Extrusion of second polar body from egg nucleus occurs:

Question

Explain the processing of heterogeneous nuclear RNA (hnRNA) into a fully functional mRNA in eukaryotes. Where does this processing occur in the cell?

Answer 1

The extrusion of the second polar body from the egg nucleus is a crucial step in the process of oocyte maturation and fertilization in humans. Let's explore this process and determine the correct answer:

1. **Oogenesis Process Background**: Oogenesis occurs in the ovaries, where primary oocytes undergo maturation to form mature egg cells. During meiosis I, a primary oocyte divides to form a secondary oocyte and the first polar body. The secondary oocyte is then arrested at the metaphase of meiosis II until fertilization.

2. **Role of Sperm Entry**: The secondary oocyte completes meiosis II only after the entry of a sperm cell. This completion results in the formation of the ovum and the extrusion of the second polar body.

3. **Timing of the Second Polar Body Extrusion**: The second polar body is extruded after the sperm has entered the egg cytoplasm but before the actual fusion of the sperm and egg nuclei (syngamy), which marks fertilization.

Given these points, we can analyze the options:

**After entry of sperm but before fertilization**: This is correct because the second polar body is expelled after the sperm’s entry but prior to the fusion of the genetic material, aligning with this option.
**After fertilization**: Incorrect because extrusion of the second polar body occurs before the egg and sperm nuclei fuse.
**Before entry of sperm into ovum**: Incorrect, as the second polar body is extruded only following sperm entry.
**Simultaneously with first cleavage**: Incorrect, as the first cleavage occurs post-fertilization, not during the extrusion of the second polar body.

Thus, the correct answer is: after entry of sperm but before fertilization.

An understanding of this process is vital for exams that focus on reproductive biology and developmental biology.

Answer 2

The extrusion of the second polar body from the egg nucleus is a crucial step in the process of oocyte maturation and fertilization in humans. Let's explore this process and determine the correct answer:

1. **Oogenesis Process Background**: Oogenesis occurs in the ovaries, where primary oocytes undergo maturation to form mature egg cells. During meiosis I, a primary oocyte divides to form a secondary oocyte and the first polar body. The secondary oocyte is then arrested at the metaphase of meiosis II until fertilization.

2. **Role of Sperm Entry**: The secondary oocyte completes meiosis II only after the entry of a sperm cell. This completion results in the formation of the ovum and the extrusion of the second polar body.

3. **Timing of the Second Polar Body Extrusion**: The second polar body is extruded after the sperm has entered the egg cytoplasm but before the actual fusion of the sperm and egg nuclei (syngamy), which marks fertilization.

Given these points, we can analyze the options:

**After entry of sperm but before fertilization**: This is correct because the second polar body is expelled after the sperm’s entry but prior to the fusion of the genetic material, aligning with this option.
**After fertilization**: Incorrect because extrusion of the second polar body occurs before the egg and sperm nuclei fuse.
**Before entry of sperm into ovum**: Incorrect, as the second polar body is extruded only following sperm entry.
**Simultaneously with first cleavage**: Incorrect, as the first cleavage occurs post-fertilization, not during the extrusion of the second polar body.

Thus, the correct answer is: after entry of sperm but before fertilization.

An understanding of this process is vital for exams that focus on reproductive biology and developmental biology.

Extrusion of second polar body from egg nucleus occurs:

The Correct Option is A

Solution and Explanation

Top Questions on Human Reproduction

Questions Asked in NEET (UG) exam