Fertilisation

• What happens when the sperm head comes into contact with the jelly coat surrounding the oocyte?

  Triggers the entry of calcium ions through the sperm plasma membrane via active transport
• What do the calcium ions cause?

  The outer membrane of the acrosome (sperm head coating) to fuse with the plasma membrane of the sperm, releasing enzymes
• What enzymes are released?

  Hyaluronidase and acrosin, which digest a pathway through the jelly coat
• What happens when the sperm head comes into contact with the plasma membrane of the oocyte?

  The nucleus of the sperm enters and fusion occurs- fertilises the oocyte and blocks the entry of other sperm