Oocyte activation

Oocyte (or ovum/egg) activation is a series of processes that occur in the oocyte during fertilization.

Sperm entry causes calcium release into the oocyte. In mammals, this is caused by the introduction of phospholipase C isoform zeta (PLCζ) from the sperm cytoplasm.^[1] Activation of the ovum includes the following events:

Cortical reaction to block against other sperm cells
Activation of egg metabolism
Reactivation of meiosis
DNA synthesis

^ Saleh A, Kashir J, Thanassoulas A, Safieh-Garabedian B, Lai FA, Nomikos M (2020). "Essential Role of Sperm-Specific PLC-Zeta in Egg Activation and Male Factor Infertility: An Update". Front. Cell Dev. Biol. 8 (28). doi:10.3389/fcell.2020.00028. PMC 7000359.

[1] Saleh A, Kashir J, Thanassoulas A, Safieh-Garabedian B, Lai FA, Nomikos M (2020). "Essential Role of Sperm-Specific PLC-Zeta in Egg Activation and Male Factor Infertility: An Update". Front. Cell Dev. Biol. 8 (28). doi:10.3389/fcell.2020.00028. PMC 7000359.

[1]