Cancer and Control of the Cell Cycle by wuyunyi


									Control of the Cell Cycle
Normal Control of the Cell Cycle

   Enzymes control cell cycle by monitoring
    progress from phase to phase.
   Some enzymes are needed to begin and keep
    the cell cycle running.
   Enzyme production is regulated by genes
    –   Genes are segments of DNA that control the
        production of a protein.

   Sometimes, cells lose control of the cell cycle.
   This can be due to:
    –   Failure to produce certain enzymes
    –   Overproduction of enzymes
    –   Production of enzymes at the wrong time
    –   Environmental factors
   Uncontrolled cell division is CANCER!
When does this happen?

   The period of Interphase before DNA
    replication is a critical point in the cell cycle.
   Some scientists think this is when most
    mistakes in the cell cycle occur because there
    are several enzymes that need to trigger DNA
    replication at this point.
Why does CANCER occur?

   Cancer is due to a change in one or more of
    the genes that produce enzymes involved in
    controlling the cell cycle.
   Cancerous cells form masses of tissue called
    tumors that deprive normal cells of nutrients.
   Eventually, cancer cells will invade the rest of
    the body and affect organ function (metastasis)
How common is CANCER?

   Cancer is the second leading cause of death in
    the United States!
   It can affect any tissue in the body.
   In the United States, the most common kinds
    of cancer are:
    –   Lung
    –   Breast
    –   Colon
    –   Prostate
Statistics from 1999
    Causes of Cancer: Both Genetic
         and Environmental

   Environmental Factors
    –   For immigrants, cancer rates follow the pattern of
        the country in which people live, not their country of
    –   Cigarette smoke
    –   Air/Water Pollution
    –   Exposure to UV rays
    –   Viral infections
   All of these damage the genes that control the
    cell cycle.
Cancer Prevention

   Diets low in fat and high in fiber
   Vitamins and minerals, especially carotenoids,
    A, C, E, and calcium.
   Daily exercise
   No tobacco use
Breast Cancer
Skin Cancer
Stomach Cancer
Ovarian Cancer Cell
Mouth Cancer

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