Key facts & rules

• Carbohydrates: made of C, H, O. Glucose (C₆H₁₂O₆) is a monosaccharide.
• Glucose + Glucose → Maltose (disaccharide) + water (condensation).
• Starch and glycogen are polysaccharides (storage) made of glucose monomers.
• Proteins: made of amino acid monomers joined by peptide bonds. Contain C, H, O, N (and sometimes S).
• Lipids (fats/oils): made of glycerol + 3 fatty acids. Insoluble in water.
• Test for starch: iodine solution — blue-black if positive.
• Test for reducing sugars: Benedict's solution — brick-red precipitate if positive.
• Test for protein: Biuret solution — purple/violet if positive.
• Test for lipids: ethanol emulsion test — milky-white emulsion if positive.