This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lipids, Subject name: Biochemistry
Second messenger is produced from: 
Select and explain. 
A. Phosphatidylinositol, B. Phosphatidylserine, C. Phosphatidylcholine, D. None
A: Phosphatidylinositol
Answer: A: Phosphatidylinositol 
Explanation: Ans. A. Phosphatidylinositol(Ref: Harper 31/e page 202)PhosphatidylinositolPhosphatidylinositol presents in the cell membrane.The inositol is present as its stereoisomer, myoinositol.Plays an important role in cell signaling and membrane trafficking.Phosphatidyl inositol is a precursor of second messenger in hormonal pathways.Action of Phospholipase C on Phosphatidyl Inositol 4,5 Bisphosphate (PiP2 )Diacyl Glycerol and Inositol Tris phosphate IP3 are formed and both act as second messengers.