This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Physiology
Decreased protein : lipid ratio is seen in: 
Select and explain. 
A. Inner mitochondrial membrane, B. Outer mitochondrial membrane, C. Sarcoplasmic reticulum, D. Myelin sheath membrane
D: Myelin sheath membrane
Answer: D: Myelin sheath membrane 
Explanation: Ans. (d) Myelin sheath membrane(Ref: Ganong, 25th ed/p.34)Proteins are the major constituents of cell membraneInner mitochondria membrane has maximum protein concentrationThe only exception where lipids outnumber proteins is Myelin sheath of nerve cell membrane