Q101 / 120 · NEET 2011 (Mains) · Zoology

What happens during fertilization in humans after many sperms reach close to the ovum?

  • Correct answer
    A
    Secretions of acrosome helps one sperm enter cytoplasm of ovum through zona pellucida
  • B
    All sperms except the one nearest to the ovum lose their tails
  • C
    Cells of corona radiata trap all the sperms except one
  • D
    Only two sperms nearest the ovum penetrate zona pellucida

Solution

The process of fusion of a sperm with an ovum is called fertilization. During fertilization, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane that blocks the entry of additional sperms. Thus, it ensures that only one sperm can fertilize an ovum. The secretions of the acrosome help the sperm enter into the cytoplasm of the ovum through the zona pellucida and the plasma membrane.

Hence, the correct answer is option: 'A'.

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