Practice question

Sea urchin sperm head contains acrosomal vesicle originating from Golgi complex during spermiogenesis. This membrane-bound vesicle caps nucleus and stores enzymes like bindin localized on acrosomal process and acrosin protease. During acrosome reaction triggered by egg jelly fucose sulfate polymer and calcium influx, vesicle fuses with sperm plasma membrane, exposing bindin for egg binding and releasing lytic enzymes that digest jelly coat. Cortical granules are egg structures, micromeres and macromeres are embryonic blastomeres, not sperm organelles. Acrosomal vesicle thus mediates gamete interaction and species-specific recognition.