1. Chapter 10: Cell Growth and Division
Mitosis/Cancer

2. Why is it necessary for cells to divide?
DNA Overload-not enough information for the cell as it grows larger in size
To improve material exchange
Surface area to volume-not enough cell membrane surface for exchange that’s required of larger volume cell as it grows

3. Ratio of Surface Area to Volume in Cells
Section 10-1
Cell Size
Surface Area (length x width x 6)
Volume
(length x width x height)
Ratio of Surface Area to Volume

4. What is Cell Division (M phase)?
process where a cell divides into two new daughter cells
Before cell division takes place, the cell must copy or replicate its DNA.
Each daughter cells gets a complete copy of the original DNA
Cell division has 2 parts
Mitosis: division of nucleus and DNA
Cytokinesis: division of cytoplasm and organelles

5. Mitosis (1st stage of cell division)
4 parts of mitosis
Prophase
Metaphase
Anaphase
Telophase
Mitosis is followed by 2nd part of cell division; cytokinesis

6. Interphase
Prophase
Anaphase
Telophase/Cytokinesis

7. Preparation for division-organelle replication
Cell Growth-protein and organelle production
DNA Replication
Preparation for division-organelle replication

8. Figure 10–4 The Cell Cycle
G1 phase
M phase
S phase
G2 phase

9. Interphase G1 phase: Cell Growth S phase: DNA replication
G2 phase: Preparation for Mitosis
Longest phase of cell cycle

10. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

11. Prophase-Phase #1 of Mitosis
Longest Phase-50% to 60% of total time to complete mitosis
Chromatin condenses into Chromosomes
Centromeres connect sister chromatids
Centrioles separate to opposite poles
Spindle is organized
Nucleolus disappears and nuclear envelope breaks down.

12. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

13. Metaphase-Phase #2 of Mitosis
Centromeres attach to spindle fibers
Chromosomes line up across the equator of the cell-metaphase plate

14. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

15. Anaphase-Phase #3 of Mitosis
Sister chromatids separate becoming individual chromosomes and moving to opposite poles of cell

16. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

17. Telophase-Phase #4 of Mitosis
Chromosomes disperse into chromatin
Nuclear envelope re-forms around each cluster of chromatin
Spindle breaks apart
Nucleolus visible in each new daughter cell (2 new nuclei form)

18. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

19. Cytokinesis Division of cytoplasm and organelles
Animal Cells: Cleavage Furrow-cell membrane pinches inward
Plant Cells: Cell Plate-develops into separating membrane (cell wall appears shortly after)
2 new daughter cells each with nucleus and identical chromosomes

20. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Nuclear envelope
Chromatin
Centromere
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming

21. Cytokinesis

22. Longest Phase-50% to 60% of total time to complete mitosis-Prophase

24. Prophase
Interphase

25. Metaphase
Prophase

26. Anaphase

27. Telophase

28. Cyclins: proteins that regulate timing of cell cycle
Two types of regulatory proteins
Internal regulators: proteins that respond to events inside the cell (ex. No mitosis until all chromosomes are replicated)
External regulators: Proteins that respond to events outside cell
Speed up, or slow down cell cycle
Ex: wound healing and embryonic development

29. Figure 10–8 Effect of Cyclins-
The sample is injected into a second cell in G2 of interphase.
A sample of cytoplasm is removed from a cell in mitosis.
As a result, the second cell enters mitosis.

30. Cancer: Disorder in which some cells lose ability to control growth
Density-Dependent Inhibition- ability to respond to signals that regulate the growth of cells
Cancer cells do not exhibit this characteristicform tumors
Carcinogen- cancer causing agent (ex. Cigarettes, UV radiation from sun)

31. Cancer Divide uncontrollably and form tumors
Damage surrounding tissues
P53 Gene: stops cell cycle until replication is complete
defect in this gene present in a large number of cancers

32. Tumors Masses of cells that can damage surrounding tissue
Benign-non-cancerous growth
Localized and not spread
Malignant-cancerous growth
Invade and damage nearby tissues and organs
Metastasis-spread of cancer

33. Regulating the Cell Cycle

34. Why didn’t the cells keep dividing until they spilled over the edge of the petri dish?
What would happen if the cells continued to divide?

36. Asymmetrical, Borders, Color, Diameter, Elevation
Skin Cancer : Melanoma
Asymmetrical, Borders, Color, Diameter, Elevation