Question

Differentiate between zona pellucida and corona radiata.

Answer 1

Sr. No.	Aspect	Zona pellucida	Corona radiata
1.	Nature	It is a transparent, non-cellular layer secreted by the oocyte.	It is an outer layer consisting of radially elongated follicle cells.
2.	Position	It directly surrounds the plasma membrane of the ovum.	It is the outermost layer located outside the zona pellucida.
3.	Composition	It is composed of a thick, non-cellular glycoprotein envelope.	It is a cellular layer made up of several follicular cells.
4.	Function	It primarily functions to prevent polyspermy during fertilization.	It primarily functions to provide vital proteins and nourishment to the egg.