what is zona pellucida

Answer 1

The zona pellucida is a glycoprotein-rich layer surrounding the oocyte (egg cell) in mammals. It is a critical barrier between the oocyte and surrounding cells or sperm. The zona pellucida plays a crucial role in fertilization, as it allows the passage of sperm to bind to the oocyte and prevents multiple sperm from fertilizing the same egg. It also provides protection for the developing embryo before implantation into the uterus.