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Cell cycle

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					Cell cycle
Cell cycle
  Most of the cell’s life is spent growing.
  The cycle of growth and division is called the
   cell cycle.
  Interphase – period of growth & activity
  A. G1 phase is a time of intense growth.
      Most of the cells’ life is spent is this
      phase.
   B. S phase – stands for synthesis
       An exact copy of each chromosome is
   made.
Cell Cycle

  C. G2 phase is the final stage of
   interphase.
  Cell is busy duplicating cell organelles.
  D. M phase – mitosis – cell division
  E. C Phase – cytokinesis – 2 identical
   cells
  Usual time for the cell cycle – 10 -30 hrs.
Cancer
  Cancer is a malignant growth resulting from
   uncontrolled cell division.
  Loss of control my be caused by
   environmental factors or by changes in
   enzyme production.
  Tumors are masses of tissue that deprive
   normal cells of nutrients.
  Metatasis occurs in later stages and allows the
   cancer cells to spread by using the circulatory
   system.
Causes of Cancer

  Environmental factors such as cigarette
   smoke, air & water pollution, UV
   radiation from the sun.
  Viral infections may damage genes.
  Cancer prevention –
  Diet low in fat & high in fiber
  Vitamins & minerals – Carotenoids,
   vitamins A, C, E, & calcium
Cancer
Skin Cancer

  1/3 of all malignancies in US.
  Skin composed of 2 layers –
  Epidermis – surface – composed of
   several layers of closely packed cells
  Melanin is a pigment that absorbs the
   UV rays before they reach basal cells.
Types of Skin Cancer

  Squamous cell carcinoma affects cells
   throughout the epidermis.
  Pink or red tumors
  Basal cell carcinoma – cancer cell are
   from the layer of epidermis that
   replenishes the epithelial cells
  Melanomas – cancer of the melanocytes
   that protect other cells from the UV rays
   of the sun

				
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