A lab technician is given three test tubes: one contains pure oil mixed with water, one contains a solution of phospholipids and water, and one contains pure cholesterol crystals in water. After centrifugation, which patterns of separation or assembly will you expect and why?

Oil + water will form two distinct immiscible layers with oil floating; phospholipids in water will self-assemble into micelles or bilayers depending on concentration (forming dispersed particles rather than a separate bulk layer); cholesterol crystals will largely remain insoluble and may form sediment or small aggregates due to its largely hydrophobic nature with minimal polar headgroups.

Oil will form micelles identical to phospholipids at any concentration; the cholesterol will act as a surfactant and prevent any phase separation in all tubes, producing a single phase.

Oil will immediately polymerize into a gel that binds water molecules; phospholipids will form crystalline salts with water at room temperature; cholesterol will segregate into the air phase above the solution due to its low density.

Oil will dissolve uniformly because stirring negates hydrophobic effects; phospholipids will form a single homogeneous solution identical to water; cholesterol will chemically react with water to form soluble ions and disappear after centrifugation.