This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
Changes in which amyloid structure makes it insoluble? 
Select and explain. 
A. Primary, B. Secondary, C. Tertiary, D. Quaternary
B: Secondary
Answer: B: Secondary 
Explanation: Ans. is 'b' i.e., Secondary * Amyloid is a protein that has an alteration in its secondary structure which imparts it a particular insoluble form, called the beta-pleated sheet conformation.* Amyloid material is composed of two components -i) Major component (95%) - Fibril amyloid protein.ii) Minor components (5%) - P-component, proteoglycans and sulfated glycosaminoglycans.* Fibril amyloid protein is responsible for tissue dysfunction due to pressure effect, while Pcomponent contributes to amyloid deposition by stabilizing fibril amyloid protein and decreasing their clearance.