the cell cycle

• Cell Cycle


  The process by which a eukaryotic cell divides to produce two genetically identical daughter cells, each with an identical set of chromosomes
• Mitosis


  • One round of division
  • Cells made are genetically identical
  • Diploid cells made
  • For growth & repair
• Mitotic index


  Number of cells undergoing mitosis divided by total number of cells x 100
• Prophase


  • Chromosomes condense & become visible
  • Nucleolus disappears
  • In animal cells, centrioles separate & move to opposite cell poles
  • Spindle fibers form between poles
  • Plants have a spindle apparatus but no centrioles
• Metaphase


  • Chromosomes line up along equator of cell
  • Spindle fibres attach to centromeres & chromosomes
• Anaphase

  • Chromosomes break at centromeres
  • Sister chromatids move to opposite ends of cell
  • Spindle fibers retract, pulling centromeres & chromatids to opposite poles
• Telophase


  • Nuclear membrane reforms
  • Nucleolus reappears
  • Chromosomes unwind into chromatin
  • Chromosomes are at each cell pole & longer & thinner again
  • Spindle fibers disintegrate, nucleus starts to reform
• Cytokinesis


  1. Cell pinches in the middle

  2. Cytoplasm splits into two
• Interphase


  • Longest stage
  • Organelles double
  • Cell grows
  • DNA replicates