Question

An example of glycoprotein is
A) Mucin
B) Lecithin
C) Casein
D) Haemoglobin

Answer 1

Hint: Glycoproteins are actually important for white blood cell recognition. In proteins that have segments that extend extracellularly, the extracellular segments are also glycosylated. The carbohydrate is combined with the protein in a posttranslational modification. This is known as glycosylation.

Complete answer:
Glycoproteins are basically proteins that contain oligosaccharide chains that are covalently attached to amino acid side chains. Carbohydrates are joined to some of the proteins in order to produce glycoproteins.

Mucins have high molecular weight and are proteins that are highly glycosylated that are produced by epithelial tissues in organisms of the Kingdom Animalia. Some mucins are membrane-bound due to the presence of a hydrophobic membrane that helps in retention in the plasma membrane, the concentration here is on those mucins that are secreted on mucosal surfaces and saliva.

Lecithin is lipid phosphatidylcholine. Lecithin is a fat that is necessary for the body. Lecithin is taken as a medicine and is also used for medicine manufacturing. It is also used for treating memory disorders like dementia and Alzheimer's disease and so on.

Casein and haemoglobin are proteins. Casein is a family of phosphoproteins that are usually found in mammalian milk. Haemoglobin is a protein found in the red blood cells that transport oxygen in your body and give blood its red colour. Its levels vary from person to person. Men usually have higher levels than women due to menses.

Therefore the correct answer is option ‘A’.

Note: A glycoprotein is a compound that contains carbohydrates covalently bonded to protein. The carbohydrate can be a monosaccharide, disaccharide, oligosaccharide, polysaccharide, or their derivatives. Proteoglycans are a subclass of glycoproteins in which the carbohydrate units are polysaccharides that have amino sugars. Such polysaccharides are also known as glycosaminoglycans.