Chapter 10 Cell Growth

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Chapter 10Cell Growth Division

• Section 10-3
• Regulating Cell Growth

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Controls On Cell Division

• When Cells In Cell Cultures Come In Contact With
  Each Other, They Stop Growing.
• Why?

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Controls On Cell Division

• If A Hole Is Made In The Cell Culture, Cell
  Growth Will Restart Continue Until The Hole Is
  Filled.
• Why?

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Controls On Cell Division

• In Your Body The Rate Of Cell Growth Is
  Controlled.
• Injury Causes Rapid Division Until The Wound Is
  Healed. Then Division Slows Again.
• Why?

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Cell Cycle Regulators

• Key Concept
• Cyclins Regulate The Timing Of The Cell Cycle In
  Eukaryote Cells.
• Discovered In The 1980s
• Cyclins Are A Family Of Closely Related Proteins
  That Rise Fall Within The Cell With The Cell
  Cycle

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Cyclins Cell Cycle
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Cell Cycle Regulators

• Cyclins
• When Injected Into Non-Dividing Cells, Cyclins
  Cause Mitotic Spindles To Form.

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Cell Cycle Regulators

• Cyclins
• When Injected Into Non-Dividing Cells, Cyclins
  Cause Mitotic Spindles To Form.

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Cell Cycle Regulators

• Cyclins
• When Injected Into Non-Dividing Cells, Cyclins
  Cause Mitotic Spindles To Form.

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Cell Cycle Regulators

• Other Regulator Proteins Continue To Be Found.

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Other Internal Regulators

• These Proteins Respond To Events Inside The Cell.
• Several Make Sure The Cell Does Not Enter Mitosis
  Until All Chromosomes Have Been Replicated.
• Others Stop The Cell From Entering Anaphase Until
  All Chromosomes Are Attached To The Mitotic
  Spindle

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Cyclins Cell Cycle
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External Regulators

• These Respond To Events Outside The Cell
• They Direct The Cell To Speed Up Or Slow Down The
  Cell Cycle
• These Include Growth Factors

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Growth Factors

• Very Active During
• Embryonic Development
• Wound Healing

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Other External Regulators

• Molecules On The Cell Membrane Of Neighboring
  Cells Slow The Growth Process
• They are like sensors that signal the cell to
  slow/stop growth

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Uncontrolled Cell Growth
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Uncontrolled Cell Growth

• Key Concept
• Cancer Cells Do Not Respond To The Signals That
  Regulate The Growth Of Most Cells. As A Result,
  They Form Masses Of Cells Called Tumors That Can
  Damage Surrounding Tissue.

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Uncontrolled Cell Growth

• Metastasis
• Cancer Cells Break Loose From The Tumor And
  Invade Tissues Throughout The Body

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Some Carcinogen Sources

• Smoking
• Radiation
• Viral Infection

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p53 Gene

• Usually Stops The Cell Cycle Until Chromosomes
  Have Been Properly Replicated.
• High Percentage Of Cancers Cells Have Defects At
  This Gene Site