Fertilization is the process by which an energized sperm meets a secondary oocyte in the juxtaposition of the fallopian tube and then combines to form a fertilized egg. Usually, fertilization occurs within 12 hours of ovulation and the entire process takes about 24 hours. What usually happens is that the semen is ejaculated within the vagina and the sperm leaves the semen and travels through the cervical canal uterine cavity and then into the tubal cavity. During this process, the glycoproteins on the surface of the acrosome of the sperm are degraded by the amylase enzyme in the reproductive secretions, and the ratio of cholesterol to phospholipids in the acrosomal membrane structure and the membrane potential change, which is known as the process of sperm capacitation. After being energized, the sperm reaches the juxta-pubic area of the fallopian tube and combines with the waiting follicle in the fallopian tube.