Middle piece is formed of mitochondiral spiral , nebenkern around the proximal part of axoneme. The mitochondria are the carriers of the oxidative enzymes and the enzymes which are responsible for oxidative phosphorylation. So the middle piece is the power house of a sperm
The head of the sperm cell contains chromosomes, and at the leading end it has a cap, the ACROSOME, which contains enzymes necessary for the sperm cell to penetrate the female sex cell. Answer- Acrosome
Using the enzymes that are built into its surface, the sperm cell digests its way through the outer eggshell called the zona pellucida. The sperm cell is then able to enter into the main part of the egg, the ooplasm, achieving successful fertilization.
The nucleus is a part of the cell containing DNA and RNA and responsible for growth and reproduction. It is sometimes called the control centre of the cell, regulating the activities and actions of the cell. It is responsible for cell maintenance and replication of genetic material.