<P> A sperm penetration assay includes an acrosome reaction test that assesses how well a sperm is able to perform during the fertilization process . Sperm that are unable to properly go through the acrosome reaction will not be able to fertilize an egg . However, this problem only occurs in about 5% of men that have the test done . This test is rather expensive and provides limited information on a man's fertility . </P> <P> In other cases, such as in the wood mouse Apodemus sylvaticus, premature acrosome reactions have been found to cause increased motility in aggregates of spermatozoa promoting fertilization . </P> <P> The acrosomal reaction normally takes place in the ampulla of the fallopian tube (site of fertilization) when the sperm penetrates the secondary oocyte . A few events precede the actual acrosome reaction . The sperm cell acquires a "hyperactive motility pattern" by which its flagellum produces vigorous whip - like movements that propel the sperm through the cervical canal and uterine cavity, until it reaches the isthmus of the fallopian tube . The sperm approaches the ovum in the ampulla of the fallopian tube with the help of various mechanisms, including chemotaxis . Glycoproteins on the outer surface of the sperm then bind with glycoproteins on the zona pellucida of the ovum . </P> <P> Sperm that did not initiate the acrosome reaction prior to reaching to the zona pellucida are unable to penetrate the zona pellucida . Since the acrosome reaction has already occurred, sperm are then able to penetrate the zona pellucida due to mechanical action of the tail, not because of the acrosome reaction itself . </P>

What is the place of secretion of fertilisin