Question

The middle piece of the sperm contains _______.
A. Proteins
B. Mitochondria
C. Centriole
D. Nucleus

Answer 1

The sperm is the male gamete. It is formed by the process of spermatogenesis. The sperms are formed and stored in the testis. Moreover, the process of spermatogenesis begins at puberty and occurs throughout the life of a male individual.

Complete answer: Sperms are male gametes that carry male genes. Sperms are flagellated and they reach the female ova to fertilize it. A mature sperm cell consists of four main parts, namely the head, neck, middle piece and tail. The sperm is covered with a plasma membrane. The head of the sperm has very little cytoplasm. It has a haploid nucleus that is elongated in shape. At the anterior portion of the head, a cap-like structure is present that is known as the acrosome. The acrosome consists of egg fertilizing enzymes. It is derived from the Golgi apparatus. The neck of the sperm consists of the proximal and the distal centrioles. The proximal centriole helps in the cleavage of the fertilized ovum. The distal centriole gives rise to the tail. The middle piece consists of twenty-five to thirty spirally arranged mitochondria. These mitochondria provide energy for the movement of the sperm. Due to this reason, it is known as the powerhouse of the sperm. The tail is made up of the central axial filament that is surrounded by a small amount of cytoplasm and cell membrane.

Hence, the correct answer is option B.
Note: The human male ejaculates semen in the female tract during sexual intercourse. This insignificant amount of semen consists of 200 to 300 million sperms. For normal fertility, at least 60 percent of the sperms should have a normal shape and forty percent must show vigorous motility.