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42 Shake the contents of the tube. A white precipitate appears. Write the equation for the formation of the calcium salt of stearic acid. Experiment 4. Salting out soap with sodium chloride . Place 10 drops of soap solution into the tube and add dry NaCl on the tip of the spatula. Vigorously shake. As the salt dissolves, the solution begins to grow turbid and eventually a white curd mass appears on the transparent liquid. Explain this phenomenon. This process is called salting out, where the soap is precipitated. LESSON 19. CHEMISTRY OF COMPLEX LIPIDS Required basic level of knowledge. Structure and properties of simple lipids. The concept of the structure and properties of surface-active substances. Micelle formation in solutions of surfactants. The structure of the biological membrane. Questions for the preparation for the lesson. 1. Complex lipids. Definition, classification of complex lipids. 2. Phosphatidic acid. Glycerophospholipids: phosphatidylserines, phospha- tidylethanolamines, phosphatidylcholines, phosphatidylinositols. Definition, composition, formulas, biological role. 3. The structure of sphingosine and ceramide. Sphingophospholipids: sphin- gomyelin, definition, general formula, biological role. 4. Glycolipids: determination, structure and composition of cerebrosides, gangliosides and sulfatides. 5. Structure of the sterane (cyclopentane perhydrophenanthrene). Steroids (sterols and sterols). Cholesterol formulas with numbering of atoms, bile (cho- levic, desoxycholic, chenodeoxycholic) acids, biological role. Test control on the topic «Simple and complex lipids». Homework exercises. 1. Write the formula for cerebroside. 2. Write the formula of the ester of cholesterol and stearic acid, write the equation of hydrolysis of this ether. 3. Write the formulas of lysolecithin (lysophosphatidylcholine), lysocephalin (lysophosphatidylethanolamine). 4. Write the equation of acid and alkaline hydrolysis of glycerophospholipids: phosphatidylcholine and phosphatidylserine.