chromosomes and mitosis

• chromosomes contain genetic information
• chromosomes are coiled-up lengths of DNA molecules
• each chromosome carries a large number of genes
• body cells usually have two copies of each chromosome - one from the mother and one from the father
• humans have 23 pairs of chromosomes
• the cell cycle makes cells for growth, development and repair
• the stage of cell cycle when the cell divides is called mitosis
• multicellular organisms use mitosis to grow or replace cells that have been damaged
• the end of the cell cycle results in two new cells identical to the original cells with the same number of chromosomes
• in a cell that's not dividing, the DNA will be spread out in long strings
• before a cell divides, it must grow and increase the amount of subcellular structures such a mitochondria and ribosomes
• the chromosomes line up at the centre of the cell and cell fibres pull them apart. the two arms of each chromosome go to opposite ends of the cell
• membranes form around each of the sets of chromosomes. these become the nuclei of the two new cells
• lastly, the cytoplasm and cell membrane divide (cytokinesis)
• the cell have now produced two new daughter cells. the daughter cells contain exactly the same DNA - they're identical