MEIOSIS VS. MITOSIS

Every day, our skin cells and other somatic (body) cells undergo division to replenish the dying cells. When this happens, the new cell will have the same amount of chromosomes and organelles. This process is called mitosis. A diagram of this event is given.

The four phases include:

  • Prophase - doubling of chromosomes and organelles and centrioles visible

  • Metaphase - chromosomes line-up in the middle and spindles from centrioles connect to each chromatid (half of chromosome)

  • Anaphase - chromatids are pulled apart to separate ends, and the membrane begins to pinch off in the middle

  • Telophase - complete division of cytoplasm, and two cells are formed

    This process occurs in all diploid (2n) cells, except for the sex cells, which will produce gametes for reproductive purposes. The process for the production of gametes is called meiosis.

    In this process, there are seven stages:

  • Prophase I - doubling of homologous chromosomes (identical chromosomes - 2 pairs of each sister chromatids)

  • Metaphase I - lining of homologous chromosomes in the middle

  • Anaphase I - separation of homologous chromosomes to form two cells with 2n of the chromosomes

  • Telophase I - two cells - 2n of chromosome number

  • Metaphase II - lining up of chromosomes in the middle

  • Anaphase II - separation of chromosomes into chromatids (2n to 1n)

  • Telophase II - four new 1n cells

    In the male, all four of the 1n (haploid) cells will become sperm. However, in the female, only one cell will become an egg and the rest will be polar bodies.

     

    © 2003-2024: USA · USDA · NRPSP8 · Program to Accelerate Animal Genomics Applications. Contact: Bioinformatics Team