1. Lipids are a class of organic compounds that are insoluble in ___________ but soluble in organic solvents. Answer: water Rationale: Lipids are hydrophobic molecules that do not mix well with water but can dissolve in nonpolar solvents. 2. Cholesterol is a type of steroid lipid that is essential for the structure of cell ___________ and for the synthesis of steroid hormones. Answer: membranes Rationale: Cholesterol plays a crucial role in maintaining the fluidity and integrity of cell membranes. 3. The isolation of cholesterol from egg yolk involves the extraction of lipids using a solvent such as ___________. Answer: chloroform Rationale: Chloroform is commonly used as a solvent for lipid extraction due to its ability to dissolve nonpolar molecules like lipids. 4. True or False: Cholesterol is a polar molecule that readily dissolves in water. Answer: False Rationale: Cholesterol is a nonpolar molecule that is insoluble in water. 5. The process of isolating cholesterol from egg yolk often involves the use of ___________ to separate the cholesterol from other lipids. A) TLC (thin layer chromatography) B) steam distillation C) recrystallization D) column chromatography