A sperm cell undergoes capacitation once it enters the female reproductive tract. It is a process in which cholesterol and glycoproteins are removed from the sperm cell head which allows the cell to bind to the zona pellucida of the egg cell or ovum. It is the penultimate step in the maturation of mammalian spermatozoa and is important to render the sperm cell to be competent to fertilise an oocyte or egg. Capacitation is a biochemical event and prior to this the sperm cell is mature and shows normal motility.