mitosis

• Why do multicellular eukaryotic organisms need new cells?

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

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

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

  The cell increases in size and organelles
• 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 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?

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

  An X shape
• What does each half of an X-shaped chromosome represent?

  A duplicate of the original chromosome
• What are the arms of a chromosome?

  Each half of the X-shaped chromosome
• 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 do the fibers do during cell division?

  They pull the arms of the chromosomes apart
• What is cytokinesis?

  The division of the cell membrane and cytoplasm
• What do the resulting daughter cells contribute to?

  Growth, development, or repair
• What happens to daughter cells after division?

  They undergo the cell cycle again
• Steps of mitosis & cytokinesis?

  1. DNA condenses to form chromosomes.
  2. Chromosomes line up along the centre of the cells.
  3. Cell fibres pull the two arms of each chromosome to opposite sides (poles) of the cell.
  4. Cytokinesis - the entire cell divides to form two identical daughter cells.
• Steps of the cell cycle?

  1. Cellular growth - the cell gets larger and produces more sub-cellular structures, such as mitochondria and ribosomes. 
  2. DNA replication - chromosomes duplicate, so that each consists of two arms (copies).
  3. More cell growth.
  4. Mitosis - the DNA divides into two.
  5. Cytokinesis - the cell divides into two.
• What is the purpose of mitosis?

  Growth and repair of tissues
• What are chromosomes made of?

  DNA molecules
• What are the two types of stem cells in mammals?

  • Adult stem cells
  • Embryonic stem cells
• Why do multicellular eukaryotic organisms need new cells?

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

  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 in the cell cycle?

  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 when 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?

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

  An X shape
• What is the significance of the right and left arms of a chromosome?

  They are duplicates of each other
• 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