Question

What is Gametogenesis?

Answer 1

Gametogenesis plays a crucial role in humans to support the continuation of generations. In males this process is called spermatogenesis and in females it is called oogenesis. The formation of a zygote requires fusion of two cells. The zygote contains $23$ pairs of chromosomes and hence each parent cell must have half the total number of chromosomes that should be in a somatic cell. Therefore, through gametogenesis specialized sex cells are produced.

Complete answer:
Gametogenesis is a biological process through which diploid cells undergo cell division to form mature haploid gametes. The gametes are the sex cells which are needed for reproduction in plants and animals. Gametogenesis occurs through meiosis.
In males, gametogenesis occurs to produce sperms. The process begins at the start of puberty. First, the immature, diploid spermatogonia undergo mitotic division to increase their number. The resultant primary spermatocytes undergo meiosis to produce haploid cells called the secondary spermatocytes. These secondary spermatocytes will then undergo the second meiotic division to produce spermatids. The spermatids undergo spermiogenesis to transform into sperms. The entire process takes place under the influence of gonadotropin releasing hormone, luteinizing hormone, follicle stimulating hormone and androgens.
In females, ovum is produced. During female fetal development millions of oogonia are formed in the ovary. The oogonia undergoes meiosis and rests at the prophase-I stage. The resultant cells are called primary oocytes. At the stage of puberty, each primary oocyte completes meiosis and forms a secondary oocyte and a polar body. The secondary oocyte undergoes second meiotic division to form an ovum. The entire process takes place under the influence of follicle stimulating hormone, oestrogen, luteinizing hormone and progesterone.

Note:
The ovum and the sperm fuse during fertilization to form the zygote. The zygote then divides mitotically to develop into a fetus. Gametogenesis is the preliminary step of the reproduction process. If gametogenesis is hampered, the process of reproduction and offspring generation will be greatly affected. It may lead to the formation of genetic disorders like Down's syndrome, Edwards syndrome, Patau’s syndrome etc.