Chromosomes and mitosis

• Most cells in the body have a nucleus. The nucleus contains genetic material in the form of chromosomes.
• Chromosomes are coiled up lengths of DNA molecules.
• Each chromosome carries a long number of genes. Different genes control the development of different characteristics. e.g. hair colour
• Body cells normally have two copies of each chromosome - one from each parent.
• A human cell has 23 pairs of chromosomes.
• Body cells in multicellular organisms divide to produce new cells as part of a series of stages called the cell cycle.
• The stage go the cell cycle when the cell divides is called mitosis.
• Mulitcellular organisms use mitosis to grow or replace damaged cells.
• The end of the cell cycle results in two new cells identical to the original cell, with the same number of chromosomes.