Question

In spermatogenesis, the phase of maturation involve

• A. Formation of oogonia from spermatocytes through meiosis.
  
• B. Formation of spermatogonia from gonocytes through mitosis
  
• C. Growth of spermatogonia into spermatocytes
  
• D. Formation of spermatogonia from primary spermatocytes through meiosis
  

Answer 1

The correct option is C Growth of spermatogonia into spermatocytes


Spermatogenesis
Spermatogenesis is the formation of sperm from the primordial germ cells in testis. It starts at puberty and involves three phases as follows:
Multiplication phase
Growth phase
Maturation phase

Multiplication phase
Multiplication phase of spermatogenesis involves the following:
Primordial germ cells present in the walls of the seminiferous tubule undergo mitosis to form more spermatogonium.
The spermatogonia multiply by mitotic division and increase in number.

Formation of spermatogonia from gonocytes
Gonocytes are the precursors of spermatogonia formed from the primordial cells present in the testes. It is part of the multiplication phase.

Growth phase
In the growth phase, some spermatogonia increase in cell size and volume and are referred to as primary spermatocytes. Both spermatogonia and primary spermatocytes are diploid and contain 46 chromosomes.

Maturation phase
Maturation phase involves the following:
Primary spermatocytes (46) undergo meiosis I (reduction division) and produce secondary spermatocytes having 23 chromosomes.
Secondary spermatocytes undergo meiosis II to form spermatids (23).
Spermatids undergo cell differentiation and form spermatozoa.

Formation of oogonia
During foetal development, certain cells in the germinal epithelium of the ovary divide by mitosis and produce egg mother cells or oogonia.