Question

What is the cortical granule reaction?

Answer 1

Cortical granule reaction:

1. To prevent polyspermy, the cortical reaction occurs after a sperm has successfully invaded an egg.
2. The egg's cytoplasm contains cortical granules that release enzymes into the zona pellucida (through exocytosis).
3. These enzymes degrade sperm binding sites while also thickening and hardening the jelly coat's glycoprotein matrix.
4. This stops other sperms from penetrating the egg (polyspermy), ensuring a diploid zygote is formed.
5. Unfertilized oocytes have cortical granules, which are secretory organelles located beneath the cell membrane.
6. Cortical granules fuse with the oocyte's cell membrane during fertilization and release their contents into the extracellular matrix.
7. All mammals and many other vertebrates, as well as certain invertebrates, have cortical granules.