Question

The primary egg membrane of mammalian egg is termed as

• A. Chorion
• B. Corona radiata
• C. Zona pellucida
• D. Vitelline membrane

Answer 1

The correct option is C Zona pellucida

Zona pellucida is the outermost layer of egg cell in mammalian egg. It is pierced by sperm during fertilization. The process of fusion of a sperm with an ovum is called as fertilisation. During fertilisation, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane that block the entry of additional sperms. Thus, it ensures that only one sperm can fertilise an ovum. The secretions of the acrosome help the sperm enter into the cytoplasm of the ovum through the zona pellucida and the plasma membrane.

Therefore, the correct answer is option C.