Practice question

Acrosome reaction is calcium-triggered exocytosis fusing outer acrosomal membrane with overlying plasma membrane releasing enzymatic contents stored during spermiogenesis. Key enzymes liberated include hyaluronidase which hydrolyzes hyaluronan matrix surrounding cumulus cells, and serine protease acrosin plus esterases that locally digest ZP glycoproteins to create penetration slit. Additional glycosidases modify sugar residues. Enzymatic dispersal allows sperm to traverse cumulus oophorus and zona barriers. Without these hydrolases sperm cannot access oolemma, rendering fertilization impossible despite normal motility, capacitation status, successful cumulus navigation and zona binding and attachment attempts.