Target Exam

CUET

Subject

Biology

Chapter

Human Reproduction

Question:

The chromosome number per cell is 46 in:

Options:

Primary oocyte

Secondary oocyte

Polar body

Ovum

Correct Answer:

Primary oocyte

Explanation:

The correct answer is Option (1) → Primary oocyte   

The process of formation of a mature female gamete is called oogenesis which is markedly different from spermatogenesis. Oogenesis is initiated during the embryonic development stage when a couple of million gamete mother cells (oogonia) are formed within each fetal ovary; no more oogonia are formed and added after birth. These cells start division and enter into prophase-I of the meiotic division and get temporarily arrested at that stage, called primary oocytes. Each primary oocyte then gets surrounded by a layer of granulosa cells and is called the primary follicle . A large number of these follicles degenerate during the phase from birth to puberty. Therefore, at puberty only 60,000-80,000 primary follicles are left in each ovary. The primary follicles get surrounded by more layers of granulosa cells and a new theca and are called secondary follicles.

                                                  Oogenesis