Question

Explain the role of gametes in the process of reproduction.

Answer 1

Hint: Haploid structures produced by the reproductive systems of male (sperm/pollen grain) and female (ova/egg cell) helps in the process of reproduction. They are produced by reductional division or meiosis division.

Complete answer: Sperms are formed by the process of spermatogenesis. A typical mammalian sperm is a flagellated microscopic structure and composed of four parts namely head, neck, middle piece, and tail. The whole body of the sperm is covered with the plasma membrane. The Head of the sperm contains a haploid nucleus which becomes compact forming the major part of the sperm. The anterior portion of the head is covered by a cap-like structure known as acrosome which contains lytic enzymes.
-The acrosome of sperm produces lysins known as hyaluronidase which dissolves the egg membrane for fertilization of an ovum. In the middle piece, mitochondria are coiled around an axial filament known as a mitochondrial spiral. They provide energy for the movement of the sperm tail to facilitate fertilization. The tail helps in the movement of sperm and is longer than the head.
-Ova is produced by the process of oogenesis. Oogenesis is the process in which the primary egg cell develops into a mature ovum. The diploid egg cell increases in size and transforms into a primary oocyte. The secondary oocyte is produced by the reductional division or meiosis I of the primary oocyte. It has 23 chromosomes.
-Male gamete can carry X or Y chromosome whereas female gamete carries only X chromosome. The male gamete is smaller in size than the female gamete. The male and female gametes fuse and this process is known as fertilization.
-Reproductive cells that are used for the process of sexual reproduction to produce a diploid cell is known as a zygote. The gametes are produced by reproductive organs in males and females. The gametes are haploid in nature.

Note: Fusion of male gamete carrying an X chromosome or a Y chromosome with the female gamete or ova determines the sex of the offspring. These processes result in the formation of the zygote that undergoes several changes to form a foetus.