This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition and Health, Subject name: Social & Preventive Medicine
Which of the following glycoprotein has both lubricant and protective action: 
Select and explain. 
A. Mucin, B. Immunoglobulin, C. Collagen, D. Albumin
A: Mucin
Answer: A: Mucin 
Explanation: Ans. (A) Mucin(Ref: Harpers Illustrated Biochemistry 31st Ed; Page No- 547)Glycoprotein and their FunctionsGlycoproteinsFunctionMucinsLubricant and protective agentImmunoglobulins, histocompatibilityantigensImmunologic moleculeCollagensStructural moleculeCalnexin, calreticulinRegulate folding of proteins that are exported from the cellPlasma proteins of cold-water fishAntifreezeTransferrin, ceruloplasminTransport moleculeLectins, selectin (cell adhesion lectins), antibodiesInteract with specific carbohydratesNotch and its analogs, key proteins in developmentRegulation of differentiation and development