Question

Immediate membrane covering the mammalian egg is

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

Answer 1

The correct option is C Vitelline membrane


Structure of egg
Egg is the mature female gamete. It possesses a nucleus with a haploid number of chromosomes and different layers from outside to inside as follows:

• Corona radiata
• Zona pellucida
• Vitelline membrane

Corona radiata
Corona radiata is the outermost membranous cover of follicular cells that is formed around the developing oocyte in the ovary. It remains around the ovum at ovulation.

Zona pellucida
Zona pellucida is a glycoprotein layer secreted by the follicular cells that surrounds the plasma membrane of the egg.

Vitelline membrane
Vitelline membrane is the outer covering of the ovum present outside the plasma membrane, interior to the zona pellucida. Thus, it is the immediate membrane covering the ovum.

Chorion

• Chorion is the outermost fetal membrane present around the embryo in mammals.
• It protects and nurtures the embryo.

Pictorial representation of egg
Pictorial representation of the structure of egg:

Final answer
(C) Vitelline membrane