Capacitation is the process that makes sperm able to fertilize an egg.
A traveling sperm undergoes capacitation which takes approximately seven hours. If a sperm reaches the ovum before completing capitation it fails to fertilize the egg.
Some of the key processes involved in capacitation include:
The tail of the sperm which is composed of a long flagellum moves faster by rotating in a whiplike motion
'Sperm head membrane' changes so that it can fuse with the ovum
The acrosomal enzyme are prepared to digest 'protective layers surrounding the egg' consequently allowing male DNA to enter egg.