Question

Cortical granule reactions does not include:

• A. Release of cortical granules outside the oocyte membrane
• B. Inactivation of sperm receptors
• C. Hardening of zona pellucida
• D. Degeneration of corona radiata

Answer 1

The correct option is D Degeneration of corona radiata

The cortical granule reactions are initiated as soon as one sperm enters the oocyte. These reactions make sure that multiple sperms are not allowed to enter the cytoplasm of the oocyte.

It involves the depolarisation of the plasma membrane of the oocyte after the entry of the sperm, which triggers the release of calcium ions inside the oocyte. These calcium ions stimulate the release of secretory vesicles located just under the plasma membrane of the oocyte to outside. These secretory vesicles release chemicals that inactivate the sperm receptors and harden the zona pellucida layer.

The corona radiata is not degenerated during the cortical granule reactions.