Question

The event which ensures that only one sperm fertilizes an ovum is:
​​​​​​​[0.7 mark]

• A. Removal of the cells of corona radiata
• B. Formation of first polar body
• C. Changes in the plasma membrane of ovum on contact with sperm
• D. Dissolution of hyaluronic acid present in the membrane of ovum

Answer 1

The correct option is C Changes in the plasma membrane of ovum on contact with sperm

During fertilisation, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane that blocks the entry of additional sperms. Thus, it ensures that only one sperm can fertilise an ovum.