What is the difference between mitosis and meiosis?

Meiosis is the process by which new gametes are formed in the testes and ovaries. Mitosis is the process by which all other cells of the body divide, for tissue growth and repair. One way of remembering this is that mitosis has the sound 'toe' in it, so that's the way that cells divide in normal tissues like your toes. Mitosis produces 2 daughter cells that have the same number of chromosomes as the parent cell, which is 46 in humans. Meiosis produces 4 daughter cells, each with half the number of chromosomes as the original parent cell. This is necessary because two gametes made by meiosis will fuse during fertilisation, and the resulting cell needs to have the normal number of chromosomes, not double. Before mitosis happens, the chromosomes of the cell duplicate. Mitosis has four stages: prophase, metaphase, anaphase and telophase. In prophase, the chromosomes condense to become visible, and the envelope around the nucleus disappears. In metaphase, the chromosomes line up in the middle of the cell and attach to the spindle. Next, in anaphase, the spindle pulls the duplicated chromosomes apart, one of each copy to each side of the cell. Then in telophase, two new nuclear envelopes reform around the chromosomes, and two identical cells have formed from one. The process is similar in meiosis, with the four named stages still taking place. However, the whole process happens twice so that each new cell contains half the number of chromosomes. Additionally, during the first prophase, the duplicated chromosomes pair up and swap fragments of their DNA in a process called crossing over. The paired homologous chromosomes then separate in the second division. This does not happen in mitosis. It's important because this is one major way that variation is introduced, so that we look similar to our siblings but not identical because gametes do not all contain the same DNA.