Question

What is the difference between zona pellucida and corona radiata?

Answer 1

Zona pellucida:

It is the noncellular, translucent, and more or less elastic outer covering or envelope of a mammalian ovum consisting of glycoproteins.

Corona radiata:

It is the zone of tiny follicular cells that surrounds the ovum in the Graafian follicle and follows the ovum as it exits the follicle.

Difference between zona pellucida and corona radiata:

Zona Pellucida	Corona Radiata
1. Zona pellucida is a non-cellular in nature.	1. Corona radiata is a multicellular in nature.
2. It is a thick glycoprotein coating released by secondary oocytes and inner follicular cells working together.	2. It is a granulosa cell remnant that stays surrounding the ovum during fertilisation.
3. It encircles the ovum's plasma membrane.	3. It encircles the zona pellucida.
4. The zona pellucida contains follicular cell ingrowths for the delivery of nutrients and biochemicals to the egg.	4. Corona radiata is connected to the zona pellucida and serves to give critical proteins to the cell.
5. It contains three receptor proteins, ZP1, ZP2, and ZP3, that determine sperm attachment or non-attachment. It prevents the occurrence of polyspermy.	5. It protects the ovum.