During the process of spermatogenesis, the secondary spermatocytes undergo ________ division to produce ________ spermatids.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Meiotic, haploid
Option (1) Mitotic, haploid — Incorrect. Mitosis takes place earlier, when the spermatogonia multiply. The secondary spermatocytes are already in the middle of meiosis.
Option (2) Mitotic, diploid — Incorrect. Both words are wrong. The division is not mitotic, and a spermatid is never diploid. Only the spermatogonia and the primary spermatocytes are diploid.
Option (3) Meiotic, diploid — Incorrect. The division is meiotic, but the product is wrong. The chromosome number is already halved in the first meiotic division, so the spermatids cannot be diploid.
Option (4) Meiotic, haploid — Correct. A secondary spermatocyte has 23 chromosomes. It completes the second meiotic division, and each one gives two spermatids with 23 chromosomes. So one primary spermatocyte gives four haploid spermatids, which later change into sperms.
NCERT Extract:
Gametogenesis – “The primary sex organs – the testis in the males and the ovaries in the females – produce gametes, i.e, sperms and ovum, respectively, by the process called gametogenesis. In testis, the immature male germ cells (spermatogonia) produce sperms by spermatogenesis that begins at puberty. The spermatogonia (sing. spermatogonium) present on the inside wall of seminiferous tubules multiply by mitotic division and increase in numbers. Each spermatogonium is diploid and contains 46 chromosomes. Some of the spermatogonia called primary spermatocytes periodically undergo meiosis. A primary spermatocyte completes the first meiotic division (reduction division) leading to formation of two equal, haploid cells called secondary spermatocytes, which have only 23 chromosomes each. The secondary spermatocytes undergo the second meiotic division to produce four equal, haploid spermatids (Figure 2.5).”
