Each sperm cell has three distinct regions: the head, the middle piece, and the tail. The head consists of a nucleus with the genetic material (DNA) and an acrosome at the tip. The acrosome contains enzymes to help the sperm penetrate the oocyte (egg). The middle piece contains mostly mitochondria which provide energy for movement. The tail moves the sperm cell from one place to another. The tail is the only flagellum in the human body.