2. Getting Through Materials move through cells by diffusion. MITOSIS
Oxygen and food move into cells, while waste products move out of cells.
How does the size of a cell affect how efficiently materials get to all parts of a cell?
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3. Why must cells divide in order to grow? Why is this so important?
to reach maximum efficiency for molecular transport, and maintain the functions of the cell.
limits to how large a cell can become, so when those limits are reached the cells divide.
replace old cells that are worn down or damaged
Cells are composed of atoms, and carbon atoms are essential in cells.
Carbon is essentail to life

4. Why do cells divide? Efficiency Replacement of old worn out cells
If a cell get’s to large it is to difficult to carry out daily functions in a timely manner
Replacement of old worn out cells
Organism growth and
To produce specialized cells for plants/animals
Skin cells, blood cells, etc.…
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5. The process by which a cell divides into 2 new daughter cells.
Division of the Cell
The process by which a cell divides into 2 new daughter cells.
Before the cell divides, DNA replication takes place.
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6. Section Outline
10–2 Cell Division A. Chromosomes B. The Cell Cycle C. Events of the Cell Cycle D. Mitosis 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase E. Cytokinesis
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7. chromosomes
Chromosomes-are comprised of DNA and protein. These carry the genetic information in eukaryotic cells. Only visible during cell division.
Before cell division, each chromosome is replicated, creating identical “sister” chromatids. During cell division each chromatid will go to the 2 new cells.
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8. Biology Prentice Hall Copyright Pearson Prentice Hall

9. Cell Cycle Cell grows Prepares for division
Divides to form 2 daughter cells
Daughter cells begin cycle again
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10. Cell Cycle
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11. Part of eukaryotic cell division in which the nucleus divides
Mitosis
Part of eukaryotic cell division in which the nucleus divides
Lasts a few minutes to several days.
Four phases:
Prophase
Metaphase
Anaphase
Telophase
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12. Video 1
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13. Mitosis Is the precise distribution of DNA to daughter cells IPMAT
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14. Interphase This phase consists of: G1 phase-main growth of a cell
S phase- DNA replicated
G2 phase-many organelles and molecules required for cell division are produced
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15. Mitosis: Interphase Interphase: Long and active cycle
DNA and chromosomes are duplicated in the nucleus
Mitochondria are made in the cytoplasm
Cell grows
This Photo by Unknown Author is licensed under CC BY-SA

16. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming
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17. Mitosis: Prophase Prophase: Chromosomes coil, condense & shorten.
Each Chromosome appears as a double structure joined at the centromere
Nuclear envelope breaks down
Prometaphase:
Centrioles move to opposite ends of the cell
except in plants, there are no centrioles, but these events still occur as described here
Spindle Fibers grow from Centrioles
This Photo by Unknown Author is licensed under CC BY-SA

18. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming
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19. Mitosis: Metaphase Metaphase: Doubled chromosomes line up
Spindle fibers are now attached to each doubled chromosome at the centromere
This Photo by Unknown Author is licensed under CC BY-SA

20. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming
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21. Mitosis: Anaphase Anaphase: Doubled chromosomes separate
New chromosomes are pushed and pulled to the opposite ends of the cell by the spindle fibers
Each side now has identical sets of genes
This Photo by Unknown Author is licensed under CC BY-SA

22. Figure 10–5 Mitosis and Cytokinesis
Spindle forming
Centrioles
Chromatin
Centromere
Nuclear envelope
Centriole
Chromosomes (paired chromatids)
Interphase
Prophase
Spindle
Cytokinesis
Centriole
Metaphase
Telophase
Individual chromosomes
Anaphase
Nuclear envelope reforming
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23. Mitosis: Telophase-Cytokinesis
Chromosomes approach the ends and group together
New nuclear membrane
Cytokinesis:
Cytoplasm divides
New cell membrane forms (cell wall laid between new cells in plants)
The new cells enter interphase
This Photo by Unknown Author is licensed under CC BY-SA

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

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

26. How is the DNA of a parent cell and daughter cell related in mitosis?
There is absolutely no difference in DNA between the parent cell and daughter cell in mitosis. During mitosis, the DNA is copied exactly and transferred, so the DNA is exactly the same in both cells.

27. Section Outline 10–3 Regulating the Cell Cycle
A. Controls on Cell Division
B. Cell Cycle Regulators
1. Internal Regulators
2. External Regulators
C. Uncontrolled Cell Growth
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28. Regulating the Cell Cycle
Different types of cells go through the cell cycle at different rates.
Contact Inhibition
- in normal tissues cells stop dividing when
they come into contact with other cells
- when contact is lost they begin dividing again
- ex.: cut in your skin
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29. Control of Cell Division
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30. Cyclins are chemicals that cells produce which regulate the timing of the cell cycle in eukaryotic cells.
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.
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31. regulators
Internal regulators – proteins that respond to events inside the cell and allow the cell cycle to proceed or not.
- produced only when all DNA is replicated
- controls until all chromosomes attached to spindle fibers
External regulators – proteins that respond to events outside the cell.
- growth factors and surface receptors
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32. cancer Uncontrolled Cell Growth = Cancer
cancer cells do not respond to normal controls
divide uncontrollably and form masses of cells called tumors
cells may metastasize – break loose from tumor and spread
mutations in a gene called p53 are often what triggers cancer
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33. Stem cells
Stem Cells – unspecialized cells which can give rise to other cell types.
in an embryo there are many stem cells which will give rise to the specialized cells of your body
adult stem cells are present, but harder to find
medical research is trying to use stem cells to cure disease.
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34. Click the image to play the video segment.