2.18.6 Roles of Waxes

1. Polishing – Waxes are effective in polishing.

2. Waterproofing – Waxes provide waterproofing.

3. Anti-fouling – Waxes prevent fouling (accumulation of organisms).

4. Cosmetics and crayons – Waxes are used to form cosmetics and crayons.

5. Candles – Waxes are used to make candles.

6. Car waxes – Waxes are used in car waxes.

7. Paints, inks, adhesives, and tyres – Waxes are used to produce paints, inks, adhesives, and tyres.

Intermediate Level

Properties and Roles of Acylglycerols

Properties and Functions of Phospholipids

Roles of Terpenes

Roles of Waxes

Comparison of Acylglycerols, Phospholipids, Terpenes, and Waxes

Important Points

• 1. Acylglycerols are esters of glycerol and fatty acids.
• 2. Properties of acylglycerols:
• - Low density than water.
• - Insoluble in water; soluble in organic solvents (chloroform, ether, hot alcohol).
• - Saturated and long-chain fatty acids → higher melting point; unsaturated and short-chain → lower melting point.
• - Example: Tristearin melts at 71°C; Triolein melts at −17°C.
• - Great emulsifying power.
• - Hydrolysis releases fatty acids and glycerol.
• - Oxidation produces odorous and flavored compounds on decay.
• 3. Roles of acylglycerols:
• - Make the major part of lipids in the body.
• - Triacylglycerols are the major lipids in fat deposits and in food.
• - High levels may cause obesity, diabetes, and hyperlipoproteinemia.
• - Hydrogenation produces margarine and butter.
• 4. Phospholipids are derived from phosphatidic acid.
• 5. Properties of phospholipids:
• - Amphipathic molecules (both polar and non-polar ends).
• - Fix proteins within the lipid bilayer cell membranes.
• - Important components of bile and lipoproteins.
• 6. Functions of phospholipids:
• - Regulate permeability of the membrane.
• - Involved in absorption of fat from the intestine.
• - Help in electron transport chain (ETC) in mitochondria.
• - Inhibit accumulation of fats in the liver.
• - Transport and remove cholesterol from cells.
• - Structural components of cell membrane.
• - Act as surfactants in the respiratory system.
• 7. Terpenes are synthesized from a five-carbon building block known as the isoprene unit.
• 8. Roles of terpenes:
• - Anti-inflammatory, analgesic.
• - Antioxidant, anticonvulsive, antidepressant.
• - Anticancer, antitumor, anti-mutagenic.
• - Neuroprotective, anti-allergic, antibiotic.
• - Anti-diabetic activities.
• 9. Roles of waxes:
• - Effective in polishing, waterproofing, anti-fouling.
• - Used to form cosmetics and crayons, candles, car waxes.
• - Used to produce paints, inks, adhesives, and tyres.

Remember

• - Acylglycerols = glycerol + fatty acids
• - Properties: Low density, insoluble in water, soluble in organic solvents, high emulsifying power
• - Roles: Energy storage, fat deposits, food
• - Phospholipids = glycerol + fatty acids + phosphate
• - Properties: Amphipathic, fix proteins, components of bile and lipoproteins
• - Functions: Membrane permeability, fat absorption, ETC, inhibit fat accumulation, transport cholesterol, structural, surfactants
• - Terpenes = isoprene units
• - Roles: Anti-inflammatory, analgesic, antioxidant, anticonvulsive, antidepressant, anticancer, antitumor, anti-mutagenic, neuroprotective, anti-allergic, antibiotic, anti-diabetic
• - Waxes = long-chain fatty acids + long-chain alcohols
• - Roles: Polishing, waterproofing, anti-fouling, cosmetics, crayons, candles, car waxes, paints, inks, adhesives, tyres

