Question

Fertilizin is
(a) Phospholipid
(b) Steroid
(c) Carbohydrate
(d) Glycoprotein

Answer 1

Hint: The ovum secretes a material called fertilizin. It mixes with the water to form egg water that attracts its own species sperms. Fertilizin consists of a molecule formed by both monosaccharides and amino acids.

Complete answer:
When sperm enters the ovum it releases a substance known as antifertilizin in the oviduct. It is an acidic protein that the acrosome secretes. The ovum releases yet another chemical compound known as fertilizin. It is a glycoprotein. The carbohydrate is attached to a protein through a post-translational modification process called glycosylation. These proteins are often referred to as glycosylated proteins.
Fertilizin interacts with the antifertilizin in the same manner as an antigen-antibody reaction. The reaction to fertilizin-antifertilizin is unique and this allows a route for the sperm to enter the ovum surface.

So, the correct answer is, ‘Glycoprotein’.

Additional Information: Spermatozoon adhesion to the egg surface is due to the presence of fertilizin molecules in the egg cytoplasm surface layer, which receives molecules of antifertilizin present on the spermatozoon surface. Fertilizin blends the same species with the same sperm antifertilizin. The main purpose of the antifertilizin complex is to decrease the sperm count around the egg so that the likelihood of polyspermy, i.e. two or more sperm fusing with the egg at the same time, can be minimized.

Note: There is a fertilizin present on the ovum membrane. Fertilizin is the chemical compound that the ovum releases and is present in an egg that plays a primary role in fertilization. Sperm adhesion through chemical recognition to the egg of the same species is known as agglutination.