Question

Given below is the schematic representation of spermatogenesis in human males:

Choose the option that shows the correct labelling of ‘I’, ‘II’, ‘III’ and ‘IV’ in the given diagram.

• A. spermatozoa, spermatid, sec. spermatocyte, spermatogonia
• B. spermatid, spermatogonia, sec. spermatocyte, spermatozoa
• C. spermatogonia, sec. spermatocyte, spermatozoa, spermatid
• D. spermatogonia, sec. spermatocyte, spermatid, spermatozoa

Hint:

In spermatogenesis, the sequence of cell divisions is: Spermatogonia \( \to \) Primary Spermatocytes \( \to \) Secondary Spermatocytes \( \to \) Spermatids \( \to \) Spermatozoa.

Answer 1

The Correct Option is D

Spermatogenesis and Labelling of Stages 

Step 1: Understanding the Process of Spermatogenesis

Spermatogenesis is the process of sperm cell development in males, occurring in the seminiferous tubules of the testes. The key stages are:

• Spermatogonia: The primordial germ cells that divide by mitosis to form primary spermatocytes.
• Primary Spermatocytes: These undergo meiosis to form secondary spermatocytes.
• Secondary Spermatocytes: These undergo a second meiotic division to form spermatids.
• Spermatids: These undergo maturation (spermiogenesis) to become spermatozoa (mature, motile sperm cells).

Step 2: Analyzing the Diagram

The diagram below represents the stages of spermatogenesis. Based on the description:

• I represents spermatogonia, the undifferentiated germ cells that divide to produce primary spermatocytes.
• II represents secondary spermatocytes, which are produced after the first meiotic division of primary spermatocytes.
• III represents spermatids, which are formed after the second meiotic division of secondary spermatocytes.
• IV represents spermatozoa, the fully mature sperm cells after spermiogenesis.

Step 3: Conclusion

The correct labelling of 'I', 'II', 'III', and 'IV' in the diagram is: Option (D): Spermatogonia, Secondary Spermatocyte, Spermatid, Spermatozoa.