Carbohydrates, proteins and the polymer parts of lipids are all assembled from small monomers joined by condensation (which releases water). Hydrolysis reverses it. ▶ Play to watch the building blocks link up.
Many glucose units link into the polysaccharide starch (the plant energy store) — or glycogen, or structural cellulose. Tests: reducing sugar → Benedict's (brick-red on heating); starch → iodine (blue-black).
About 20 kinds of amino acid join by peptide bonds into chains that fold into exact shapes — giving enzymes, haemoglobin, antibodies, structure. Test: Biuret reagent turns violet.
A triglyceride is one glycerol joined to three fatty acids. Lipids are a concentrated energy store, give insulation, and (as phospholipids) build cell membranes. Test: the emulsion test → cloudy white.
Each family has a colour test: Benedict's (reducing sugar → brick-red, with heat), iodine (starch → blue-black), Biuret (protein → violet), emulsion/ethanol (lipid → cloudy white). Try them all in the practical.