Embryology is a fascinating subject. First, you have to learn about the sex cells. Sex cells as in male or female. The male sex cell is the sperm and the female's sex cell is the egg. The egg cell is about 10 thousand times bigger than the sperm cell. The picture to the right is a comparison.
Sperm and Egg cell
The female sex cell is the egg cell. It has a zona pellucida, which is a thick outer shell made of glycoproteins. A glycoprotein is a protein with a bunch of little branches branching off of the plasma membrane. Right underneath the plasma membrane is an enzyme called cortical granules. Inside, there is mitochondria and a nucleus. Within the nucleus, there is the mothers DNA.
Inside the sperm cell is a nucleus. Inside the nucleus is the male DNA. In the tip of the sperm, there is something called acrosome. It is made up of enzymes, and you'll learn about what that does in the next paragraph. In the middle section of the sperm, there is mitochondria. That makes the sperm go fast like a torpedo. The tail of the sperm is just a little flagellum.
The next part is the actual fertilization part. Here is where you learn about what the enzymes do. A sperm goes up to an egg and fertilizes it. It can get through the plasma membrane by ejecting the acrosome in its tip into the egg. The cortical granules help the sperm get through by helping disintegrate away the plasma membrane. Then the sperm's DNA goes into the egg and the DNA's fuse together. Next you will learn from a zygote to blastocoel.
