So fertilization is the interaction between sperm cell and our egg cell. The sperm cell is shown in blue and the egg cell is this entire structure. So notice the sperm cell contains a tail, that is the flagellum. It allows our cell, our sperm cell, to move within the fluid. And it also contains a head that contains the cytoplasm, the organelles such as the mitochondria and the nucleus that is shown in blue. And it also contains a specialized structure known as the acrosome, found on the tip of the head, that contains special digestive enzymes that are responsible for digesting a hole in the membrane surrounding our excel, as we'll see in just a moment.