How does the egg cell and the sperm cell fuse together to form a zygote?

Egg cell contains various membranes: the important ones are :-

PRIMARY EGG MEMBRANES Vitelline membrane Zona Pellucida Zona Radiata

SECONDARY EGG MEMBRANES Corona Radiata Chorion

Sperm cell also contain various zones, those which is responsible for fertilisation is: Acrosome

Fertilisation : process whereby two sex cell fuse together to create new individual with genetic potential derived from both the parents

Recognition of egg and sperm :

the interaction of sperm and egg generally proceed by five steps

a) the chemo attraction of sperm to egg by soluble molecule secreted by the egg b) the exocytosis of acrosomal vesicles to release its enzyme c) binding of sperm to the extra cellular envelope (Vitellius membrane/zonal pellucid) of the egg d) passing of sperm through this extra cellular envelope e) fusion of egg and sperm plasma cell membrane