the process of fertilisation in mammals

• 1 – sperm reach the egg by following chemicals released by the egg
• 2 – The acrosome swells, fusing with the sperm cell surface membrane
• 3 – Acrosome reaction - digestive enzymes are released from the acrosome breaking down the zona pellucida
• 4 – the sperm fuses with the ovum membrane
• 5 – Cortical Reaction- enzymes released from the lysosomes in the ovum thicken the jelly-like layer preventing entry of other sperm
• 6 – Fusion of the nuclei