of growth for the cell Includes G1, S, G2
Plant cell
Animal Cell
Period of growth for the cell
Includes G1, S, G2
Chromosomes are not visible (chromatin)

7. Mitosis PMAT Division of the nucleus occurs in 4 phases:
Prophase - Pro- (beginning)
Metaphase - Meta- (between)
PMAT
Anaphase - Ana- (up from)
Telophase - Tel- (end)

8. Prophase DNA (chromatin) condenses (thickens) into chromosomes
Nuclear membrane breaks down so the nucleus can divide
Centrioles begin to separate creating a spindle in between them

9. Metaphase Chromosomes line up on the equator
Centrioles have migrated to the poles
Each chromosome is attached to a spindle fiber
at the centromere

10. Anaphase The spindle separates the chromosomes pulling
the chromatids towards the poles

11. Telophase Chromosomes gather at the poles and cytokinesis begins
Cytokinesis is division of the cytoplasm

12. Division of the cytoplasm
Cytokinesis
Division of the cytoplasm
Plant Cell
Animal Cell

13. Prophase?
Metaphase?
Anaphase?
Telophase?

14. Eukaryotes Prokaryotes Egg or Sperm 2 identical cells
Gamete Production
Egg or Sperm
2 identical cells

15. How do cells know when to divide?
White blood cell
Red Blood Cells
Some cells never divide
Why not?
They do not have a nucleus

16. Different Cell Cycle Rates for Different Cells
Digestive lining cells move through the cycle quickly
Cardiac muscle cells
do not divide

17. Why don’t cells just continue dividing?
Contact inhibition - cell division stops when a cell comes into contact with another cell
No contact inhibition - cells growing on top of one another
Contact inhibition - cells are spread apart

18. Cyclins - proteins that regulate the timing
Cell Cycle Regulators
Cyclins - proteins that regulate the timing
of the cell cycle
Internal regulators - proteins that respond to events inside the cell, e.g. check to see that all of the chromosomes have replicated correctly
External regulators - proteins that respond to events outside of the cell, hormones

19. Cancer Occurs when a cell loses the ability to regulate its cell cycle
Overgrowth of cells - no contact inhibition
Benign tumor - does not spread beyond the original site
Metastasis - cancer cells that have moved to other parts of the body

20. Cancer Cells
Breast Cancer Cell
Brain Cancer Cell
Prostate Cancer Cell