Tay-Sachs disease is a rare lysosomal storage disorder characterized by the dysfunctional breakdown of GM2 gangliosides, causing these lipids to accumulate to toxic levels inside neurons. If a neuropathologist extracts these accumulated biomolecules from a cellular sample, which biochemical test and subsequent observation would successfully confirm the presence of lipids in the extract?
Mix with iodine in potassium iodide solution; observation of a deep blue-black coloration.
Add Benedict's reagent and heat in a water bath; formation of a brick-red precipitate.
Shake the sample with absolute ethanol, then pour into water; formation of a cloudy white emulsion.
Add Biuret reagent (sodium hydroxide and copper(II) sulfate); color change from light blue to purple.