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: Microbiology
Endotoxin from gram negative organism is : 
Select and explain. 
A. Polysaccharide, B. Glycoprotein, C. Lipoprotein, D. Lipo-polysaccharide
D: Lipo-polysaccharide
Answer: D: Lipo-polysaccharide 
Explanation: Ans. is 'd' i.e. Lipopolysaccharide Distinguishing feature of Exotoxin and endotoxiinsExotoxinsEndotoxins* Proteins** Lipopolysaccharide** Heat labile** Heat stable** Secreted by cells** forms part of cell wall** Action enzymic** No enzymic action** Active in minute dose ** Active only in large dose** Highly antigenic** Weakly antigenic** Action specifically neutralised by antibody* Neutralisation of antibody ineffective* Specific pharmacologic effect for each toxin ** Effect nonspecific** Can be toxoided* Cannot be toxoided