Question

Explain the process of fusion of gametes in humans.

Answer 1

Gametes are haploid reproductive cells produced during sexual reproduction. The fusion of a male gamete (sperm) with a female gamete (ovum) is called fertilization and gives rise to a diploid zygote. The process of fertilization mainly occurs in two steps, the first being the 'acrosomal reaction' and 'cortical reaction', the second. When a sperm enters the female genital tract, it migrates towards the ovum in the fallopian tube. On reaching the ovum, it receives signals from the ovum and thus digestive enzymes from the acrosome of the sperm are released which help the sperm to penetrate the zona pellucida and fuse with the oocyte membrane. In the cortical reaction, the first sperm cell to interact with the plasma membrane of the ovum, fuses with it. The pronucleus of the sperm now fuses with the pronucleus of the ovum in its cytoplasm thus combining two sets of haploid genetic material and giving rise to a totipotent diploid zygote.