Question

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

• 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. Only two sperms nearest the ovum penetrate zona pellucida.
  
• D. All of the above.

Answer 1

Answer: (A)

Secretions of acrosome helps one sperm enter cytoplasm of ovum through zona pellucida.

During fertilisation, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane. This blocks the entry of additional sperms and only one sperm can fertilise an ovum, the secretions of acrosome help the sperm enter into the cytoplasm of the ovum through zona pellucida and the plasma membrane.