Chromosomes/ chromatid

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• Chromosomes/ chromatid

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Friday November 19, 2010

• Homework stamps
• Cell Growth and Division WS
• 10-3 Learning Targets
• Mitosis models
• Clean up!
• Review for test next Tuesday
• Chapter 10 Assessment in textbook (pg. 257-258)
  1-10, 11, 12, 14, 17, 18, 20, 21,
  22,23,25,29,31,32
• Notes on cell regulation

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Cell Cycle Regulators Notes

• Monday November 22, 2010

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Mitosis Review

• Cells divide through a process called mitosis
• For example Onion Root Tips
• http//www.cellsalive.com/cell_cycle.htm

Interphase                                                                    Prophase                                                                    Metaphase                                                                    Anaphase                                                                    Telophase                                                                   
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Cell Division

• Cell divide at different rates
• Nerve cells dont divide once developed
• Skin cells grow rapidly through life
• liver cells, retain but do not normally utilize
  their capacity for division. Liver cells will
  divide if part of the liver is removed. The
  division continues until the liver reaches its
  former size. (REGENERATION SWEET!!!)

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What controls cell division?

• Observation cells stop growing when in contact
  with other cells (fig. 10-7, pg. 250)
• Conclusion controls on cell division can be
  turned on and off

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What regulates the cell cycle?

• Cyclins discovered in 1980s proteins that
  regulate the timing of the cell cycle
• During the cell cycle, amount of cyclin increases
  and decreases
• Experimental evidence cyclin injected into a
  cell in G2 interphase entered into Mitosis when
  cyclin present (pg. 251, Fig. 10-8)

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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Other regulatory proteins

• Internal Regulators (inside cell)
• Proteins that respond to events inside the cell
  for example will not let cell continue cycle
  unless all chromosomes replicated
• External Regulators ( outside cell)
• Speed up or slow down cell cycle
• Growth factors stimulate growth and division
  (embryos and wound healing)
• Surface molecules of neighbor cells slow or stop
  division prevent excessive growth

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Uncontrolled Cell Growth

• Cancer cells that lose their ability to control
  growth
• Dont respond to internal/external regulators
  uncontrolled growth --- masses of cells
  tumors/growth

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Cancer

• Some causes?
• Environmental Hereditary
• Smoking
• Radiation
• Viral infection
• Mutations in DNA
• Defect in p53 gene which usually provides a
  checkpoint to test whether the chromosomes have
  properly replicated

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Video links

• Cells Alive Cell Cycle w/checkpoints
  http//www.cellsalive.com/cell_cycle.htm
• Skin Cancer Foundation http//www.skincancer.org/s
  kin-cancer-video.html

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Homework

• Lab book self-check (lab books due tomorrow)
• Study for test tomorrow