Why do lipids whose molecular weight do not exceed 800 Da come under acid insoluble fraction?

Why do lipids whose molecular weight do not exceed 800 Da come under a

1.	Why do lipids whose molecular weight do not exceed 800 Da come under acid insoluble fraction?
Answer» The size of lipids are much smaller compared to the other macro molecules.However lipids come under acid insoluble fraction.This is because in compounds lipids are present not only as such but also as structures like cell and other membranes..When we grind a tissue, cell membrane .etc will break and form vesicles which are not water soluble. Therefore this membrane fragments in the form of vesicles get separated along with acid insoluble pool.