The Cell Cycle The Cell Cycle - PDF by steepslope9876


									             The Cell Cycle

  Multicellular organisms constantly make new
  cells from _______________ cells. Making new
  cells allows organisms to __________ and
  replace cells that have __________.

The Life of a Cell:
   Cells pass through different stages in their
   life cycle.
  Cell cycle – The life cycle of a cell.
   The cell cycle begins when the cell is
   _______________ and ends when the cell
   _______________ and forms new cells.
   Before a cell divides, it must copy its ______.
   The DNA of a eukaryotic cell is located in
   the ___________________ on structures called
  Chromosomes – In a eukaryotic cell, one of
      the structures of the nucleus that are
      made up of DNA and protein; in a
      prokaryotic cell, the main ring of DNA.
   Copying chromosomes ensures that each
   new cell will be an exact _________ of its
   parent cell.
  Making More Prokaryotic Cells:
   Cell division in prokaryotic cells involves
   ____________ ____________, which means
   “splitting into two parts”.
   The result of binary fission is two cells that
   each contain one copy of the circular DNA.
   Prokaryotic cells reproduce by binary
   fission because they are less _______________
   than eukaryotic cells.

Eukaryotic Cells and Their DNA:
   The chromosomes of eukaryotic cells
   contain more DNA that those of prokaryotic
   cells do.
   Different kinds of eukaryotes have different
   numbers of chromosomes. The number of
   chromosomes an organism has has nothing
   to do with the ______________________ of the
   EX: fruit flies have 8 chromosomes
       humans have 46 chromosomes
       potatoes have 48 chromosomes
   An organism’s chromosomes are matched
   up in pairs called ____________________________
Homologous chromosomes – Chromosomes
   that have the same sequence of genes
   and the same structure.
   EX: Humans have 46 chromosomes so
       they have 23 pairs of homologous
       chromosomes. (46 ÷ 2 = 23)

Making More Eukaryotic Cells:
Three Stages of the Cell Cycle:     Interphase
      o Interphase – The cell grows and ________
            its organelles and chromosomes.
               After each chromosome is
               duplicated, the two copies are
               called ______________________.
               Chromatids are held together at a
               region called the _________________.
               The joined chromatids twist and
               condense into an ”X” shape.

      o Mitosis – The complicated process of
            chromosome ______________________ in
            eukaryotic cells.
        When mitosis is complete, each
        new cell has a copy of each
        Mitosis is divided into four
        phases: (PMAT)
        • P____________________
        • M____________________
        • A____________________
        • T____________________
o Cytokinesis – The _____________________ of
      the cytoplasm of a cell.
      In animal cells, cytokinesis takes
      place by pinching in the cell
      membrane until two daughter cells
      are formed.
      In eukaryotic cells with a cell wall,
      a ____________ ____________ forms in
      the middle of the cell. After the
      cell splits in two, a new cell wall
      forms where the cell plate was.
    * The result of cytokinesis is two new
      daughter cells that are _____________
      to each other and to the original
      cell. These cells now enter
      interphase and the ________ _________

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