Question

During the process of mammalian fertilization, a sperm cell encounters glycoproteins in the gelatinous extracellular matrix that surrounds the ovum. Experimental removal of sugars from these glycoproteins prevents fertilization. Which carbohydrate function is demonstrated by these results?

Answer 1

Answer:

Carbohydrates, particularly glycoproteins act as ligands for cell surface receptors.

Explanation:

Glycoproteins

• Glyproteins are conjugate molecules comprising of carbohydrates conjugated with proteins.
• Glycoproteins play a vital role in cell-cell recognition, pathogen recognition and and cell adhesion.
• Glycoproteins on the surface of pathogens act as prominent antigens for the immune system.

Glycoproteins in Fertilization:

Several glycoproteins are attached to the surface of the zona pellucida, the envelope of the oocyte. In humans, these have been termed as ZP1-4.

Glycoprotein-sperm interaction is one of the most crucial steps in fertilization. This receptor-ligand interaction ensures the entry of the sperm into the zona pellucida, the extracellular coat, covered in glycoproteins that surrounds the oocyte or egg.

Carbohydrate binding proteins present on the surface of the sperm recognize the glycoproteins on the zona pellucida (ZP). This enables them to adhere to the surface of the ZP and also to gain access to the oocyte.