Which part of sperm contains hydrolytic enzymes?

The correct answer is Option (2) → Acrosome

A human sperm has four parts: a head, a neck, a middle piece and a tail. The head holds a haploid nucleus. The front part of the nucleus is covered by a cap-like structure, the acrosome. The acrosome is filled with enzymes; these are the hydrolytic (digestive) enzymes the question means. These enzymes help the sperm get through the layers around the ovum and fertilise it.

Option (1) Middle piece — Incorrect. The middle piece holds many mitochondria. They make the energy that moves the tail, not digestive enzymes.

Option (2) Acrosome — Correct. The acrosome is the enzyme-filled cap on the sperm head. Its enzymes help the sperm enter the ovum during fertilisation.

Option (3) Tail — Incorrect. The tail moves the sperm forward and gives it motility. It does not store enzymes.

Option (4) Nucleus — Incorrect. The nucleus carries the haploid set of chromosomes, the father’s genetic material. The enzymes lie in the acrosome that covers it.

NCERT Extract:
Gametogenesis – “… Let us examine the structure of a sperm. It is a microscopic structure composed of a head, neck, a middle piece and a tail (Figure 2.6). A plasma membrane envelops the whole body of sperm. The sperm head contains an elongated haploid nucleus, the anterior portion of which is covered by a cap-like structure, acrosome. The acrosome is filled with enzymes that help fertilisation of the ovum. The middle piece possesses numerous mitochondria, which produce energy for the movement of tail that facilitate sperm motility essential for fertilisation.”

Figure 2.6 Structure of a sperm