Sex Sperm

  1. i just learn that before a lady have an embryo in her body, one male sex cell swims into her egg, but right before entering, the cell will cut itself its tail and destroy its head, only the part containing dna falls into the middle of the egg. i am wondering how can the that sex cell knows it already comes to its destination such that it can cut its tail ? if it can signal and receive signals from egg, can you please give me details the that signals too? :wink:
    thank you very much

    --sorry for my bad english--
     
  2. jcsd
  3. Moonbear

    Moonbear 12,265
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    The tail stays on the sperm while it is entering the egg, to help propel it as it penetrates the outer membranes. There is a reaction that takes place when the sperm encounters the egg due to an interaction of proteins on the surface of the cells. This does cause changes to the sperm so enzymes are released to help it penetrate into the egg. Look up "acrosome reaction" for more information about that.
     
  4. Acrosomes

    Thanks for that explanation, Moonbear. I found some more information on acrosomes (on a webpage where, happily, the entire Microsoft Encarta article on fertilization is plagiarized):


    • The third step is a complex process in which the sperm penetrate the egg’s surface coat. The head, or front end, of the sperm of almost all animals except fish contains an acrosome, a membrane-enclosed compartment. The acrosome releases proteins that dissolve the surface coat of an egg of the same species.

      In mammals, a molecule of the egg’s surface coat triggers the sperm's acrosome to explosively release its contents onto the surface coat, where the proteins dissolve a tiny hole. A single sperm is then able to make a slitlike channel in the surface coat, through which it swims to reach the egg's cell membrane.
     
  5. Moonbear

    Moonbear 12,265
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    I'm glad you were able to find a website with a simplified explanation. Everything I found was very technical, so I didn't post it...since kronecker was apologizing for his/her English, I didn't think references with a lot of technical terms would be very understandable.
     
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