mitosis

• Multicellular eukaryotic organisms require a continuous supply of new cells for growth, development and repair
• The process through which these cells are generated is known as the cell cycle
• Cell cycle


  1. Growth

  2. DNA replication

  3. Mitosis and division (cytokinesis)
• DNA


  Usually spread out in long strings when cell is not dividing, condenses into chromosomes when cell starts to prepare for division
• Chromosomes


  • Packets of DNA, each containing a large number of genes that control the development of different characteristics
  • Eukaryotic cells have two copies of each chromosome, one from mother and one from father
• Humans have 23 pairs of chromosomes, 46 chromosomes in total
• Chromosome duplication


  1. Duplicate stays attached to the original chromosome, forming an X shape

  2. Each chromosome is colored half green to highlight the fact that the right half is a duplicate of the left half
• Cell division


  1. All 46 chromosomes line up along the center of the cell

  2. Fibers from either side of the cell attach to their respective half of each chromosome and pull the arms to opposite sides

  3. Cell membrane and cytoplasm pull apart, forming two daughter cells with identical DNA
• The resulting daughter cells can then contribute to growth, development or repair and undergo the cell cycle all over again