Select the correct statement/s from the following:
A. Spermatogonia always undergo meiotic cell division.
B. Primary spermatocytes divide by mitotic cell division.
C. Secondary spermatocytes have 23 chromosomes and undergo second meiotic division
D. Spermatozoa are transformed into spermatids.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → C only
A. Spermatogonia always undergo meiotic cell division. — Incorrect. Spermatogonia multiply by mitosis. Only some of them grow into primary spermatocytes, which then undergo meiosis.
B. Primary spermatocytes divide by mitotic cell division. — Incorrect. A primary spermatocyte completes the first meiotic division, giving two secondary spermatocytes.
C. Secondary spermatocytes have 23 chromosomes and undergo second meiotic division — Correct. They are haploid and their second meiotic division gives four haploid spermatids.
D. Spermatozoa are transformed into spermatids. — Incorrect. This is the reverse: spermatids are transformed into spermatozoa by spermiogenesis.
NCERT Extract:
Gametogenesis – “… 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).”
Gametogenesis – “… The spermatids are transformed into spermatozoa (sperms) by the process called spermiogenesis.”