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

Step 1: Understanding the process of spermatogenesis: - Spermatogenesis is the process of sperm cell development in males, which occurs in the seminiferous tubules of the testes.
- The process begins with the primordial germ cells, called spermatogonia, which divide by mitosis to form primary spermatocytes.
- Each primary spermatocyte undergoes meiosis to produce secondary spermatocytes.
- The secondary spermatocytes further divide to form spermatids.
- The spermatids undergo a maturation process (spermiogenesis) to become spermatozoa, which are the mature, motile sperm cells.
Step 2: Analyzing the diagram:
- 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.
Thus, the correct labelling is:
- I: Spermatogonia
- II: Secondary spermatocyte
- III: Spermatid
- IV: Spermatozoa
Step 3: Conclusion:
The correct labelling of 'I', 'II', 'III', and 'IV' is option (D): spermatogonia, sec. spermatocyte, spermatid, spermatozoa.