Question

Consider a female animal that undergoes an oogenesis process similar to that in humans. If the somatic cells of this animal have 40 chromosomes, then what should be the number of the chromosome in oogonia, primary oocyte and secondary oocyte respectively?

• A. 40, 20, 20
• B. 40,40, 20
• C. 20,20,20
• D. 40,20, 40

Answer 1

The correct option is B 40,40, 20

Oogenesis is a sequential process in which germ cells undergo various processes to form ovum.

Oogonia (2n) are primordial germ cells that are source mother cells which on mitosis produce primary oocytes (2n). Primary oocyte undergo meiosis I that produces secondary oocyte (n).

Therefore, oogonia and primary oocytes will have 40 chromosomes whereas secondary oocytes will have 20 chromosomes.