Amazingly, a female human egg is about 2,000 times the size of a sperm; it also has all the organelles and proteins required of a living cell but only half of the necessary DNA. Thus, because of this, the egg cannot be considered a functional cell. Without fertilization, human egg cells survive about twenty-four hours after ovulation. Prior to that, the egg is maintained by the support structures known as follicular cells, which transfer nutrients to the egg.