Question

a) In three sentences, describe the process of fertilization in humans.

b) What prevents polyspermy?

Answer 1

ANSWRR :-

a.) Fertilization in humans :- The process of fusion of a sperm with an ovum is called fertilization.

1.) During copulating, the semen is released by the male sex organ to female sex organ (Insemination), the motile sperm pass through cervix, enters the uterus and finally to ampulla-isthmus junction of the fallopian tube and the ovum released by ovary is also transported to the ampulla-isthmus junction where fertilization takes place.

2.) Fertilization can only occurs if the ovum and sperms are transported simultaneously to the ampulla-isthmus junction thus the process of fusion of sperm with an ovum is called fertilisation.

3.) During fertilization, a sperm comes in contact with the zona pellucida layer of the ovum and induces changes in the membrane that block the entry of additional sperms.

b.) Polyspermy is the fusion of multiple sperm with an egg. In humans the zona pellucida is seen as a thick clear girdle surrounded by the cells of the corona radiata. The cortical reaction, a process initiated during fertilization by the release of cortical granules from the egg, which prevents the polyspermy.