polyspermy

…normally enters an egg (polyspermy), only one spermatozoal nucleus actually merges with the egg nucleus. The most important result of fertilization is egg activation, which allows the egg to undergo cell division. Activation, however, does not necessarily require the intervention of a spermatozoon; during parthenogenesis, in which fertilization does…

…more than one spermatozoon (polyspermy) is due to some property of the egg surface; in others, however, the egg envelopes are responsible. The ability of some eggs to develop a polyspermy-preventing reaction depends on a molecular rearrangement of the egg surface that occurs during egg maturation (oogenesis). Although immature…