Rights: University of Waikato Published 13 February 2009 Size: 43 KB

Diagram showing the steps in fertilisation. The sperm attaches (1), binds (2) and penetrates (3) the zona pellucida. When the sperm fuses with the egg's membrane genetic material is released inside the egg. Fertilisation (4) occurs when the sperm's genetic material eventually combines with the egg's genetic material.