what is acid soluble fraction and acid insoluble fraction?what is the special case of lipids?pls expain

Acid soluble fraction is the fraction of the cell's components which are soluble in acid, while acid insoluble fraction is the fraction of the cell's components which are insoluble in acid. Biomacromolecules are found in the acid insoluble fraction. These include proteins, nucleic acids, polysaccharides and lipids. Of these four, except lipids all have a molecular weight of more than ten thousand daltons. Lipids are smaller molecules but still are separated with acid insoluble fraction because during separation a number of lipid molecules come together and form vesicles. These vesicles gets separated in the acid insoluble fraction.