B2 cell division

• Chromosome

  Structure in the nucleus of a cell that carries the genes
• Gene


  Small packet of information that controls a characteristic, or part of a characteristic, of the body
• DNA


  Unique molecule that makes up chromosomes
• Cell cycle


  1. Stage 1: Cells grow bigger, increase mass, replicate DNA

  2. Stage 2 - Mitosis: One set of chromosomes pulled to each end, nucleus divides

  3. Stage 3: Cytoplasm and cell membranes divide to form two identical daughter cells
• Mitotic cell division


  • Important in the growth, repair, and development of multicellular organisms
• In a child


  Mitotic divisions produce new cells faster than the old ones die
• As an adult


  Cell death and mitosis keep more or less in balance
• When you get very old

  Mitosis slows down and you show the typical signs of ageing
• The cell divides in two to form two daughter cells, each with a nucleus containing four chromosomes identical to the ones in the original parent cell
• Cells produced when the nucleus divides by mitosis are genetically identical
• In body cells, chromosomes are found in pairs
• Before a cell can divide it needs to grow, replicate the DNA to form two copies of each chromosome and increase the number of subcellular structures
• In mitosis one set of chromosomes is pulled to each end of the cell and the nucleus divides
• Finally the cytoplasm and cell membranes divide to form two identical cells