Biology · BIOMOLECULES

Why do lipids, despite having a molecular weight that does not exceed 800 Da, appear in the acid-insoluble fraction during tissue fractionation?

1. They polymerize into giant covalent macromolecules of over 10,000 Da upon treatment with trichloroacetic acid.
2. They form insoluble covalent bonds with acidic nuclear histones and sediment during filtration.
3. They are part of disrupted cell membranes that form water-insoluble vesicles, which do not pass through the filter.
4. They are degraded into volatile hydrocarbons that adhere tightly to cellulose filter membranes.