Question

Primary spermatocyte differs from spermatogonium in
A. Size and volume
B. Size of chromosomes
C. DNA content
D. Number of chromosomes

Answer 1

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 a process spermatogenesis that begins at puberty.

Complete answer:
Spermatogenesis is completed in four stages: (i) Spermatocytogenesis, (ii) Meiosis-I, (it)
Meiosis-II and (iv) Spermiogenesis.
Spermatocytogenesis : In spermatocytogenesis, the spermatogonia remains present on the inside wall of the seminiferous tubules and they multiply by mitotic division that is usually equational division and increase in numbers. Each spermatogonia is diploid containing 46 chromosomes. Some spermatogonia undergo changes as they grow and increase in size by accumulating and assimilating the nourishing materials and are called primary spermatocytes which periodically undergo meiosis and others that are left behind are termed as spermatogonia.
Size and volume :- when spermatogonia takes nourishment they grow in size and have more volume so they are called as primary spermatocytes and the left behind are called as spermatogonia which do not grow in size . So this option is correct.
Size of chromosomes :- the size of chromosomes remains the same as the length is predefined . It only changes when some mutation or recombination occurs which is not possible in spermatocyte or spermatogonia.
DNA content :- the spermatogonium divides by mitotic division so they have the same number of chromosomes and hence same DNA content as that of primary spermatocyte . Thus this option is not correct.
Number of chromosomes :- the spermatogonium divides by mitotic division so they have the same number of chromosomes. They contain 46 chromosomes so they are haploid as those of primary spermatocytes . Thus this option is not correct.

Our required answer is A. size and volume.

Note: A mature sperm is usually made up of head , a neck and middle piece and lastly the tail, a plasma membrane, covers the body of the sperm fully. Head of the sperm consists of a little amount of cytoplasm and a long haploid nucleus . The anterior part of the head remains covered with acrosome . Acrosomes are made from Golgi apparatus .