Final answer:
The acrosomal reactions involve the release of enzymes by the sperm to penetrate the egg's layers and fuse with its membrane.
Step-by-step explanation:
The acrosomal reactions are a series of biochemical reactions that occur in the fertilization process. When a sperm binds to the zona pellucida of an egg, the acrosome, which contains enzymes, releases these enzymes to degrade the protective layers of the egg and penetrate it. These reactions involve the fusion of the sperm and egg membranes, allowing the transfer of the sperm's nucleus into the egg.