Cell cycles, chromosomes & Mitosis

• Why do multicellular eukaryotic organisms need 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
• What happens during the first step of the cell cycle?

  The cell grows and increases subcellular structures
• What occurs during DNA replication?

  The DNA is duplicated for 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 pairs of chromosomes do humans have?

  23 pairs
• How many copies of each chromosome do eukaryotic cells have?

  Two copies, one from each parent
• Why can't animals of different species reproduce fertile offspring?

  They have different numbers of chromosomes
• What shape do duplicated chromosomes take?

  An X shape
• What do the arms of the X-shaped chromosome represent?

  Identical DNA from both halves
• What happens to chromosomes during cell division?

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

  Fibers from either side of the cell
• What is the term for the two sides of the cell during division?

  Poles
• What happens to the chromosomes during the pulling process?

  They break into two separate arms
• What is the final stage of the cell cycle called?

  Cytokinesis
• What occurs during cytokinesis?

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

  Growth, development, or repair
• What can daughter cells do after division?

  Undergo the cell cycle again