The steroid lipid cholesterol is a component of membranes. Identify true statements about cholesterol and its role in membrane fluidity. Select all the true statements.
1.Cholesterol decreases membrane fluidity in areas called rafts, which contain large amounts of sphingolipids and cholesterol.
2.Cholesterol increases membrane fluidity in a membrane that otherwise contains mostly long-chain saturated fatty acids.
3.Cholesterol inhibits the crystallization that would otherwise occur in membranes rich in unsaturated fatty acids.
4.Cholesterol is generally buried in the bilayer, with its planar rings oriented toward the solvent and its hydroxyl group aligned with the fatty acid tails of the bilayer.