Question

Brief about mammalian fertilization.

Answer 1

Mammalian fertilization:

1. Mammals are warm-blooded animals that are characterized by the presence of mammary glands (milk-producing glands).
2. Fertilization refers to the fusion of male and female gametes. It takes place in the fallopian tube.
3. The process of fertilization begins when the sperm’s head gets attached to the zona pellucida layer that surrounds the ovum.
4. This results in an acrosomal reaction in which the acrosome releases enzymes (sperm lysin) that digest the zona pellucida and penetrate the cell membrane of the ovum.
5. In the next step, the cell membranes of the sperm and ovum fuse together and the sperm releases its content inside the ovum.
6. After the fusion of the plasma membrane, the ovum exhibit a calcium-dependent cortical reaction.
7. Cortical granules present under the plasma membrane release cortical enzymes that hardens the zona pellucida, thereby blocking the entry of additional sperms.
8. The haploid nucleus of the sperm and ovum fuse together resulting in the formation of a zygote.