Mitosis

• Why do multicellular eukaryotic organisms require a continuous supply of new cells?


  For growth, development, and repair
• What is the process through which new cells are generated called?

  The cell cycle
• What are the three main stages of the cell cycle?

  Growth, DNA replication, and mitosis (cytokinesis)
• What happens during the growth stage of the cell cycle?


  The cell increases in size and the number of subcellular structures
• What occurs during DNA replication in the cell cycle?

  The DNA is duplicated for the two new cells
• How does DNA appear when a cell is not dividing?


  It is spread out in long strings
• What happens to DNA as a cell prepares for division?


  It condenses into chromosomes
• What do chromosomes contain?


  A large number of genes
• How many copies of each chromosome do eukaryotic cells have?


  Two copies, one from each parent
• How many pairs of chromosomes do humans have?


  23 pairs
• Why can't animals of different species reproduce fertile offspring?

  Due to differences in the number of chromosomes
• What shape do duplicated chromosomes take?

  An X shape
• What is the significance of the arms of the X-shaped chromosome?


  The right arm is a duplicate of the left arm
• What happens to the chromosomes during cell division?

  They line up along the center of the cell
• What attaches to the chromosomes during cell division?


  Fibers from either side of the cell
• What is the term for the final stage of cell division?

  Cytokinesis
• What occurs during cytokinesis?


  The cell membrane and cytoplasm pull apart to form two daughter cells
• What do the resulting daughter cells contribute to after division?

  Growth, development, or repair
• What are the stages of the cell cycle?

  1. Growth
  2. DNA replication
  3. Mitosis (division)
  4. Cytokinesis
• How do the daughter cells compare to each other and the parent cell?


  • Each daughter cell has the same DNA
  • They are identical to each other
  • They are identical to the parent cell
• What is the role of chromosomes in cell division?

  • Carry genetic information
  • Ensure proper distribution of DNA during cell division
  • Control development of characteristics