Courtesy of Chris Patton, Stanford University |
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A sperm undergoes the acrosome reaction and binds with the egg receptor. The cortical vesicles fuse with the plasma membrane and undergo exocytosis releasing their contents into the peri-vitelline space. The modified fertilization membrane detaches and starts to rise. The sperm is pulled into the egg with help from the fertilization cone. Microtubules radiating from the centrosome associated with the male pronucleus helps guide the nucleus to the center of the egg where it fuses with the female pro-nucleus. |