Common Mistakes

• 1. Confusing acylglycerols and phospholipids – Acylglycerols = glycerol + fatty acids; Phospholipids = glycerol + fatty acids + phosphate.
• 2. Thinking all lipids are acylglycerols – Acylglycerols are just one group of lipids.
• 3. Thinking phospholipids are hydrophobic only – Phospholipids are amphipathic (both hydrophilic and hydrophobic).
• 4. Confusing the roles of terpenes and waxes – Terpenes = medicinal properties; Waxes = waterproofing.
• 5. Thinking waxes are only synthetic – Waxes can be natural (beeswax, carnauba wax) or synthetic (paraffin wax).
• 6. Forgetting that terpenes are made of isoprene units – Terpenes are synthesized from isoprene units.
• 7. Confusing the melting points of saturated and unsaturated acylglycerols – Saturated = higher melting point; Unsaturated = lower melting point.
• 8. Thinking phospholipids are only in cell membranes – Phospholipids also have other functions (fat absorption, ETC, cholesterol transport).
• 9. Forgetting the role of phospholipids as surfactants – Phospholipids act as surfactants in the respiratory system.
• 10. Thinking acylglycerols are only harmful – Acylglycerols are essential for energy storage and insulation.
• 11. Confusing the roles of different terpenes – Different terpenes have different medicinal properties.
• 12. Thinking waxes are only for waterproofing – Waxes also have polishing, anti-fouling, and industrial uses.

Quick Revision

• 2.18.1 Properties of Acyl glycerol:
• Acyl glycerol have low density than water.
• They are insoluble in water, but they are soluble in some organic solvents like chloroform, ether and hot alcohol.
• Acyl glycerides having saturated and long chain fatty acids have higher melting point, compare to unsaturated and short chains. For example, tristearin melts at 71°C, while triolein at −17°C.
• Acyl glycerol have great emulsifying power.
• Hydrolysis of acyl glycerol release fatty acid and glycerol when heated in an aqueous acidic medium.
• Acyl glycerol can undergo oxidation to produce odorous and flavored compounds on decayed.
• 2.18.2 Roles of acyl glycerides:
• Acyl glycerol make the major part of lipids in the body.
• Triacyl glycerol are the major lipids in fat de-posits and in food.
• When high in levels, may cause various diseases such as obesity, diabetes, and hyperlipoproteinemia.
• Hydrogenation of acyl glycerol produce margarine and butter. Margarine lacks the vitamins that are present in butter.
• 2.18.3 Properties of phospholipids:
• Phospholipids have a unique property being amphipathic molecules as they have both polar and non-polar ends.
• They fix the proteins within the lipid bilayer cell membranes.
• They are important components of bile and lipoproteins.
• 2.18.4 Functions of Phospholipids:
• Phospholipids regulate the permeability of the membrane.
• They are involved in the absorption of fat from the intestine.
• They help in electron transport chain (ETC) in the mitochondria.
• Phospholipids inhibit the accumulation of fats in the liver.
• They transport and remove of cholesterol from the cells.
• They are structural components of the cell membrane and are associated with proteins.
• They act as surfactants in the respiratory system.
• 2.18.5 Roles of Terpenes:
• They are anti-inflammatory, analgesic.
• They are antioxidant, anticonvulsive, depressive.
• They are anticancer, antitumor, anti-mutagenic.
• They are neuroprotective, anti-allergic, antibiotic.
• They have anti-diabetic activities or role.
• 2.18.6 Roles of Waxes:
• Wax is effective in polishing, water proofing, anti-fouling.
• It is used to from cosmetics and crayons, candles, car waxes.
• Waxes are used to produce paints, inks, adhesives, and tyres.

60-Second Revision

• Acylglycerols = glycerol + fatty acids
• Properties: Low density, insoluble in water, soluble in organic solvents, high emulsifying power
• Roles: Energy storage, fat deposits, food
• Phospholipids = glycerol + fatty acids + phosphate
• Properties: Amphipathic, fix proteins, components of bile and lipoproteins
• Functions: Membrane permeability, fat absorption, ETC, inhibit fat accumulation, transport cholesterol, structural, surfactants
• Terpenes = isoprene units
• Roles: Anti-inflammatory, analgesic, antioxidant, anticonvulsive, antidepressant, anticancer, antitumor, anti-mutagenic, neuroprotective, anti-allergic, antibiotic, anti-diabetic
• Waxes = long-chain fatty acids + long-chain alcohols
• Roles: Polishing, waterproofing, anti-fouling, cosmetics, crayons, candles, car waxes, paints, inks, adhesives, tyres
• Warning: Acylglycerols and phospholipids are not the same. Phospholipids are amphipathic. Terpenes are made of isoprene units. Waxes are not only for waterproofing. Saturated acylglycerols have higher melting points than unsaturated ones.