Question

(a) Name the hormone that initiates spermatogenesis in humans. Describe the process of spermatogenesis in sequence mentioning the ploidy of the cells at each step.

(b) Draw the diagram of a mature human ***** and label the parts that

(i) helps it reaching to the ovum.

(ii) providing energy for it to reach the ovum.

(iii) helping it to gain entry into the ovum.

Answer 1

(a) Gonadotropin releasing hormone/GnRH.

Process of spermatogenesis :

• The spermatogonia (present on inside wall of seminiferous tubules) are diploid (2N).
• Primary spermatocytes undergo Ist meiosis leading to formation of two equal haploid cells (N) called secondary spermatocyte.
• The secondary spermatocytes undergo the second meiotic division to form 4 equal haploid (N) Spermatids.
• Now spermatids transform into spermatozoa (N)

(b)

Correct diagram :

(i) Tail

(ii) Middle piece/mitochondria

(iii) Acrosome