How does a sperm penetrate an egg? October 4, 2022 by 8i9x6 Enzymes in the acrosome dissolve the zona pellucida. The sperm melts its way inside,using the nucleic acids in its DNA. The forward pressure of the flagellum forces it through the plasma membrane. Spermatids are wedge-shaped and are chemically attracted to the inside cytoplasm of the egg cell. The haploid sets of chromosomes match across the membrane and this triggers the membrane to dissolve. See Answer Enzymes in the acrosome dissolve the zona pellucida.