Practice question

Sperm acrosome is specialized cap-like secretory vesicle positioned anterior to nucleus, containing hydrolytic enzymes to penetrate egg coats during fertilization. Ultrastructural studies and pulse-chase labeling demonstrate it derives from Golgi apparatus during spermiogenesis stage of spermatid differentiation. Golgi complex packages enzymes like acrosin, hyaluronidase, and recognition protein bindin into proacrosomal granule which progressively coalesces and flattens over condensing nucleus. Lysosomal markers appear secondarily but origin is Golgi-mediated regulated secretory pathway, not endoplasmic reticulum, mitochondria or conventional lysosomes. Acrosome thus represents modified secretory vesicle essential for gamete interaction.