Which of the following statements regarding fertilization is/are correct ?
(i) The acrosome is filled with hydrolytic enzymes which help in dissolving the membrane of the ovum at the time of fertilization.
(ii) Vitelline membrane is the first membrane to be faced by sperms while trying to fuse with the ovum .
(iii) There must be synchronicity in the release of ovum and entry of sperm for the formation of zygote .
(iv) The meiotic division of the secondary oocyte is concluded with the entry of male gamete.

Options

A. i and ii only
B. ii and iii only
C. i ,iii and iv
D. i,ii and iv

Answer

To determine which statements regarding fertilization are correct, let's analyze each statement step by step.

### Step 1: Analyze Statement (i)
**Statement (i)**: The acrosome is filled with hydrolytic enzymes which help in dissolving the membrane of the ovum at the time of fertilization.

- The acrosome is a cap-like structure located at the front of the sperm. It contains hydrolytic enzymes known as sperm lysins.
- These enzymes are crucial for breaking down the protective layers surrounding the ovum, allowing the sperm to penetrate and fertilize the egg.

**Conclusion**: This statement is **correct**.

### Step 2: Analyze Statement (ii)
**Statement (ii)**: Vitelline membrane is the first membrane to be faced by sperms while trying to fuse with the ovum.

- The first membrane encountered by the sperm is not the vitelline membrane but the corona radiata, followed by the zona pellucida, and finally the plasma membrane of the ovum.
- The vitelline membrane is actually the inner layer that is encountered after the sperm has penetrated the outer layers.

**Conclusion**: This statement is **incorrect**.

### Step 3: Analyze Statement (iii)
**Statement (iii)**: There must be synchronicity in the release of ovum and entry of sperm for the formation of zygote.

- The ovum is viable for fertilization for about 24 hours after ovulation, while sperm can survive in the female reproductive tract for about 4 to 5 days.
- For successful fertilization, sperm must enter the female reproductive tract around the time of ovulation to maximize the chances of meeting the ovum.

**Conclusion**: This statement is **correct**.

### Step 4: Analyze Statement (iv)
**Statement (iv)**: The meiotic division of the secondary oocyte is concluded with the entry of male gamete.

- The secondary oocyte is arrested in metaphase II of meiosis until fertilization occurs.
- The entry of the sperm triggers the completion of meiosis, resulting in the formation of a mature ovum and the second polar body.

**Conclusion**: This statement is **correct**.

### Final Conclusion
Based on the analysis:
- **Correct Statements**: (i), (iii), and (iv)
- **Incorrect Statement**: (ii)

### Summary of Correct Statements
The correct statements regarding fertilization are:
1. The acrosome is filled with hydrolytic enzymes which help in dissolving the membrane of the ovum at the time of fertilization.
2. There must be synchronicity in the release of ovum and entry of sperm for the formation of zygote.
3. The meiotic division of the secondary oocyte is concluded with the entry of male gamete.