cell division, mitosis and meiosis

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cell division, mitosis and meiosis
2011-11-02 20:07:09
biology cell division mitosis meiosis

biology 160 cell division
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  1. cell division
    the process by which a cell reproduces itself
  2. why do normal healthy cells divide
    • normal growth
    • development
    • repair
  3. how do cells divide
    before dividing it makes a copy of its contents so that each new cell has the same amount of organelles, DNA, and cytoplasm as the original cell
  4. cell cycle
    ordered sequence of stages that a cell progresses through in order to divide during its life
  5. stages of cell cycle
    • preparatory stages G1 S G2
    • division stages (mitosis and cytokinesis)
  6. interphase
    • the preparatory phases of cell divisioncell makes a copy of the DNA, and produces more organelles and cytoplasm
    • includes G1, S, and G2
  7. mitosis
    the sister chromatids of each chromosome are separated from one another, setting up the 2 identical nuclei of the daughter cells
  8. G1 phase
    cell grows and prepares to divide both its DNA and its organelles
  9. S phase
    • DNA replication occurs
    • chromosomes are duplicated during this phase
  10. G2 phase
    cell prepares for division
  11. sister chromatid
    • one of the 2 identical DNA molecules that make up a duplicated chromosome following DNA replication
    • joined together at a region of the chromosome known as the centromere
    • during mitosis and cytokinesis, they pull apart and move into separate daughter cells
  12. cytokinesis
    • the cytoplasm divides into 2 cells, each containing a full complement of organelles and DNA
    • cell membrane pinches in to completely surround each new daughter cell
  13. phases of mitosis
    • 1 prophase
    • 2 prometaphase
    • 3 metaphase
    • 4 anaphase
    • 5 telophase
  14. prophase
    • replicated chromosomes begin to coil up
    • nuclear membrane begins to disassemble
    • protein fibers of the mitotic spindle begin to form
  15. prometaphase
    • chromosomes condense to shorten them, making it easier to separate
    • spindle fibers attach to chromosomes on both sides at the centromere region
  16. metaphase
    • spindle fibers from opposite ends of the cell pull on chromosomes
    • chromosomes are aligned along the middle of the cell
  17. anaphase
    spindle fibers shorten and pull sister chromatids to opposite ends of the cell
  18. telophase
    • identical set of chromosomes reaches each pole
    • spindle fibers dissemble
    • nuclear membrane forms around each set of chromosomes, forming the daughter cell nuclei
  19. interphase
    2 identical daughter cells are formed, each with the same number of chromosomes as the parent cell
  20. cell cycle checkpoints
    system of checkpoints to prevent a cell from progressing to the next stage of division until it accurately finishes the current stage
  21. apoptosis
    programmed cell death to prevent cells from producing more damaged daughter cells
  22. cancer
    disease of unregulated cell division
  23. cancer cells
    damaged checkpoint mechanisms - allows them to divide when they shouldn't and bypass apoptosis, passing damaged DNA to daughter cells